From d3bd7413e0ca40b60cf60d4003246d067cafdeda Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sun, 6 Jan 2019 00:54:37 +0100 Subject: bpf: fix sanitation of alu op with pointer / scalar type from different paths While 979d63d50c0c ("bpf: prevent out of bounds speculation on pointer arithmetic") took care of rejecting alu op on pointer when e.g. pointer came from two different map values with different map properties such as value size, Jann reported that a case was not covered yet when a given alu op is used in both "ptr_reg += reg" and "numeric_reg += reg" from different branches where we would incorrectly try to sanitize based on the pointer's limit. Catch this corner case and reject the program instead. Fixes: 979d63d50c0c ("bpf: prevent out of bounds speculation on pointer arithmetic") Reported-by: Jann Horn Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov --- include/linux/bpf_verifier.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/bpf_verifier.h') diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 27b74947cd2b..573cca00a0e6 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -172,6 +172,7 @@ struct bpf_verifier_state_list { #define BPF_ALU_SANITIZE_SRC 1U #define BPF_ALU_SANITIZE_DST 2U #define BPF_ALU_NEG_VALUE (1U << 2) +#define BPF_ALU_NON_POINTER (1U << 3) #define BPF_ALU_SANITIZE (BPF_ALU_SANITIZE_SRC | \ BPF_ALU_SANITIZE_DST) -- cgit