From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Slaby Subject: [PATCH 4.4-stable 5/6] bpf: adjust insn_aux_data when patching insns Date: Fri, 12 Jan 2018 17:17:20 +0100 Message-ID: <20180112161721.8843-6-jslaby@suse.cz> References: <20180112161721.8843-1-jslaby@suse.cz> Cc: stable@vger.kernel.org, ast@kernel.org, netdev@vger.kernel.org, Alexei Starovoitov , "David S . Miller" , Jiri Slaby To: gregkh@linuxfoundation.org Return-path: Received: from mx2.suse.de ([195.135.220.15]:42980 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934101AbeALQR0 (ORCPT ); Fri, 12 Jan 2018 11:17:26 -0500 In-Reply-To: <20180112161721.8843-1-jslaby@suse.cz> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexei Starovoitov commit 8041902dae5299c1f194ba42d14383f734631009 upstream. convert_ctx_accesses() replaces single bpf instruction with a set of instructions. Adjust corresponding insn_aux_data while patching. It's needed to make sure subsequent 'for(all insn)' loops have matching insn and insn_aux_data. Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby --- kernel/bpf/verifier.c | 40 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 37 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 47bb3eee950c..bb4b5405d1a5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2107,6 +2107,41 @@ static void convert_pseudo_ld_imm64(struct verifier_env *env) insn->src_reg = 0; } +/* single env->prog->insni[off] instruction was replaced with the range + * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying + * [0, off) and [off, end) to new locations, so the patched range stays zero + */ +static int adjust_insn_aux_data(struct verifier_env *env, u32 prog_len, + u32 off, u32 cnt) +{ + struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; + + if (cnt == 1) + return 0; + new_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog_len); + if (!new_data) + return -ENOMEM; + memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); + memcpy(new_data + off + cnt - 1, old_data + off, + sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); + env->insn_aux_data = new_data; + vfree(old_data); + return 0; +} + +static struct bpf_prog *bpf_patch_insn_data(struct verifier_env *env, u32 off, + const struct bpf_insn *patch, u32 len) +{ + struct bpf_prog *new_prog; + + new_prog = bpf_patch_insn_single(env->prog, off, patch, len); + if (!new_prog) + return NULL; + if (adjust_insn_aux_data(env, new_prog->len, off, len)) + return NULL; + return new_prog; +} + /* convert load instructions that access fields of 'struct __sk_buff' * into sequence of instructions that access fields of 'struct sk_buff' */ @@ -2132,7 +2167,7 @@ static int convert_ctx_accesses(struct verifier_env *env) else continue; - if (env->insn_aux_data[i].ptr_type != PTR_TO_CTX) + if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX) continue; cnt = env->prog->aux->ops-> @@ -2143,8 +2178,7 @@ static int convert_ctx_accesses(struct verifier_env *env) return -EINVAL; } - new_prog = bpf_patch_insn_single(env->prog, i + delta, insn_buf, - cnt); + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM; -- 2.15.1