bpf, selftests: Update test case for atomic cmpxchg on r0 with pointer

Fix up unprivileged test case results for 'Dest pointer in r0' verifier tests given they now need to reject R0 containing a pointer value, and add a couple of new related ones with 32bit cmpxchg as well. root@foo:~/bpf/tools/testing/selftests/bpf# ./test_verifier #0/u invalid and of negative number OK #0/p invalid and of negative number OK [...] #1268/p XDP pkt read, pkt_meta' <= pkt_data, bad access 1 OK #1269/p XDP pkt read, pkt_meta' <= pkt_data, bad access 2 OK #1270/p XDP pkt read, pkt_data <= pkt_meta', good access OK #1271/p XDP pkt read, pkt_data <= pkt_meta', bad access 1 OK #1272/p XDP pkt read, pkt_data <= pkt_meta', bad access 2 OK Summary: 1900 PASSED, 0 SKIPPED, 0 FAILED Acked-by: Brendan Jackman <jackmanb@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
raspberrypi · Dec 15, 2021 · e523102 · e523102
1 parent a82fe08
commit e523102
Showing 1 changed file with 65 additions and 2 deletions.
diff --git a/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c b/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
@@ -138,6 +138,8 @@
 		BPF_EXIT_INSN(),
 	},
 	.result = ACCEPT,
+	.result_unpriv = REJECT,
+	.errstr_unpriv = "R0 leaks addr into mem",
 },
 {
 	"Dest pointer in r0 - succeed",
@@ -157,7 +159,7 @@
 	},
 	.result = ACCEPT,
 	.result_unpriv = REJECT,
-	.errstr_unpriv = "leaking pointer from stack off -8",
+	.errstr_unpriv = "R0 leaks addr into mem",
 },
 {
 	"Dest pointer in r0 - succeed, check 2",
@@ -178,5 +180,66 @@
 	},
 	.result = ACCEPT,
 	.result_unpriv = REJECT,
-	.errstr_unpriv = "R5 leaks addr into mem",
+	.errstr_unpriv = "R0 leaks addr into mem",
+},
+{
+	"Dest pointer in r0 - succeed, check 3",
+	.insns = {
+		/* r0 = &val */
+		BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+		/* val = r0; */
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+		/* r5 = &val */
+		BPF_MOV64_REG(BPF_REG_5, BPF_REG_10),
+		/* r0 = atomic_cmpxchg(&val, r0, r5); */
+		BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_5, -8),
+		/* exit(0); */
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.errstr = "invalid size of register fill",
+	.errstr_unpriv = "R0 leaks addr into mem",
+},
+{
+	"Dest pointer in r0 - succeed, check 4",
+	.insns = {
+		/* r0 = &val */
+		BPF_MOV32_REG(BPF_REG_0, BPF_REG_10),
+		/* val = r0; */
+		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -8),
+		/* r5 = &val */
+		BPF_MOV32_REG(BPF_REG_5, BPF_REG_10),
+		/* r0 = atomic_cmpxchg(&val, r0, r5); */
+		BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_5, -8),
+		/* r1 = *r10 */
+		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -8),
+		/* exit(0); */
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.result_unpriv = REJECT,
+	.errstr_unpriv = "R10 partial copy of pointer",
+},
+{
+	"Dest pointer in r0 - succeed, check 5",
+	.insns = {
+		/* r0 = &val */
+		BPF_MOV32_REG(BPF_REG_0, BPF_REG_10),
+		/* val = r0; */
+		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -8),
+		/* r5 = &val */
+		BPF_MOV32_REG(BPF_REG_5, BPF_REG_10),
+		/* r0 = atomic_cmpxchg(&val, r0, r5); */
+		BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_5, -8),
+		/* r1 = *r0 */
+		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, -8),
+		/* exit(0); */
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.errstr = "R0 invalid mem access",
+	.errstr_unpriv = "R10 partial copy of pointer",
 },