From 6fba89813ccf333d2bc4d5caea04cd5f3c39eb50 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Wed, 23 Oct 2024 14:21:54 -0700 Subject: [PATCH 1/8] lsm: ensure the correct LSM context releaser Add a new lsm_context data structure to hold all the information about a "security context", including the string, its size and which LSM allocated the string. The allocation information is necessary because LSMs have different policies regarding the lifecycle of these strings. SELinux allocates and destroys them on each use, whereas Smack provides a pointer to an entry in a list that never goes away. Update security_release_secctx() to use the lsm_context instead of a (char *, len) pair. Change its callers to do likewise. The LSMs supporting this hook have had comments added to remind the developer that there is more work to be done. The BPF security module provides all LSM hooks. While there has yet to be a known instance of a BPF configuration that uses security contexts, the possibility is real. In the existing implementation there is potential for multiple frees in that case. Cc: linux-integrity@vger.kernel.org Cc: netdev@vger.kernel.org Cc: audit@vger.kernel.org Cc: netfilter-devel@vger.kernel.org To: Pablo Neira Ayuso Cc: linux-nfs@vger.kernel.org Cc: Todd Kjos Signed-off-by: Casey Schaufler [PM: subject tweak] Signed-off-by: Paul Moore --- drivers/android/binder.c | 24 +++++++-------- fs/ceph/xattr.c | 6 +++- fs/nfs/nfs4proc.c | 8 +++-- fs/nfsd/nfs4xdr.c | 8 +++-- include/linux/lsm_hook_defs.h | 2 +- include/linux/security.h | 35 ++++++++++++++++++++-- include/net/scm.h | 11 +++---- kernel/audit.c | 30 +++++++++---------- kernel/auditsc.c | 23 +++++++------- net/ipv4/ip_sockglue.c | 10 +++---- net/netfilter/nf_conntrack_netlink.c | 10 +++---- net/netfilter/nf_conntrack_standalone.c | 9 +++--- net/netfilter/nfnetlink_queue.c | 13 +++++--- net/netlabel/netlabel_unlabeled.c | 40 +++++++++++-------------- net/netlabel/netlabel_user.c | 11 ++++--- security/apparmor/include/secid.h | 2 +- security/apparmor/secid.c | 11 +++++-- security/security.c | 8 ++--- security/selinux/hooks.c | 11 +++++-- 19 files changed, 165 insertions(+), 107 deletions(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index ef353ca13c35..e8245df63289 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3017,8 +3017,7 @@ static void binder_transaction(struct binder_proc *proc, struct binder_context *context = proc->context; int t_debug_id = atomic_inc_return(&binder_last_id); ktime_t t_start_time = ktime_get(); - char *secctx = NULL; - u32 secctx_sz = 0; + struct lsm_context lsmctx; struct list_head sgc_head; struct list_head pf_head; const void __user *user_buffer = (const void __user *) @@ -3297,7 +3296,8 @@ static void binder_transaction(struct binder_proc *proc, size_t added_size; security_cred_getsecid(proc->cred, &secid); - ret = security_secid_to_secctx(secid, &secctx, &secctx_sz); + ret = security_secid_to_secctx(secid, &lsmctx.context, + &lsmctx.len); if (ret) { binder_txn_error("%d:%d failed to get security context\n", thread->pid, proc->pid); @@ -3306,7 +3306,7 @@ static void binder_transaction(struct binder_proc *proc, return_error_line = __LINE__; goto err_get_secctx_failed; } - added_size = ALIGN(secctx_sz, sizeof(u64)); + added_size = ALIGN(lsmctx.len, sizeof(u64)); extra_buffers_size += added_size; if (extra_buffers_size < added_size) { binder_txn_error("%d:%d integer overflow of extra_buffers_size\n", @@ -3340,23 +3340,23 @@ static void binder_transaction(struct binder_proc *proc, t->buffer = NULL; goto err_binder_alloc_buf_failed; } - if (secctx) { + if (lsmctx.context) { int err; size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) + ALIGN(tr->offsets_size, sizeof(void *)) + ALIGN(extra_buffers_size, sizeof(void *)) - - ALIGN(secctx_sz, sizeof(u64)); + ALIGN(lsmctx.len, sizeof(u64)); t->security_ctx = t->buffer->user_data + buf_offset; err = binder_alloc_copy_to_buffer(&target_proc->alloc, t->buffer, buf_offset, - secctx, secctx_sz); + lsmctx.context, lsmctx.len); if (err) { t->security_ctx = 0; WARN_ON(1); } - security_release_secctx(secctx, secctx_sz); - secctx = NULL; + security_release_secctx(&lsmctx); + lsmctx.context = NULL; } t->buffer->debug_id = t->debug_id; t->buffer->transaction = t; @@ -3400,7 +3400,7 @@ static void binder_transaction(struct binder_proc *proc, off_end_offset = off_start_offset + tr->offsets_size; sg_buf_offset = ALIGN(off_end_offset, sizeof(void *)); sg_buf_end_offset = sg_buf_offset + extra_buffers_size - - ALIGN(secctx_sz, sizeof(u64)); + ALIGN(lsmctx.len, sizeof(u64)); off_min = 0; for (buffer_offset = off_start_offset; buffer_offset < off_end_offset; buffer_offset += sizeof(binder_size_t)) { @@ -3779,8 +3779,8 @@ static void binder_transaction(struct binder_proc *proc, binder_alloc_free_buf(&target_proc->alloc, t->buffer); err_binder_alloc_buf_failed: err_bad_extra_size: - if (secctx) - security_release_secctx(secctx, secctx_sz); + if (lsmctx.context) + security_release_secctx(&lsmctx); err_get_secctx_failed: kfree(tcomplete); binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE); diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 1a9f12204666..2a14335a4bb7 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -1446,12 +1446,16 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode, void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx) { +#ifdef CONFIG_CEPH_FS_SECURITY_LABEL + struct lsm_context scaff; /* scaffolding */ +#endif #ifdef CONFIG_CEPH_FS_POSIX_ACL posix_acl_release(as_ctx->acl); posix_acl_release(as_ctx->default_acl); #endif #ifdef CONFIG_CEPH_FS_SECURITY_LABEL - security_release_secctx(as_ctx->sec_ctx, as_ctx->sec_ctxlen); + lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0); + security_release_secctx(&scaff); #endif #ifdef CONFIG_FS_ENCRYPTION kfree(as_ctx->fscrypt_auth); diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 405f17e6e0b4..2daeb6f663d9 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -138,8 +138,12 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry, static inline void nfs4_label_release_security(struct nfs4_label *label) { - if (label) - security_release_secctx(label->label, label->len); + struct lsm_context scaff; /* scaffolding */ + + if (label) { + lsmcontext_init(&scaff, label->label, label->len, 0); + security_release_secctx(&scaff); + } } static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label) { diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 53fac037611c..95ec6a4b4da3 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3644,8 +3644,12 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, out: #ifdef CONFIG_NFSD_V4_SECURITY_LABEL - if (args.context) - security_release_secctx(args.context, args.contextlen); + if (args.context) { + struct lsm_context scaff; /* scaffolding */ + + lsmcontext_init(&scaff, args.context, args.contextlen, 0); + security_release_secctx(&scaff); + } #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */ kfree(args.acl); if (tempfh) { diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index eb2937599cb0..c13df23132eb 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -300,7 +300,7 @@ LSM_HOOK(int, -EOPNOTSUPP, secid_to_secctx, u32 secid, char **secdata, LSM_HOOK(int, -EOPNOTSUPP, lsmprop_to_secctx, struct lsm_prop *prop, char **secdata, u32 *seclen) LSM_HOOK(int, 0, secctx_to_secid, const char *secdata, u32 seclen, u32 *secid) -LSM_HOOK(void, LSM_RET_VOID, release_secctx, char *secdata, u32 seclen) +LSM_HOOK(void, LSM_RET_VOID, release_secctx, struct lsm_context *cp) LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode) LSM_HOOK(int, 0, inode_notifysecctx, struct inode *inode, void *ctx, u32 ctxlen) LSM_HOOK(int, 0, inode_setsecctx, struct dentry *dentry, void *ctx, u32 ctxlen) diff --git a/include/linux/security.h b/include/linux/security.h index cbdba435b798..68e56935716b 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -225,6 +225,37 @@ extern unsigned long dac_mmap_min_addr; #define dac_mmap_min_addr 0UL #endif +/* + * A "security context" is the text representation of + * the information used by LSMs. + * This structure contains the string, its length, and which LSM + * it is useful for. + */ +struct lsm_context { + char *context; /* Provided by the module */ + u32 len; + int id; /* Identifies the module */ +}; + +/** + * lsmcontext_init - initialize an lsmcontext structure. + * @cp: Pointer to the context to initialize + * @context: Initial context, or NULL + * @size: Size of context, or 0 + * @id: Which LSM provided the context + * + * Fill in the lsmcontext from the provided information. + * This is a scaffolding function that will be removed when + * lsm_context integration is complete. + */ +static inline void lsmcontext_init(struct lsm_context *cp, char *context, + u32 size, int id) +{ + cp->id = id; + cp->context = context; + cp->len = size; +} + /* * Values used in the task_security_ops calls */ @@ -556,7 +587,7 @@ int security_ismaclabel(const char *name); int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); int