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samples/bpf: add verifier tests for the helper access to the packet
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test various corner cases of the helper function access to the packet
via crafted XDP programs.

Signed-off-by: Aaron Yue <haoxuany@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Aaron Yue authored and David S. Miller committed Aug 13, 2016
1 parent 6841de8 commit 1633ac0
Showing 1 changed file with 110 additions and 4 deletions.
114 changes: 110 additions & 4 deletions samples/bpf/test_verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1449,7 +1449,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"pkt: test1",
"direct packet access: test1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
Expand All @@ -1466,7 +1466,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"pkt: test2",
"direct packet access: test2",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
Expand Down Expand Up @@ -1499,7 +1499,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"pkt: test3",
"direct packet access: test3",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
Expand All @@ -1511,7 +1511,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
},
{
"pkt: test4",
"direct packet access: test4",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
Expand All @@ -1528,6 +1528,112 @@ static struct bpf_test tests[] = {
.result = REJECT,
.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,
offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 5),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_2),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_update_elem),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup = {5},
.result_unpriv = ACCEPT,
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"helper access to packet: test2, unchecked packet_ptr",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup = {1},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"helper access to packet: test3, variable add",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 10),
BPF_LDX_MEM(BPF_B, BPF_REG_5, BPF_REG_2, 0),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_5),
BPF_MOV64_REG(BPF_REG_5, BPF_REG_4),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_5, BPF_REG_3, 4),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_4),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup = {11},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"helper access to packet: test4, packet_ptr with bad range",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup = {7},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"helper access to packet: test5, packet_ptr with too short range",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 7),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 3),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup = {6},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
};

static int probe_filter_length(struct bpf_insn *fp)
Expand Down

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