From: Daniel Borkmann <daniel@iogearbox.net>
Date: Tue, 23 Mar 2021 08:32:59 +0100
Subject: bpf: Use correct permission flag for mixed signed bounds arithmetic
Patch-mainline: v5.12-rc8
Git-commit: 9601148392520e2e134936e76788fc2a6371e7be
References: bsc#1184942 CVE-2021-29155

We forbid adding unknown scalars with mixed signed bounds due to the
spectre v1 masking mitigation. Hence this also needs bypass_spec_v1
flag instead of allow_ptr_leaks.

Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Gary Lin <glin@suse.com>
---
 kernel/bpf/verifier.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5283,7 +5283,7 @@ static int adjust_ptr_min_max_vals(struc
 			dst, reg_type_str[ptr_reg->type]);
 		return -EACCES;
 	case PTR_TO_MAP_VALUE:
-		if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) {
+		if (!env->bypass_spec_v1 && !known && (smin_val < 0) != (smax_val < 0)) {
 			verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n",
 				off_reg == dst_reg ? dst : src);
 			return -EACCES;