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authorWilliam Tu2017-02-04 08:37:29 -0800
committerDavid S. Miller2017-02-06 22:50:04 -0500
commit63dfef75ed75364901d7caa52c6420cec3e73519 (patch)
tree8c3065d18a1b80da112ec1ee9a1074240cd100ca /tools
parent29200c199cc9bde59033ab30fcc40b6c8ae630b0 (diff)
bpf: enable verifier to add 0 to packet ptr
The patch fixes the case when adding a zero value to the packet pointer. The zero value could come from src_reg equals type BPF_K or CONST_IMM. The patch fixes both, otherwise the verifer reports the following error: [...] R0=imm0,min_value=0,max_value=0 R1=pkt(id=0,off=0,r=4) R2=pkt_end R3=fp-12 R4=imm4,min_value=4,max_value=4 R5=pkt(id=0,off=4,r=4) 269: (bf) r2 = r0 // r2 becomes imm0 270: (77) r2 >>= 3 271: (bf) r4 = r1 // r4 becomes pkt ptr 272: (0f) r4 += r2 // r4 += 0 addition of negative constant to packet pointer is not allowed Signed-off-by: William Tu <u9012063@gmail.com> Signed-off-by: Mihai Budiu <mbudiu@vmware.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index df194e1d56c2..71f6407cde60 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2404,6 +2404,29 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
+ "direct packet access: test14 (pkt_ptr += 0, CONST_IMM, good access)",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct __sk_buff, data)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+ offsetof(struct __sk_buff, data_end)),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 22),
+ BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 7),
+ BPF_MOV64_IMM(BPF_REG_5, 12),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_5, 4),
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_2),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_5),
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_6, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
"helper access to packet: test1, valid packet_ptr range",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,