samples/bpf: add verifier tests for the helper access to the packet

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>

1 files changed, 110 insertions, 4 deletions

diff --git a/samples/bpf/test_verifier.c b/samples/bpf/test_verifier.c
index fe2fcec98c1f..78c6f131d94f 100644
--- a/samples/bpf/test_verifier.c
+++ b/samples/bpf/test_verifier.c
@@ -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)),
@@ -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,
@@ -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)),
@@ -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)),
@@ -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)