[PATCH v2 4/7] crypto: qce - do not free an uninitialized dst_tbl on the error path

[ZhaoJinming]

qce_aead_async_req_handle() jumps to error_free when mapping or starting
a request fails.  For a CCM request without associated data that is
decrypted in place, qce_aead_ccm_prepare_buf() does not allocate
rctx->dst_tbl, so the else branch of error_free releases an uninitialized
sg_table:

	} else {
		sg_free_table(&rctx->dst_tbl);
	}

The request context comes from aead_request_alloc(), which uses
kmalloc(), so this can pass a garbage sgl pointer to sg_free_table() and
crash the kernel.

qce_aead_done() already skips this case with
!(IS_DECRYPT(rctx->flags) && !diff_dst).  Apply the same check to the
error path so the uninitialized table is not freed.

Fixes: 9363efb4181c ("crypto: qce - Add support for AEAD algorithms")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: ZhaoJinming <zhaojinming@xxxxxxxxxxxxx>
---
 drivers/crypto/qce/aead.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/qce/aead.c b/drivers/crypto/qce/aead.c
index 15ce778f019a..dd369328c8a6 100644
--- a/drivers/crypto/qce/aead.c
+++ b/drivers/crypto/qce/aead.c
@@ -493,7 +493,7 @@ qce_aead_async_req_handle(struct crypto_async_request *async_req)
 		if (diff_dst)
 			sg_free_table(&rctx->dst_tbl);
 		kfree(rctx->adata);
-	} else {
+	} else if (!(IS_CCM(rctx->flags) && IS_DECRYPT(rctx->flags) && !diff_dst)) {
 		sg_free_table(&rctx->dst_tbl);
 	}
 	return ret;

-- 
2.50.1