security_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, u32 *seclen); int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid); -void security_release_secctx(char *secdata, u32 seclen); +void security_release_secctx(struct lsm_context *cp); void security_inode_invalidate_secctx(struct inode *inode); int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen); @@ -1545,7 +1576,7 @@ static inline int security_secctx_to_secid(const char *secdata, return -EOPNOTSUPP; } -static inline void security_release_secctx(char *secdata, u32 seclen) +static inline void security_release_secctx(struct lsm_context *cp) { } diff --git a/include/net/scm.h b/include/net/scm.h index 0d35c7c77a74..f75449e1d876 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -105,16 +105,17 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, #ifdef CONFIG_SECURITY_NETWORK static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) { - char *secdata; - u32 seclen; + struct lsm_context ctx; int err; if (test_bit(SOCK_PASSSEC, &sock->flags)) { - err = security_secid_to_secctx(scm->secid, &secdata, &seclen); + err = security_secid_to_secctx(scm->secid, &ctx.context, + &ctx.len); if (!err) { - put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata); - security_release_secctx(secdata, seclen); + put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, ctx.len, + ctx.context); + security_release_secctx(&ctx); } } } diff --git a/kernel/audit.c b/kernel/audit.c index 6a95a6077953..1d48d0654a46 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1221,8 +1221,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh, struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; struct audit_sig_info *sig_data; - char *ctx = NULL; - u32 len; + struct lsm_context lsmctx; err = audit_netlink_ok(skb, msg_type); if (err) @@ -1472,27 +1471,29 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh, break; } case AUDIT_SIGNAL_INFO: - len = 0; if (lsmprop_is_set(&audit_sig_lsm)) { - err = security_lsmprop_to_secctx(&audit_sig_lsm, &ctx, - &len); + err = security_lsmprop_to_secctx(&audit_sig_lsm, + &lsmctx.context, + &lsmctx.len); if (err) return err; } - sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL); + sig_data = kmalloc(struct_size(sig_data, ctx, lsmctx.len), + GFP_KERNEL); if (!sig_data) { if (lsmprop_is_set(&audit_sig_lsm)) - security_release_secctx(ctx, len); + security_release_secctx(&lsmctx); return -ENOMEM; } sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); sig_data->pid = audit_sig_pid; if (lsmprop_is_set(&audit_sig_lsm)) { - memcpy(sig_data->ctx, ctx, len); - security_release_secctx(ctx, len); + memcpy(sig_data->ctx, lsmctx.context, lsmctx.len); + security_release_secctx(&lsmctx); } audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, - sig_data, struct_size(sig_data, ctx, len)); + sig_data, struct_size(sig_data, ctx, + lsmctx.len)); kfree(sig_data); break; case AUDIT_TTY_GET: { @@ -2180,23 +2181,22 @@ void audit_log_key(struct audit_buffer *ab, char *key) int audit_log_task_context(struct audit_buffer *ab) { struct lsm_prop prop; - char *ctx = NULL; - unsigned len; + struct lsm_context ctx; int error; security_current_getlsmprop_subj(&prop); if (!lsmprop_is_set(&prop)) return 0; - error = security_lsmprop_to_secctx(&prop, &ctx, &len); + error = security_lsmprop_to_secctx(&prop, &ctx.context, &ctx.len); if (error) { if (error != -EINVAL) goto error_path; return 0; } - audit_log_format(ab, " subj=%s", ctx); - security_release_secctx(ctx, len); + audit_log_format(ab, " subj=%s", ctx.context); + security_release_secctx(&ctx); return 0; error_path: diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 279ba5c420a4..de8fac6c5bd3 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1098,8 +1098,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, char *comm) { struct audit_buffer *ab; - char *ctx = NULL; - u32 len; + struct lsm_context ctx; int rc = 0; ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID); @@ -1110,12 +1109,12 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, from_kuid(&init_user_ns, auid), from_kuid(&init_user_ns, uid), sessionid); if (lsmprop_is_set(prop)) { - if (security_lsmprop_to_secctx(prop, &ctx, &len)) { + if (security_lsmprop_to_secctx(prop, &ctx.context, &ctx.len)) { audit_log_format(ab, " obj=(none)"); rc = 1; } else { - audit_log_format(ab, " obj=%s", ctx); - security_release_secctx(ctx, len); + audit_log_format(ab, " obj=%s", ctx.context); + security_release_secctx(&ctx); } } audit_log_format(ab, " ocomm="); @@ -1371,6 +1370,7 @@ static void audit_log_time(struct audit_context *context, struct audit_buffer ** static void show_special(struct audit_context *context, int *call_panic) { + struct lsm_context lsmcxt; struct audit_buffer *ab; int i; @@ -1401,7 +1401,8 @@ static void show_special(struct audit_context *context, int *call_panic) *call_panic = 1; } else { audit_log_format(ab, " obj=%s", ctx); - security_release_secctx(ctx, len); + lsmcontext_init(&lsmcxt, ctx, len, 0); + security_release_secctx(&lsmcxt); } } if (context->ipc.has_perm) { @@ -1560,15 +1561,15 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n, MAJOR(n->rdev), MINOR(n->rdev)); if (lsmprop_is_set(&n->oprop)) { - char *ctx = NULL; - u32 len; + struct lsm_context ctx; - if (security_lsmprop_to_secctx(&n->oprop, &ctx, &len)) { + if (security_lsmprop_to_secctx(&n->oprop, &ctx.context, + &ctx.len)) { if (call_panic) *call_panic = 2; } else { - audit_log_format(ab, " obj=%s", ctx); - security_release_secctx(ctx, len); + audit_log_format(ab, " obj=%s", ctx.context); + security_release_secctx(&ctx); } } diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index cf377377b52d..a8180dcc2a32 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -128,20 +128,20 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb, static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb) { - char *secdata; - u32 seclen, secid; + struct lsm_context ctx; + u32 secid; int err; err = security_socket_getpeersec_dgram(NULL, skb, &secid); if (err) return; - err = security_secid_to_secctx(secid, &secdata, &seclen); + err = security_secid_to_secctx(secid, &ctx.context, &ctx.len); if (err) return; - put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata); - security_release_secctx(secdata, seclen); + put_cmsg(msg, SOL_IP, SCM_SECURITY, ctx.len, ctx.context); + security_release_secctx(&ctx); } static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb) diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 36168f8b6efa..22f46be33f1e 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -357,10 +357,10 @@ static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct, static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct) { struct nlattr *nest_secctx; - int len, ret; - char *secctx; + struct lsm_context ctx; + int ret; - ret = security_secid_to_secctx(ct->secmark, &secctx, &len); + ret = security_secid_to_secctx(ct->secmark, &ctx.context, &ctx.len); if (ret) return 0; @@ -369,13 +369,13 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct) if (!nest_secctx) goto nla_put_failure; - if (nla_put_string(skb, CTA_SECCTX_NAME, secctx)) + if (nla_put_string(skb, CTA_SECCTX_NAME, ctx.context)) goto nla_put_failure; nla_nest_end(skb, nest_secctx); ret = 0; nla_put_failure: - security_release_secctx(secctx, len); + security_release_secctx(&ctx); return ret; } #else diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c index 7d4f0fa8b609..5f7fd23b7afe 100644 --- a/net/netfilter/nf_conntrack_standalone.c +++ b/net/netfilter/nf_conntrack_standalone.c @@ -172,17 +172,16 @@ static void ct_seq_stop(struct seq_file *s, void *v) #ifdef CONFIG_NF_CONNTRACK_SECMARK static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct) { + struct lsm_context ctx; int ret; - u32 len; - char *secctx; - ret = security_secid_to_secctx(ct->secmark, &secctx, &len); + ret = security_secid_to_secctx(ct->secmark, &ctx.context, &ctx.len); if (ret) return; - seq_printf(s, "secctx=%s ", secctx); + seq_printf(s, "secctx=%s ", ctx.context); - security_release_secctx(secctx, len); + security_release_secctx(&ctx); } #else static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct) diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index d2773ce9b585..37757cd77cf1 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -567,6 +567,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, enum ip_conntrack_info ctinfo = 0; const struct nfnl_ct_hook *nfnl_ct; bool csum_verify; + struct lsm_context scaff; /* scaffolding */ char *secdata = NULL; u32 seclen = 0; ktime_t tstamp; @@ -810,8 +811,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, } nlh->nlmsg_len = skb->len; - if (seclen) - security_release_secctx(secdata, seclen); + if (seclen) { + lsmcontext_init(&scaff, secdata, seclen, 0); + security_release_secctx(&scaff); + } return skb; nla_put_failure: @@ -819,8 +822,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, kfree_skb(skb); net_err_ratelimited("nf_queue: error creating packet message\n"); nlmsg_failure: - if (seclen) - security_release_secctx(secdata, seclen); + if (seclen) { + lsmcontext_init(&scaff, secdata, seclen, 0); + security_release_secctx(&scaff); + } return NULL; } diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c index 1bc2d0890a9f..921fa8eeb451 100644 --- a/net/netlabel/netlabel_unlabeled.c +++ b/net/netlabel/netlabel_unlabeled.c @@ -374,8 +374,7 @@ int netlbl_unlhsh_add(struct net *net, struct net_device *dev; struct netlbl_unlhsh_iface *iface; struct audit_buffer *audit_buf = NULL; - char *secctx = NULL; - u32 secctx_len; + struct lsm_context ctx; if (addr_len != sizeof(struct in_addr) && addr_len != sizeof(struct in6_addr)) @@ -439,10 +438,10 @@ int netlbl_unlhsh_add(struct net *net, rcu_read_unlock(); if (audit_buf != NULL) { if (security_secid_to_secctx(secid, - &secctx, - &secctx_len) == 0) { - audit_log_format(audit_buf, " sec_obj=%s", secctx); - security_release_secctx(secctx, secctx_len); + &ctx.context, + &ctx.len) == 0) { + audit_log_format(audit_buf, " sec_obj=%s", ctx.context); + security_release_secctx(&ctx); } audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0); audit_log_end(audit_buf); @@ -473,8 +472,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net, struct netlbl_unlhsh_addr4 *entry; struct audit_buffer *audit_buf; struct net_device *dev; - char *secctx; - u32 secctx_len; + struct lsm_context ctx; spin_lock(&netlbl_unlhsh_lock); list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr, @@ -495,9 +493,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net, dev_put(dev); if (entry != NULL && security_secid_to_secctx(entry->secid, - &secctx, &secctx_len) == 0) { - audit_log_format(audit_buf, " sec_obj=%s", secctx); - security_release_secctx(secctx, secctx_len); + &ctx.context, &ctx.len) == 0) { + audit_log_format(audit_buf, " sec_obj=%s", ctx.context); + security_release_secctx(&ctx); } audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0); audit_log_end(audit_buf); @@ -534,8 +532,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net, struct netlbl_unlhsh_addr6 *entry; struct audit_buffer *audit_buf; struct net_device *dev; - char *secctx; - u32 secctx_len; + struct lsm_context ctx; spin_lock(&netlbl_unlhsh_lock); list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list); @@ -555,9 +552,9 @@ static int netlbl_unlhsh_remove_addr6(struct net *net, dev_put(dev); if (entry != NULL && security_secid_to_secctx(entry->secid, - &secctx, &secctx_len) == 0) { - audit_log_format(audit_buf, " sec_obj=%s", secctx); - security_release_secctx(secctx, secctx_len); + &ctx.context, &ctx.len) == 0) { + audit_log_format(audit_buf, " sec_obj=%s", ctx.context); + security_release_secctx(&ctx); } audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0); audit_log_end(audit_buf); @@ -1069,10 +1066,9 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd, int ret_val = -ENOMEM; struct netlbl_unlhsh_walk_arg *cb_arg = arg; struct net_device *dev; + struct lsm_context ctx; void *data; u32 secid; - char *secctx; - u32 secctx_len; data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid, cb_arg->seq, &netlbl_unlabel_gnl_family, @@ -1127,14 +1123,14 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd, secid = addr6->secid; } - ret_val = security_secid_to_secctx(secid, &secctx, &secctx_len); + ret_val = security_secid_to_secctx(secid, &ctx.context, &ctx.len); if (ret_val != 0) goto list_cb_failure; ret_val = nla_put(cb_arg->skb, NLBL_UNLABEL_A_SECCTX, - secctx_len, - secctx); - security_release_secctx(secctx, secctx_len); + ctx.len, + ctx.context); + security_release_secctx(&ctx); if (ret_val != 0) goto list_cb_failure; diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c index 81635a13987b..f5e7a9919df1 100644 --- a/net/netlabel/netlabel_user.c +++ b/net/netlabel/netlabel_user.c @@ -84,8 +84,7 @@ struct audit_buffer *netlbl_audit_start_common(int type, struct netlbl_audit *audit_info) { struct audit_buffer *audit_buf; - char *secctx; - u32 secctx_len; + struct lsm_context ctx; if (audit_enabled == AUDIT_OFF) return NULL; @@ -99,10 +98,10 @@ struct audit_buffer *netlbl_audit_start_common(int type, audit_info->sessionid); if (lsmprop_is_set(&audit_info->prop) && - security_lsmprop_to_secctx(&audit_info->prop, &secctx, - &secctx_len) == 0) { - audit_log_format(audit_buf, " subj=%s", secctx); - security_release_secctx(secctx, secctx_len); + security_lsmprop_to_secctx(&audit_info->prop, &ctx.context, + &ctx.len) == 0) { + audit_log_format(audit_buf, " subj=%s", ctx.context); + security_release_secctx(&ctx); } return audit_buf; diff --git a/security/apparmor/include/secid.h b/security/apparmor/include/secid.h index f6a515640950..1bcde2f45f24 100644 --- a/security/apparmor/include/secid.h +++ b/security/apparmor/include/secid.h @@ -29,7 +29,7 @@ int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, u32 *seclen); int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid); -void apparmor_release_secctx(char *secdata, u32 seclen); +void apparmor_release_secctx(struct lsm_context *cp); int aa_alloc_secid(struct aa_label *label, gfp_t gfp); diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c index 47dc08fc583e..43e4dab7f6e6 100644 --- a/security/apparmor/secid.c +++ b/security/apparmor/secid.c @@ -106,9 +106,16 @@ int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) return 0; } -void apparmor_release_secctx(char *secdata, u32 seclen) +void apparmor_release_secctx(struct lsm_context *cp) { - kfree(secdata); + /* + * stacking scaffolding: + * When it is possible for more than one LSM to provide a + * release hook, do this check: + * if (cp->id == LSM_ID_APPARMOR || cp->id == LSM_ID_UNDEF) + */ + + kfree(cp->context); } /** diff --git a/security/security.c b/security/security.c index 09664e09fec9..b7f8ec93f6f0 100644 --- a/security/security.c +++ b/security/security.c @@ -4360,14 +4360,14 @@ EXPORT_SYMBOL(security_secctx_to_secid); /** * security_release_secctx() - Free a secctx buffer - * @secdata: secctx - * @seclen: length of secctx + * @cp: the security context * * Release the security context. */ -void security_release_secctx(char *secdata, u32 seclen) +void security_release_secctx(struct lsm_context *cp) { - call_void_hook(release_secctx, secdata, seclen); + call_void_hook(release_secctx, cp); + memset(cp, 0, sizeof(*cp)); } EXPORT_SYMBOL(security_release_secctx); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f5a08f94e094..aabc724f4d44 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6657,9 +6657,16 @@ static int selinux_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) secid, GFP_KERNEL); } -static void selinux_release_secctx(char *secdata, u32 seclen) +static void selinux_release_secctx(struct lsm_context *cp) { - kfree(secdata); + /* + * stacking scaffolding: + * When it is possible for more than one LSM to provide a + * release hook, do this check: + * if (cp->id == LSM_ID_SELINUX || cp->id == LSM_ID_UNDEF) + */ + + kfree(cp->context); } static void selinux_inode_invalidate_secctx(struct inode *inode) From 2d470c778120d3cdb8d8ab250329ca85f49f12b1 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Wed, 23 Oct 2024 14:21:55 -0700 Subject: [PATCH 2/8] lsm: replace context+len with lsm_context Replace the (secctx,seclen) pointer pair with a single lsm_context pointer to allow return of the LSM identifier along with the context and context length. This allows security_release_secctx() to know how to release the context. Callers have been modified to use or save the returned data from the new structure. security_secid_to_secctx() and security_lsmproc_to_secctx() will now return the length value on success instead of 0. Cc: netdev@vger.kernel.org Cc: audit@vger.kernel.org Cc: netfilter-devel@vger.kernel.org Cc: Todd Kjos Signed-off-by: Casey Schaufler [PM: subject tweak, kdoc fix, signedness fix from Dan Carpenter] Signed-off-by: Paul Moore --- drivers/android/binder.c | 5 ++- include/linux/lsm_hook_defs.h | 5 ++- include/linux/security.h | 9 +++-- include/net/scm.h | 5 ++- kernel/audit.c | 9 +++-- kernel/auditsc.c | 16 ++++----- net/ipv4/ip_sockglue.c | 4 +-- net/netfilter/nf_conntrack_netlink.c | 12 +++---- net/netfilter/nf_conntrack_standalone.c | 4 +-- net/netfilter/nfnetlink_queue.c | 27 ++++++--------- net/netlabel/netlabel_unlabeled.c | 14 +++----- net/netlabel/netlabel_user.c | 3 +- security/apparmor/include/secid.h | 5 ++- security/apparmor/secid.c | 26 +++++++------- security/security.c | 34 +++++++++---------- security/selinux/hooks.c | 23 ++++++++++--- security/smack/smack_lsm.c | 45 ++++++++++++++----------- 17 files changed, 121 insertions(+), 125 deletions(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index e8245df63289..919da8e674f5 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3296,9 +3296,8 @@ static void binder_transaction(struct binder_proc *proc, size_t added_size; security_cred_getsecid(proc->cred, &secid); - ret = security_secid_to_secctx(secid, &lsmctx.context, - &lsmctx.len); - if (ret) { + ret = security_secid_to_secctx(secid, &lsmctx); + if (ret < 0) { binder_txn_error("%d:%d failed to get security context\n", thread->pid, proc->pid); return_error = BR_FAILED_REPLY; diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index c13df23132eb..01e5a8e09bba 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -295,10 +295,9 @@ LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, const char *name, char **value) LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size) LSM_HOOK(int, 0, ismaclabel, const char *name) -LSM_HOOK(int, -EOPNOTSUPP, secid_to_secctx, u32 secid, char **secdata, - u32 *seclen) +LSM_HOOK(int, -EOPNOTSUPP, secid_to_secctx, u32 secid, struct lsm_context *cp) LSM_HOOK(int, -EOPNOTSUPP, lsmprop_to_secctx, struct lsm_prop *prop, - char **secdata, u32 *seclen) + struct lsm_context *cp) LSM_HOOK(int, 0, secctx_to_secid, const char *secdata, u32 seclen, u32 *secid) LSM_HOOK(void, LSM_RET_VOID, release_secctx, struct lsm_context *cp) LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode) diff --git a/include/linux/security.h b/include/linux/security.h index 68e56935716b..58518bbc00a6 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -584,8 +584,8 @@ int security_getprocattr(struct task_struct *p, int lsmid, const char *name, int security_setprocattr(int lsmid, const char *name, void *value, size_t size); int security_netlink_send(struct sock *sk, struct sk_buff *skb); int security_ismaclabel(const char *name); -int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); -int security_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, u32 *seclen); +int security_secid_to_secctx(u32 secid, struct lsm_context *cp); +int security_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp); int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid); void security_release_secctx(struct lsm_context *cp); void security_inode_invalidate_secctx(struct inode *inode); @@ -1557,14 +1557,13 @@ static inline int security_ismaclabel(const char *name) return 0; } -static inline int security_secid_to_secctx(u32 secid, char **secdata, - u32 *seclen) +static inline int security_secid_to_secctx(u32 secid, struct lsm_context *cp) { return -EOPNOTSUPP; } static inline int security_lsmprop_to_secctx(struct lsm_prop *prop, - char **secdata, u32 *seclen) + struct lsm_context *cp) { return -EOPNOTSUPP; } diff --git a/include/net/scm.h b/include/net/scm.h index f75449e1d876..22bb49589fde 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -109,10 +109,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc int err; if (test_bit(SOCK_PASSSEC, &sock->flags)) { - err = security_secid_to_secctx(scm->secid, &ctx.context, - &ctx.len); + err = security_secid_to_secctx(scm->secid, &ctx); - if (!err) { + if (err >= 0) { put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, ctx.len, ctx.context); security_release_secctx(&ctx); diff --git a/kernel/audit.c b/kernel/audit.c index 1d48d0654a46..13d0144efaa3 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1473,9 +1473,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh, case AUDIT_SIGNAL_INFO: if (lsmprop_is_set(&audit_sig_lsm)) { err = security_lsmprop_to_secctx(&audit_sig_lsm, - &lsmctx.context, - &lsmctx.len); - if (err) + &lsmctx); + if (err < 0) return err; } sig_data = kmalloc(struct_size(sig_data, ctx, lsmctx.len), @@ -2188,8 +2187,8 @@ int audit_log_task_context(struct audit_buffer *ab) if (!lsmprop_is_set(&prop)) return 0; - error = security_lsmprop_to_secctx(&prop, &ctx.context, &ctx.len); - if (error) { + error = security_lsmprop_to_secctx(&prop, &ctx); + if (error < 0) { if (error != -EINVAL) goto error_path; return 0; diff --git a/kernel/auditsc.c b/kernel/auditsc.c index de8fac6c5bd3..bb0e7346d916 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1109,7 +1109,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, from_kuid(&init_user_ns, auid), from_kuid(&init_user_ns, uid), sessionid); if (lsmprop_is_set(prop)) { - if (security_lsmprop_to_secctx(prop, &ctx.context, &ctx.len)) { + if (security_lsmprop_to_secctx(prop, &ctx) < 0) { audit_log_format(ab, " obj=(none)"); rc = 1; } else { @@ -1370,7 +1370,6 @@ static void audit_log_time(struct audit_context *context, struct audit_buffer ** static void show_special(struct audit_context *context, int *call_panic) { - struct lsm_context lsmcxt; struct audit_buffer *ab; int i; @@ -1393,16 +1392,14 @@ static void show_special(struct audit_context *context, int *call_panic) from_kgid(&init_user_ns, context->ipc.gid), context->ipc.mode); if (lsmprop_is_set(&context->ipc.oprop)) { - char *ctx = NULL; - u32 len; + struct lsm_context lsmctx; if (security_lsmprop_to_secctx(&context->ipc.oprop, - &ctx, &len)) { + &lsmctx) < 0) { *call_panic = 1; } else { - audit_log_format(ab, " obj=%s", ctx); - lsmcontext_init(&lsmcxt, ctx, len, 0); - security_release_secctx(&lsmcxt); + audit_log_format(ab, " obj=%s", lsmctx.context); + security_release_secctx(&lsmctx); } } if (context->ipc.has_perm) { @@ -1563,8 +1560,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n, if (lsmprop_is_set(&n->oprop)) { struct lsm_context ctx; - if (security_lsmprop_to_secctx(&n->oprop, &ctx.context, - &ctx.len)) { + if (security_lsmprop_to_secctx(&n->oprop, &ctx) < 0) { if (call_panic) *call_panic = 2; } else { diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index a8180dcc2a32..dadbf619b20f 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -136,8 +136,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb) if (err) return; - err = security_secid_to_secctx(secid, &ctx.context, &ctx.len); - if (err) + err = security_secid_to_secctx(secid, &ctx); + if (err < 0) return; put_cmsg(msg, SOL_IP, SCM_SECURITY, ctx.len, ctx.context); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 22f46be33f1e..7b74b24348fc 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -360,8 +360,8 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct) struct lsm_context ctx; int ret; - ret = security_secid_to_secctx(ct->secmark, &ctx.context, &ctx.len); - if (ret) + ret = security_secid_to_secctx(ct->secmark, &ctx); + if (ret < 0) return 0; ret = -1; @@ -663,14 +663,14 @@ static inline size_t ctnetlink_acct_size(const struct nf_conn *ct) static inline int ctnetlink_secctx_size(const struct nf_conn *ct) { #ifdef CONFIG_NF_CONNTRACK_SECMARK - int len, ret; + int ret; - ret = security_secid_to_secctx(ct->secmark, NULL, &len); - if (ret) + ret = security_secid_to_secctx(ct->secmark, NULL); + if (ret < 0) return 0; return nla_total_size(0) /* CTA_SECCTX */ - + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */ + + nla_total_size(sizeof(char) * ret); /* CTA_SECCTX_NAME */ #else return 0; #endif diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c index 5f7fd23b7afe..502cf10aab41 100644 --- a/net/netfilter/nf_conntrack_standalone.c +++ b/net/netfilter/nf_conntrack_standalone.c @@ -175,8 +175,8 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct) struct lsm_context ctx; int ret; - ret = security_secid_to_secctx(ct->secmark, &ctx.context, &ctx.len); - if (ret) + ret = security_secid_to_secctx(ct->secmark, &ctx); + if (ret < 0) return; seq_printf(s, "secctx=%s ", ctx.context); diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 37757cd77cf1..5110f29b2f40 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -470,18 +470,18 @@ static int nfqnl_put_sk_classid(struct sk_buff *skb, struct sock *sk) return 0; } -static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata) +static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsm_context *ctx) { u32 seclen = 0; #if IS_ENABLED(CONFIG_NETWORK_SECMARK) + if (!skb || !sk_fullsock(skb->sk)) return 0; read_lock_bh(&skb->sk->sk_callback_lock); if (skb->secmark) - security_secid_to_secctx(skb->secmark, secdata, &seclen); - + seclen = security_secid_to_secctx(skb->secmark, ctx); read_unlock_bh(&skb->sk->sk_callback_lock); #endif return seclen; @@ -567,8 +567,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, enum ip_conntrack_info ctinfo = 0; const struct nfnl_ct_hook *nfnl_ct; bool csum_verify; - struct lsm_context scaff; /* scaffolding */ - char *secdata = NULL; + struct lsm_context ctx; u32 seclen = 0; ktime_t tstamp; @@ -643,8 +642,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, } if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) { - seclen = nfqnl_get_sk_secctx(entskb, &secdata); - if (seclen) + seclen = nfqnl_get_sk_secctx(entskb, &ctx); + if (seclen >= 0) size += nla_total_size(seclen); } @@ -783,7 +782,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, if (nfqnl_put_sk_classid(skb, entskb->sk) < 0) goto nla_put_failure; - if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata)) + if (seclen && nla_put(skb, NFQA_SECCTX, ctx.len, ctx.context)) goto nla_put_failure; if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0) @@ -811,10 +810,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, } nlh->nlmsg_len = skb->len; - if (seclen) { - lsmcontext_init(&scaff, secdata, seclen, 0); - security_release_secctx(&scaff); - } + if (seclen >= 0) + security_release_secctx(&ctx); return skb; nla_put_failure: @@ -822,10 +819,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, kfree_skb(skb); net_err_ratelimited("nf_queue: