[PATCH v4 net-next 09/13] selftests/bpf: don't try to access past MAX_PACKET_OFF in test_verifier
From: Edward Cree via iovisor-dev <hidden>
Date: 2017-08-03 16:15:11
Also in:
lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
A number of selftests fell foul of the changed MAX_PACKET_OFF handling. For instance, "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 (checks against pkt_end didn't give us any reg->range). Increase the shifts by one so that R2 is now mask 0x7fff instead of mask 0xffff. Signed-off-by: Edward Cree <ecree-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org> --- tools/testing/selftests/bpf/test_verifier.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 0691494..876b878 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),
@@ -2710,11 +2710,11 @@ static struct bpf_test tests[] = { BPF_MOV64_IMM(BPF_REG_0, 0xffffffff), BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8), BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8), - BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xffff), + BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0x7fff), BPF_MOV64_REG(BPF_REG_4, BPF_REG_0), BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_2), BPF_MOV64_REG(BPF_REG_5, BPF_REG_4), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 0xffff - 1), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 0x7fff - 1), BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 1), BPF_STX_MEM(BPF_DW, BPF_REG_5, BPF_REG_4, 0), BPF_MOV64_IMM(BPF_REG_0, 0),
@@ -2736,10 +2736,10 @@ static struct bpf_test tests[] = { BPF_MOV64_IMM(BPF_REG_4, 0xffffffff), BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_4, -8), BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8), - BPF_ALU64_IMM(BPF_AND, BPF_REG_4, 0xffff), + BPF_ALU64_IMM(BPF_AND, BPF_REG_4, 0x7fff), BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_2), BPF_MOV64_REG(BPF_REG_5, BPF_REG_4), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 0xffff - 1), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 0x7fff - 1), BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 1), BPF_STX_MEM(BPF_DW, BPF_REG_5, BPF_REG_4, 0), BPF_MOV64_IMM(BPF_REG_0, 0),
@@ -2765,7 +2765,7 @@ static struct bpf_test tests[] = { BPF_MOV64_IMM(BPF_REG_4, 0xffffffff), BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_4, -8), BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8), - BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 48), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 49), BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_2), BPF_MOV64_REG(BPF_REG_0, BPF_REG_4), BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 2),
@@ -2820,7 +2820,7 @@ static struct bpf_test tests[] = { BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4), BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_2), BPF_MOV64_REG(BPF_REG_5, BPF_REG_0), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 0xffff - 1), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 0x7fff - 1), BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1), BPF_STX_MEM(BPF_DW, BPF_REG_5, BPF_REG_0, 0), BPF_MOV64_IMM(BPF_REG_0, 0),