net: bpf: correctly handle errors in sk_attach_filter()

Commit "net: bpf: make eBPF interpreter images read-only" has changed bpf_prog
to be vmalloc()ed but never handled some of the errors paths of the old code.

On error within sk_attach_filter (which userspace can easily trigger), we'd
kfree() the vmalloc()ed memory, and leak the internal bpf_work_struct.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/filter.c b/net/core/filter.c
index 601f28de73112875eb70f3f18873b5c83023efa1..fcd3f6742a6aa192efaf179b0a656377c98c31ce 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1047,7 +1047,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
                return -ENOMEM;
 
        if (copy_from_user(prog->insns, fprog->filter, fsize)) {
-               kfree(prog);
+               __bpf_prog_free(prog);
                return -EFAULT;
        }
 
@@ -1055,7 +1055,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
 
        err = bpf_prog_store_orig_filter(prog, fprog);
        if (err) {
-               kfree(prog);
+               __bpf_prog_free(prog);
                return -ENOMEM;
        }