error creating packet message\n"); nlmsg_failure: - if (seclen) { - lsmcontext_init(&scaff, secdata, seclen, 0); - security_release_secctx(&scaff); - } + if (seclen >= 0) + security_release_secctx(&ctx); return NULL; } diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c index 921fa8eeb451..bd7094f225d1 100644 --- a/net/netlabel/netlabel_unlabeled.c +++ b/net/netlabel/netlabel_unlabeled.c @@ -437,9 +437,7 @@ int netlbl_unlhsh_add(struct net *net, unlhsh_add_return: rcu_read_unlock(); if (audit_buf != NULL) { - if (security_secid_to_secctx(secid, - &ctx.context, - &ctx.len) == 0) { + if (security_secid_to_secctx(secid, &ctx) == 0) { audit_log_format(audit_buf, " sec_obj=%s", ctx.context); security_release_secctx(&ctx); } @@ -492,8 +490,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net, addr->s_addr, mask->s_addr); dev_put(dev); if (entry != NULL && - security_secid_to_secctx(entry->secid, - &ctx.context, &ctx.len) == 0) { + security_secid_to_secctx(entry->secid, &ctx) == 0) { audit_log_format(audit_buf, " sec_obj=%s", ctx.context); security_release_secctx(&ctx); } @@ -551,8 +548,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net, addr, mask); dev_put(dev); if (entry != NULL && - security_secid_to_secctx(entry->secid, - &ctx.context, &ctx.len) == 0) { + security_secid_to_secctx(entry->secid, &ctx) == 0) { audit_log_format(audit_buf, " sec_obj=%s", ctx.context); security_release_secctx(&ctx); } @@ -1123,8 +1119,8 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd, secid = addr6->secid; } - ret_val = security_secid_to_secctx(secid, &ctx.context, &ctx.len); - if (ret_val != 0) + ret_val = security_secid_to_secctx(secid, &ctx); + if (ret_val < 0) goto list_cb_failure; ret_val = nla_put(cb_arg->skb, NLBL_UNLABEL_A_SECCTX, diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c index f5e7a9919df1..0d04d23aafe7 100644 --- a/net/netlabel/netlabel_user.c +++ b/net/netlabel/netlabel_user.c @@ -98,8 +98,7 @@ struct audit_buffer *netlbl_audit_start_common(int type, audit_info->sessionid); if (lsmprop_is_set(&audit_info->prop) && - security_lsmprop_to_secctx(&audit_info->prop, &ctx.context, - &ctx.len) == 0) { + security_lsmprop_to_secctx(&audit_info->prop, &ctx) > 0) { audit_log_format(audit_buf, " subj=%s", ctx.context); security_release_secctx(&ctx); } diff --git a/security/apparmor/include/secid.h b/security/apparmor/include/secid.h index 1bcde2f45f24..6025d3849cf8 100644 --- a/security/apparmor/include/secid.h +++ b/security/apparmor/include/secid.h @@ -25,9 +25,8 @@ struct aa_label; extern int apparmor_display_secid_mode; struct aa_label *aa_secid_to_label(u32 secid); -int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); -int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, - u32 *seclen); +int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp); +int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp); int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid); void apparmor_release_secctx(struct lsm_context *cp); diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c index 43e4dab7f6e6..b08969ec34b7 100644 --- a/security/apparmor/secid.c +++ b/security/apparmor/secid.c @@ -47,23 +47,21 @@ struct aa_label *aa_secid_to_label(u32 secid) return xa_load(&aa_secids, secid); } -static int apparmor_label_to_secctx(struct aa_label *label, char **secdata, - u32 *seclen) +static int apparmor_label_to_secctx(struct aa_label *label, + struct lsm_context *cp) { /* TODO: cache secctx and ref count so we don't have to recreate */ int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT; int len; - AA_BUG(!seclen); - if (!label) return -EINVAL; if (apparmor_display_secid_mode) flags |= FLAG_SHOW_MODE; - if (secdata) - len = aa_label_asxprint(secdata, root_ns, label, + if (cp) + len = aa_label_asxprint(&cp->context, root_ns, label, flags, GFP_ATOMIC); else len = aa_label_snxprint(NULL, 0, root_ns, label, flags); @@ -71,26 +69,28 @@ static int apparmor_label_to_secctx(struct aa_label *label, char **secdata, if (len < 0) return -ENOMEM; - *seclen = len; + if (cp) { + cp->len = len; + cp->id = LSM_ID_APPARMOR; + } - return 0; + return len; } -int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp) { struct aa_label *label = aa_secid_to_label(secid); - return apparmor_label_to_secctx(label, secdata, seclen); + return apparmor_label_to_secctx(label, cp); } -int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, - u32 *seclen) +int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp) { struct aa_label *label; label = prop->apparmor.label; - return apparmor_label_to_secctx(label, secdata, seclen); + return apparmor_label_to_secctx(label, cp); } int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) diff --git a/security/security.c b/security/security.c index b7f8ec93f6f0..1edf8fb2046c 100644 --- a/security/security.c +++ b/security/security.c @@ -4304,40 +4304,36 @@ EXPORT_SYMBOL(security_ismaclabel); /** * security_secid_to_secctx() - Convert a secid to a secctx * @secid: secid - * @secdata: secctx - * @seclen: secctx length + * @cp: the LSM context * - * Convert secid to security context. If @secdata is NULL the length of the - * result will be returned in @seclen, but no @secdata will be returned. This + * Convert secid to security context. If @cp is NULL the length of the + * result will be returned, but no data will be returned. This * does mean that the length could change between calls to check the length and - * the next call which actually allocates and returns the @secdata. + * the next call which actually allocates and returns the data. * - * Return: Return 0 on success, error on failure. + * Return: Return length of data on success, error on failure. */ -int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +int security_secid_to_secctx(u32 secid, struct lsm_context *cp) { - return call_int_hook(secid_to_secctx, secid, secdata, seclen); + return call_int_hook(secid_to_secctx, secid, cp); } EXPORT_SYMBOL(security_secid_to_secctx); /** * security_lsmprop_to_secctx() - Convert a lsm_prop to a secctx * @prop: lsm specific information - * @secdata: secctx - * @seclen: secctx length + * @cp: the LSM context * - * Convert a @prop entry to security context. If @secdata is NULL the - * length of the result will be returned in @seclen, but no @secdata - * will be returned. This does mean that the length could change between - * calls to check the length and the next call which actually allocates - * and returns the @secdata. + * Convert a @prop entry to security context. If @cp is NULL the + * length of the result will be returned. This does mean that the + * length could change between calls to check the length and the + * next call which actually allocates and returns the @cp. * - * Return: Return 0 on success, error on failure. + * Return: Return length of data on success, error on failure. */ -int security_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, - u32 *seclen) +int security_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp) { - return call_int_hook(lsmprop_to_secctx, prop, secdata, seclen); + return call_int_hook(lsmprop_to_secctx, prop, cp); } EXPORT_SYMBOL(security_lsmprop_to_secctx); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index aabc724f4d44..ddc24db7c0b2 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6640,15 +6640,28 @@ static int selinux_ismaclabel(const char *name) return (strcmp(name, XATTR_SELINUX_SUFFIX) == 0); } -static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +static int selinux_secid_to_secctx(u32 secid, struct lsm_context *cp) { - return security_sid_to_context(secid, secdata, seclen); + u32 seclen; + int ret; + + if (cp) { + cp->id = LSM_ID_SELINUX; + ret = security_sid_to_context(secid, &cp->context, &cp->len); + if (ret < 0) + return ret; + return cp->len; + } + ret = security_sid_to_context(secid, NULL, &seclen); + if (ret < 0) + return ret; + return seclen; } -static int selinux_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, - u32 *seclen) +static int selinux_lsmprop_to_secctx(struct lsm_prop *prop, + struct lsm_context *cp) { - return selinux_secid_to_secctx(prop->selinux.secid, secdata, seclen); + return selinux_secid_to_secctx(prop->selinux.secid, cp); } static int selinux_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 0c476282e279..4084f99c493c 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4817,41 +4817,48 @@ static int smack_ismaclabel(const char *name) return (strcmp(name, XATTR_SMACK_SUFFIX) == 0); } +/** + * smack_to_secctx - fill a lsm_context + * @skp: Smack label + * @cp: destination + * + * Fill the passed @cp and return the length of the string + */ +static int smack_to_secctx(struct smack_known *skp, struct lsm_context *cp) +{ + int len = strlen(skp->smk_known); + + if (cp) { + cp->context = skp->smk_known; + cp->len = len; + cp->id = LSM_ID_SMACK; + } + return len; +} + /** * smack_secid_to_secctx - return the smack label for a secid * @secid: incoming integer - * @secdata: destination - * @seclen: how long it is + * @cp: destination * * Exists for networking