diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/verifier_stack_arg.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_stack_arg.c | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c new file mode 100644 index 000000000000..7e0ce5db28a0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c @@ -0,0 +1,447 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include "bpf_misc.h" + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, 1); + __type(key, long long); + __type(value, long long); +} map_hash_8b SEC(".maps"); + +#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \ + defined(__BPF_FEATURE_STACK_ARGUMENT) + +__noinline __used +static int subprog_6args(int a, int b, int c, int d, int e, int f) +{ + return a + b + c + d + e + f; +} + +__noinline __used +static int subprog_7args(int a, int b, int c, int d, int e, int f, int g) +{ + return a + b + c + d + e + f + g; +} + +__noinline __used +static long subprog_deref_arg6(long a, long b, long c, long d, long e, long *f) +{ + return *f; +} + +SEC("tc") +__description("stack_arg: subprog with 6 args") +__success __retval(21) +__naked void stack_arg_6args(void) +{ + asm volatile ( + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "*(u64 *)(r11 - 8) = 6;" + "call subprog_6args;" + "exit;" + ::: __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: two subprogs with >5 args") +__success __retval(90) +__naked void stack_arg_two_subprogs(void) +{ + asm volatile ( + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "*(u64 *)(r11 - 8) = 10;" + "call subprog_6args;" + "r6 = r0;" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "*(u64 *)(r11 - 16) = 30;" + "*(u64 *)(r11 - 8) = 20;" + "call subprog_7args;" + "r0 += r6;" + "exit;" + ::: __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: read from uninitialized stack arg slot") +__failure +__msg("invalid read from stack arg off 8 depth 0") +__naked void stack_arg_read_uninitialized(void) +{ + asm volatile ( + "r0 = *(u64 *)(r11 + 8);" + "r0 = 0;" + "exit;" + ::: __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: gap at offset -8, only wrote -16") +__failure +__msg("callee expects 7 args, stack arg1 is not initialized") +__naked void stack_arg_gap_at_minus8(void) +{ + asm volatile ( + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "*(u64 *)(r11 - 16) = 30;" + "call subprog_7args;" + "exit;" + ::: __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: pruning with different stack arg types") +__failure __log_level(2) +__flag(BPF_F_TEST_STATE_FREQ) +__msg("arg JOIN insn 9 -> 10 r1: fp0-8 + _ => fp0-8|fp0+0") +__msg("arg JOIN insn 9 -> 10 sa0: fp0-8 + _ => fp0-8|fp0+0") +__msg("R{{[0-9]}} invalid mem access 'scalar'") +__naked void stack_arg_pruning_type_mismatch(void) +{ + asm volatile ( + "call %[bpf_get_prandom_u32];" + "r6 = r0;" + /* local = 0 on program stack */ + "r7 = 0;" + "*(u64 *)(r10 - 8) = r7;" + /* Branch based on random value */ + "if r6 s> 3 goto l0_%=;" + /* Path 1: store stack pointer to outgoing arg6 */ + "r1 = r10;" + "r1 += -8;" + "*(u64 *)(r11 - 8) = r1;" + "goto l1_%=;" + "l0_%=:" + /* Path 2: store scalar to outgoing arg6 */ + "*(u64 *)(r11 - 8) = 42;" + "l1_%=:" + /* Call subprog that dereferences arg6 */ + "r1 = r6;" + "r2 = 0;" + "r3 = 0;" + "r4 = 0;" + "r5 = 0;" + "call subprog_deref_arg6;" + "exit;" + :: __imm(bpf_get_prandom_u32) + : __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: release_reference invalidates stack arg slot") +__failure +__msg("callee expects 6 args, stack arg1 is not initialized") +__naked void stack_arg_release_ref(void) +{ + asm volatile ( + "r6 = r1;" + /* struct bpf_sock_tuple tuple = {} */ + "r2 = 0;" + "*(u32 *)(r10 - 8) = r2;" + "*(u64 *)(r10 - 16) = r2;" + "*(u64 *)(r10 - 24) = r2;" + "*(u64 *)(r10 - 32) = r2;" + "*(u64 *)(r10 - 40) = r2;" + "*(u64 *)(r10 - 48) = r2;" + /* sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple), 0, 0) */ + "r1 = r6;" + "r2 = r10;" + "r2 += -48;" + "r3 = %[sizeof_bpf_sock_tuple];" + "r4 = 0;" + "r5 = 0;" + "call %[bpf_sk_lookup_tcp];" + /* r0 = sk (PTR_TO_SOCK_OR_NULL) */ + "if r0 == 0 goto l0_%=;" + /* Store sock ref to outgoing arg6 slot */ + "*(u64 *)(r11 - 8) = r0;" + /* Release the reference — invalidates the stack arg slot */ + "r1 = r0;" + "call %[bpf_sk_release];" + /* Call subprog that dereferences arg6 — should fail */ + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_deref_arg6;" + "l0_%=:" + "r0 = 0;" + "exit;" + : + : __imm(bpf_sk_lookup_tcp), + __imm(bpf_sk_release), + __imm_const(sizeof_bpf_sock_tuple, sizeof(struct bpf_sock_tuple)) + : __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: pkt pointer in stack arg slot invalidated after pull_data") +__failure +__msg("callee expects 6 args, stack arg1 is not initialized") +__naked void