The patch titled
drivers/char/agp/generic.c: fix OOM and buffer overflow
has been added to the -mm tree. Its filename is
drivers-char-agp-genericc-fix-oom-and-buffer-overflow.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: drivers/char/agp/generic.c: fix OOM and buffer overflow
From: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
page_count is copied from userspace. agp_allocate_memory() tries to check
whether this number is too big, but doesn't take into account the wrap
case. Also agp_create_user_memory() doesn't check whether alloc_size is
calculated from num_agp_pages variable without overflow. This may lead to
allocation of too small buffer with following buffer overflow.
Another problem in agp code is not addressed in the patch - kernel memory
exhaustion (AGPIOC_RESERVE and AGPIOC_ALLOCATE ioctls). It is not checked
whether requested pid is a pid of the caller (no check in
agpioc_reserve_wrap()). Each allocation is limited to 16KB, though, there
is no per-process limit. This might lead to OOM situation, which is not
even solved in case of the caller death by OOM killer - the memory is
allocated for another (faked) process.
Signed-off-by: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/agp/generic.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff -puN drivers/char/agp/generic.c~drivers-char-agp-genericc-fix-oom-and-buffer-overflow drivers/char/agp/generic.c
--- a/drivers/char/agp/generic.c~drivers-char-agp-genericc-fix-oom-and-buffer-overflow
+++ a/drivers/char/agp/generic.c
@@ -115,6 +115,9 @@ static struct agp_memory *agp_create_use
struct agp_memory *new;
unsigned long alloc_size = num_agp_pages*sizeof(struct page *);
+ if (INT_MAX/sizeof(struct page *) < num_agp_pages)
+ return NULL;
+
new = kzalloc(sizeof(struct agp_memory), GFP_KERNEL);
if (new == NULL)
return NULL;
@@ -234,11 +237,14 @@ struct agp_memory *agp_allocate_memory(s
int scratch_pages;
struct agp_memory *new;
size_t i;
+ int cur_memory;
if (!bridge)
return NULL;
- if ((atomic_read(&bridge->current_memory_agp) + page_count) > bridge->max_memory_agp)
+ cur_memory = atomic_read(&bridge->current_memory_agp);
+ if ((cur_memory + page_count > bridge->max_memory_agp) ||
+ (cur_memory + page_count < page_count))
return NULL;
if (type >= AGP_USER_TYPES) {
_
Patches currently in -mm which might be from segoon@xxxxxxxxxxxx are
drivers-char-agp-genericc-fix-arbitrary-kernel-memory-writes.patch
drivers-char-agp-genericc-fix-oom-and-buffer-overflow.patch
arch-arm-mach-ux500-mbox-db5500c-world-writable-sysfs-fifo-file.patch
aic94xx-world-writable-sysfs-update_bios-file.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
