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