[PATCH 2/3] crypto: qce - fix memory leak of the CCM AAD buffer

[ZhaoJinming]

qce_aead_ccm_prepare_buf_assoclen() allocates rctx->adata with kzalloc()
for every CCM request that carries associated data, but the buffer is
never freed: qce_aead_done() releases only the scatterlist tables, and
none of the error paths release it either.  Every such request therefore
leaks a small allocation.

Free rctx->adata in the completion handler and on all error paths: the
sg_copy_to_buffer() and sg_alloc_table() failures in
qce_aead_ccm_prepare_buf_assoclen() (through the new err_free_adata
label) and the error cleanup of qce_aead_async_req_handle().

The buffer is referenced by a scatterlist that is DMA-mapped, so it is
freed only after dma_unmap_sg() has run.  The frees are guarded the same
way as the surrounding sg_free_table() calls, so no path frees the
buffer twice or frees a stale pointer.

Fixes: 9363efb4181c ("crypto: qce - Add support for AEAD algorithms")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: ZhaoJinming <zhaojinming@xxxxxxxxxxxxx>
---
 drivers/crypto/qce/aead.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/qce/aead.c b/drivers/crypto/qce/aead.c
index f8e6054ff15d..5bf59cb9ae9a 100644
--- a/drivers/crypto/qce/aead.c
+++ b/drivers/crypto/qce/aead.c
@@ -53,6 +53,7 @@ static void qce_aead_done(void *data)
 			sg_free_table(&rctx->src_tbl);
 			if (diff_dst)
 				sg_free_table(&rctx->dst_tbl);
+			kfree(rctx->adata);
 		} else {
 			if (!(IS_DECRYPT(rctx->flags) && !diff_dst))
 				sg_free_table(&rctx->dst_tbl);
@@ -220,8 +221,10 @@ qce_aead_ccm_prepare_buf_assoclen(struct aead_request *req)
 	/* Copy the associated data */
 	if (sg_copy_to_buffer(req->src, sg_nents_for_len(req->src, assoclen),
 			      rctx->adata + adata_header_len,
-			      assoclen) != assoclen)
-		return -EINVAL;
+			      assoclen) != assoclen) {
+		ret = -EINVAL;
+		goto err_free_adata;
+	}
 
 	/* Pad associated data to block size */
 	rctx->assoclen = ALIGN(assoclen + adata_header_len, 16);
@@ -236,7 +239,7 @@ qce_aead_ccm_prepare_buf_assoclen(struct aead_request *req)
 	gfp = (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ? GFP_KERNEL : GFP_ATOMIC;
 	ret = sg_alloc_table(&rctx->src_tbl, rctx->src_nents, gfp);
 	if (ret)
-		return ret;
+		goto err_free_adata;
 
 	/* Associated Data */
 	sg_init_one(&rctx->adata_sg, rctx->adata, rctx->assoclen);
@@ -288,6 +291,9 @@ qce_aead_ccm_prepare_buf_assoclen(struct aead_request *req)
 	return 0;
 err_free:
 	sg_free_table(&rctx->src_tbl);
+err_free_adata:
+	kfree(rctx->adata);
+	rctx->adata = NULL;
 	return ret;
 }
 
@@ -486,6 +492,7 @@ qce_aead_async_req_handle(struct crypto_async_request *async_req)
 		sg_free_table(&rctx->src_tbl);
 		if (diff_dst)
 			sg_free_table(&rctx->dst_tbl);
+		kfree(rctx->adata);
 	} else {
 		sg_free_table(&rctx->dst_tbl);
 	}

-- 
2.50.1