Commit f513c363 authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
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selftests/bpf: Add test for reading from STACK_INVALID slots 



Ensure that when CAP_PERFMON is dropped, and the verifier sees
allow_ptr_leaks as false, we are not permitted to read from a
STACK_INVALID slot. Without the fix, the test will report unexpected
success in loading.

Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241204044757.1483141-5-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent adfdd9c6

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

+18 −0
Original line number Diff line number Diff line
@@ -1244,4 +1244,22 @@ __naked void old_stack_misc_vs_cur_ctx_ptr(void) 
	: __clobber_all);

}



SEC("socket")

__description("stack_noperfmon: reject read of invalid slots")

__success

__caps_unpriv(CAP_BPF)

__failure_unpriv __msg_unpriv("invalid read from stack off -8+1 size 8")

__naked void stack_noperfmon_reject_invalid_read(void)

{

	asm volatile ("					\

	r2 = 1;						\

	r6 = r10;					\

	r6 += -8;					\

	*(u8 *)(r6 + 0) = r2;				\

	r2 = *(u64 *)(r6 + 0);				\

	r0 = 0;						\

	exit;						\

"	::: __clobber_all);

}



char _license[] SEC("license") = "GPL";