linux-kernel - [023/143] agp: fix arbitrary kernel memory writes

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 linux-cve-announce PHC
Open Source and information security mailing list archives

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

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

Message-Id: <20110506002207.383185601@clark.kroah.org>
Date:	Thu, 05 May 2011 17:20:08 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Vasiliy Kulikov <segoon@...nwall.com>,
	Dave Airlie <airlied@...hat.com>
Subject: [023/143] agp: fix arbitrary kernel memory writes

2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------

From: Vasiliy Kulikov <segoon@...nwall.com>

commit 194b3da873fd334ef183806db751473512af29ce upstream.

pg_start is copied from userspace on AGPIOC_BIND and AGPIOC_UNBIND ioctl
cmds of agp_ioctl() and passed to agpioc_bind_wrap().  As said in the
comment, (pg_start + mem->page_count) may wrap in case of AGPIOC_BIND,
and it is not checked at all in case of AGPIOC_UNBIND.  As a result, user
with sufficient privileges (usually "video" group) may generate either
local DoS or privilege escalation.

Signed-off-by: Vasiliy Kulikov <segoon@...nwall.com>
Signed-off-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/char/agp/generic.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -1123,8 +1123,8 @@ int agp_generic_insert_memory(struct agp
 		return -EINVAL;
 	}
 
-	/* AK: could wrap */
-	if ((pg_start + mem->page_count) > num_entries)
+	if (((pg_start + mem->page_count) > num_entries) ||
+	    ((pg_start + mem->page_count) < pg_start))
 		return -EINVAL;
 
 	j = pg_start;
@@ -1158,7 +1158,7 @@ int agp_generic_remove_memory(struct agp
 {
 	size_t i;
 	struct agp_bridge_data *bridge;
-	int mask_type;
+	int mask_type, num_entries;
 
 	bridge = mem->bridge;
 	if (!bridge)
@@ -1170,6 +1170,11 @@ int agp_generic_remove_memory(struct agp
 	if (type != mem->type)
 		return -EINVAL;
 
+	num_entries = agp_num_entries();
+	if (((pg_start + mem->page_count) > num_entries) ||
+	    ((pg_start + mem->page_count) < pg_start))
+		return -EINVAL;
+
 	mask_type = bridge->driver->agp_type_to_mask_type(bridge, type);
 	if (mask_type != 0) {
 		/* The generic routines know nothing of memory types */


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/