Multi-level pointer params and return value test coverage for BPF trampolines: - fentry/fexit programs covering struct and void double/triple pointer parameters - nullable pointer cases to validate required NULL checks - verifier context tests for lsm to check trusted parameters handling - verifier context tests to exercise PTR_TO_MEM sizing and read-only behavior - verifier BPF helper tests to validate no change in verifier behaviour
Signed-off-by: Slava Imameev <[email protected]> --- net/bpf/test_run.c | 128 ++++++ .../prog_tests/fentry_fexit_multi_level_ptr.c | 204 +++++++++ .../selftests/bpf/prog_tests/verifier.c | 2 + .../progs/fentry_fexit_pptr_nullable_test.c | 52 +++ .../bpf/progs/fentry_fexit_pptr_test.c | 60 +++ .../bpf/progs/fentry_fexit_void_ppptr_test.c | 31 ++ .../bpf/progs/fentry_fexit_void_pptr_test.c | 64 +++ .../bpf/progs/verifier_ctx_multilevel_ptr.c | 429 ++++++++++++++++++ 8 files changed, 970 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/fentry_fexit_multi_level_ptr.c create mode 100644 tools/testing/selftests/bpf/progs/fentry_fexit_pptr_nullable_test.c create mode 100644 tools/testing/selftests/bpf/progs/fentry_fexit_pptr_test.c create mode 100644 tools/testing/selftests/bpf/progs/fentry_fexit_void_ppptr_test.c create mode 100644 tools/testing/selftests/bpf/progs/fentry_fexit_void_pptr_test.c create mode 100644 tools/testing/selftests/bpf/progs/verifier_ctx_multilevel_ptr.c diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 178c4738e63b..19c82ae9bfe6 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -24,6 +24,8 @@ #include <net/netdev_rx_queue.h> #include <net/xdp.h> #include <net/netfilter/nf_bpf_link.h> +#include <linux/set_memory.h> +#include <linux/string.h> #define CREATE_TRACE_POINTS #include <trace/events/bpf_test_run.h> @@ -563,6 +565,41 @@ noinline int bpf_fentry_test10(const void *a) return (long)a; } +struct bpf_fentry_test_pptr_t { + int value; +}; + +noinline int bpf_fentry_test11_pptr_nullable(struct bpf_fentry_test_pptr_t **pptr__nullable) +{ + if (!pptr__nullable) + return -1; + + return (*pptr__nullable)->value; +} + +noinline u32 **bpf_fentry_test12_pptr(u32 id, u32 **pptr) +{ + /* prevent DCE */ + asm volatile("" : "+r"(id)); + asm volatile("" : "+r"(pptr)); + return pptr; +} + +noinline u8 bpf_fentry_test13_pptr(void **pptr) +{ + void *ptr; + + return copy_from_kernel_nofault(&ptr, pptr, sizeof(pptr)) == 0; +} + +/* Test the verifier can handle multi-level pointer types with qualifiers. */ +noinline void ***bpf_fentry_test14_ppptr(void **volatile *const ppptr) +{ + /* prevent DCE */ + asm volatile("" :: "r"(ppptr) : "memory"); + return (void ***)ppptr; +} + noinline void bpf_fentry_test_sinfo(struct skb_shared_info *sinfo) { } @@ -670,20 +707,110 @@ static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size, return data; } +static void *create_bad_kaddr(void) +{ + /* + * Try to get an address that passes kernel range checks but causes + * a page fault handler invocation if accessed from a BPF program. + */ +#if defined(CONFIG_ARCH_HAS_SET_MEMORY) && defined(CONFIG_X86) + void *addr = vmalloc(PAGE_SIZE); + + if (!addr) + return NULL; + /* Make it non-present - any access will fault */ + if (set_memory_np((unsigned long)addr, 1)) { + vfree(addr); + return NULL; + } + return addr; +#elif defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) + struct page *page = alloc_page(GFP_KERNEL); + + if (!page) + return NULL; + /* Remove from direct map - any access will fault */ + if (set_direct_map_invalid_noflush(page)) { + __free_page(page); + return NULL; + } + flush_tlb_kernel_range((unsigned long)page_address(page), + (unsigned long)page_address(page) + PAGE_SIZE); + return page_address(page); +#endif + return NULL; +} + +static void free_bad_kaddr(void *addr) +{ + if (!addr) + return; + + /* + * Free an invalid test address created by get_invalid_address(). + * Restores the page to present state before freeing. + */ +#if