selftests/bpf: verifier/jeq_infer_not_null converted to inline assembly

Test verifier/jeq_infer_not_null automatically converted to use inline assembly.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230421174234.2391278-9-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
index ce2436b..6585432 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/verifier.c
+++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
@@ -29,6 +29,7 @@
 #include "verifier_helper_restricted.skel.h"
 #include "verifier_helper_value_access.skel.h"
 #include "verifier_int_ptr.skel.h"
+#include "verifier_jeq_infer_not_null.skel.h"
 #include "verifier_ld_ind.skel.h"
 #include "verifier_leak_ptr.skel.h"
 #include "verifier_map_ptr.skel.h"
@@ -111,6 +112,7 @@ void test_verifier_helper_packet_access(void) { RUN(verifier_helper_packet_acces
 void test_verifier_helper_restricted(void)    { RUN(verifier_helper_restricted); }
 void test_verifier_helper_value_access(void)  { RUN(verifier_helper_value_access); }
 void test_verifier_int_ptr(void)              { RUN(verifier_int_ptr); }
+void test_verifier_jeq_infer_not_null(void)   { RUN(verifier_jeq_infer_not_null); }
 void test_verifier_ld_ind(void)               { RUN(verifier_ld_ind); }
 void test_verifier_leak_ptr(void)             { RUN(verifier_leak_ptr); }
 void test_verifier_map_ptr(void)              { RUN(verifier_map_ptr); }

diff --git a/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c b/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c
new file mode 100644 (file)
index 0000000..bf16b00
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Converted from tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct {
+       __uint(type, BPF_MAP_TYPE_XSKMAP);
+       __uint(max_entries, 1);
+       __type(key, int);
+       __type(value, int);
+} map_xskmap SEC(".maps");
+
+/* This is equivalent to the following program:
+ *
+ *   r6 = skb->sk;
+ *   r7 = sk_fullsock(r6);
+ *   r0 = sk_fullsock(r6);
+ *   if (r0 == 0) return 0;    (a)
+ *   if (r0 != r7) return 0;   (b)
+ *   *r7->type;                (c)
+ *   return 0;
+ *
+ * It is safe to dereference r7 at point (c), because of (a) and (b).
+ * The test verifies that relation r0 == r7 is propagated from (b) to (c).
+ */
+SEC("cgroup/skb")
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JNE false branch")
+__success __failure_unpriv __msg_unpriv("R7 pointer comparison")
+__retval(0)
+__naked void socket_for_jne_false_branch(void)
+{
+       asm volatile ("                                 \
+       /* r6 = skb->sk; */                             \
+       r6 = *(u64*)(r1 + %[__sk_buff_sk]);             \
+       /* if (r6 == 0) return 0; */                    \
+       if r6 == 0 goto l0_%=;                          \
+       /* r7 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       r7 = r0;                                        \
+       /* r0 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       /* if (r0 == null) return 0; */                 \
+       if r0 == 0 goto l0_%=;                          \
+       /* if (r0 == r7) r0 = *(r7->type); */           \
+       if r0 != r7 goto l0_%=;         /* Use ! JNE ! */\
+       r0 = *(u32*)(r7 + %[bpf_sock_type]);            \
+l0_%=: /* return 0 */                                  \
+       r0 = 0;                                         \
+       exit;                                           \
+"      :
+       : __imm(bpf_sk_fullsock),
+         __imm_const(__sk_buff_sk, offsetof(struct __sk_buff, sk)),
+         __imm_const(bpf_sock_type, offsetof(struct bpf_sock, type))
+       : __clobber_all);
+}
+
+/* Same as above, but verify that another branch of JNE still
+ * prohibits access to PTR_MAYBE_NULL.
