[PATCH 4.14 130/156] staging: ccree: NULLify backup_info when unused

From: Greg Kroah-Hartman
Date: Fri Feb 02 2018 - 12:22:05 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>

commit 46df8824982e4fb0198776078d4a8c3e2d531464 upstream.

backup_info field is only allocated for decrypt code path.
The field was not nullified when not used causing a kfree
in an error handling path to attempt to free random
addresses as uncovered in stress testing.

Fixes: 737aed947f9b ("staging: ccree: save ciphertext for CTS IV")
Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/staging/ccree/ssi_cipher.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/staging/ccree/ssi_cipher.c
+++ b/drivers/staging/ccree/ssi_cipher.c
@@ -904,6 +904,7 @@ static int ssi_ablkcipher_decrypt(struct
scatterwalk_map_and_copy(req_ctx->backup_info, req->src,
(req->nbytes - ivsize), ivsize, 0);
req_ctx->is_giv = false;
+ req_ctx->backup_info = NULL;

return ssi_blkcipher_process(tfm, req_ctx, req->dst, req->src, req->nbytes, req->info, ivsize, (void *)req, DRV_CRYPTO_DIRECTION_DECRYPT);
}