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selftests/bpf: Test assigning ID to scalars on spill

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The previous commit implemented assigning IDs to registers holding
scalars before spill. Add the test cases to check the new functionality.

Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240108205209.838365-10-maxtram95@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Maxim Mikityanskiy 2024-01-08 22:52:03 +02:00 committed by Alexei Starovoitov
parent 8ecfc371d8
commit 3893f0b6a0
1 changed files with 133 additions and 0 deletions
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133
tools/testing/selftests/bpf/progs/verifier_spill_fill.c
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@ -766,4 +766,137 @@ l0_%=: r0 = 0; \
: __clobber_all);
}
SEC("xdp")
__description("64-bit spill of 64-bit reg should assign ID")
__success __retval(0)
__naked void spill_64bit_of_64bit_ok(void)
{
asm volatile (" \
/* Roll one bit to make the register inexact. */\
call %[bpf_get_prandom_u32]; \
r0 &= 0x80000000; \
r0 <<= 32; \
/* 64-bit spill r0 to stack - should assign an ID. */\
*(u64*)(r10 - 8) = r0; \
/* 64-bit fill r1 from stack - should preserve the ID. */\
r1 = *(u64*)(r10 - 8); \
/* Compare r1 with another register to trigger find_equal_scalars.\
* Having one random bit is important here, otherwise the verifier cuts\
* the corners. \
*/ \
r2 = 0; \
if r1 != r2 goto l0_%=; \
/* The result of this comparison is predefined. */\
if r0 == r2 goto l0_%=; \
/* Dead branch: the verifier should prune it. Do an invalid memory\
* access if the verifier follows it. \
*/ \
r0 = *(u64*)(r9 + 0); \
exit; \
l0_%=: r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("xdp")
__description("32-bit spill of 32-bit reg should assign ID")
__success __retval(0)
__naked void spill_32bit_of_32bit_ok(void)
{
asm volatile (" \
/* Roll one bit to make the register inexact. */\
call %[bpf_get_prandom_u32]; \
w0 &= 0x80000000; \
/* 32-bit spill r0 to stack - should assign an ID. */\
*(u32*)(r10 - 8) = r0; \
/* 32-bit fill r1 from stack - should preserve the ID. */\
r1 = *(u32*)(r10 - 8); \
/* Compare r1 with another register to trigger find_equal_scalars.\
* Having one random bit is important here, otherwise the verifier cuts\
* the corners. \
*/ \
r2 = 0; \
if r1 != r2 goto l0_%=; \
/* The result of this comparison is predefined. */\
if r0 == r2 goto l0_%=; \
/* Dead branch: the verifier should prune it. Do an invalid memory\
* access if the verifier follows it. \
*/ \
r0 = *(u64*)(r9 + 0); \
exit; \
l0_%=: r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("xdp")
__description("16-bit spill of 16-bit reg should assign ID")
__success __retval(0)
__naked void spill_16bit_of_16bit_ok(void)
{
asm volatile (" \
/* Roll one bit to make the register inexact. */\
call %[bpf_get_prandom_u32]; \
r0 &= 0x8000; \
/* 16-bit spill r0 to stack - should assign an ID. */\
*(u16*)(r10 - 8) = r0; \
/* 16-bit fill r1 from stack - should preserve the ID. */\
r1 = *(u16*)(r10 - 8); \
/* Compare r1 with another register to trigger find_equal_scalars.\
* Having one random bit is important here, otherwise the verifier cuts\
* the corners. \
*/ \
r2 = 0; \
if r1 != r2 goto l0_%=; \
/* The result of this comparison is predefined. */\
if r0 == r2 goto l0_%=; \
/* Dead branch: the verifier should prune it. Do an invalid memory\
* access if the verifier follows it. \
*/ \
r0 = *(u64*)(r9 + 0); \
exit; \
l0_%=: r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("xdp")
__description("8-bit spill of 8-bit reg should assign ID")
__success __retval(0)
__naked void spill_8bit_of_8bit_ok(void)
{
asm volatile (" \
/* Roll one bit to make the register inexact. */\
call %[bpf_get_prandom_u32]; \
r0 &= 0x80; \
/* 8-bit spill r0 to stack - should assign an ID. */\
*(u8*)(r10 - 8) = r0; \
/* 8-bit fill r1 from stack - should preserve the ID. */\
r1 = *(u8*)(r10 - 8); \
/* Compare r1 with another register to trigger find_equal_scalars.\
* Having one random bit is important here, otherwise the verifier cuts\
* the corners. \
*/ \
r2 = 0; \
if r1 != r2 goto l0_%=; \
/* The result of this comparison is predefined. */\
if r0 == r2 goto l0_%=; \
/* Dead branch: the verifier should prune it. Do an invalid memory\
* access if the verifier follows it. \
*/ \
r0 = *(u64*)(r9 + 0); \
exit; \
l0_%=: r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
char _license[] SEC("license") = "GPL";