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From: Jan Kara <jack@suse.cz>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com,
	Jan Kara <jack@suse.cz>,
	stable@vger.kernel.org
Subject: [PATCH 1/5] fs: Fix S_NOSEC handling
Date: Tue,  3 Mar 2015 11:38:35 +0100	[thread overview]
Message-ID: <1425379119-3773-2-git-send-email-jack@suse.cz> (raw)
In-Reply-To: <1425379119-3773-1-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 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;
-- 
2.1.4

WARNING: multiple messages have this Message-ID (diff)
From: Jan Kara <jack@suse.cz>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@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: Tue,  3 Mar 2015 11:38:35 +0100	[thread overview]
Message-ID: <1425379119-3773-2-git-send-email-jack@suse.cz> (raw)
In-Reply-To: <1425379119-3773-1-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 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;
-- 
2.1.4

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  reply	other threads:[~2015-03-03 10:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-03 10:38 [PATCH 0/5 v2 RESEND] fs: Fixes for removing xid bits and security labels Jan Kara
2015-03-03 10:38 ` Jan Kara
2015-03-03 10:38 ` Jan Kara [this message]
2015-03-03 10:38   ` [PATCH 1/5] fs: Fix S_NOSEC handling Jan Kara
2015-03-03 10:38 ` [PATCH 2/5] fs: Rename file_remove_suid() to file_remove_privs() Jan Kara
2015-03-03 10:38   ` Jan Kara
2015-03-03 10:38 ` [PATCH 3/5] fs: Provide function telling whether file_remove_privs() will do anything Jan Kara
2015-03-03 10:38   ` Jan Kara
2015-03-03 10:38 ` [PATCH 4/5] fs: Call security_ops->inode_killpriv on truncate Jan Kara
2015-03-03 10:38   ` Jan Kara
2015-03-03 10:38 ` [PATCH 5/5] xfs: Correctly lock inode when removing suid and security marks Jan Kara
2015-03-03 10:38   ` Jan Kara
2015-03-03 21:34   ` Dave Chinner
2015-03-03 21:34     ` Dave Chinner
2015-04-14 16:54   ` Eric Sandeen
2015-04-14 16:54     ` Eric Sandeen
2015-04-14 23:03     ` Dave Chinner
2015-04-14 23:03       ` Dave Chinner
2015-05-04 23:13 ` [PATCH 0/5 v2 RESEND] fs: Fixes for removing xid bits and security labels Dave Chinner
2015-05-04 23:13   ` Dave Chinner
2015-05-05  7:56   ` Jan Kara
2015-05-05  7:56     ` Jan Kara
  -- strict thread matches above, loose matches on Subject: below --
2015-05-21 14:05 [PATCH 0/5 v4] " Jan Kara
2015-05-21 14:05 ` [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
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 ` [PATCH 1/5] fs: Fix S_NOSEC handling Jan Kara

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