bpf: add various verifier test cases

This patch adds various verifier test cases:

1) A test case for the pruning issue when tracking alignment
   is used.
2) Various PTR_TO_MAP_VALUE_OR_NULL tests to make sure pointer
   arithmetic turns such register into UNKNOWN_VALUE type.
3) Test cases for the special treatment of LD_ABS/LD_IND to
   make sure verifier doesn't break calling convention here.
   Latter is needed, since f.e. arm64 JIT uses r1 - r5 for
   storing temporary data, so they really must be marked as
   NOT_INIT.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 56197f8..62d948f 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -272,6 +272,16 @@ struct bpf_prog_aux;
                .off   = OFF,                                   \
                .imm   = IMM })
 
+/* Unconditional jumps, goto pc + off16 */
+
+#define BPF_JMP_A(OFF)                                         \
+       ((struct bpf_insn) {                                    \
+               .code  = BPF_JMP | BPF_JA,                      \
+               .dst_reg = 0,                                   \
+               .src_reg = 0,                                   \
+               .off   = OFF,                                   \
+               .imm   = 0 })
+
 /* Function call */
 
 #define BPF_EMIT_CALL(FUNC)                                    \

diff --git a/tools/include/linux/filter.h b/tools/include/linux/filter.h
index 390d7c9..4ce25d4 100644 (file)
--- a/tools/include/linux/filter.h
+++ b/tools/include/linux/filter.h
@@ -208,6 +208,16 @@
                .off   = OFF,                                   \
                .imm   = IMM })
 
+/* Unconditional jumps, goto pc + off16 */
+
+#define BPF_JMP_A(OFF)                                         \
+       ((struct bpf_insn) {                                    \
+               .code  = BPF_JMP | BPF_JA,                      \
+               .dst_reg = 0,                                   \
+               .src_reg = 0,                                   \
+               .off   = OFF,                                   \
+               .imm   = 0 })
+
 /* Function call */
 
 #define BPF_EMIT_CALL(FUNC)                                    \

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 3773562..cabb19b 100644 (file)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -49,6 +49,7 @@
 #define MAX_NR_MAPS    4
 
 #define F_NEEDS_EFFICIENT_UNALIGNED_ACCESS     (1 << 0)
+#define F_LOAD_WITH_STRICT_ALIGNMENT           (1 << 1)
 
 struct bpf_test {
        const char *descr;
@@ -2614,6 +2615,30 @@ static struct bpf_test tests[] = {
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
        },
+       {
+               "direct packet access: test17 (pruning, alignment)",
+               .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_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
+                                   offsetof(struct __sk_buff, mark)),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 14),
+                       BPF_JMP_IMM(BPF_JGT, BPF_REG_7, 1, 4),
+                       BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+                       BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, -4),
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_A(-6),
+               },
+               .errstr = "misaligned packet access off 2+15+-4 size 4",
+               .result = REJECT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+               .flags = F_LOAD_WITH_STRICT_ALIGNMENT,
+       },
        {
                "helper access to packet: test1, valid packet_ptr range",
                .insns = {
@@ -3340,6 +3365,70 @@ static struct bpf_test tests[] = {
                .result = ACCEPT,
                .prog_type = BPF_PROG_TYPE_SCHED_CLS
        },
+       {
+               "alu ops on ptr_to_map_value_or_null, 1",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_1, 10),
+                       BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       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_REG(BPF_REG_4, BPF_REG_0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -2),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 2),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+                       BPF_ST_MEM(BPF_DW, BPF_REG_4, 0, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 4 },
+               .errstr = "R4 invalid mem access",
+               .result = REJECT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS
+       },
+       {
+               "alu ops on ptr_to_map_value_or_null, 2",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_1, 10),
+                       BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       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_REG(BPF_REG_4, BPF_REG_0),
+                       BPF_ALU64_IMM(BPF_AND, BPF_REG_4, -1),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+                       BPF_ST_MEM(BPF_DW, BPF_REG_4, 0, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 4 },
+               .errstr = "R4 invalid mem access",
+               .result = REJECT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS
+       },
+       {
+               "alu ops on ptr_to_map_value_or_null, 3",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_1, 10),
+                       BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       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_REG(BPF_REG_4, BPF_REG_0),
+                       BPF_ALU64_IMM(BPF_LSH, BPF_REG_4, 1),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+                       BPF_ST_MEM(BPF_DW, BPF_REG_4, 0, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 4 },
+               .errstr = "R4 invalid mem access",
+               .result = REJECT,
+               .prog_type = BPF_PROG_TYPE_SCHED_CLS
+       },
        {
                "invalid memory access with multiple map_lookup_elem calls",
                .insns = {
@@ -4937,7 +5026,149 @@ static struct bpf_test tests[] = {
                .fixup_map_in_map = { 3 },
                .errstr = "R1 type=map_value_or_null expected=map_ptr",
                .result = REJECT,
-       }
+       },
+       {
+               "ld_abs: check calling conv, r1",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_1, 0),
+                       BPF_LD_ABS(BPF_W, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R1 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_abs: check calling conv, r2",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_2, 0),
+                       BPF_LD_ABS(BPF_W, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R2 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_abs: check calling conv, r3",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_3, 0),
+                       BPF_LD_ABS(BPF_W, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R3 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_abs: check calling conv, r4",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_4, 0),
+                       BPF_LD_ABS(BPF_W, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_4),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R4 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_abs: check calling conv, r5",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_5, 0),
+                       BPF_LD_ABS(BPF_W, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R5 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_abs: check calling conv, r7",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_7, 0),
+                       BPF_LD_ABS(BPF_W, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_7),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+       },
+       {
+               "ld_ind: check calling conv, r1",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_1, 1),
+                       BPF_LD_IND(BPF_W, BPF_REG_1, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R1 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_ind: check calling conv, r2",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_2, 1),
+                       BPF_LD_IND(BPF_W, BPF_REG_2, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R2 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_ind: check calling conv, r3",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_3, 1),
+                       BPF_LD_IND(BPF_W, BPF_REG_3, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R3 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_ind: check calling conv, r4",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_4, 1),
+                       BPF_LD_IND(BPF_W, BPF_REG_4, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_4),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R4 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_ind: check calling conv, r5",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_5, 1),
+                       BPF_LD_IND(BPF_W, BPF_REG_5, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R5 !read_ok",
+               .result = REJECT,
+       },
+       {
+               "ld_ind: check calling conv, r7",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_MOV64_IMM(BPF_REG_7, 1),
+                       BPF_LD_IND(BPF_W, BPF_REG_7, -0x200000),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_7),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+       },
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)
@@ -5059,9 +5290,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 
        do_test_fixup(test, prog, map_fds);
 
-       fd_prog = bpf_load_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER,
-                                  prog, prog_len, "GPL", 0, bpf_vlog,
-                                  sizeof(bpf_vlog));
+       fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER,
+                                    prog, prog_len, test->flags & F_LOAD_WITH_STRICT_ALIGNMENT,
+                                    "GPL", 0, bpf_vlog, sizeof(bpf_vlog));
 
        expected_ret = unpriv && test->result_unpriv != UNDEF ?
                       test->result_unpriv : test->result;