Commit 61f506ea authored Oct 14, 2024 by Dimitar Kanaliev Committed by Alexei Starovoitov Oct 15, 2024

selftests/bpf: Add test for truncation after sign extension in coerce_reg_to_size_sx()

Add test that checks whether unsigned ranges deduced by the verifier for
sign extension instruction is correct. Without previous patch that
fixes truncation in coerce_reg_to_size_sx() this test fails.

Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Dimitar Kanaliev <dimitar.kanaliev@siteground.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241014121155.92887-3-dimitar.kanaliev@siteground.com

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent ae67b9fb

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

+20 −0

Original line number	Diff line number	Diff line
		@@ -287,6 +287,26 @@ l0_%=: \
		: __clobber_all);
		}

		SEC("socket")
		__description("MOV64SX, S8, unsigned range_check")
		__success __retval(0)
		__naked void mov64sx_s8_range_check(void)
		{
		asm volatile (" \
		call %[bpf_get_prandom_u32]; \
		r0 &= 0x1; \
		r0 += 0xfe; \
		r0 = (s8)r0; \
		if r0 < 0xfffffffffffffffe goto label_%=; \
		r0 = 0; \
		exit; \
		label_%=: \
		exit; \
		" :
		: __imm(bpf_get_prandom_u32)
		: __clobber_all);
		}

		#else

		SEC("socket")