From 687f07156b0c99205c21aa4e2986564046d342fe Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 8 Sep 2015 13:40:01 -0700 Subject: [PATCH] bpf: fix out of bounds access in verifier log when the verifier log is enabled the print_bpf_insn() is doing bpf_alu_string[BPF_OP(insn->code) >> 4] and bpf_jmp_string[BPF_OP(insn->code) >> 4] where BPF_OP is a 4-bit instruction opcode. Malformed insns can cause out of bounds access. Fix it by sizing arrays appropriately. The bug was found by clang address sanitizer with libfuzzer. Reported-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ed12e385fb75..b074b23000d6 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -283,7 +283,7 @@ static const char *const bpf_class_string[] = { [BPF_ALU64] = "alu64", }; -static const char *const bpf_alu_string[] = { +static const char *const bpf_alu_string[16] = { [BPF_ADD >> 4] = "+=", [BPF_SUB >> 4] = "-=", [BPF_MUL >> 4] = "*=", @@ -307,7 +307,7 @@ static const char *const bpf_ldst_string[] = { [BPF_DW >> 3] = "u64", }; -static const char *const bpf_jmp_string[] = { +static const char *const bpf_jmp_string[16] = { [BPF_JA >> 4] = "jmp", [BPF_JEQ >> 4] = "==", [BPF_JGT >> 4] = ">", -- 2.11.0