CVE-2021-47249

In the Linux kernel, the following vulnerability has been resolved: net: rds: fix memory leak in rds_recvmsg Syzbot reported memory leak in rds. The problem was in unputted refcount in case of error. int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int msg_flags) { ... if (!rds_next_incoming(rs, &inc)) { ... } After this "if" inc refcount incremented and if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; goto out; } ... out: return ret; } in case of rds_cmsg_recv() fail the refcount won't be decremented. And it's easy to see from ftrace log, that rds_inc_addref() don't have rds_inc_put() pair in rds_recvmsg() after rds_cmsg_recv() 1) | rds_recvmsg() { 1) 3.721 us | rds_inc_addref(); 1) 3.853 us | rds_message_inc_copy_to_user(); 1) + 10.395 us | rds_cmsg_recv(); 1) + 34.260 us | }

• linux linux kernel (>= 2.6.30 < 4.4.274) • linux linux kernel (>= 4.5 < 4.9.274) • linux linux kernel (>= 4.10 < 4.14.238) • linux linux kernel (>= 4.15 < 4.19.196) • linux linux kernel (>= 4.20 < 5.4.128) • linux linux kernel (>= 5.5 < 5.10.46) • linux linux kernel (>= 5.11 < 5.12.13) • linux linux kernel 5.13