Patch "crypto: xts - Handle EBUSY correctly" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    crypto: xts - Handle EBUSY correctly

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-xts-handle-ebusy-correctly.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 4dd59ec8d76da57a695bdec7205e98eb7bb67e4e
Author: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date:   Sun Jan 22 16:07:37 2023 +0800

    crypto: xts - Handle EBUSY correctly
    
    [ Upstream commit 51c082514c2dedf2711c99d93c196cc4eedceb40 ]
    
    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: 8083b1bf8163 ("crypto: xts - add support for ciphertext stealing")
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/crypto/xts.c b/crypto/xts.c
index 63c85b9e64e08..de6cbcf69bbd6 100644
--- a/crypto/xts.c
+++ b/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;
 		}
 	}