defined(CONFIG_ARCH_HAS_SET_MEMORY) && defined(CONFIG_X86) + set_memory_p((unsigned long)addr, 1); + vfree(addr); +#elif defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) + struct page *page = virt_to_page(addr); + + set_direct_map_default_noflush(page); + flush_tlb_kernel_range((unsigned long)addr, + (unsigned long)addr + PAGE_SIZE); + __free_page(page); +#endif +} + +#define CONSUME(val) do { \ + typeof(val) __var = (val); \ + __asm__ __volatile__("" : "+r" (__var)); \ + (void)__var; \ +} while (0) + int bpf_prog_test_run_tracing(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr) { struct bpf_fentry_test_t arg = {}; + struct bpf_fentry_test_pptr_t ts = { .value = 1979 }; + struct bpf_fentry_test_pptr_t *ptr = &ts; + void *kaddr = NULL; + u32 *u32_ptr = (u32 *)29; u16 side_effect = 0, ret = 0; int b = 2, err = -EFAULT; u32 retval = 0; + const char *attach_name; if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size) return -EINVAL; + attach_name = prog->aux->attach_func_name; + if (!attach_name) + attach_name = "!"; + switch (prog->expected_attach_type) { case BPF_TRACE_FENTRY: + if (!strcmp(attach_name, "bpf_fentry_test11_pptr_nullable")) { + CONSUME(bpf_fentry_test11_pptr_nullable(&ptr)); + break; + } else if (!strcmp(attach_name, "bpf_fentry_test12_pptr")) { + CONSUME(bpf_fentry_test12_pptr(0, &u32_ptr)); + CONSUME(bpf_fentry_test12_pptr(1, (u32 **)17)); + break; + } else if (!strcmp(attach_name, "bpf_fentry_test13_pptr")) { + kaddr = create_bad_kaddr(); + WARN_ON(!kaddr); + CONSUME(bpf_fentry_test13_pptr(kaddr)); + CONSUME(bpf_fentry_test13_pptr((void **)19)); + CONSUME(bpf_fentry_test13_pptr(ERR_PTR(-ENOMEM))); + break; + } else if (!strcmp(attach_name, "bpf_fentry_test14_ppptr")) { + CONSUME(bpf_fentry_test14_ppptr(ERR_PTR(-ENOMEM))); + break; + } + fallthrough; case BPF_TRACE_FEXIT: case BPF_TRACE_FSESSION: if (bpf_fentry_test1(1) != 2 || @@ -717,6 +844,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog, err = 0; out: + free_bad_kaddr(kaddr); trace_bpf_test_finish(&err); return err; } diff --git a/tools/testing/selftests/bpf/prog_tests/fentry_fexit_multi_level_ptr.c b/tools/testing/selftests/bpf/prog_tests/fentry_fexit_multi_level_ptr.c new file mode 100644 index 000000000000..48cb8a3d3967 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/fentry_fexit_multi_level_ptr.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 CrowdStrike, Inc. */ +#include <test_progs.h> +#include "fentry_fexit_pptr_nullable_test.skel.h" +#include "fentry_fexit_pptr_test.skel.h" +#include "fentry_fexit_void_pptr_test.skel.h" +#include "fentry_fexit_void_ppptr_test.skel.h" + +static void test_fentry_fexit_pptr_nullable(void) +{ + struct fentry_fexit_pptr_nullable_test *skel = NULL; + int err, prog_fd; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + skel = fentry_fexit_pptr_nullable_test__open_and_load(); + if (!ASSERT_OK_PTR(skel, "fentry_fexit_pptr_nullable_test__open_and_load")) + return; + + err = fentry_fexit_pptr_nullable_test__attach(skel); + if (!ASSERT_OK(err, "fentry_fexit_pptr_nullable_test__attach")) + goto cleanup; + + /* Trigger fentry/fexit programs. */ + prog_fd = bpf_program__fd(skel->progs.test_fentry_pptr_nullable); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, 0, "test_run retval"); + + /* Verify fentry was called and captured the correct value. */ + ASSERT_EQ(skel->bss->fentry_called, 1, "fentry_called"); + ASSERT_EQ(skel->bss->fentry_ptr_field_value, 1979, "fentry_ptr_field_value"); + + /* Verify fexit captured correct values and return code. */ + ASSERT_EQ(skel->bss->fexit_called, 1, "fexit_called"); + ASSERT_EQ(skel->bss->fexit_ptr_field_value, 1979, "fexit_ptr_field_value"); + ASSERT_EQ(skel->bss->fexit_retval, 1979, "fexit_retval"); + +cleanup: + fentry_fexit_pptr_nullable_test__destroy(skel); +} + +static void test_fentry_fexit_pptr(void) +{ + struct fentry_fexit_pptr_test *skel = NULL; + int err, prog_fd, i; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + skel = fentry_fexit_pptr_test__open_and_load(); + if (!ASSERT_OK_PTR(skel, "fentry_fexit_pptr_test__open_and_load")) + return; + + /* Poison some values which should be modified by BPF programs. */ + for (i = 0; i < ARRAY_SIZE(skel->bss->telemetry); ++i) { + skel->bss->telemetry[i].id = 30; + skel->bss->telemetry[i].fentry_pptr = 31; + skel->bss->telemetry[i].fentry_ptr = 32; + skel->bss->telemetry[i].fexit_pptr = 33; + skel->bss->telemetry[i].fexit_ptr = 34; + skel->bss->telemetry[i].fexit_ret_pptr = 35; + skel->bss->telemetry[i].fexit_ret_ptr = 36; + } + + err = fentry_fexit_pptr_test__attach(skel); + if (!ASSERT_OK(err, "fentry_fexit_pptr_test__attach")) + goto cleanup; + + /* Trigger fentry/fexit programs */ + prog_fd = bpf_program__fd(skel->progs.test_fentry_pptr); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, 0, "test_run retval"); + + for (i = 0; i < ARRAY_SIZE(skel->bss->telemetry); ++i) { + ASSERT_TRUE(skel->bss->telemetry[i].id == 0 || + skel->bss->telemetry[i].id == 1, "id"); + if (skel->bss->telemetry[i].id == 0) { + /* Verify fentry captured the correct value. */ + ASSERT_EQ(skel->bss->telemetry[i].fentry_called, 1, "fentry_called"); + ASSERT_EQ(skel->bss->telemetry[i].fentry_ptr, (u64)29, "fentry_ptr"); + + /* Verify fexit captured correct values and return address. */ + ASSERT_EQ(skel->bss->telemetry[i].fexit_called, 1, "fexit_called"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_pptr, + skel->bss->telemetry[i].fentry_pptr, "fexit_pptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ptr, (u64)29, "fexit_ptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ret_pptr, + skel->bss->telemetry[i].fentry_pptr, "fexit_ret_pptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ret_ptr, (u64)29, "fexit_ret_ptr"); + } else if (skel->bss->telemetry[i].id == 1) { + /* Verify fentry captured the correct value */ + ASSERT_EQ(skel->bss->telemetry[i].fentry_called, 1, "fentry_called"); + ASSERT_EQ(skel->bss->telemetry[i].fentry_pptr, 17, "fentry_pptr"); + + /* + * Verify fexit captured correct values and return address, + * fentry_ptr value depends on kernel address space layout + * and a mapped page presence at NULL. + */ + ASSERT_EQ(skel->bss->telemetry[i].fexit_called, 1, "fexit_called"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_pptr, 17, "fexit_pptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ptr, + skel->bss->telemetry[i].fentry_ptr, "fexit_ptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ret_pptr, 17, "fexit_ret_pptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ret_ptr, + skel->bss->telemetry[i].fentry_ptr, "fexit_ret_ptr"); + } + } + +cleanup: + fentry_fexit_pptr_test__destroy(skel); +} + +static void test_fentry_fexit_void_pptr(void) +{ + struct fentry_fexit_void_pptr_test *skel = NULL; + int err, prog_fd, i; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + skel = fentry_fexit_void_pptr_test__open_and_load(); + if (!ASSERT_OK_PTR(skel, "fentry_fexit_void_pptr_test__open_and_load")) + return; + + /* Poison some values which should be modified by BPF programs. */ + for (i = 0; i < ARRAY_SIZE(skel->bss->telemetry); ++i) { + skel->bss->telemetry[i].fentry_pptr = 30; + skel->bss->telemetry[i].fentry_ptr = 31; + skel->bss->telemetry[i].fexit_pptr = 32; + skel->bss->telemetry[i].fexit_ptr = 33; + } + + err = fentry_fexit_void_pptr_test__attach(skel); + if (!ASSERT_OK(err, "fentry_fexit_void_pptr_test__attach")) + goto cleanup; + + /* Trigger fentry/fexit programs. */ + prog_fd = bpf_program__fd(skel->progs.test_fentry_void_pptr); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, 0, "test_run retval"); + for (i = 0; i < ARRAY_SIZE(skel->bss->telemetry); ++i) { + ASSERT_EQ(skel->bss->telemetry[i].fentry_called, 1, "fentry_called"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_called, 1, "fexit_called"); + ASSERT_EQ(skel->bss->telemetry[i].fentry_pptr, skel->bss->telemetry[i].fexit_pptr, + "fentry_pptr == fexit_pptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ptr, skel->bss->telemetry[i].fentry_ptr, + "fexit_ptr"); + ASSERT_EQ(skel->bss->telemetry[i].fentry_pptr_addr_valid, + skel->bss->telemetry[i].fexit_pptr_addr_valid, "fexit_pptr_addr_valid"); + if (!skel->bss->telemetry[i].fentry_pptr_addr_valid) { + /* Should be set to 0 by kernel address boundaries check or an exception handler. */ + ASSERT_EQ(skel->bss->telemetry[i].fentry_ptr, 0, "fentry_ptr"); + ASSERT_EQ(skel->bss->telemetry[i].fexit_ptr, 0, "fexit_ptr"); + } + } +cleanup: + fentry_fexit_void_pptr_test__destroy(skel); +} + +static void test_fentry_fexit_void_ppptr(void) +{ + struct fentry_fexit_void_ppptr_test *skel = NULL; + int err, prog_fd; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + skel = fentry_fexit_void_ppptr_test__open_and_load(); + if (!ASSERT_OK_PTR(skel, "fentry_fexit_void_ppptr_test__open_and_load")) + return; + + /* Poison some values which should be modified by BPF programs */ + skel->bss->fentry_pptr = 31; + + err = fentry_fexit_void_ppptr_test__attach(skel); + if (!ASSERT_OK(err, "fentry_fexit_void_ppptr_test__attach")) + goto cleanup; + + /* Trigger fentry/fexit programs */ + prog_fd = bpf_program__fd(skel->progs.test_fentry_void_ppptr); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, 0, "test_run retval"); + + /* Verify invalid memory access results in zeroed register */ + ASSERT_EQ(skel->bss->fentry_called, 1, "fentry_called"); + ASSERT_EQ(skel->bss->fentry_pptr, 0, "fentry_pptr"); + + /* Verify fexit captured correct values and return value */ + ASSERT_EQ(skel->bss->fexit_called, 1, "fexit_called"); + ASSERT_EQ(skel->bss->fexit_retval, (u64)ERR_PTR(-ENOMEM), "fexit_retval"); + +cleanup: + fentry_fexit_void_ppptr_test__destroy(skel); +} + +void test_fentry_fexit_multi_level_ptr(void) +{ + if (test__start_subtest("pptr_nullable")) + test_fentry_fexit_pptr_nullable(); + if (test__start_subtest("pptr")) + test_fentry_fexit_pptr(); + if (test__start_subtest("void_pptr")) + test_fentry_fexit_void_pptr(); + if (test__start_subtest("void_ppptr")) + test_fentry_fexit_void_ppptr(); +} diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 8cdfd74c95d7..5bcc6406c0b2 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -115,6 +115,7 @@ #include "verifier_lsm.skel.h" #include "verifier_jit_inline.skel.h" #include "irq.skel.h" +#include "verifier_ctx_multilevel_ptr.skel.h" #define MAX_ENTRIES 11 @@ -259,6 +260,7 @@ void test_verifier_lsm(void) { RUN(verifier_lsm); } void test_irq(void) { RUN(irq); } void test_verifier_mtu(void) { RUN(verifier_mtu); } void test_verifier_jit_inline(void) { RUN(verifier_jit_inline); } +void test_verifier_ctx_multilevel_ptr(void) { RUN(verifier_ctx_multilevel_ptr); } static int init_test_val_map(struct bpf_object *obj, char *map_name) { diff --git a/tools/testing/selftests/bpf/progs/fentry_fexit_pptr_nullable_test.c b/tools/testing/selftests/bpf/progs/fentry_fexit_pptr_nullable_test.c new file mode 100644 index 000000000000..b88d4a1ebba2 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_fexit_pptr_nullable_test.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 CrowdStrike, Inc. */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +struct bpf_fentry_test_pptr_t { + __u32 value; +}; + +__u32 fentry_called = 0; +__u32 fentry_ptr_field_value = 0; +__u32 fexit_called = 0; +__u32 fexit_ptr_field_value = 0; +__u32 fexit_retval = 0; + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +int BPF_PROG(test_fentry_pptr_nullable, struct bpf_fentry_test_pptr_t **pptr__nullable) +{ + struct bpf_fentry_test_pptr_t *ptr; + + fentry_called = 1; + if (!pptr__nullable) + return 0; + + ptr = *pptr__nullable; + if (!ptr) + return 0; + + bpf_probe_read_kernel(&fentry_ptr_field_value, sizeof(fentry_ptr_field_value), &ptr->value); + return 0; +} + +SEC("fexit/bpf_fentry_test11_pptr_nullable") +int BPF_PROG(test_fexit_pptr_nullable, struct bpf_fentry_test_pptr_t **pptr__nullable, int ret) +{ + struct bpf_fentry_test_pptr_t *ptr; + + fexit_called = 1; + fexit_retval = ret; + if (!pptr__nullable) + return 0; + + ptr = *pptr__nullable; + if (!ptr) + return 0; + + bpf_probe_read_kernel(&fexit_ptr_field_value, sizeof(fexit_ptr_field_value), &ptr->value); + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/fentry_fexit_pptr_test.c b/tools/testing/selftests/bpf/progs/fentry_fexit_pptr_test.c new file mode 100644 index 000000000000..37764b030669 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_fexit_pptr_test.