+ */
+SEC("cgroup/skb")
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JNE true branch")
+__failure __msg("R7 invalid mem access 'sock_or_null'")
+__failure_unpriv __msg_unpriv("R7 pointer comparison")
+__naked void unchanged_for_jne_true_branch(void)
+{
+       asm volatile ("                                 \
+       /* r6 = skb->sk */                              \
+       r6 = *(u64*)(r1 + %[__sk_buff_sk]);             \
+       /* if (r6 == 0) return 0; */                    \
+       if r6 == 0 goto l0_%=;                          \
+       /* r7 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       r7 = r0;                                        \
+       /* r0 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       /* if (r0 == null) return 0; */                 \
+       if r0 != 0 goto l0_%=;                          \
+       /* if (r0 == r7) return 0; */                   \
+       if r0 != r7 goto l1_%=;         /* Use ! JNE ! */\
+       goto l0_%=;                                     \
+l1_%=: /* r0 = *(r7->type); */                         \
+       r0 = *(u32*)(r7 + %[bpf_sock_type]);            \
+l0_%=: /* return 0 */                                  \
+       r0 = 0;                                         \
+       exit;                                           \
+"      :
+       : __imm(bpf_sk_fullsock),
+         __imm_const(__sk_buff_sk, offsetof(struct __sk_buff, sk)),
+         __imm_const(bpf_sock_type, offsetof(struct bpf_sock, type))
+       : __clobber_all);
+}
+
+/* Same as a first test, but not null should be inferred for JEQ branch */
+SEC("cgroup/skb")
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JEQ true branch")
+__success __failure_unpriv __msg_unpriv("R7 pointer comparison")
+__retval(0)
+__naked void socket_for_jeq_true_branch(void)
+{
+       asm volatile ("                                 \
+       /* r6 = skb->sk; */                             \
+       r6 = *(u64*)(r1 + %[__sk_buff_sk]);             \
+       /* if (r6 == null) return 0; */                 \
+       if r6 == 0 goto l0_%=;                          \
+       /* r7 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       r7 = r0;                                        \
+       /* r0 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       /* if (r0 == null) return 0; */                 \
+       if r0 == 0 goto l0_%=;                          \
+       /* if (r0 != r7) return 0; */                   \
+       if r0 == r7 goto l1_%=;         /* Use ! JEQ ! */\
+       goto l0_%=;                                     \
+l1_%=: /* r0 = *(r7->type); */                         \
+       r0 = *(u32*)(r7 + %[bpf_sock_type]);            \
+l0_%=: /* return 0; */                                 \
+       r0 = 0;                                         \
+       exit;                                           \
+"      :
+       : __imm(bpf_sk_fullsock),
+         __imm_const(__sk_buff_sk, offsetof(struct __sk_buff, sk)),
+         __imm_const(bpf_sock_type, offsetof(struct bpf_sock, type))
+       : __clobber_all);
+}
+
+/* Same as above, but verify that another branch of JNE still
+ * prohibits access to PTR_MAYBE_NULL.
+ */
+SEC("cgroup/skb")
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JEQ false branch")
+__failure __msg("R7 invalid mem access 'sock_or_null'")
+__failure_unpriv __msg_unpriv("R7 pointer comparison")
+__naked void unchanged_for_jeq_false_branch(void)
+{
+       asm volatile ("                                 \
+       /* r6 = skb->sk; */                             \
+       r6 = *(u64*)(r1 + %[__sk_buff_sk]);             \
+       /* if (r6 == null) return 0; */                 \
+       if r6 == 0 goto l0_%=;                          \
+       /* r7 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       r7 = r0;                                        \
+       /* r0 = sk_fullsock(skb); */                    \
+       r1 = r6;                                        \
+       call %[bpf_sk_fullsock];                        \
+       /* if (r0 == null) return 0; */                 \
+       if r0 == 0 goto l0_%=;                          \
+       /* if (r0 != r7) r0 = *(r7->type); */           \
+       if r0 == r7 goto l0_%=;         /* Use ! JEQ ! */\
+       r0 = *(u32*)(r7 + %[bpf_sock_type]);            \
+l0_%=: /* return 0; */                                 \
+       r0 = 0;                                         \
+       exit;                                           \
+"      :
+       : __imm(bpf_sk_fullsock),
+         __imm_const(__sk_buff_sk, offsetof(struct __sk_buff, sk)),
+         __imm_const(bpf_sock_type, offsetof(struct bpf_sock, type))
+       : __clobber_all);
+}
+
+/* Maps are treated in a different branch of `mark_ptr_not_null_reg`,
+ * so separate test for maps case.
+ */
+SEC("xdp")
+__description("jne/jeq infer not null, PTR_TO_MAP_VALUE_OR_NULL -> PTR_TO_MAP_VALUE")
+__success __retval(0)
+__naked void null_ptr_to_map_value(void)
+{
+       asm volatile ("                                 \
+       /* r9 = &some stack to use as key */            \
+       r1 = 0;                                         \
+       *(u32*)(r10 - 8) = r1;                          \
+       r9 = r10;                                       \
+       r9 += -8;                                       \
+       /* r8 = process local map */                    \
+       r8 = %[map_xskmap] ll;                          \
+       /* r6 = map_lookup_elem(r8, r9); */             \
+       r1 = r8;                                        \
+       r2 = r9;                                        \
+       call %[bpf_map_lookup_elem];                    \
+       r6 = r0;                                        \
+       /* r7 = map_lookup_elem(r8, r9); */             \
+       r1 = r8;                                        \
+       r2 = r9;                                        \
+       call %[bpf_map_lookup_elem];                    \
+       r7 = r0;                                        \
+       /* if (r6 == 0) return 0; */                    \
+       if r6 == 0 goto l0_%=;                          \
+       /* if (r6 != r7) return 0; */                   \
+       if r6 != r7 goto l0_%=;                         \
+       /* read *r7; */                                 \
+       r0 = *(u32*)(r7 + %[bpf_xdp_sock_queue_id]);    \
+l0_%=: /* return 0; */                                 \
+       r0 = 0;                                         \
+       exit;                                           \
+"      :
+       : __imm(bpf_map_lookup_elem),
+         __imm_addr(map_xskmap),
+         __imm_const(bpf_xdp_sock_queue_id, offsetof(struct bpf_xdp_sock, queue_id))
+       : __clobber_all);
+}
+
+char _license[] SEC("license") = "GPL";

diff --git a/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c b/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c
deleted file mode 100644 (file)
index 67a1c07..0000000
--- a/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c
+++ /dev/null
@@ -1,174 +0,0 @@
-{
-       /* This is equivalent to the following program:
-        *
-        *   r6 = skb->sk;
-        *   r7 = sk_fullsock(r6);
-        *   r0 = sk_fullsock(r6);
-        *   if (r0 == 0) return 0;    (a)
-        *   if (r0 != r7) return 0;   (b)
-        *   *r7->type;                (c)
-        *   return 0;
-        *
-        * It is safe to dereference r7 at point (c), because of (a) and (b).
