From: Daniel Borkmann <daniel@iogearbox.net>
Date: Mon, 10 Jan 2022 13:44:18 +0000 (+0000)
Subject: bpf, selftests: Add various ringbuf tests with invalid offset
X-Git-Tag: v6.1-rc5~2173^2~7^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=722e4db3ae0d52b2e3801280afbe19cf2d188e91;p=platform%2Fkernel%2Flinux-starfive.git

bpf, selftests: Add various ringbuf tests with invalid offset

Assert that the verifier is rejecting invalid offsets on the ringbuf entries:

  # ./test_verifier | grep ring
  #947/u ringbuf: invalid reservation offset 1 OK
  #947/p ringbuf: invalid reservation offset 1 OK
  #948/u ringbuf: invalid reservation offset 2 OK
  #948/p ringbuf: invalid reservation offset 2 OK

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/tools/testing/selftests/bpf/verifier/ringbuf.c b/tools/testing/selftests/bpf/verifier/ringbuf.c
new file mode 100644
index 0000000..68cae69
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/ringbuf.c
@@ -0,0 +1,64 @@
+{
+	"ringbuf: invalid reservation offset 1",
+	.insns = {
+	/* reserve 8 byte ringbuf memory */
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+	BPF_LD_MAP_FD(BPF_REG_1, 0),
+	BPF_MOV64_IMM(BPF_REG_2, 8),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve),
+	/* store a pointer to the reserved memory in R6 */
+	BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+	/* check whether the reservation was successful */
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
+	/* spill R6(mem) into the stack */
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, -8),
+	/* fill it back in R7 */
+	BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, -8),
+	/* should be able to access *(R7) = 0 */
+	BPF_ST_MEM(BPF_DW, BPF_REG_7, 0, 0),
+	/* submit the reserved ringbuf memory */
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
+	/* add invalid offset to reserved ringbuf memory */
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0xcafe),
+	BPF_MOV64_IMM(BPF_REG_2, 0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_submit),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.fixup_map_ringbuf = { 1 },
+	.result = REJECT,
+	.errstr = "dereference of modified mem ptr R1",
+},
+{
+	"ringbuf: invalid reservation offset 2",
+	.insns = {
+	/* reserve 8 byte ringbuf memory */
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+	BPF_LD_MAP_FD(BPF_REG_1, 0),
+	BPF_MOV64_IMM(BPF_REG_2, 8),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve),
+	/* store a pointer to the reserved memory in R6 */
+	BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+	/* check whether the reservation was successful */
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
+	/* spill R6(mem) into the stack */
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, -8),
+	/* fill it back in R7 */
+	BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, -8),
+	/* add invalid offset to reserved ringbuf memory */
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, 0xcafe),
+	/* should be able to access *(R7) = 0 */
+	BPF_ST_MEM(BPF_DW, BPF_REG_7, 0, 0),
+	/* submit the reserved ringbuf memory */
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
+	BPF_MOV64_IMM(BPF_REG_2, 0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_submit),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.fixup_map_ringbuf = { 1 },
+	.result = REJECT,
+	.errstr = "R7 min value is outside of the allowed memory range",
+},