bpf, s390: fix potential memleak when later bpf_jit_prog fails

If we would ever fail in the bpf_jit_prog() pass that writes the
actual insns to the image after we got header via bpf_jit_binary_alloc()
then we also need to make sure to free it through bpf_jit_binary_free()
again when bailing out. Given we had prior bpf_jit_prog() passes to
initially probe for clobbered registers, program size and to fill in
addrs arrray for jump targets, this is more of a theoretical one,
but at least make sure this doesn't break with future changes.

Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index d2db8acb1a55480895e38fdf142c3d074610230d..5f0234ec8038eb2d11e93b190f3f35e29f29207b 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -1286,6 +1286,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
                goto free_addrs;
        }
        if (bpf_jit_prog(&jit, fp)) {
+               bpf_jit_binary_free(header);
                fp = orig_fp;
                goto free_addrs;
        }