Scott Mayhew eebec98791 selinux,smack: don't bypass permissions check in inode_setsecctx hook ... commit 76a0e79bc8 upstream. Marek Gresko reports that the root user on an NFS client is able to change the security labels on files on an NFS filesystem that is exported with root squashing enabled. The end of the kerneldoc comment for __vfs_setxattr_noperm() states: * This function requires the caller to lock the inode's i_mutex before it * is executed. It also assumes that the caller will make the appropriate * permission checks. nfsd_setattr() does do permissions checking via fh_verify() and nfsd_permission(), but those don't do all the same permissions checks that are done by security_inode_setxattr() and its related LSM hooks do. Since nfsd_setattr() is the only consumer of security_inode_setsecctx(), simplest solution appears to be to replace the call to __vfs_setxattr_noperm() with a call to __vfs_setxattr_locked(). This fixes the above issue and has the added benefit of causing nfsd to recall conflicting delegations on a file when a client tries to change its security label. Cc: stable@kernel.org Reported-by: Marek Gresko <marek.gresko@protonmail.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218809 Signed-off-by: Scott Mayhew <smayhew@redhat.com> Tested-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com> [Shivani: Modified to apply on v5.15.y-v6.1.y] Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-10-17 15:21:15 +02:00
..
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
smack_access.c	smack: Replace kzalloc + strncpy with kstrndup	2022-08-01 11:26:09 -07:00
smack_lsm.c	selinux,smack: don't bypass permissions check in inode_setsecctx hook	2024-10-17 15:21:15 +02:00
smack_netfilter.c	smack: remove duplicated hook function	2021-10-12 08:23:52 -07:00
smack.h	smack: Record transmuting in smk_transmuted	2023-10-06 14:56:59 +02:00
smackfs.c	smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso	2024-10-17 15:20:59 +02:00