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

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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>
This commit is contained in:
Dimitar Kanaliev 2024-10-14 15:11:54 +03:00 committed by Alexei Starovoitov
parent ae67b9fb8c
commit 61f506eacc
1 changed files with 20 additions and 0 deletions
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20
tools/testing/selftests/bpf/progs/verifier_movsx.c
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@ -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")