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net: abstract out normal and compat msghdr import

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This splits it into two parts, one that imports the message, and one
that imports the iovec. This allows a caller to only do the first part,
and import the iovec manually afterwards.

No functional changes in this patch.

Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2020-02-27 08:11:20 -07:00
parent 4d954c258a
commit 0a384abfae
4 changed files with 51 additions and 11 deletions
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4
include/linux/socket.h
View File

@ -391,6 +391,10 @@ extern int recvmsg_copy_msghdr(struct msghdr *msg,
struct user_msghdr __user *umsg, unsigned flags,
struct sockaddr __user **uaddr,
struct iovec **iov);
extern int __copy_msghdr_from_user(struct msghdr *kmsg,
struct user_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec __user **uiov, size_t *nsegs);
/* helpers which do the actual work for syscalls */
extern int __sys_recvfrom(int fd, void __user *ubuf, size_t size,

3
include/net/compat.h
View File

@ -38,6 +38,9 @@ struct compat_cmsghdr {
#define compat_mmsghdr mmsghdr
#endif /* defined(CONFIG_COMPAT) */
int __get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg,
struct sockaddr __user **save_addr, compat_uptr_t *ptr,
compat_size_t *len);
int get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,
struct sockaddr __user **, struct iovec **);
struct sock_fprog __user *get_compat_bpf_fprog(char __user *optval);

30
net/compat.c
View File

@ -33,10 +33,10 @@
#include <linux/uaccess.h>
#include <net/compat.h>
int get_compat_msghdr(struct msghdr *kmsg,
struct compat_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec **iov)
int __get_compat_msghdr(struct msghdr *kmsg,
struct compat_msghdr __user *umsg,
struct sockaddr __user **save_addr,
compat_uptr_t *ptr, compat_size_t *len)
{
struct compat_msghdr msg;
ssize_t err;
@ -79,10 +79,26 @@ int get_compat_msghdr(struct msghdr *kmsg,
return -EMSGSIZE;
kmsg->msg_iocb = NULL;
*ptr = msg.msg_iov;
*len = msg.msg_iovlen;
return 0;
}
err = compat_import_iovec(save_addr ? READ : WRITE,
compat_ptr(msg.msg_iov), msg.msg_iovlen,
UIO_FASTIOV, iov, &kmsg->msg_iter);
int get_compat_msghdr(struct msghdr *kmsg,
struct compat_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec **iov)
{
compat_uptr_t ptr;
compat_size_t len;
ssize_t err;
err = __get_compat_msghdr(kmsg, umsg, save_addr, &ptr, &len);
if (err)
return err;
err = compat_import_iovec(save_addr ? READ : WRITE, compat_ptr(ptr),
len, UIO_FASTIOV, iov, &kmsg->msg_iter);
return err < 0 ? err : 0;
}

25
net/socket.c
View File

@ -2226,10 +2226,10 @@ struct used_address {
unsigned int name_len;
};
static int copy_msghdr_from_user(struct msghdr *kmsg,
struct user_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec **iov)
int __copy_msghdr_from_user(struct msghdr *kmsg,
struct user_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec __user **uiov, size_t *nsegs)
{
struct user_msghdr msg;
ssize_t err;
@ -2271,6 +2271,23 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
return -EMSGSIZE;
kmsg->msg_iocb = NULL;
*uiov = msg.msg_iov;
*nsegs = msg.msg_iovlen;
return 0;
}
static int copy_msghdr_from_user(struct msghdr *kmsg,
struct user_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec **iov)
{
struct user_msghdr msg;
ssize_t err;
err = __copy_msghdr_from_user(kmsg, umsg, save_addr, &msg.msg_iov,
&msg.msg_iovlen);
if (err)
return err;
err = import_iovec(save_addr ? READ : WRITE,
msg.msg_iov, msg.msg_iovlen,