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authorJan Engelhardt <jengelh@inai.de>2017-12-19 19:09:07 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-10 09:31:18 +0100
commit491062a0099c8bf6841dece8dd501d9fc2b80e34 (patch)
parent95a362c9a6892085f714eb6e31eea6a0e3aa93bf (diff)
crypto: n2 - cure use after free
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@inai.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/crypto/n2_core.c b/drivers/crypto/n2_core.c
index a9fd8b9e86cd..699ee5a9a8f9 100644
--- a/drivers/crypto/n2_core.c
+++ b/drivers/crypto/n2_core.c
@@ -1625,6 +1625,7 @@ static int queue_cache_init(void)
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;
@@ -1634,6 +1635,8 @@ 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 long spu_queue_register_workfn(void *arg)