lkml.org 
[lkml]   [2017]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 net-next 10/12] selftests/bpf: don't try to access past MAX_PACKET_OFF in test_verifier
Date
"direct packet access: test2" was potentially reading four bytes from
pkt + 0xffff, which could take it past the verifier's limit, causing
the program to be rejected.
Increase the shifts by one so that R2 is now mask 0x7fff instead of
mask 0xffff.

Signed-off-by: Edward Cree <ecree@solarflare.com>
---
tools/testing/selftests/bpf/test_verifier.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 210a031..7df3c34 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2330,8 +2330,8 @@ static struct bpf_test tests[] = {
offsetof(struct __sk_buff, data)),
BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_4),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
- BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 48),
- BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 48),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 49),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 49),
BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_2),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_3),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 8),
\
 
 \ /
  Last update: 2017-06-27 15:01    [W:0.278 / U:0.608 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site