From: Jan Kara <jack@suse.cz>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org, Jan Kara <jack@suse.cz>,
stable@vger.kernel.org, xfs@oss.sgi.com
Subject: [PATCH 1/5] fs: Fix S_NOSEC handling
Date: Thu, 18 Dec 2014 13:49:02 +0100 [thread overview]
Message-ID: <1418906946-30695-2-git-send-email-jack@suse.cz> (raw)
In-Reply-To: <1418906946-30695-1-git-send-email-jack@suse.cz>
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 --git a/fs/inode.c b/fs/inode.c
index 26753ba7b6d6..f5e01704a5c8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1631,7 +1631,8 @@ 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;
--
1.8.4.5
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next prev parent reply other threads:[~2014-12-18 12:49 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-18 12:49 [PATCH 0/5 v2] fs: Fixes for removing xid bits and security labels Jan Kara
2014-12-18 12:49 ` Jan Kara [this message]
2014-12-18 12:49 ` [PATCH 2/5] fs: Rename file_remove_suid() to file_remove_privs() Jan Kara
2014-12-18 12:49 ` [PATCH 3/5] fs: Provide function telling whether file_remove_privs() will do anything Jan Kara
2014-12-18 12:49 ` [PATCH 4/5] fs: Call security_ops->inode_killpriv on truncate Jan Kara
2014-12-18 12:49 ` [PATCH 5/5] xfs: Correctly lock inode when removing suid and security marks Jan Kara
2015-01-08 9:18 ` [PATCH 0/5 v2] fs: Fixes for removing xid bits and security labels Jan Kara
2015-03-03 10:38 [PATCH 0/5 v2 RESEND] " Jan Kara
2015-03-03 10:38 ` [PATCH 1/5] fs: Fix S_NOSEC handling Jan Kara
2015-05-19 9:46 [PATCH 0/5 v3] fs: Fixes for removing xid bits and security labels Jan Kara
2015-05-19 9:46 ` [PATCH 1/5] fs: Fix S_NOSEC handling Jan Kara
2015-05-21 14:05 [PATCH 0/5 v4] fs: Fixes for removing xid bits and security labels Jan Kara
2015-05-21 14:05 ` [PATCH 1/5] fs: Fix S_NOSEC handling Jan Kara
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