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()
| rds_recvmsg() {
git.kernel.org/stable/c/06b7cb0194bd1ede0dd27f3a946e7c0279fba44a
git.kernel.org/stable/c/1f79bc8ae81c05eb112a53f981cb2c244ee50d02
git.kernel.org/stable/c/2038cd15eacdf7512755c27686822e0052eb9042
git.kernel.org/stable/c/423c6939758fb3b9cf5abbd1e7792068a5c4ae8c
git.kernel.org/stable/c/49bfcbfd989a8f1f23e705759a6bb099de2cff9f
git.kernel.org/stable/c/5946fbf48355f5a8caeff72580c7658da5966b86
git.kernel.org/stable/c/8c3ec88b03e9e4ca117dcdc4204fd3edcd02084f
git.kernel.org/stable/c/b25b60d076164edb3025e85aabd2cf50a5215b91