diff mbox series

[bpf,2/2] selftests: bpf: add test for JMP32 JSET BPF_X with upper bits set

Message ID 20200305234416.31597-2-luke.r.nels@gmail.com (mailing list archive)
State Mainlined
Commit 93e5fbb18cec70b3b5c614f67b65388829113bdd
Headers show
Series [bpf,1/2] bpf, x32: fix bug with JMP32 JSET BPF_X checking upper bits | expand

Commit Message

Luke Nelson March 5, 2020, 11:44 p.m. UTC 
The existing tests attempt to check that JMP32 JSET ignores the upper
bits in the operand registers. However, the tests missed one such bug in
the x32 JIT that is only uncovered when a previous instruction pollutes
the upper 32 bits of the registers.

This patch adds a new test case that catches the bug by first executing
a 64-bit JSET to pollute the upper 32-bits of the temporary registers,
followed by a 32-bit JSET which should ignore the upper 32 bits.

Co-developed-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
---
 tools/testing/selftests/bpf/verifier/jmp32.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/verifier/jmp32.c b/tools/testing/selftests/bpf/verifier/jmp32.c
index bf0322eb5346..bd5cae4a7f73 100644
--- a/tools/testing/selftests/bpf/verifier/jmp32.c
+++ b/tools/testing/selftests/bpf/verifier/jmp32.c
@@ -61,6 +61,21 @@ 
 	},
 	.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
 },
+{
+	"jset32: ignores upper bits",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_LD_IMM64(BPF_REG_7, 0x8000000000000000),
+	BPF_LD_IMM64(BPF_REG_8, 0x8000000000000000),
+	BPF_JMP_REG(BPF_JSET, BPF_REG_7, BPF_REG_8, 1),
+	BPF_EXIT_INSN(),
+	BPF_JMP32_REG(BPF_JSET, BPF_REG_7, BPF_REG_8, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 2,
+},
 {
 	"jset32: min/max deduction",
 	.insns = {