[PATCH 4.9 062/130] bpf, s390: fix potential memleak when later bpf_jit_prog fails

From: Greg Kroah-Hartman
Date: Thu Aug 23 2018 - 04:09:06 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

[ Upstream commit f605ce5eb26ac934fb8106d75d46a2c875a2bf23 ]

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@xxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
arch/s390/net/bpf_jit_comp.c | 1 +
1 file changed, 1 insertion(+)

--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -1386,6 +1386,7 @@ struct bpf_prog *bpf_int_jit_compile(str
goto free_addrs;
if (bpf_jit_prog(&jit, fp)) {
+ bpf_jit_binary_free(header);
fp = orig_fp;
goto free_addrs;