diff options
| -rw-r--r-- | kernel/bpf/verifier.c | 27 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 123 |
2 files changed, 138 insertions, 12 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index eb062b0..13551e6 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1895,17 +1895,13 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, dst_reg = ®s[dst]; - if (WARN_ON_ONCE(known && (smin_val != smax_val))) { - print_verifier_state(env, env->cur_state); - verbose(env, - "verifier internal error: known but bad sbounds\n"); - return -EINVAL; - } - if (WARN_ON_ONCE(known && (umin_val != umax_val))) { - print_verifier_state(env, env->cur_state); - verbose(env, - "verifier internal error: known but bad ubounds\n"); - return -EINVAL; + if ((known && (smin_val != smax_val || umin_val != umax_val)) || + smin_val > smax_val || umin_val > umax_val) { + /* Taint dst register if offset had invalid bounds derived from + * e.g. dead branches. + */ + __mark_reg_unknown(dst_reg); + return 0; } if (BPF_CLASS(insn->code) != BPF_ALU64) { @@ -2097,6 +2093,15 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, src_known = tnum_is_const(src_reg.var_off); dst_known = tnum_is_const(dst_reg->var_off); + if ((src_known && (smin_val != smax_val || umin_val != umax_val)) || + smin_val > smax_val || umin_val > umax_val) { + /* Taint dst register if offset had invalid bounds derived from + * e.g. dead branches. + */ + __mark_reg_unknown(dst_reg); + return 0; + } + if (!src_known && opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) { __mark_reg_unknown(dst_reg); diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 67e7c41..5ed4175 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -6732,7 +6732,7 @@ static struct bpf_test tests[] = { BPF_JMP_IMM(BPF_JA, 0, 0, -7), }, .fixup_map1 = { 4 }, - .errstr = "unbounded min value", + .errstr = "R0 invalid mem access 'inv'", .result = REJECT, }, { @@ -8634,6 +8634,127 @@ static struct bpf_test tests[] = { .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { + "check deducing bounds from const, 1", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 1, 0), + BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R0 tried to subtract pointer from scalar", + }, + { + "check deducing bounds from const, 2", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 1, 1), + BPF_EXIT_INSN(), + BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 1, 1), + BPF_EXIT_INSN(), + BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + }, + { + "check deducing bounds from const, 3", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 0, 0), + BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R0 tried to subtract pointer from scalar", + }, + { + "check deducing bounds from const, 4", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + }, + { + "check deducing bounds from const, 5", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1), + BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R0 tried to subtract pointer from scalar", + }, + { + "check deducing bounds from const, 6", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R0 tried to subtract pointer from scalar", + }, + { + "check deducing bounds from const, 7", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, ~0), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 0), + BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0), + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, + offsetof(struct __sk_buff, mark)), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "dereference of modified ctx ptr", + }, + { + "check deducing bounds from const, 8", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, ~0), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1), + BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0), + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, + offsetof(struct __sk_buff, mark)), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "dereference of modified ctx ptr", + }, + { + "check deducing bounds from const, 9", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 0), + BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R0 tried to subtract pointer from scalar", + }, + { + "check deducing bounds from const, 10", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 0, 0), + /* Marks reg as unknown. */ + BPF_ALU64_IMM(BPF_NEG, BPF_REG_0, 0), + BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "math between ctx pointer and register with unbounded min value is not allowed", + }, + { "bpf_exit with invalid return code. test1", .insns = { BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0), |
