From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Thu, 20 Dec 2018 06:13:06 +0000 (-0800)
Subject: bpf: verifier: reorder stack size check with dead code sanitization
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=9b38c4056b2736bb5902e8b0911832db666fd19b;p=android-x86%2Fkernel.git

bpf: verifier: reorder stack size check with dead code sanitization

Reorder the calls to check_max_stack_depth() and sanitize_dead_code()
to separate functions which can rewrite instructions from pure checks.

No functional changes.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 98ed27bbd045..d27d5a880015 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6983,10 +6983,11 @@ skip_full_check:
 	free_states(env);
 
 	if (ret == 0)
-		sanitize_dead_code(env);
+		ret = check_max_stack_depth(env);
 
+	/* instruction rewrites happen after this point */
 	if (ret == 0)
-		ret = check_max_stack_depth(env);
+		sanitize_dead_code(env);
 
 	if (ret == 0)
 		/* program is valid, convert *(u32*)(ctx + off) accesses */