From a5828e3154d17d9fec53910a1aa161d028339ada Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 21 Apr 2023 20:42:18 +0300 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20230421174234.2391278-9-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/prog_tests/verifier.c | 2 + .../bpf/progs/verifier_jeq_infer_not_null.c | 213 +++++++++++++++++++++ .../selftests/bpf/verifier/jeq_infer_not_null.c | 174 ----------------- 3 files changed, 215 insertions(+), 174 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c delete mode 100644 tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index ce2436b..6585432 100644 --- 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 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 +#include +#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 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, -}, -- 2.7.4