[PATCH 4.19 095/205] crypto: hisilicon - Fix reference after free of memories on error path

Greg Kroah-Hartman
2018-11-19T16:34:22Z

From: John Garry <john.garry@huawei.com>

commit 0b0cf6af3f3151c26c27e8e51def5527091c3e69 upstream.

coccicheck currently warns of the following issues in the driver:
drivers/crypto/hisilicon/sec/sec_algs.c:864:51-66: ERROR: reference preceded by free on line 812
drivers/crypto/hisilicon/sec/sec_algs.c:864:40-49: ERROR: reference preceded by free on line 813
drivers/crypto/hisilicon/sec/sec_algs.c:861:8-24: ERROR: reference preceded by free on line 814
drivers/crypto/hisilicon/sec/sec_algs.c:860:41-51: ERROR: reference preceded by free on line 815
drivers/crypto/hisilicon/sec/sec_algs.c:867:7-18: ERROR: reference preceded by free on line 816

It would appear than on certain error paths that we may attempt reference-
after-free some memories.

This patch fixes those issues. The solution doesn't look perfect, but
having same memories free'd possibly from separate functions makes it
tricky.

Fixes: 915e4e8413da ("crypto: hisilicon - SEC security accelerator driver")
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/crypto/hisilicon/sec/sec_algs.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

--- a/drivers/crypto/hisilicon/sec/sec_algs.c
+++ b/drivers/crypto/hisilicon/sec/sec_algs.c
@@ -808,13 +808,6 @@ static int sec_alg_skcipher_crypto(struc
* more refined but this is unlikely to happen so no need.
*/

- /* Cleanup - all elements in pointer arrays have been coppied */
- kfree(splits_in_nents);
- kfree(splits_in);
- kfree(splits_out_nents);
- kfree(splits_out);
- kfree(split_sizes);
-
/* Grab a big lock for a long time to avoid concurrency issues */
mutex_lock(&queue->queuelock);

@@ -829,13 +822,13 @@ static int sec_alg_skcipher_crypto(struc
(!queue->havesoftqueue ||
kfifo_avail(&queue->softqueue) > steps)) ||
!list_empty(&ctx->backlog)) {
+ ret = -EBUSY;
if ((skreq->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)) {
list_add_tail(&sec_req->backlog_head, &ctx->backlog);
mutex_unlock(&queue->queuelock);
- return -EBUSY;
+ goto out;
}

- ret = -EBUSY;
mutex_unlock(&queue->queuelock);
goto err_free_elements;
}
@@ -844,7 +837,15 @@ static int sec_alg_skcipher_crypto(struc
if (ret)
goto err_free_elements;

- return -EINPROGRESS;
+ ret = -EINPROGRESS;
+out:
+ /* Cleanup - all elements in pointer arrays have been copied */
+ kfree(splits_in_nents);
+ kfree(splits_in);
+ kfree(splits_out_nents);
+ kfree(splits_out);
+ kfree(split_sizes);
+ return ret;

err_free_elements:
list_for_each_entry_safe(el, temp, &sec_req->elements, head) {