9p/net: fix possible memory leak in p9_check_errors()

[ Upstream commit ce07087964208eee2ca2f9ee4a98f8b5d9027fe6 ]

When p9pdu_readf() is called with "s?d" attribute, it allocates a pointer
that will store a string. But when p9pdu_readf() fails while handling "d"
then this pointer will not be freed in p9_check_errors().

Fixes: 51a87c552dfd ("9p: rework client code to use new protocol support functions")
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Message-ID: <20231027030302.11927-1-hbh25y@gmail.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/9p/client.c b/net/9p/client.c
index af59c3f..a96e127 100644 (file)
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -537,12 +537,14 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
                return 0;
 
        if (!p9_is_proto_dotl(c)) {
-               char *ename;
+               char *ename = NULL;
 
                err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
                                  &ename, &ecode);
-               if (err)
+               if (err) {
+                       kfree(ename);
                        goto out_err;
+               }
 
                if (p9_is_proto_dotu(c) && ecode < 512)
                        err = -ecode;