crypto: af_alg - limit RX SG extraction by receive buffer budget

[ Upstream commit 8eceab19eba9dcbfd2a0daec72e1bf48aa100170 ]

Make af_alg_get_rsgl() limit each RX scatterlist extraction to the
remaining receive buffer budget.

af_alg_get_rsgl() currently uses af_alg_readable() only as a gate
before extracting data into the RX scatterlist. Limit each extraction
to the remaining af_alg_rcvbuf(sk) budget so that receive-side
accounting matches the amount of data attached to the request.

If skcipher cannot obtain enough RX space for at least one chunk while
more data remains to be processed, reject the recvmsg call instead of
rounding the request length down to zero.

Fixes: e870456d8e7c8d57c059ea479b5aadbb55ff4c3a ("crypto: algif_skcipher - overhaul memory management")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Douya Le <ldy3087146292@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index bc78c915eabc4ad2520ada97ed47a269b1ef67b0..7373f7dd8f41705497b3862e593d89792ff5931e 100644 (file)
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1229,6 +1229,8 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 
                seglen = min_t(size_t, (maxsize - len),
                               msg_data_left(msg));
+               /* Never pin more pages than the remaining RX accounting budget. */
+               seglen = min_t(size_t, seglen, af_alg_rcvbuf(sk));
 
                if (list_empty(&areq->rsgl_list)) {
                        rsgl = &areq->first_rsgl;

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 82735e51be108dbed0f6e6348ba5c466360eeea2..ba0a17fd95aca22aa58ebf510c7d9b5f0cea2c2e 100644 (file)
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -130,6 +130,11 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
         * full block size buffers.
         */
        if (ctx->more || len < ctx->used) {
+               if (len < bs) {
+                       err = -EINVAL;
+                       goto free;
+               }
+
                len -= len % bs;
                cflags |= CRYPTO_SKCIPHER_REQ_NOTFINAL;
        }