From: Maxim Mikityanskiy maxim@isovalent.com
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 --- .../selftests/bpf/progs/verifier_spill_fill.c | 133 ++++++++++++++++++ 1 file changed, 133 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c index f2c1fe5b1dba..86881eaab4e2 100644 --- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c +++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c @@ -768,4 +768,137 @@ 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";