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 CrowdStrike, Inc. */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +#define TELEMETRY_COUNT 2 + +struct { + __u32 id; + __u32 fentry_called; + __u32 fexit_called; + __u64 fentry_pptr; + __u64 fentry_ptr; + __u64 fexit_pptr; + __u64 fexit_ptr; + __u64 fexit_ret_pptr; + __u64 fexit_ret_ptr; +} telemetry[TELEMETRY_COUNT]; + +volatile unsigned int current_index = 0; + +SEC("fentry/bpf_fentry_test12_pptr") +int BPF_PROG(test_fentry_pptr, __u32 id, __u32 **pptr) +{ + void *ptr; + unsigned int i = current_index; + + if (i >= TELEMETRY_COUNT) + return 0; + + if (bpf_probe_read_kernel(&ptr, sizeof(ptr), pptr) != 0) + ptr = NULL; + + telemetry[i].id = id; + telemetry[i].fentry_called = 1; + telemetry[i].fentry_pptr = (__u64)pptr; + telemetry[i].fentry_ptr = (__u64)ptr; + return 0; +} + +SEC("fexit/bpf_fentry_test12_pptr") +int BPF_PROG(test_fexit_pptr, __u32 id, __u32 **pptr, __u32 **ret) +{ + unsigned int i = current_index; + + if (i >= TELEMETRY_COUNT) + return 0; + + telemetry[i].fexit_called = 1; + telemetry[i].fexit_pptr = (__u64)pptr; + telemetry[i].fexit_ptr = (__u64)*pptr; + telemetry[i].fexit_ret_pptr = (__u64)ret; + telemetry[i].fexit_ret_ptr = ret ? (__u64)*ret : 0; + + current_index = i + 1; + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/fentry_fexit_void_ppptr_test.c b/tools/testing/selftests/bpf/progs/fentry_fexit_void_ppptr_test.c new file mode 100644 index 000000000000..3e0e908f6eda --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_fexit_void_ppptr_test.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 CrowdStrike, Inc. */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +__u32 fentry_called = 0; +__u32 fexit_called = 0; +__u64 fentry_pptr = 0; +__u64 fexit_retval = 0; + +typedef void **volatile *const ppvpc_t; + +SEC("fentry/bpf_fentry_test14_ppptr") +int BPF_PROG(test_fentry_void_ppptr, ppvpc_t ppptr) +{ + fentry_called = 1; + /* Invalid memory access is fixed by boundaries check or exception handler */ + fentry_pptr = (unsigned long)*ppptr; + return 0; +} + +SEC("fexit/bpf_fentry_test14_ppptr") +int BPF_PROG(test_fexit_void_ppptr, ppvpc_t ppptr, void ***ret) +{ + fexit_called = 1; + fexit_retval = ret ? (__u64)ret : 0; + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/fentry_fexit_void_pptr_test.c b/tools/testing/selftests/bpf/progs/fentry_fexit_void_pptr_test.c new file mode 100644 index 000000000000..0ec86da97ec5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_fexit_void_pptr_test.c @@ -0,0 +1,64 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 CrowdStrike, Inc. */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +#define TELEMETRY_COUNT 3 + +struct { + __u32 fentry_called; + __u32 fexit_called; + __u32 fentry_pptr_addr_valid; + __u32 fexit_pptr_addr_valid; + __u64 fentry_pptr; + __u64 fentry_ptr; + __u64 fexit_pptr; + __u64 fexit_ptr; +} telemetry[TELEMETRY_COUNT]; + +volatile unsigned int current_index = 0; + +SEC("fentry/bpf_fentry_test13_pptr") +int BPF_PROG(test_fentry_void_pptr, void **pptr) +{ + void *ptr; + unsigned int i = current_index; + + if (i >= TELEMETRY_COUNT) + return 0; + + telemetry[i].fentry_pptr_addr_valid = + (bpf_probe_read_kernel(&ptr, sizeof(ptr), pptr) == 0); + if (!telemetry[i].fentry_pptr_addr_valid) + ptr = NULL; + + telemetry[i].fentry_called = 1; + telemetry[i].fentry_pptr = (__u64)pptr; + telemetry[i].fentry_ptr = (__u64)ptr; + return 0; +} + +SEC("fexit/bpf_fentry_test13_pptr") +int BPF_PROG(test_fexit_void_pptr, void **pptr, __u8 ret) +{ + unsigned int i = current_index; + + if (i >= TELEMETRY_COUNT) + return 0; + + telemetry[i].fexit_called = 1; + telemetry[i].fexit_pptr = (__u64)pptr; + telemetry[i].fexit_pptr_addr_valid = ret; + + /* + * For invalid addresses, the destination register for *dptr is set + * to 0 by the BPF exception handler, JIT address range check, or + * the BPF interpreter. + */ + telemetry[i].fexit_ptr = (__u64)*pptr; + current_index = i + 1; + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/verifier_ctx_multilevel_ptr.c b/tools/testing/selftests/bpf/progs/verifier_ctx_multilevel_ptr.c new file mode 100644 index 000000000000..9635aed66ba4 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_ctx_multilevel_ptr.c @@ -0,0 +1,429 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Verifier tests for double and triple pointer parameter handling + * Copyright (c) 2026 CrowdStrike, Inc. + */ + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include "bpf_misc.h" + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - valid ctx access") +__success __retval(0) +__naked void ctx_double_ptr_valid_load(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - invalid load without null") +__failure __msg("R2 invalid mem access 'rdonly_untrusted_mem_or_null'") +__naked void ctx_double_ptr_load_no_check_nullable(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + /* \ + * invalid dereference without check for NULL when a parameter \ + * is marked nullable (PTR_MAYBE_NULL) \ + */ \ + r3 = *(u64 *)(r2 + 0); \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test12_pptr") +__description("fentry/double pointer parameter (rdonly, untrusted) - valid load without null") +__success __retval(0) +__naked void ctx_double_ptr_load_no_check(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED */\ + r2 = *(u64 *)(r1 + 8); \ + /* valid dereference without check for NULL as the parameter is not marked as nullable */\ + r3 = *(u64 *)(r2 + 0); \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - valid load with null") +__success __retval(0) +__naked void ctx_double_ptr_readonly(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null */\ + r3 = *(u64 *)(r2 + 0); \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted) - valid load with arbitrary offset") +__success __retval(0) +__naked void ctx_double_ptr_valid_load_with_offset(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null (PTR_MAYBE_NULL) */\ + /* load with arbitrary offset is protected by an exception handler */\ + r3 = *(u64 *)(r2 + 0x1000); \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - invalid load with double dereference with offset") +__failure __msg("R3 invalid mem access 'scalar'") +__naked void ctx_double_ptr_invalid_load_with_offset(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null (PTR_MAYBE_NULL) */\ + r3 = *(u64 *)(r2 + 0); \ + r4 = *(u64 *)(r3 + 0x1000); \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - invalid narrow load") +__failure __msg("size 4 must be 8") +__naked void ctx_double_ptr_size_check(void) +{ + asm volatile (" \ + r2 = *(u32 *)(r1 + 0); /* invalid narrow load */\ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - invalid store to read only memory") +__failure __msg("R2 cannot write into rdonly_untrusted_mem") +__naked void ctx_double_ptr_write_readonly(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null */\ + *(u64 *)(r2 + 0x0) = 1; /* read only */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - invalid store with offset") +__failure __msg("R2 cannot write into rdonly_untrusted_mem") +__naked void ctx_double_ptr_write_offset_readonly(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null */\ + *(u64 *)(r2 + 0x1000) = 1; /* read only */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fentry/double pointer parameter (rdonly, untrusted, nullable) - invalid store with offset, scalar type") +__failure __msg("R3 invalid mem access 'scalar'") +__naked void ctx_double_ptr_write2_readonly(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null */\ + r3 = *(u64 *)(r2 + 0); /* R3 is a scalar */ \ + *(u64 *)(r3 + 0) = 1; /* scalar */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test14_ppptr") +__description("fentry/triple pointer parameter (rdonly, untrusted, nullable) - invalid store to read only memory") +__failure __msg("R2 cannot write into rdonly_untrusted_mem") +__naked void ctx_double_ptr_write3_readonly(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null */\ + *(u64 *)(r2 + 0) = 1; /* read only */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fentry/bpf_fentry_test14_ppptr") +__description("fentry/triple pointer parameter (rdonly, untrusted, nullable) - invalid mem access (scalar)") +__failure __msg("R3 invalid mem access 'scalar'") +__naked void ctx_double_ptr_write4_readonly(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 0); \ + if r2 == 0 goto l0_%=; /* check for null (PTR_MAYBE_NULL) */\ + r3 = *(u64 *)(r2 + 0); /* R3 type is scalar */ \ + *(u64 *)(r3 + 0) = 1; /* mem access for scalar */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("lsm/sb_eat_lsm_opts") +__description("lsm/double pointer parameter (rdonly, trusted) - invalid load outside boundaries") +__failure __msg("R2 min value is outside of the allowed memory range") +__naked void sb_eat_lsm_opts_trusted_offset_outside_boundaries(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY, PTR_UNTRUSTED is not set */\ + r2 = *(u64 *)(r1 + 8); \ + if r2 == 0 goto l0_%=; /* check for null */\ + /* should fail as for a trusted parameter verifier checks boundaries */\ + r3 = *(u64 *)(r2 + 0x1000); \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("lsm/sb_eat_lsm_opts") +__description("lsm/double pointer parameter (rdonly, trusted) - load within boundaries") +__success +__naked void sb_eat_lsm_opts_trusted_offset_within_boundaries(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY , PTR_UNTRUSTED is not set */\ + r2 = *(u64 *)(r1 + 8); \ + if r2 == 0 goto l0_%=; /* check for null */\ + /* \ + * should pass as for a trusted parameter verifier checks boundaries \ + * and access is within boundaries \ + */ \ + r3 = *(u64 *)(r2 + 0x0); \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("lsm/sb_eat_lsm_opts") +__description("lsm/double pointer parameter (rdonly, trusted) - load within boundaries, no check for null") +__success +__naked void sb_eat_lsm_opts_trusted_offset_within_boundaries_no_null_check(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY , PTR_UNTRUSTED is not set */\ + r2 = *(u64 *)(r1 + 8); \ + /* \ + * should pass as for a trusted parameter verifier checks boundaries \ + * and PTR_MAYBE_NULL is not set \ + */ \ + r3 = *(u64 *)(r2 + 0x0); \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("lsm/sb_eat_lsm_opts") +__description("lsm/double pointer parameter (rdonly, trusted) - invalid store within boundaries to read only mem") +__failure __msg("R2 cannot write into rdonly_mem") +__naked void sb_eat_lsm_opts_trusted_modification_within_boundaries(void) +{ + asm volatile (" \ + /* load double pointer - should be PTR_TO_MEM | MEM_RDONLY , PTR_UNTRUSTED is not set */\ + r2 = *(u64 *)(r1 + 8); \ + if r2 == 0 goto l0_%=; /* check for null */\ + *(u64 *)(r2 + 0x0) = 1; /* read only */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("lsm/sb_eat_lsm_opts") +__description("lsm/double pointer parameter (rdonly, trusted) - invalid store outside boundaries to read only mem") +__failure __msg("R2 cannot write into rdonly_mem") +__naked void sb_eat_lsm_opts_trusted_modification_outside_boundaries(void) +{ + asm volatile (" \ + /* load double pointer - PTR_TO_MEM | MEM_RDONLY , PTR_UNTRUSTED is not set */\ + r2 = *(u64 *)(r1 + 8); \ + if r2 == 0 goto l0_%=; /* check for null */\ + *(u64 *)(r2 + 0x1000) = 1; /* read only */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - valid load") +__success __retval(0) +__naked void ctx_double_ptr_return_load1(void) +{ + asm volatile (" \ + /* load double pointer return value - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 16); \ + if r2 == 0 goto l0_%=; /* check for null */\ + r3 = *(u64 *)(r2 + 0); /* R3 is a scalar */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - valid load with offset") +__success __retval(0) +__naked void ctx_double_ptr_return_load2(void) +{ + asm volatile (" \ + /* load double pointer return value - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 16); \ + if r2 == 0 goto l0_%=; /* check for null */\ + /* verifier doesn't check boundaries for access protect by an exception handler */\ + r3 = *(u64 *)(r2 - 0x100); \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - invalid load with double dereference") +__failure __msg("R3 invalid mem access 'scalar'") +__naked void ctx_double_ptr_return_load3(void) +{ + asm volatile (" \ + /* load double pointer return value - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 16); \ + if r2 == 0 goto l0_%=; /* check for null */\ + r3 = *(u64 *)(r2 + 0); /* R3 is a scalar */ \ + r4 = *(u64 *)(r3 + 0); /* load from scalar */\ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - invalid store to read only memory") +__failure __msg("R2 cannot write into rdonly_untrusted_mem") +__naked void ctx_double_ptr_return_write1(void) +{ + asm volatile (" \ + /* load double pointer return value - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 16); \ + if r2 == 0 goto l0_%=; /* check for null */\ + *(u64 *)(r2 + 0) = 1; /* R2 contains read only memory address */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - invalid store to read only memory with double dereference") +__failure __msg("R3 invalid mem access 'scalar'") +__naked void ctx_double_ptr_return_write2(void) +{ + asm volatile (" \ + /* load double pointer return value - PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED | PTR_MAYBE_NULL */\ + r2 = *(u64 *)(r1 + 16); \ + if r2 == 0 goto l0_%=; /* check for null */\ + r3 = *(u64 *)(r2 + 0); /* R3 is a scalar */ \ + *(u64 *)(r3 + 0) = 1; /* mem access for scalar */ \ +l0_%=: \ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + +struct bpf_fentry_test_pptr_t; + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - bpf helpers with nullable var") +__success __retval(0) +int BPF_PROG(ctx_double_ptr_nulable_var_access_bpf_helpers, + struct bpf_fentry_test_pptr_t **pptr__nullable) +{ + /* Check compatibility with BPF helpers; NULL checks should not be required. */ + void *ptr; + + bpf_probe_read_kernel(&ptr, sizeof(ptr), pptr__nullable); + return 0; +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - bpf helpers with return val") +__success __retval(0) +int BPF_PROG(ctx_double_ptr_return_access_bpf_helpers, __u32 id, + __u32 **pptr, __u32 **ret) +{ + /* Check compatibility with BPF helpers; NULL checks should not be required. */ + void *ptr; + + bpf_probe_read_kernel(&ptr, sizeof(ptr), pptr); + bpf_probe_read_kernel(&ptr, sizeof(ptr), ret); + return 0; +} + +SEC("fentry/bpf_fentry_test11_pptr_nullable") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - bpf helpers with nullable var, direct ctx pointer") +__success __retval(0) +int BPF_PROG(ctx_double_ptr_nulable_var_access_bpf_helpers_ctx, + struct bpf_fentry_test_pptr_t **pptr__nullable) +{ + /* Check compatibility with BPF helpers; NULL checks should not be required. */ + void *ptr; + + bpf_probe_read_kernel(&ptr, sizeof(ptr), &ctx[0] /*pptr__nullable*/); + return 0; +} + +SEC("fexit/bpf_fentry_test12_pptr") +__description("fexit/double pointer return (rdonly, untrusted, nullable) - bpf helpers with return val, direct ctx pointer") +__success __retval(0) +int BPF_PROG(ctx_double_ptr_return_access_bpf_helpers_ctx, __u32 id, + __u32 **pptr, __u32 **ret) +{ + /* Check compatibility with BPF helpers; NULL checks should not be required. */ + void *ptr; + + bpf_probe_read_kernel(&ptr, sizeof(ptr), &ctx[1] /*pptr*/); + bpf_probe_read_kernel(&ptr, sizeof(ptr), &ctx[2] /*ret*/); + return 0; +} + + +char _license[] SEC("license") = "GPL"; -- 2.50.1 (Apple Git-155)
