tools/testing/selftests/bpf/progs/verifier_value_or_null.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/verifier_value_or_null.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/verifier_value_or_null.c
Extension
.c
Size
6877 bytes
Lines
289
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct test_val {
	unsigned int index;
	int foo[MAX_ENTRIES];
};

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, 1);
	__type(key, long long);
	__type(value, struct test_val);
} map_hash_48b SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, 1);
	__type(key, long long);
	__type(value, long long);
} map_hash_8b SEC(".maps");

SEC("tc")
__description("multiple registers share map_lookup_elem result")
__success __retval(0)
__naked void share_map_lookup_elem_result(void)
{
	asm volatile ("					\
	r1 = 10;					\
	*(u64*)(r10 - 8) = r1;				\
	r2 = r10;					\
	r2 += -8;					\
	r1 = %[map_hash_8b] ll;				\
	call %[bpf_map_lookup_elem];			\
	r4 = r0;					\
	if r0 == 0 goto l0_%=;				\
	r1 = 0;						\
	*(u64*)(r4 + 0) = r1;				\
l0_%=:	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b)
	: __clobber_all);
}

SEC("tc")
__description("alu ops on ptr_to_map_value_or_null, 1")
__failure __msg("R4 pointer arithmetic on map_value_or_null")
__naked void map_value_or_null_1(void)
{
	asm volatile ("					\
	r1 = 10;					\
	*(u64*)(r10 - 8) = r1;				\
	r2 = r10;					\
	r2 += -8;					\
	r1 = %[map_hash_8b] ll;				\
	call %[bpf_map_lookup_elem];			\
	r4 = r0;					\
	r4 += -2;					\
	r4 += 2;					\
	if r0 == 0 goto l0_%=;				\
	r1 = 0;						\
	*(u64*)(r4 + 0) = r1;				\
l0_%=:	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b)
	: __clobber_all);
}

SEC("tc")
__description("alu ops on ptr_to_map_value_or_null, 2")
__failure __msg("R4 pointer arithmetic on map_value_or_null")
__naked void map_value_or_null_2(void)
{
	asm volatile ("					\
	r1 = 10;					\
	*(u64*)(r10 - 8) = r1;				\
	r2 = r10;					\
	r2 += -8;					\
	r1 = %[map_hash_8b] ll;				\
	call %[bpf_map_lookup_elem];			\
	r4 = r0;					\
	r4 &= -1;					\
	if r0 == 0 goto l0_%=;				\
	r1 = 0;						\
	*(u64*)(r4 + 0) = r1;				\
l0_%=:	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b)
	: __clobber_all);
}

Annotation

Implementation Notes