From: Maxim Mikityanskiy <maxim@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
---
.../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";
--
2.42.1
