rxrpc: Fix missing error checks for rxkad encryption/decryption failure

Add error checking for failure of crypto_skcipher_en/decrypt() to various
rxkad function as the crypto functions can fail with ENOMEM at least.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Closes: https://sashiko.dev/#/patchset/20260401105614.1696001-10-dhowells@redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jeffrey Altman <jaltman@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/20260408121252.2249051-17-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 0f79d694cb08892652d501ee35969ec9ca2d71b7..eb7f2769d2b1211b8dd6092d766ccffd895e6f33 100644 (file)
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -197,6 +197,7 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
        struct rxrpc_crypt iv;
        __be32 *tmpbuf;
        size_t tmpsize = 4 * sizeof(__be32);
+       int ret;
 
        _enter("");
 
@@ -225,13 +226,13 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
        skcipher_request_set_sync_tfm(req, ci);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
-       crypto_skcipher_encrypt(req);
+       ret = crypto_skcipher_encrypt(req);
        skcipher_request_free(req);
 
        memcpy(&conn->rxkad.csum_iv, tmpbuf + 2, sizeof(conn->rxkad.csum_iv));
        kfree(tmpbuf);
-       _leave(" = 0");
-       return 0;
+       _leave(" = %d", ret);
+       return ret;
 }
 
 /*
@@ -264,6 +265,7 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
        struct scatterlist sg;
        size_t pad;
        u16 check;
+       int ret;
 
        _enter("");
 
@@ -286,11 +288,11 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
        skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
-       crypto_skcipher_encrypt(req);
+       ret = crypto_skcipher_encrypt(req);
        skcipher_request_zero(req);
 
-       _leave(" = 0");
-       return 0;
+       _leave(" = %d", ret);
+       return ret;
 }
 
 /*
@@ -345,7 +347,7 @@ static int rxkad_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
        union {
                __be32 buf[2];
        } crypto __aligned(8);
-       u32 x, y;
+       u32 x, y = 0;
        int ret;
 
        _enter("{%d{%x}},{#%u},%u,",
@@ -376,8 +378,10 @@ static int rxkad_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
        skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
-       crypto_skcipher_encrypt(req);
+       ret = crypto_skcipher_encrypt(req);
        skcipher_request_zero(req);
+       if (ret < 0)
+               goto out;
 
        y = ntohl(crypto.buf[1]);
        y = (y >> 16) & 0xffff;
@@ -413,6 +417,7 @@ static int rxkad_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
                memset(p + txb->pkt_len, 0, gap);
        }
 
+out:
        skcipher_request_free(req);
        _leave(" = %d [set %x]", ret, y);
        return ret;
@@ -453,8 +458,10 @@ static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
        skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
-       crypto_skcipher_decrypt(req);
+       ret = crypto_skcipher_decrypt(req);
        skcipher_request_zero(req);
+       if (ret < 0)
+               return ret;
 
        /* Extract the decrypted packet length */
        if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
@@ -531,10 +538,14 @@ static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
        skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, sg, sg, sp->len, iv.x);
-       crypto_skcipher_decrypt(req);
+       ret = crypto_skcipher_decrypt(req);
        skcipher_request_zero(req);
        if (sg != _sg)
                kfree(sg);
+       if (ret < 0) {
+               WARN_ON_ONCE(ret != -ENOMEM);
+               return ret;
+       }
 
        /* Extract the decrypted packet length */
        if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
@@ -602,8 +613,10 @@ static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
        skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
-       crypto_skcipher_encrypt(req);
+       ret = crypto_skcipher_encrypt(req);
        skcipher_request_zero(req);
+       if (ret < 0)
+               goto out;
 
        y = ntohl(crypto.buf[1]);
        cksum = (y >> 16) & 0xffff;
@@ -1077,21 +1090,23 @@ static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
 /*
  * decrypt the response packet
  */
-static void rxkad_decrypt_response(struct rxrpc_connection *conn,
-                                  struct rxkad_response *resp,
-                                  const struct rxrpc_crypt *session_key)
+static int rxkad_decrypt_response(struct rxrpc_connection *conn,
+                                 struct rxkad_response *resp,
+                                 const struct rxrpc_crypt *session_key)
 {
        struct skcipher_request *req = rxkad_ci_req;
        struct scatterlist sg[1];
        struct rxrpc_crypt iv;
+       int ret;
 
        _enter(",,%08x%08x",
               ntohl(session_key->n[0]), ntohl(session_key->n[1]));
 
        mutex_lock(&rxkad_ci_mutex);
-       if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
-                                       sizeof(*session_key)) < 0)
-               BUG();
+       ret = crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
+                                         sizeof(*session_key));
+       if (ret < 0)
+               goto unlock;
 
        memcpy(&iv, session_key, sizeof(iv));
 
@@ -1100,12 +1115,14 @@ static void rxkad_decrypt_response(struct rxrpc_connection *conn,
        skcipher_request_set_sync_tfm(req, rxkad_ci);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
-       crypto_skcipher_decrypt(req);
+       ret = crypto_skcipher_decrypt(req);
        skcipher_request_zero(req);
 
+unlock:
        mutex_unlock(&rxkad_ci_mutex);
 
        _leave("");
+       return ret;
 }
 
 /*
@@ -1198,7 +1215,9 @@ static int rxkad_verify_response(struct rxrpc_connection *conn,
 
        /* use the session key from inside the ticket to decrypt the
         * response */
-       rxkad_decrypt_response(conn, response, &session_key);
+       ret = rxkad_decrypt_response(conn, response, &session_key);
+       if (ret < 0)
+               goto temporary_error_free_ticket;
 
        if (ntohl(response->encrypted.epoch) != conn->proto.epoch ||
            ntohl(response->encrypted.cid) != conn->proto.cid ||