Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 6.4 45/54] ovl: Always reevaluate the file signature for IMA | Date | Sun, 13 Aug 2023 11:49:24 -0400 |
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From: Eric Snowberg <eric.snowberg@oracle.com>
[ Upstream commit 18b44bc5a67275641fb26f2c54ba7eef80ac5950 ]
Commit db1d1e8b9867 ("IMA: use vfs_getattr_nosec to get the i_version") partially closed an IMA integrity issue when directly modifying a file on the lower filesystem. If the overlay file is first opened by a user and later the lower backing file is modified by root, but the extended attribute is NOT updated, the signature validation succeeds with the old original signature.
Update the super_block s_iflags to SB_I_IMA_UNVERIFIABLE_SIGNATURE to force signature reevaluation on every file access until a fine grained solution can be found.
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/overlayfs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index ae1058fbfb5b2..8c60da7b4afd8 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -2052,7 +2052,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) ovl_trusted_xattr_handlers; sb->s_fs_info = ofs; sb->s_flags |= SB_POSIXACL; - sb->s_iflags |= SB_I_SKIP_SYNC; + sb->s_iflags |= SB_I_SKIP_SYNC | SB_I_IMA_UNVERIFIABLE_SIGNATURE; err = -ENOMEM; root_dentry = ovl_get_root(sb, upperpath.dentry, oe); -- 2.40.1
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