The patch titled
drivers/char/agp/generic.c: fix arbitrary kernel memory writes
has been added to the -mm tree. Its filename is
drivers-char-agp-genericc-fix-arbitrary-kernel-memory-writes.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: drivers/char/agp/generic.c: fix arbitrary kernel memory writes
From: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/agp/generic.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff -puN drivers/char/agp/generic.c~drivers-char-agp-genericc-fix-arbitrary-kernel-memory-writes drivers/char/agp/generic.c
--- a/drivers/char/agp/generic.c~drivers-char-agp-genericc-fix-arbitrary-kernel-memory-writes
+++ a/drivers/char/agp/generic.c
@@ -1089,8 +1089,8 @@ 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;
@@ -1124,7 +1124,7 @@ 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)
@@ -1136,6 +1136,11 @@ 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 */
_
Patches currently in -mm which might be from segoon@xxxxxxxxxxxx are
drivers-char-agp-genericc-fix-arbitrary-kernel-memory-writes.patch
arch-arm-mach-ux500-mbox-db5500c-world-writable-sysfs-fifo-file.patch
aic94xx-world-writable-sysfs-update_bios-file.patch
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