Use bpf_packet_pointer to obtain such pkt pointers, and verify various
behaviors, like find_good_pkt_pointers skipping pkt pointers with
unequal pkt_uid, ensuring that offset, len to bpf_packet_pointer are
within limits imposed statically by verifier, rejecting comparion of pkt
pointer with pkt_uid against unequal pkt_uid, ensuring
clear_all_pkt_pointers doens't skip pkt_uid pkts.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
tools/testing/selftests/bpf/verifier/xdp.c | 146 +++++++++++++++++++++
1 file changed, 146 insertions(+)
diff --git a/tools/testing/selftests/bpf/verifier/xdp.c b/tools/testing/selftests/bpf/verifier/xdp.c
index 5ac390508139..580b294cde11 100644
--- a/tools/testing/selftests/bpf/verifier/xdp.c
+++ b/tools/testing/selftests/bpf/verifier/xdp.c
@@ -12,3 +12,149 @@
.prog_type = BPF_PROG_TYPE_XDP,
.retval = 1,
},
+{
+ "XDP bpf_packet_pointer offset cannot be > 0xffff",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 0x10000),
+ BPF_MOV64_IMM(BPF_REG_3, 42),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "R2 must be in range [0, 0xffff]",
+},
+{
+ "XDP bpf_packet_pointer len must be constant",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, ingress_ifindex)),
+ BPF_JMP32_IMM(BPF_JSGE, BPF_REG_2, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_JMP32_IMM(BPF_JSLE, BPF_REG_2, 0xffff, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_2),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "R3 is not a known constant",
+},
+{
+ "XDP bpf_packet_pointer len cannot be 0",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, ingress_ifindex)),
+ BPF_JMP32_IMM(BPF_JSGE, BPF_REG_2, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_JMP32_IMM(BPF_JSLE, BPF_REG_2, 0xffff, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "R3 must be in range [1, 0xffff]",
+},
+{
+ "XDP bpf_packet_pointer R0 cannot be compared with xdp_md pkt ptr",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 42),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct xdp_md, data_end)),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 16),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_0, BPF_REG_1, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "R0, R1 pkt pointer comparison prohibited",
+},
+{
+ "XDP bpf_packet_pointer R0 range propagation skips unequal pkt_uid",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 1),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct xdp_md, data)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_6, offsetof(struct xdp_md, data)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_6, offsetof(struct xdp_md, data)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_6, offsetof(struct xdp_md, data_end)),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 16),
+ BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_4, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, -16),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_2, 4),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_3, 8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "invalid access to packet, off=0 size=8, R0(id=0,off=0,r=1)",
+},
+{
+ "XDP clear_all_pkt_pointers doesn't skip pkt_uid != 0",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 16),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_MOV64_IMM(BPF_REG_2, 1),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_xdp_adjust_tail),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_7, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "R7 invalid mem access 'scalar'",
+},
+{
+ "XDP pkt_uid preserved when resetting range on rX += var",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 16),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_packet_pointer),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct xdp_md, ingress_ifindex)),
+ BPF_JMP32_IMM(BPF_JGE, BPF_REG_1, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_JMP32_IMM(BPF_JLE, BPF_REG_1, 4, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6, offsetof(struct xdp_md, data_end)),
+ BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .result_unpriv = REJECT,
+ .result = REJECT,
+ .errstr = "R1, R0 pkt pointer comparison prohibited",
+},
--
2.35.1
