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From: Sasha Levin <sasha.levin@oracle.com>
To: mingo@kernel.org, akpm@linux-foundation.org,
	torvalds@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, Sasha Levin <sasha.levin@oracle.com>
Subject: [RFC v2 2/2] fs: correctly check for signed integer overflow in vfs_fallocate
Date: Wed, 26 Nov 2014 18:58:02 -0500	[thread overview]
Message-ID: <1417046282-31825-2-git-send-email-sasha.levin@oracle.com> (raw)
In-Reply-To: <1417046282-31825-1-git-send-email-sasha.levin@oracle.com>

Both "offset" and "len" are signed integers who's addition may overflow
and trigger undefined behaviour.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
 fs/open.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/open.c b/fs/open.c
index 813be03..33d5cae 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -287,7 +287,8 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 		return -ENODEV;
 
 	/* Check for wrap through zero too */
-	if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
+	if (check_add_overflow(offset, len) ||
+	   (offset + len) > inode->i_sb->s_maxbytes)
 		return -EFBIG;
 
 	if (!file->f_op->fallocate)
-- 
1.7.10.4


  reply	other threads:[~2014-11-26 23:58 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-26 23:58 [RFC v2 1/2] compiler: use compiler to detect integer overflows Sasha Levin
2014-11-26 23:58 ` Sasha Levin [this message]
2014-11-27  0:33 ` Linus Torvalds
2014-11-27  1:37   ` Sasha Levin
2014-11-27  3:13     ` Linus Torvalds
2014-11-29 15:07       ` Sasha Levin
2014-11-29 18:08         ` Linus Torvalds
2014-11-30  3:47           ` Sasha Levin

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