From 1a776b9ce82d2df9c7ba140588a49721ffb0dc8f Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 17 Oct 2016 14:28:35 +0200 Subject: [PATCH] bpf: add various tests around spill/fill of regs Add several spill/fill tests. Besides others, one that performs xadd on the spilled register, one ldx/stx test where different types are spilled from two branches and read out from common path. Verfier does handle all correctly. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/test_verifier.c | 116 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) diff --git a/samples/bpf/test_verifier.c b/samples/bpf/test_verifier.c index 369ffaa..45cf740 100644 --- a/samples/bpf/test_verifier.c +++ b/samples/bpf/test_verifier.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -1128,6 +1129,108 @@ static struct bpf_test tests[] = { .result = REJECT, }, { + "unpriv: spill/fill of ctx", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + }, + { + "unpriv: spill/fill of ctx 2", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_hash_recalc), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + }, + { + "unpriv: spill/fill of ctx 3", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_hash_recalc), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R1 type=fp expected=ctx", + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + }, + { + "unpriv: spill/fill of ctx 4", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_10, BPF_REG_0, -8, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_hash_recalc), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R1 type=inv expected=ctx", + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + }, + { + "unpriv: spill/fill of different pointers stx", + .insns = { + BPF_MOV64_IMM(BPF_REG_3, 42), + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_2, 0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 1), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0), + BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_3, + offsetof(struct __sk_buff, mark)), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "same insn cannot be used with different pointers", + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + }, + { + "unpriv: spill/fill of different pointers ldx", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, + -(__s32)offsetof(struct bpf_perf_event_data, + sample_period) - 8), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_2, 0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 1), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, + offsetof(struct bpf_perf_event_data, + sample_period)), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "same insn cannot be used with different pointers", + .prog_type = BPF_PROG_TYPE_PERF_EVENT, + }, + { "unpriv: write pointer into map elem value", .insns = { BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), @@ -1194,6 +1297,19 @@ static struct bpf_test tests[] = { .result = REJECT, }, { + "unpriv: spill/fill frame pointer", + .insns = { + BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .errstr = "frame pointer is read only", + .result = REJECT, + }, + { "unpriv: cmp of frame pointer", .insns = { BPF_JMP_IMM(BPF_JEQ, BPF_REG_10, 0, 0), -- 2.7.4