crypto: xts - Handle EBUSY correctly

JIRA: https://issues.redhat.com/browse/RHEL-119237
CVE: CVE-2023-53494

commit 51c0825
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date:   Sun Jan 22 16:07:37 2023 +0800

    crypto: xts - Handle EBUSY correctly

    As it is xts only handles the special return value of EINPROGRESS,
    which means that in all other cases it will free data related to the
    request.

    However, as the caller of xts may specify MAY_BACKLOG, we also need
    to expect EBUSY and treat it in the same way.  Otherwise backlogged
    requests will trigger a use-after-free.

    Fixes: 8083b1b ("crypto: xts - add support for ciphertext stealing")
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
    Acked-by: Ard Biesheuvel <ardb@kernel.org>
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: CKI Backport Bot <cki-ci-bot+cki-gitlab-backport-bot@redhat.com>

Author: CKI Backport Bot

crypto/xts.c

@@ -203,12 +203,12 @@ static void xts_encrypt_done(struct crypto_async_request *areq, int err)
 	if (!err) {
 		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
 
-		rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+		rctx->subreq.base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
 		err = xts_xor_tweak_post(req, true);
 
 		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
 			err = xts_cts_final(req, crypto_skcipher_encrypt);
-			if (err == -EINPROGRESS)
+			if (err == -EINPROGRESS || err == -EBUSY)
 				return;
 		}
 	}
@@ -223,12 +223,12 @@ static void xts_decrypt_done(struct crypto_async_request *areq, int err)
 	if (!err) {
 		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
 
-		rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+		rctx->subreq.base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
 		err = xts_xor_tweak_post(req, false);
 
 		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
 			err = xts_cts_final(req, crypto_skcipher_decrypt);
-			if (err == -EINPROGRESS)
+			if (err == -EINPROGRESS || err == -EBUSY)
 				return;
 		}
 	}