Re: [PATCH] crypto: mxs-dcp: handle zero-length skcipher requests
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From: Frank Li <hidden>
Date: 2026-08-28 19:25:33
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imx, linux-crypto, lkml
On Fri, Aug 28, 2026 at 05:32:09PM +0800, Linmao Li wrote:
[You don't often get email from lilinmao@kylinos.cn. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] Zero-length skcipher requests are valid no-ops, but MXS-DCP queues them.
Any document show it? if return 0 when cryptelen, it is async, no call crypto_request_complete. Frank
quoted hunk ↗ jump to hunk
When such a request reaches the worker, last_out_len remains zero. The CBC completion path then subtracts AES_BLOCK_SIZE from this unsigned value when updating the IV, causing the offset to underflow. On decryption, the resulting source address precedes aes_in_buf. Return success before enqueueing zero-length requests. This avoids the invalid source access and leaves the IV unchanged for a no-op. Fixes: fadd7a6e616b ("crypto: mxs-dcp - Fix AES issues") Signed-off-by: Linmao Li <redacted> --- drivers/crypto/mxs-dcp.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c index 133ebc998236..60794b4d49fa 100644 --- a/drivers/crypto/mxs-dcp.c +++ b/drivers/crypto/mxs-dcp.c@@ -473,6 +473,9 @@ static int mxs_dcp_aes_enqueue(struct skcipher_request *req, int enc, int ecb) struct dcp_aes_req_ctx *rctx = skcipher_request_ctx(req); int ret; + if (!req->cryptlen) + return 0; + if (unlikely(actx->key_len != AES_KEYSIZE_128 && !actx->key_referenced)) return mxs_dcp_block_fallback(req, enc);base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f -- 2.25.1