code. */ -static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +static int smack_secid_to_secctx(u32 secid, struct lsm_context *cp) { - struct smack_known *skp = smack_from_secid(secid); - - if (secdata) - *secdata = skp->smk_known; - *seclen = strlen(skp->smk_known); - return 0; + return smack_to_secctx(smack_from_secid(secid), cp); } /** * smack_lsmprop_to_secctx - return the smack label * @prop: includes incoming Smack data - * @secdata: destination - * @seclen: how long it is + * @cp: destination * * Exists for audit code. */ -static int smack_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, - u32 *seclen) +static int smack_lsmprop_to_secctx(struct lsm_prop *prop, + struct lsm_context *cp) { - struct smack_known *skp = prop->smack.skp; - - if (secdata) - *secdata = skp->smk_known; - *seclen = strlen(skp->smk_known); - return 0; + return smack_to_secctx(prop->smack.skp, cp); } /** From 76ecf306ae5da84ef8f48c7a2608736e6866440c Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Wed, 23 Oct 2024 14:21:56 -0700 Subject: [PATCH 3/8] lsm: use lsm_context in security_inode_getsecctx Change the security_inode_getsecctx() interface to fill a lsm_context structure instead of data and length pointers. This provides the information about which LSM created the context so that security_release_secctx() can use the correct hook. Cc: linux-nfs@vger.kernel.org Signed-off-by: Casey Schaufler [PM: subject tweak] Signed-off-by: Paul Moore --- fs/nfsd/nfs4xdr.c | 26 ++++++++++---------------- include/linux/lsm_hook_defs.h | 4 ++-- include/linux/security.h | 5 +++-- security/security.c | 12 ++++++------ security/selinux/hooks.c | 10 ++++++---- security/smack/smack_lsm.c | 7 ++++--- 6 files changed, 31 insertions(+), 33 deletions(-) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 95ec6a4b4da3..8dd2e2ada474 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2818,11 +2818,11 @@ static __be32 nfsd4_encode_nfsace4(struct xdr_stream *xdr, struct svc_rqst *rqst #ifdef CONFIG_NFSD_V4_SECURITY_LABEL static inline __be32 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp, - void *context, int len) + const struct lsm_context *context) { __be32 *p; - p = xdr_reserve_space(xdr, len + 4 + 4 + 4); + p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4); if (!p) return nfserr_resource; @@ -2832,13 +2832,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp, */ *p++ = cpu_to_be32(0); /* lfs */ *p++ = cpu_to_be32(0); /* pi */ - p = xdr_encode_opaque(p, context, len); + p = xdr_encode_opaque(p, context->context, context->len); return 0; } #else static inline __be32 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp, - void *context, int len) + struct lsm_context *context) { return 0; } #endif @@ -2920,8 +2920,7 @@ struct nfsd4_fattr_args { struct kstatfs statfs; struct nfs4_acl *acl; #ifdef CONFIG_NFSD_V4_SECURITY_LABEL - void *context; - int contextlen; + struct lsm_context context; #endif u32 rdattr_err; bool contextsupport; @@ -3376,8 +3375,7 @@ static __be32 nfsd4_encode_fattr4_suppattr_exclcreat(struct xdr_stream *xdr, static __be32 nfsd4_encode_fattr4_sec_label(struct xdr_stream *xdr, const struct nfsd4_fattr_args *args) { - return nfsd4_encode_security_label(xdr, args->rqstp, - args->context, args->contextlen); + return nfsd4_encode_security_label(xdr, args->rqstp, &args->context); } #endif @@ -3527,7 +3525,7 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, args.ignore_crossmnt = (ignore_crossmnt != 0); args.acl = NULL; #ifdef CONFIG_NFSD_V4_SECURITY_LABEL - args.context = NULL; + args.context.context = NULL; #endif /* @@ -3607,7 +3605,7 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, attrmask[0] & FATTR4_WORD0_SUPPORTED_ATTRS) { if (exp->ex_flags & NFSEXP_SECURITY_LABEL) err = security_inode_getsecctx(d_inode(dentry), - &args.context, &args.contextlen); + &args.context); else err = -EOPNOTSUPP; args.contextsupport = (err == 0); @@ -3644,12 +3642,8 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr, out: #ifdef CONFIG_NFSD_V4_SECURITY_LABEL - if (args.context) { - struct lsm_context scaff; /* scaffolding */ - - lsmcontext_init(&scaff, args.context, args.contextlen, 0); - security_release_secctx(&scaff); - } + if (args.context.context) + security_release_secctx(&args.context); #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */ kfree(args.acl); if (tempfh) { diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 01e5a8e09bba..69e1076448c6 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -303,8 +303,8 @@ LSM_HOOK(void, LSM_RET_VOID, release_secctx, struct lsm_context *cp) LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode) LSM_HOOK(int, 0, inode_notifysecctx, struct inode *inode, void *ctx, u32 ctxlen) LSM_HOOK(int, 0, inode_setsecctx, struct dentry *dentry, void *ctx, u32 ctxlen) -LSM_HOOK(int, -EOPNOTSUPP, inode_getsecctx, struct inode *inode, void **ctx, - u32 *ctxlen) +LSM_HOOK(int, -EOPNOTSUPP, inode_getsecctx, struct inode *inode, + struct lsm_context *cp) #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE) LSM_HOOK(int, 0, post_notification, const struct cred *w_cred, diff --git a/include/linux/security.h b/include/linux/security.h index 58518bbc00a6..29f8100bc7c8 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -591,7 +591,7 @@ void security_release_secctx(struct lsm_context *cp); void security_inode_invalidate_secctx(struct inode *inode); int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen); -int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen); +int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp); int security_locked_down(enum lockdown_reason what); int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len, void *val, size_t val_len, u64 id, u64 flags); @@ -1591,7 +1591,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 { return -EOPNOTSUPP; } -static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) +static inline int security_inode_getsecctx(struct inode *inode, + struct lsm_context *cp) { return -EOPNOTSUPP; } diff --git a/security/security.c b/security/security.c index 1edf8fb2046c..1aecf1696c50 100644 --- a/security/security.c +++ b/security/security.c @@ -4426,17 +4426,17 @@ EXPORT_SYMBOL(security_inode_setsecctx); /** * security_inode_getsecctx() - Get the security label of an inode * @inode: inode - * @ctx: secctx - * @ctxlen: length of secctx + * @cp: security context * - * On success, returns 0 and fills out @ctx and @ctxlen with the security - * context for the given @inode. + * On success, returns 0 and fills out @cp with the security context + * for the given @inode. * * Return: Returns 0 on success, error on failure. */ -int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) +int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp) { - return call_int_hook(inode_getsecctx, inode, ctx, ctxlen); + memset(cp, 0, sizeof(*cp)); + return call_int_hook(inode_getsecctx, inode, cp); } EXPORT_SYMBOL(security_inode_getsecctx); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ddc24db7c0b2..9254570de103 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6711,14 +6711,16 @@ static int selinux_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen) ctx, ctxlen, 0, NULL); } -static int selinux_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) +static int selinux_inode_getsecctx(struct inode *inode, struct lsm_context *cp) { - int len = 0; + int len; len = selinux_inode_getsecurity(&nop_mnt_idmap, inode, - XATTR_SELINUX_SUFFIX, ctx, true); + XATTR_SELINUX_SUFFIX, + (void **)&cp->context, true); if (len < 0) return len; - *ctxlen = len; + cp->len = len; + cp->id = LSM_ID_SELINUX; return 0; } #ifdef CONFIG_KEYS diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 4084f99c493c..55a556f17ade 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4898,12 +4898,13 @@ static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen) ctx, ctxlen, 0, NULL); } -static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) +static int smack_inode_getsecctx(struct inode *inode, struct lsm_context *cp) { struct smack_known *skp = smk_of_inode(inode); - *ctx = skp->smk_known; - *ctxlen = strlen(skp->smk_known); + cp->context = skp->smk_known; + cp->len = strlen(skp->smk_known); + cp->id = LSM_ID_SMACK; return 0; } From b530104f50e86db6f187d39fed5821b3cca755ee Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Wed, 23 Oct 2024 14:21:57 -0700 Subject: [PATCH 4/8] lsm: lsm_context in security_dentry_init_security Replace the (secctx,seclen) pointer pair with a single lsm_context pointer to allow return of the LSM identifier along with the context and context length. This allows security_release_secctx() to know how to release the context. Callers have been modified to use or save the returned data from the new structure. Cc: ceph-devel@vger.kernel.org Cc: linux-nfs@vger.kernel.org Signed-off-by: Casey Schaufler [PM: subject tweak] Signed-off-by: Paul Moore --- fs/ceph/super.h | 3 +-- fs/ceph/xattr.c | 16 ++++++---------- fs/fuse/dir.c | 35 ++++++++++++++++++----------------- fs/nfs/nfs4proc.c | 20 ++++++++++++-------- include/linux/lsm_hook_defs.h | 2 +- include/linux/security.h | 26 +++----------------------- security/security.c | 9 ++++----- security/selinux/hooks.c | 8 ++++---- 8 files changed, 49 insertions(+), 70 deletions(-) diff --git a/fs/ceph/super.h b/fs/ceph/super.h index af14ec382246..7fa1e7be50e4 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -1132,8 +1132,7 @@ struct ceph_acl_sec_ctx { void *acl; #endif #ifdef CONFIG_CEPH_FS_SECURITY_LABEL - void *sec_ctx; - u32 sec_ctxlen; + struct lsm_context lsmctx; #endif #ifdef CONFIG_FS_ENCRYPTION struct ceph_fscrypt_auth *fscrypt_auth; diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 2a14335a4bb7..537165db4519 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -1383,8 +1383,7 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode, int err; err = security_dentry_init_security(dentry, mode, &dentry->d_name, - &name, &as_ctx->sec_ctx, - &as_ctx->sec_ctxlen); + &name, &as_ctx->lsmctx); if (err < 0) { WARN_ON_ONCE(err != -EOPNOTSUPP); err = 0; /* do nothing */ @@ -1409,7 +1408,7 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode, */ name_len = strlen(name); err = ceph_pagelist_reserve(pagelist, - 4 * 2 + name_len + as_ctx->sec_ctxlen); + 4 * 2 + name_len + as_ctx->lsmctx.len); if (err) goto out; @@ -1432,8 +1431,9 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode, ceph_pagelist_encode_32(pagelist, name_len); ceph_pagelist_append(pagelist, name, name_len); - ceph_pagelist_encode_32(pagelist, as_ctx->sec_ctxlen); - ceph_pagelist_append(pagelist, as_ctx->sec_ctx, as_ctx->sec_ctxlen); + ceph_pagelist_encode_32(pagelist, as_ctx->lsmctx.len); + ceph_pagelist_append(pagelist, as_ctx->lsmctx.context, + as_ctx->lsmctx.len); err = 0; out: @@ -1446,16 +1446,12 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode, void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx) { -#ifdef CONFIG_CEPH_FS_SECURITY_LABEL - struct lsm_context scaff; /* scaffolding */ -#endif #ifdef CONFIG_CEPH_FS_POSIX_ACL posix_acl_release(as_ctx->acl); posix_acl_release(as_ctx->default_acl); #endif #ifdef CONFIG_CEPH_FS_SECURITY_LABEL - lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0); - security_release_secctx(&scaff); + security_release_secctx(&as_ctx->lsmctx); #endif #ifdef CONFIG_FS_ENCRYPTION kfree(as_ctx->fscrypt_auth); diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 494ac372ace0..0b2f8567ca30 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -467,29 +467,29 @@ static int get_security_context(struct dentry *entry, umode_t mode, { struct fuse_secctx *fctx; struct fuse_secctx_header *header; - void *ctx = NULL, *ptr; - u32 ctxlen, total_len = sizeof(*header); + struct lsm_context lsmctx = { }; + void *ptr; + u32 total_len = sizeof(*header); int err, nr_ctx = 0; - const char *name; + const char *name = NULL; size_t namelen; err = security_dentry_init_security(entry, mode, &entry->d_name, - &name, &ctx, &ctxlen); - if (err) { - if (err != -EOPNOTSUPP) - goto out_err; - /* No LSM is supporting this security hook. Ignore error */ - ctxlen = 0; - ctx = NULL; - } + &name, &lsmctx); - if (ctxlen) { + /* If no LSM is supporting this security hook ignore error */ + if (err && err != -EOPNOTSUPP) + goto out_err; + + if (lsmctx.len) { nr_ctx = 1; namelen = strlen(name) + 1; err = -EIO; - if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX)) + if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || + lsmctx.len > S32_MAX)) goto out_err; - total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen); + total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + + lsmctx.len); } err = -ENOMEM; @@ -502,19 +502,20 @@ static int get_security_context(struct dentry *entry, umode_t mode, ptr += sizeof(*header); if (nr_ctx) { fctx = ptr; - fctx->size = ctxlen; + fctx->size = lsmctx.len; ptr += sizeof(*fctx); strcpy(ptr, name); ptr += namelen; - memcpy(ptr, ctx, ctxlen); + memcpy(ptr, lsmctx.context, lsmctx.len); } ext->size = total_len; ext->value = header; err = 0; out_err: - kfree(ctx); + if (nr_ctx) + security_release_secctx(&lsmctx); return err; } diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 2daeb6f663d9..d615d520f8cf 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -114,6 +114,7 @@ static inline struct nfs4_label * nfs4_label_init_security(struct inode *dir, struct dentry *dentry, struct iattr *sattr, struct nfs4_label *label) { + struct lsm_context shim; int err; if (label == NULL) @@ -128,21 +129,24 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry, label->label = NULL; err = security_dentry_init_security(dentry, sattr->ia_mode, - &dentry->d_name, NULL, - (void **)&label->label, &label->len); - if (err == 0) - return label; + &dentry->d_name, NULL, &shim); + if (err) + return NULL; - return NULL; + label->label = shim.context; + label->len = shim.len; + return label; } static inline void nfs4_label_release_security(struct nfs4_label *label) { - struct lsm_context scaff; /* scaffolding */ + struct lsm_context shim; if (label) { - lsmcontext_init(&scaff, label->label, label->len, 0); - security_release_secctx(&scaff); + shim.context = label->label; + shim.len = label->len; + shim.id = LSM_ID_UNDEF; + security_release_secctx(&shim); } } static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label) diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 69e1076448c6..e2f1ce37c41e 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -83,7 +83,7 @@ LSM_HOOK(int, 0, move_mount, const struct path *from_path, const struct path *to_path) LSM_HOOK(int, -EOPNOTSUPP, dentry_init_security, struct dentry *dentry, int mode, const struct qstr *name, const char **xattr_name, - void **ctx, u32 *ctxlen) + struct lsm_context *cp) LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, struct cred *new) diff --git a/include/linux/security.h b/include/linux/security.h index 29f8100bc7c8..980b6c207cad 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -237,25 +237,6 @@ struct lsm_context { int id; /* Identifies the module */ }; -/** - * lsmcontext_init - initialize an lsmcontext structure. - * @cp: Pointer to the context to initialize - * @context: Initial context, or NULL - * @size: Size of context, or 0 - * @id: Which LSM provided the context - * - * Fill in the lsmcontext from the provided information. - * This is a scaffolding function that will be removed when - * lsm_context integration is complete. - */ -static inline void lsmcontext_init(struct lsm_context *cp, char *context, - u32 size, int id) -{ - cp->id = id; - cp->context = context; - cp->len = size; -} - /* * Values used in the task_security_ops calls */ @@ -409,8 +390,8 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb, int security_move_mount(const struct path *from_path, const struct path *to_path); int security_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, - const char **xattr_name, void **ctx, - u32 *ctxlen); + const char **xattr_name, + struct lsm_context *lsmcxt); int security_dentry_create_files_as(struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, @@ -883,8 +864,7 @@ static inline int security_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, const char **xattr_name, - void **ctx, - u32 *ctxlen) + struct lsm_context *lsmcxt) { return -EOPNOTSUPP; } diff --git a/security/security.c b/security/security.c index 1aecf1696c50..7523d14f31fb 100644 --- a/security/security.c +++ b/security/security.c @@ -1735,8 +1735,7 @@ void security_inode_free(struct inode *inode) * @mode: mode used to determine resource type * @name: name of the last path component * @xattr_name: name of the security/LSM xattr - * @ctx: pointer to the resulting LSM context - * @ctxlen: length of @ctx + * @lsmctx: pointer to the resulting LSM context * * Compute a context for a dentry as the inode is not yet available since NFSv4 * has no label backed by an EA anyway. It is important to note that @@ -1746,11 +1745,11 @@ void security_inode_free(struct inode *inode) */ int security_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, - const char **xattr_name, void **ctx, - u32 *ctxlen) + const char **xattr_name, + struct lsm_context *lsmctx) { return call_int_hook(dentry_init_security, dentry, mode, name, - xattr_name, ctx, ctxlen); + xattr_name, lsmctx); } EXPORT_SYMBOL(security_dentry_init_security); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9254570de103..4f8d37ae769a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2869,8 +2869,8 @@ static void selinux_inode_free_security(struct inode *inode) static int selinux_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, - const char **xattr_name, void **ctx, - u32 *ctxlen) + const char **xattr_name, + struct lsm_context *cp) { u32 newsid; int rc; @@ -2885,8 +2885,8 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode, if (xattr_name) *xattr_name = XATTR_NAME_SELINUX; - return security_sid_to_context(newsid, (char **)ctx, - ctxlen); + cp->id = LSM_ID_SELINUX; + return security_sid_to_context(newsid, &cp->context, &cp->len); } static int selinux_dentry_create_files_as(struct dentry *dentry, int mode, From