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{
/* This is equivalent to the following program:
*
* r6 = skb->sk;
* r7 = sk_fullsock(r6);
* r0 = sk_fullsock(r6);
* if (r0 == 0) return 0; (a)
* if (r0 != r7) return 0; (b)
* *r7->type; (c)
* return 0;
*
* It is safe to dereference r7 at point (c), because of (a) and (b).
* The test verifies that relation r0 == r7 is propagated from (b) to (c).
*/
"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JNE false branch",
.insns = {
/* r6 = skb->sk; */
BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
/* if (r6 == 0) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8),
/* r7 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
/* r0 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
/* if (r0 == null) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
/* if (r0 == r7) r0 = *(r7->type); */
BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
/* return 0 */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = ACCEPT,
.result_unpriv = REJECT,
.errstr_unpriv = "R7 pointer comparison",
},
{
/* Same as above, but verify that another branch of JNE still
* prohibits access to PTR_MAYBE_NULL.
*/
"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JNE true branch",
.insns = {
/* r6 = skb->sk */
BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
/* if (r6 == 0) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9),
/* r7 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
/* r0 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
/* if (r0 == null) return 0; */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
/* if (r0 == r7) return 0; */
BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
/* r0 = *(r7->type); */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
/* return 0 */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = REJECT,
.errstr = "R7 invalid mem access 'sock_or_null'",
.result_unpriv = REJECT,
.errstr_unpriv = "R7 pointer comparison",
},
{
/* Same as a first test, but not null should be inferred for JEQ branch */
"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JEQ true branch",
.insns = {
/* r6 = skb->sk; */
BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
/* if (r6 == null) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9),
/* r7 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
/* r0 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
/* if (r0 == null) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
/* if (r0 != r7) return 0; */
BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
/* r0 = *(r7->type); */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
/* return 0; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = ACCEPT,
.result_unpriv = REJECT,
.errstr_unpriv = "R7 pointer comparison",
},
{
/* Same as above, but verify that another branch of JNE still
* prohibits access to PTR_MAYBE_NULL.
*/
"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JEQ false branch",
.insns = {
/* r6 = skb->sk; */
BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
/* if (r6 == null) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8),
/* r7 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
/* r0 = sk_fullsock(skb); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
/* if (r0 == null) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
/* if (r0 != r7) r0 = *(r7->type); */
BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
/* return 0; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = REJECT,
.errstr = "R7 invalid mem access 'sock_or_null'",
.result_unpriv = REJECT,
.errstr_unpriv = "R7 pointer comparison",
},
{
/* Maps are treated in a different branch of `mark_ptr_not_null_reg`,
* so separate test for maps case.
*/
"jne/jeq infer not null, PTR_TO_MAP_VALUE_OR_NULL -> PTR_TO_MAP_VALUE",
.insns = {
/* r9 = &some stack to use as key */
BPF_ST_MEM(BPF_W, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_9, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_9, -8),
/* r8 = process local map */
BPF_LD_MAP_FD(BPF_REG_8, 0),
/* r6 = map_lookup_elem(r8, r9); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
/* r7 = map_lookup_elem(r8, r9); */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
/* if (r6 == 0) return 0; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2),
/* if (r6 != r7) return 0; */
BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_7, 1),
/* read *r7; */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_xdp_sock, queue_id)),
/* return 0; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map_xskmap = { 3 },
.prog_type = BPF_PROG_TYPE_XDP,
.result = ACCEPT,
},
|
