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[1/5] fs: Fix S_NOSEC handling

Message ID 1425379119-3773-2-git-send-email-jack@suse.cz (mailing list archive)
State New, archived
Headers show

Commit Message

Jan Kara March 3, 2015, 10:38 a.m. UTC 
file_remove_suid() could mistakenly set S_NOSEC inode bit when root was
modifying the file. As a result following writes to the file by ordinary
user would avoid clearing suid or sgid bits.

Fix the bug by checking actual mode bits before setting S_NOSEC.

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/fs/inode.c b/fs/inode.c
index f00b16f45507..be326ae7f880 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1693,7 +1693,8 @@  int file_remove_suid(struct file *file)
 		error = security_inode_killpriv(dentry);
 	if (!error && killsuid)
 		error = __remove_suid(dentry, killsuid);
-	if (!error && (inode->i_sb->s_flags & MS_NOSEC))
+	if (!error && (inode->i_sb->s_flags & MS_NOSEC) &&
+	    !is_sxid(inode->i_mode))
 		inode->i_flags |= S_NOSEC;
 
 	return error;