This is a note to let you know that I've just added the patch titled
crypto: n2 - cure use after free
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
crypto-n2-cure-use-after-free.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 203f45003a3d03eea8fa28d74cfc74c354416fdb Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@xxxxxxx>
Date: Tue, 19 Dec 2017 19:09:07 +0100
Subject: crypto: n2 - cure use after free
From: Jan Engelhardt <jengelh@xxxxxxx>
commit 203f45003a3d03eea8fa28d74cfc74c354416fdb upstream.
queue_cache_init is first called for the Control Word Queue
(n2_crypto_probe). At that time, queue_cache[0] is NULL and a new
kmem_cache will be allocated. If the subsequent n2_register_algs call
fails, the kmem_cache will be released in queue_cache_destroy, but
queue_cache_init[0] is not set back to NULL.
So when the Module Arithmetic Unit gets probed next (n2_mau_probe),
queue_cache_init will not allocate a kmem_cache again, but leave it
as its bogus value, causing a BUG() to trigger when queue_cache[0] is
eventually passed to kmem_cache_zalloc:
n2_crypto: Found N2CP at /virtual-devices@100/n2cp@7
n2_crypto: Registered NCS HVAPI version 2.0
called queue_cache_init
n2_crypto: md5 alg registration failed
n2cp f028687c: /virtual-devices@100/n2cp@7: Unable to register algorithms.
called queue_cache_destroy
n2cp: probe of f028687c failed with error -22
n2_crypto: Found NCP at /virtual-devices@100/ncp@6
n2_crypto: Registered NCS HVAPI version 2.0
called queue_cache_init
kernel BUG at mm/slab.c:2993!
Call Trace:
[0000000000604488] kmem_cache_alloc+0x1a8/0x1e0
(inlined) kmem_cache_zalloc
(inlined) new_queue
(inlined) spu_queue_setup
(inlined) handle_exec_unit
[0000000010c61eb4] spu_mdesc_scan+0x1f4/0x460 [n2_crypto]
[0000000010c62b80] n2_mau_probe+0x100/0x220 [n2_crypto]
[000000000084b174] platform_drv_probe+0x34/0xc0
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxx>
Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/crypto/n2_core.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/crypto/n2_core.c
+++ b/drivers/crypto/n2_core.c
@@ -1641,6 +1641,7 @@ static int queue_cache_init(void)
CWQ_ENTRY_SIZE, 0, NULL);
if (!queue_cache[HV_NCS_QTYPE_CWQ - 1]) {
kmem_cache_destroy(queue_cache[HV_NCS_QTYPE_MAU - 1]);
+ queue_cache[HV_NCS_QTYPE_MAU - 1] = NULL;
return -ENOMEM;
}
return 0;
@@ -1650,6 +1651,8 @@ static void queue_cache_destroy(void)
{
kmem_cache_destroy(queue_cache[HV_NCS_QTYPE_MAU - 1]);
kmem_cache_destroy(queue_cache[HV_NCS_QTYPE_CWQ - 1]);
+ queue_cache[HV_NCS_QTYPE_MAU - 1] = NULL;
+ queue_cache[HV_NCS_QTYPE_CWQ - 1] = NULL;
}
static int spu_queue_register(struct spu_queue *p, unsigned long q_type)
Patches currently in stable-queue which might be from jengelh@xxxxxxx are
queue-4.4/crypto-n2-cure-use-after-free.patch