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bpf: selftest: Add verifier tests for <8-byte scalar spill and refill
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This patch adds a few verifier tests for <8-byte spill and refill.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210922004953.627183-1-kafai@fb.com
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Martin KaFai Lau authored and Alexei Starovoitov committed Sep 26, 2021
1 parent 54ea607 commit ef97901
Showing 1 changed file with 161 additions and 0 deletions.
161 changes: 161 additions & 0 deletions tools/testing/selftests/bpf/verifier/spill_fill.c
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Original file line number Diff line number Diff line change
Expand Up @@ -104,3 +104,164 @@
.result = ACCEPT,
.retval = POINTER_VALUE,
},
{
"Spill and refill a u32 const scalar. Offset to skb->data",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
/* r4 = 20 */
BPF_MOV32_IMM(BPF_REG_4, 20),
/* *(u32 *)(r10 -8) = r4 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
/* r4 = *(u32 *)(r10 -8) */
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -8),
/* r0 = r2 */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv20 */
BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
/* if (r0 > r3) R0=pkt,off=20 R2=pkt R3=pkt_end R4=inv20 */
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
/* r0 = *(u32 *)r2 R0=pkt,off=20,r=20 R2=pkt,r=20 R3=pkt_end R4=inv20 */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"Spill a u32 const, refill from another half of the uninit u32 from the stack",
.insns = {
/* r4 = 20 */
BPF_MOV32_IMM(BPF_REG_4, 20),
/* *(u32 *)(r10 -8) = r4 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
/* r4 = *(u32 *)(r10 -4) fp-8=????rrrr*/
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid read from stack off -4+0 size 4",
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"Spill a u32 const scalar. Refill as u16. Offset to skb->data",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
/* r4 = 20 */
BPF_MOV32_IMM(BPF_REG_4, 20),
/* *(u32 *)(r10 -8) = r4 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
/* r4 = *(u16 *)(r10 -8) */
BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_10, -8),
/* r0 = r2 */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv,umax=65535 */
BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
/* if (r0 > r3) R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv,umax=65535 */
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
/* r0 = *(u32 *)r2 R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv20 */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"Spill a u32 const scalar. Refill as u16 from fp-6. Offset to skb->data",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
/* r4 = 20 */
BPF_MOV32_IMM(BPF_REG_4, 20),
/* *(u32 *)(r10 -8) = r4 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
/* r4 = *(u16 *)(r10 -6) */
BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_10, -6),
/* r0 = r2 */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv,umax=65535 */
BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
/* if (r0 > r3) R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv,umax=65535 */
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
/* r0 = *(u32 *)r2 R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv20 */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"Spill and refill a u32 const scalar at non 8byte aligned stack addr. Offset to skb->data",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
/* r4 = 20 */
BPF_MOV32_IMM(BPF_REG_4, 20),
/* *(u32 *)(r10 -8) = r4 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
/* *(u32 *)(r10 -4) = r4 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -4),
/* r4 = *(u32 *)(r10 -4), */
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -4),
/* r0 = r2 */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv,umax=U32_MAX */
BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
/* if (r0 > r3) R0=pkt,umax=U32_MAX R2=pkt R3=pkt_end R4=inv */
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
/* r0 = *(u32 *)r2 R0=pkt,umax=U32_MAX R2=pkt R3=pkt_end R4=inv */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"Spill and refill a umax=40 bounded scalar. Offset to skb->data",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_1,
offsetof(struct __sk_buff, tstamp)),
BPF_JMP_IMM(BPF_JLE, BPF_REG_4, 40, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* *(u32 *)(r10 -8) = r4 R4=inv,umax=40 */
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
/* r4 = (*u32 *)(r10 - 8) */
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -8),
/* r2 += r4 R2=pkt R4=inv,umax=40 */
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_4),
/* r0 = r2 R2=pkt,umax=40 R4=inv,umax=40 */
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
/* r2 += 20 R0=pkt,umax=40 R2=pkt,umax=40 */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 20),
/* if (r2 > r3) R0=pkt,umax=40 R2=pkt,off=20,umax=40 */
BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_3, 1),
/* r0 = *(u32 *)r0 R0=pkt,r=20,umax=40 R2=pkt,off=20,r=20,umax=40 */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},

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