Commit 8025731c authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add test for narrow ctx load for pointer args 



Ensure that performing narrow ctx loads other than size == 8 are
rejected when the argument is a pointer type.

Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241212092050.3204165-3-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 659b9ba7

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

+36 −0
Original line number Diff line number Diff line
@@ -29,4 +29,40 @@ __naked void ctx_access_u32_pointer_accept(void) 
"	::: __clobber_all);

}



SEC("fentry/bpf_fentry_test9")

__description("btf_ctx_access u32 pointer reject u32")

__failure __msg("size 4 must be 8")

__naked void ctx_access_u32_pointer_reject_32(void)

{

	asm volatile ("					\

	r2 = *(u32 *)(r1 + 0);		/* load 1st argument with narrow load */\

	r0 = 0;						\

	exit;						\

"	::: __clobber_all);

}



SEC("fentry/bpf_fentry_test9")

__description("btf_ctx_access u32 pointer reject u16")

__failure __msg("size 2 must be 8")

__naked void ctx_access_u32_pointer_reject_16(void)

{

	asm volatile ("					\

	r2 = *(u16 *)(r1 + 0);		/* load 1st argument with narrow load */\

	r0 = 0;						\

	exit;						\

"	::: __clobber_all);

}



SEC("fentry/bpf_fentry_test9")

__description("btf_ctx_access u32 pointer reject u8")

__failure __msg("size 1 must be 8")

__naked void ctx_access_u32_pointer_reject_8(void)

{

	asm volatile ("					\

	r2 = *(u8 *)(r1 + 0);		/* load 1st argument with narrow load */\

	r0 = 0;						\

	exit;						\

"	::: __clobber_all);

}



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