[ 3.5.y.z extended stable ] Patch "tg3: fix length overflow in VPD firmware parsing" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    tg3: fix length overflow in VPD firmware parsing

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From e3e70af5fb101e46bb9b9c60df61d5c47048477f Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook at chromium.org>
Date: Wed, 27 Mar 2013 06:40:50 +0000
Subject: [PATCH] tg3: fix length overflow in VPD firmware parsing

commit 715230a44310a8cf66fbfb5a46f9a62a9b2de424 upstream.

Commit 184b89044fb6e2a74611dafa69b1dce0d98612c6 ("tg3: Use VPD fw version
when present") introduced VPD parsing that contained a potential length
overflow.

Limit the hardware's reported firmware string length (max 255 bytes) to
stay inside the driver's firmware string length (32 bytes). On overflow,
truncate the formatted firmware string instead of potentially overwriting
portions of the tg3 struct.

http://cansecwest.com/slides/2013/PrivateCore%20CSW%202013.pdf

Signed-off-by: Kees Cook <keescook at chromium.org>
Reported-by: Oded Horovitz <oded at privatecore.com>
Reported-by: Brad Spengler <spender at grsecurity.net>
Cc: Matt Carlson <mcarlson at broadcom.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/broadcom/tg3.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index ca3be73..c2450f4 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -13617,8 +13617,11 @@ static void __devinit tg3_read_vpd(struct tg3 *tp)
 		if (j + len > block_end)
 			goto partno;

-		memcpy(tp->fw_ver, &vpd_data[j], len);
-		strncat(tp->fw_ver, " bc ", vpdlen - len - 1);
+		if (len >= sizeof(tp->fw_ver))
+			len = sizeof(tp->fw_ver) - 1;
+		memset(tp->fw_ver, 0, sizeof(tp->fw_ver));
+		snprintf(tp->fw_ver, sizeof(tp->fw_ver), "%.*s bc ", len,
+			 &vpd_data[j]);
 	}

 partno:
--
1.8.1.2