From 3aab8884c9eb99189a3569ac4e6b205371c9ac0b Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 2 May 2018 20:12:22 +0200 Subject: [PATCH 1/2] bpf, x64: fix memleak when not converging after image While reviewing x64 JIT code, I noticed that we leak the prior allocated JIT image in the case where proglen != oldproglen during the JIT passes. Prior to the commit e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") we would just break out of the loop, and using the image as the JITed prog since it could only shrink in size anyway. After e0ee9c12157d, we would bail out to out_addrs label where we free addrs and jit_data but not the image coming from bpf_jit_binary_alloc(). Fixes: e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: David S. Miller Signed-off-by: Alexei Starovoitov --- arch/x86/net/bpf_jit_comp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index abce27ceb411..9ae7b9372348 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1236,6 +1236,7 @@ skip_init_addrs: for (pass = 0; pass < 20 || image; pass++) { proglen = do_jit(prog, addrs, image, oldproglen, &ctx); if (proglen <= 0) { +out_image: image = NULL; if (header) bpf_jit_binary_free(header); @@ -1246,8 +1247,7 @@ skip_init_addrs: if (proglen != oldproglen) { pr_err("bpf_jit: proglen=%d != oldproglen=%d\n", proglen, oldproglen); - prog = orig_prog; - goto out_addrs; + goto out_image; } break; } From 39f56ca945af86112753646316c4c92dcd4acd82 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 2 May 2018 20:12:23 +0200 Subject: [PATCH 2/2] bpf, x64: fix memleak when not converging on calls The JIT logic in jit_subprogs() is as follows: for all subprogs we allocate a bpf_prog_alloc(), populate it (prog->is_func = 1 here), and pass it to bpf_int_jit_compile(). If a failure occurred during JIT and prog->jited is not set, then we bail out from attempting to JIT the whole program, and punt to the interpreter instead. In case JITing went successful, we fixup BPF call offsets and do another pass to bpf_int_jit_compile() (extra_pass is true at that point) to complete JITing calls. Given that requires to pass JIT context around addrs and jit_data from x86 JIT are freed in the extra_pass in bpf_int_jit_compile() when calls are involved (if not, they can be freed immediately). However, if in the original pass, the JIT image didn't converge then we leak addrs and jit_data since image itself is NULL, the prog->is_func is set and extra_pass is false in that case, meaning both will become unreachable and are never cleaned up, therefore we need to free as well on !image. Only x64 JIT is affected. Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: David S. Miller Signed-off-by: Alexei Starovoitov --- arch/x86/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 9ae7b9372348..263c8453815e 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1283,7 +1283,7 @@ out_image: prog = orig_prog; } - if (!prog->is_func || extra_pass) { + if (!image || !prog->is_func || extra_pass) { out_addrs: kfree(addrs); kfree(jit_data);