From 2cdbc339317e5f7949dbef06e8c8239cb1aa8014 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 8 May 2021 16:44:02 +0800 Subject: [PATCH] bpf: Move sanitize_val_alu out of op switch mainline inclusion from mainline-v5.12-rc8 commit f528819334881fd622fdadeddb3f7edaed8b7c9b category: bugfix bugzilla: NA CVE: CVE-2021-29155 -------------------------------- Add a small sanitize_needed() helper function and move sanitize_val_alu() out of the main opcode switch. In upcoming work, we'll move sanitize_ptr_alu() as well out of its opcode switch so this helps to streamline both. Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Acked-by: Alexei Starovoitov Conflicts: kernel/bpf/verifier.c Signed-off-by: Yang Yingliang Reviewed-by: Kuohai Xu Reviewed-by: Xiu Jianfeng Signed-off-by: Yang Yingliang --- kernel/bpf/verifier.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f293bc3c61e7..93c3246daa4c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2815,6 +2815,11 @@ static int sanitize_val_alu(struct bpf_verifier_env *env, return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0); } +static bool sanitize_needed(u8 opcode) +{ + return opcode == BPF_ADD || opcode == BPF_SUB; +} + static int sanitize_ptr_alu(struct bpf_verifier_env *env, struct bpf_insn *insn, const struct bpf_reg_state *ptr_reg, @@ -3238,11 +3243,14 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, return 0; } - switch (opcode) { - case BPF_ADD: + if (sanitize_needed(opcode)) { ret = sanitize_val_alu(env, insn); if (ret < 0) return sanitize_err(env, insn, ret, NULL, NULL); + } + + switch (opcode) { + case BPF_ADD: if (signed_add_overflows(dst_reg->smin_value, smin_val) || signed_add_overflows(dst_reg->smax_value, smax_val)) { dst_reg->smin_value = S64_MIN; @@ -3262,9 +3270,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); break; case BPF_SUB: - ret = sanitize_val_alu(env, insn); - if (ret < 0) - return sanitize_err(env, insn, ret, NULL, NULL); if (signed_sub_overflows(dst_reg->smin_value, smax_val) || signed_sub_overflows(dst_reg->smax_value, smin_val)) { /* Overflow possible, we know nothing */ -- GitLab