-        * The test verifies that relation r0 == r7 is propagated from (b) to (c).
-        */
-       "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JNE false branch",
-       .insns = {
-       /* r6 = skb->sk; */
-       BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-       /* if (r6 == 0) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8),
-       /* r7 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-       /* r0 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       /* if (r0 == null) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
-       /* if (r0 == r7) r0 = *(r7->type); */
-       BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */
-       BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-       /* return 0 */
-       BPF_MOV64_IMM(BPF_REG_0, 0),
-       BPF_EXIT_INSN(),
-       },
-       .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-       .result = ACCEPT,
-       .result_unpriv = REJECT,
-       .errstr_unpriv = "R7 pointer comparison",
-},
-{
-       /* Same as above, but verify that another branch of JNE still
-        * prohibits access to PTR_MAYBE_NULL.
-        */
-       "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JNE true branch",
-       .insns = {
-       /* r6 = skb->sk */
-       BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-       /* if (r6 == 0) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9),
-       /* r7 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-       /* r0 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       /* if (r0 == null) return 0; */
-       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
-       /* if (r0 == r7) return 0; */
-       BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */
-       BPF_JMP_IMM(BPF_JA, 0, 0, 1),
-       /* r0 = *(r7->type); */
-       BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-       /* return 0 */
-       BPF_MOV64_IMM(BPF_REG_0, 0),
-       BPF_EXIT_INSN(),
-       },
-       .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-       .result = REJECT,
-       .errstr = "R7 invalid mem access 'sock_or_null'",
-       .result_unpriv = REJECT,
-       .errstr_unpriv = "R7 pointer comparison",
-},
-{
-       /* Same as a first test, but not null should be inferred for JEQ branch */
-       "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JEQ true branch",
-       .insns = {
-       /* r6 = skb->sk; */
-       BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-       /* if (r6 == null) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9),
-       /* r7 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-       /* r0 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       /* if (r0 == null) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
-       /* if (r0 != r7) return 0; */
-       BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */
-       BPF_JMP_IMM(BPF_JA, 0, 0, 1),
-       /* r0 = *(r7->type); */
-       BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-       /* return 0; */
-       BPF_MOV64_IMM(BPF_REG_0, 0),
-       BPF_EXIT_INSN(),
-       },
-       .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-       .result = ACCEPT,
-       .result_unpriv = REJECT,
-       .errstr_unpriv = "R7 pointer comparison",
-},
-{
-       /* Same as above, but verify that another branch of JNE still
-        * prohibits access to PTR_MAYBE_NULL.
-        */
-       "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JEQ false branch",
-       .insns = {
-       /* r6 = skb->sk; */
-       BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-       /* if (r6 == null) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8),
-       /* r7 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-       /* r0 = sk_fullsock(skb); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-       BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-       /* if (r0 == null) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
-       /* if (r0 != r7) r0 = *(r7->type); */
-       BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */
-       BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-       /* return 0; */
-       BPF_MOV64_IMM(BPF_REG_0, 0),
-       BPF_EXIT_INSN(),
-       },
-       .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-       .result = REJECT,
-       .errstr = "R7 invalid mem access 'sock_or_null'",
-       .result_unpriv = REJECT,
-       .errstr_unpriv = "R7 pointer comparison",
-},
-{
-       /* Maps are treated in a different branch of `mark_ptr_not_null_reg`,
-        * so separate test for maps case.
-        */
-       "jne/jeq infer not null, PTR_TO_MAP_VALUE_OR_NULL -> PTR_TO_MAP_VALUE",
-       .insns = {
-       /* r9 = &some stack to use as key */
-       BPF_ST_MEM(BPF_W, BPF_REG_10, -8, 0),
-       BPF_MOV64_REG(BPF_REG_9, BPF_REG_10),
-       BPF_ALU64_IMM(BPF_ADD, BPF_REG_9, -8),
-       /* r8 = process local map */
-       BPF_LD_MAP_FD(BPF_REG_8, 0),
-       /* r6 = map_lookup_elem(r8, r9); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
-       BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
-       BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-       BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
-       /* r7 = map_lookup_elem(r8, r9); */
-       BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
-       BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
-       BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-       /* if (r6 == 0) return 0; */
-       BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2),
-       /* if (r6 != r7) return 0; */
-       BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_7, 1),
-       /* read *r7; */
-       BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_xdp_sock, queue_id)),
-       /* return 0; */
-       BPF_MOV64_IMM(BPF_REG_0, 0),
-       BPF_EXIT_INSN(),
-       },
-       .fixup_map_xskmap = { 3 },
-       .prog_type = BPF_PROG_TYPE_XDP,
-       .result = ACCEPT,
-},