netdev - [PATCH] NET: Fix skb_truesize

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 08 Nov 2007 11:59:19 -0500
From:	Chuck Lever <chuck.lever@...cle.com>
To:	netdev@...r.kernel.org
Subject: [PATCH] NET: Fix skb_truesize_check() assertion

The intent of the assertion in skb_truesize_check() is to check
for skb->truesize being decremented too much by other code,
resulting in a wraparound below zero.

The type of the right side of the comparison causes the compiler to
promote the left side to an unsigned type, despite the presence of an
explicit type cast.  This defeats the check for negativity.

Ensure both sides of the comparison are a signed type to prevent the
implicit type conversion.

Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
---

 include/linux/skbuff.h |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 94e4991..91140fe 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -387,7 +387,9 @@ extern void	      skb_truesize_bug(struct sk_buff *skb);

 static inline void skb_truesize_check(struct sk_buff *skb)
 {
-	if (unlikely((int)skb->truesize < sizeof(struct sk_buff) + skb->len))
+	int len = sizeof(struct sk_buff) + skb->len;
+
+	if (unlikely((int)skb->truesize < len))
 		skb_truesize_bug(skb);
 }

-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html