a4626e978677e3d3e816fdc217d8416c8b9462ae Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Wed, 23 Oct 2024 14:21:58 -0700 Subject: [PATCH 5/8] lsm: secctx provider check on release Verify that the LSM releasing the secctx is the LSM that allocated it. This was not necessary when only one LSM could create a secctx, but once there can be more than one it is. Signed-off-by: Casey Schaufler [PM: subject tweak] Signed-off-by: Paul Moore --- security/apparmor/secid.c | 13 +++++-------- security/selinux/hooks.c | 13 +++++-------- 2 files changed, 10 insertions(+), 16 deletions(-) diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c index b08969ec34b7..28caf66b9033 100644 --- a/security/apparmor/secid.c +++ b/security/apparmor/secid.c @@ -108,14 +108,11 @@ int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) void apparmor_release_secctx(struct lsm_context *cp) { - /* - * stacking scaffolding: - * When it is possible for more than one LSM to provide a - * release hook, do this check: - * if (cp->id == LSM_ID_APPARMOR || cp->id == LSM_ID_UNDEF) - */ - - kfree(cp->context); + if (cp->id == LSM_ID_APPARMOR) { + kfree(cp->context); + cp->context = NULL; + cp->id = LSM_ID_UNDEF; + } } /** diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 4f8d37ae769a..a2e72f1212a3 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6672,14 +6672,11 @@ static int selinux_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) static void selinux_release_secctx(struct lsm_context *cp) { - /* - * stacking scaffolding: - * When it is possible for more than one LSM to provide a - * release hook, do this check: - * if (cp->id == LSM_ID_SELINUX || cp->id == LSM_ID_UNDEF) - */ - - kfree(cp->context); + if (cp->id == LSM_ID_SELINUX) { + kfree(cp->context); + cp->context = NULL; + cp->id = LSM_ID_UNDEF; + } } static void selinux_inode_invalidate_secctx(struct inode *inode) From 9c76eaf784886603a010f0af7071c2b4d7f574c5 Mon Sep 17 00:00:00 2001 From: Alice Ryhl Date: Fri, 1 Nov 2024 09:56:20 +0000 Subject: [PATCH 6/8] rust: replace lsm context+len with lsm_context This brings the Rust SecurityCtx abstraction [1] up to date with the new API where context+len is replaced with an lsm_context [2] struct. Link: https://lore.kernel.org/r/20240915-alice-file-v10-5-88484f7a3dcf@google.com [1] Link: https://lore.kernel.org/r/20241023212158.18718-3-casey@schaufler-ca.com [2] Reported-by: Linux Kernel Functional Testing Closes: https://lore.kernel.org/r/CA+G9fYv_Y2tzs+uYhMGtfUK9dSYV2mFr6WyKEzJazDsdk9o5zw@mail.gmail.com Signed-off-by: Alice Ryhl [PM: subj line tweak] Signed-off-by: Paul Moore --- rust/helpers/security.c | 8 ++++---- rust/kernel/security.rs | 38 +++++++++++++++++--------------------- 2 files changed, 21 insertions(+), 25 deletions(-) diff --git a/rust/helpers/security.c b/rust/helpers/security.c index 239e5b4745fe..0c4c2065df28 100644 --- a/rust/helpers/security.c +++ b/rust/helpers/security.c @@ -8,13 +8,13 @@ void rust_helper_security_cred_getsecid(const struct cred *c, u32 *secid) security_cred_getsecid(c, secid); } -int rust_helper_security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +int rust_helper_security_secid_to_secctx(u32 secid, struct lsm_context *cp) { - return security_secid_to_secctx(secid, secdata, seclen); + return security_secid_to_secctx(secid, cp); } -void rust_helper_security_release_secctx(char *secdata, u32 seclen) +void rust_helper_security_release_secctx(struct lsm_context *cp) { - security_release_secctx(secdata, seclen); + security_release_secctx(cp); } #endif diff --git a/rust/kernel/security.rs b/rust/kernel/security.rs index 2522868862a1..25d2b1ac3833 100644 --- a/rust/kernel/security.rs +++ b/rust/kernel/security.rs @@ -15,60 +15,56 @@ /// /// # Invariants /// -/// The `secdata` and `seclen` fields correspond to a valid security context as returned by a -/// successful call to `security_secid_to_secctx`, that has not yet been destroyed by calling -/// `security_release_secctx`. +/// The `ctx` field corresponds to a valid security context as returned by a successful call to +/// `security_secid_to_secctx`, that has not yet been destroyed by `security_release_secctx`. pub struct SecurityCtx { - secdata: *mut core::ffi::c_char, - seclen: usize, + ctx: bindings::lsm_context, } impl SecurityCtx { /// Get the security context given its id. pub fn from_secid(secid: u32) -> Result { - let mut secdata = core::ptr::null_mut(); - let mut seclen = 0u32; - // SAFETY: Just a C FFI call. The pointers are valid for writes. - to_result(unsafe { bindings::security_secid_to_secctx(secid, &mut secdata, &mut seclen) })?; + // SAFETY: `struct lsm_context` can be initialized to all zeros. + let mut ctx: bindings::lsm_context = unsafe { core::mem::zeroed() }; + + // SAFETY: Just a C FFI call. The pointer is valid for writes. + to_result(unsafe { bindings::security_secid_to_secctx(secid, &mut ctx) })?; // INVARIANT: If the above call did not fail, then we have a valid security context. - Ok(Self { - secdata, - seclen: seclen as usize, - }) + Ok(Self { ctx }) } /// Returns whether the security context is empty. pub fn is_empty(&self) -> bool { - self.seclen == 0 + self.ctx.len == 0 } /// Returns the length of this security context. pub fn len(&self) -> usize { - self.seclen + self.ctx.len as usize } /// Returns the bytes for this security context. pub fn as_bytes(&self) -> &[u8] { - let ptr = self.secdata; + let ptr = self.ctx.context; if ptr.is_null() { - debug_assert_eq!(self.seclen, 0); + debug_assert_eq!(self.len(), 0); // We can't pass a null pointer to `slice::from_raw_parts` even if the length is zero. return &[]; } // SAFETY: The call to `security_secid_to_secctx` guarantees that the pointer is valid for - // `seclen` bytes. Furthermore, if the length is zero, then we have ensured that the + // `self.len()` bytes. Furthermore, if the length is zero, then we have ensured that the // pointer is not null. - unsafe { core::slice::from_raw_parts(ptr.cast(), self.seclen) } + unsafe { core::slice::from_raw_parts(ptr.cast(), self.len()) } } } impl Drop for SecurityCtx { fn drop(&mut self) { - // SAFETY: By the invariant of `Self`, this frees a pointer that came from a successful + // SAFETY: By the invariant of `Self`, this frees a context that came from a successful // call to `security_secid_to_secctx` and has not yet been destroyed by // `security_release_secctx`. - unsafe { bindings::security_release_secctx(self.secdata, self.seclen as u32) }; + unsafe { bindings::security_release_secctx(&mut self.ctx) }; } } From 012920131013208186ce0ded0ef1c47fa67a70f6 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Fri, 6 Dec 2024 14:57:13 -0800 Subject: [PATCH 7/8] binder: initialize lsm_context structure It is possible to reach the end of binder_transaction() without having set lsmctx. As the variable value is checked there it needs to be initialized. Suggested-by: Kees Bakker [PM: subj tweak to fit convention] Signed-off-by: Casey Schaufler Signed-off-by: Paul Moore --- drivers/android/binder.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 919da8e674f5..a4b98e95ab85 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3017,7 +3017,7 @@ static void binder_transaction(struct binder_proc *proc, struct binder_context *context = proc->context; int t_debug_id = atomic_inc_return(&binder_last_id); ktime_t t_start_time = ktime_get(); - struct lsm_context lsmctx; + struct lsm_context lsmctx = { }; struct list_head sgc_head; struct list_head pf_head; const void __user *user_buffer = (const void __user *) From 7a9b65ab0abd52ae646ba327522315d7500a7d4f Mon Sep 17 00:00:00 2001 From: Amit Vadhavana Date: Sat, 16 Nov 2024 20:51:36 +0530 Subject: [PATCH 8/8] selftests: refactor the lsm `flags_overset_lsm_set_self_attr` test Remove the temporary context variable `tctx` to simplify the code. use the original context `ctx` directly in calls to `lsm_get_self_attr`, eliminating redundancy without any functional changes. Reviewed-by: Casey Schaufler Reviewed-by: Shuah Khan Signed-off-by: Amit Vadhavana [PM: subject tweak] Signed-off-by: Paul Moore --- tools/testing/selftests/lsm/lsm_set_self_attr_test.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/lsm/lsm_set_self_attr_test.c b/tools/testing/selftests/lsm/lsm_set_self_attr_test.c index 66dec47e3ca3..732e89fe99c0 100644 --- a/tools/testing/selftests/lsm/lsm_set_self_attr_test.c +++ b/tools/testing/selftests/lsm/lsm_set_self_attr_test.c @@ -56,16 +56,15 @@ TEST(flags_zero_lsm_set_self_attr) TEST(flags_overset_lsm_set_self_attr) { const long page_size = sysconf(_SC_PAGESIZE); - char *ctx = calloc(page_size, 1); + struct lsm_ctx *ctx = calloc(page_size, 1); __u32 size = page_size; - struct lsm_ctx *tctx = (struct lsm_ctx *)ctx; ASSERT_NE(NULL, ctx); if (attr_lsm_count()) { - ASSERT_LE(1, lsm_get_self_attr(LSM_ATTR_CURRENT, tctx, &size, + ASSERT_LE(1, lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, &size, 0)); } - ASSERT_EQ(-1, lsm_set_self_attr(LSM_ATTR_CURRENT | LSM_ATTR_PREV, tctx, + ASSERT_EQ(-1, lsm_set_self_attr(LSM_ATTR_CURRENT | LSM_ATTR_PREV, ctx, size, 0)); free(ctx);