stack_arg_stale_pkt_ptr(void) +{ + asm volatile ( + "r6 = r1;" + "r7 = *(u32 *)(r6 + %[__sk_buff_data]);" + "r8 = *(u32 *)(r6 + %[__sk_buff_data_end]);" + /* check pkt has at least 1 byte */ + "r0 = r7;" + "r0 += 8;" + "if r0 > r8 goto l0_%=;" + /* Store valid pkt pointer to outgoing arg6 slot */ + "*(u64 *)(r11 - 8) = r7;" + /* bpf_skb_pull_data invalidates all pkt pointers */ + "r1 = r6;" + "r2 = 0;" + "call %[bpf_skb_pull_data];" + /* Call subprog that dereferences arg6 — should fail */ + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_deref_arg6;" + "l0_%=:" + "r0 = 0;" + "exit;" + : + : __imm(bpf_skb_pull_data), + __imm_const(__sk_buff_data, offsetof(struct __sk_buff, data)), + __imm_const(__sk_buff_data_end, offsetof(struct __sk_buff, data_end)) + : __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: null propagation rejects deref on null branch") +__failure +__msg("R{{[0-9]}} invalid mem access 'scalar'") +__naked void stack_arg_null_propagation_fail(void) +{ + asm volatile ( + "r1 = 0;" + "*(u64 *)(r10 - 8) = r1;" + /* r0 = bpf_map_lookup_elem(&map_hash_8b, &key) */ + "r2 = r10;" + "r2 += -8;" + "r1 = %[map_hash_8b] ll;" + "call %[bpf_map_lookup_elem];" + /* Store PTR_TO_MAP_VALUE_OR_NULL to outgoing arg6 slot */ + "*(u64 *)(r11 - 8) = r0;" + /* null check on r0 */ + "if r0 != 0 goto l0_%=;" + /* + * On null branch, outgoing slot is SCALAR(0). + * Call subprog that dereferences arg6 — should fail. + */ + "r1 = 0;" + "r2 = 0;" + "r3 = 0;" + "r4 = 0;" + "r5 = 0;" + "call subprog_deref_arg6;" + "l0_%=:" + "r0 = 0;" + "exit;" + : + : __imm(bpf_map_lookup_elem), + __imm_addr(map_hash_8b) + : __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: missing store on one branch") +__failure +__msg("callee expects 7 args, stack arg1 is not initialized") +__naked void stack_arg_missing_store_one_branch(void) +{ + asm volatile ( + "call %[bpf_get_prandom_u32];" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + /* Write arg7 (r11-16) before branch */ + "*(u64 *)(r11 - 16) = 20;" + "if r0 > 0 goto l0_%=;" + /* Path 1: write arg6 and call */ + "*(u64 *)(r11 - 8) = 10;" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_7args;" + "goto l1_%=;" + "l0_%=:" + /* Path 2: missing arg6 store, call should fail */ + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_7args;" + "l1_%=:" + "r0 = 0;" + "exit;" + :: __imm(bpf_get_prandom_u32) + : __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: share a store for both branches") +__success __retval(0) +__naked void stack_arg_shared_store(void) +{ + asm volatile ( + "call %[bpf_get_prandom_u32];" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + /* Write arg7 (r11-16) before branch */ + "*(u64 *)(r11 - 16) = 20;" + "if r0 > 0 goto l0_%=;" + /* Path 1: write arg6 and call */ + "*(u64 *)(r11 - 8) = 10;" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_7args;" + "goto l1_%=;" + "l0_%=:" + /* Path 2: also write arg6 and call */ + "*(u64 *)(r11 - 8) = 30;" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_7args;" + "l1_%=:" + "r0 = 0;" + "exit;" + :: __imm(bpf_get_prandom_u32) + : __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: write beyond max outgoing depth") +__failure +__msg("stack arg write offset -80 exceeds max 7 stack args") +__naked void stack_arg_write_beyond_max(void) +{ + asm volatile ( + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + /* Write to offset -80, way beyond any callee's needs */ + "*(u64 *)(r11 - 80) = 99;" + "*(u64 *)(r11 - 16) = 20;" + "*(u64 *)(r11 - 8) = 10;" + "call subprog_7args;" + "r0 = 0;" + "exit;" + ::: __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: write unused stack arg slot") +__failure +__msg("func#0 writes 5 stack arg slots, but calls only require 2") +__naked void stack_arg_write_unused_slot(void) +{ + asm volatile ( + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + /* Write to offset -40, unused for the callee */ + "*(u64 *)(r11 - 40) = 99;" + "*(u64 *)(r11 - 16) = 20;" + "*(u64 *)(r11 - 8) = 10;" + "call subprog_7args;" + "r0 = 0;" + "exit;" + ::: __clobber_all + ); +} + +SEC("tc") +__description("stack_arg: sequential calls reuse slots") +__failure +__msg("callee expects 7 args, stack arg1 is not initialized") +__naked void stack_arg_sequential_calls(void) +{ + asm volatile ( + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "*(u64 *)(r11 - 8) = 6;" + "*(u64 *)(r11 - 16) = 7;" + "call subprog_7args;" + "r6 = r0;" + "r1 = 1;" + "r2 = 2;" + "r3 = 3;" + "r4 = 4;" + "r5 = 5;" + "call subprog_7args;" + "r0 += r6;" + "exit;" + ::: __clobber_all + ); +} + +#else + +SEC("socket") +__description("stack_arg is not supported by compiler or jit, use a dummy test") +__success +int dummy_test(void) +{ + return 0; +} + +#endif + +char _license[] SEC("license") = "GPL"; |