diff options
Diffstat (limited to 'kernel/trace/bpf_trace.c')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 82 |
1 files changed, 62 insertions, 20 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index fa77311dadb2..cee9802cf3e0 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -76,8 +76,8 @@ static const struct bpf_func_proto bpf_probe_read_proto = { .func = bpf_probe_read, .gpl_only = true, .ret_type = RET_INTEGER, - .arg1_type = ARG_PTR_TO_RAW_STACK, - .arg2_type = ARG_CONST_STACK_SIZE, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE, .arg3_type = ARG_ANYTHING, }; @@ -109,8 +109,8 @@ static const struct bpf_func_proto bpf_probe_write_user_proto = { .gpl_only = true, .ret_type = RET_INTEGER, .arg1_type = ARG_ANYTHING, - .arg2_type = ARG_PTR_TO_STACK, - .arg3_type = ARG_CONST_STACK_SIZE, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, }; static const struct bpf_func_proto *bpf_get_probe_write_proto(void) @@ -213,8 +213,8 @@ static const struct bpf_func_proto bpf_trace_printk_proto = { .func = bpf_trace_printk, .gpl_only = true, .ret_type = RET_INTEGER, - .arg1_type = ARG_PTR_TO_STACK, - .arg2_type = ARG_CONST_STACK_SIZE, + .arg1_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_CONST_SIZE, }; const struct bpf_func_proto *bpf_get_trace_printk_proto(void) @@ -329,8 +329,8 @@ static const struct bpf_func_proto bpf_perf_event_output_proto = { .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, - .arg4_type = ARG_PTR_TO_STACK, - .arg5_type = ARG_CONST_STACK_SIZE, + .arg4_type = ARG_PTR_TO_MEM, + .arg5_type = ARG_CONST_SIZE, }; static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs); @@ -395,6 +395,36 @@ static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { .arg2_type = ARG_ANYTHING, }; +BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, + const void *, unsafe_ptr) +{ + int ret; + + /* + * The strncpy_from_unsafe() call will likely not fill the entire + * buffer, but that's okay in this circumstance as we're probing + * arbitrary memory anyway similar to bpf_probe_read() and might + * as well probe the stack. Thus, memory is explicitly cleared + * only in error case, so that improper users ignoring return + * code altogether don't copy garbage; otherwise length of string + * is returned that can be used for bpf_perf_event_output() et al. + */ + ret = strncpy_from_unsafe(dst, unsafe_ptr, size); + if (unlikely(ret < 0)) + memset(dst, 0, size); + + return ret; +} + +static const struct bpf_func_proto bpf_probe_read_str_proto = { + .func = bpf_probe_read_str, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_ANYTHING, +}; + static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) { switch (func_id) { @@ -432,6 +462,8 @@ static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) return &bpf_current_task_under_cgroup_proto; case BPF_FUNC_get_prandom_u32: return &bpf_get_prandom_u32_proto; + case BPF_FUNC_probe_read_str: + return &bpf_probe_read_str_proto; default: return NULL; } @@ -459,6 +491,13 @@ static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type return false; if (off % size != 0) return false; + /* + * Assertion for 32 bit to make sure last 8 byte access + * (BPF_DW) to the last 4 byte member is disallowed. + */ + if (off + size > sizeof(struct pt_regs)) + return false; + return true; } @@ -467,7 +506,7 @@ static const struct bpf_verifier_ops kprobe_prog_ops = { .is_valid_access = kprobe_prog_is_valid_access, }; -static struct bpf_prog_type_list kprobe_tl = { +static struct bpf_prog_type_list kprobe_tl __ro_after_init = { .ops = &kprobe_prog_ops, .type = BPF_PROG_TYPE_KPROBE, }; @@ -492,8 +531,8 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, - .arg4_type = ARG_PTR_TO_STACK, - .arg5_type = ARG_CONST_STACK_SIZE, + .arg4_type = ARG_PTR_TO_MEM, + .arg5_type = ARG_CONST_SIZE, }; BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, @@ -540,6 +579,8 @@ static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type return false; if (off % size != 0) return false; + + BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); return true; } @@ -548,7 +589,7 @@ static const struct bpf_verifier_ops tracepoint_prog_ops = { .is_valid_access = tp_prog_is_valid_access, }; -static struct bpf_prog_type_list tracepoint_tl = { +static struct bpf_prog_type_list tracepoint_tl __ro_after_init = { .ops = &tracepoint_prog_ops, .type = BPF_PROG_TYPE_TRACEPOINT, }; @@ -572,28 +613,29 @@ static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type return true; } -static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, int dst_reg, - int src_reg, int ctx_off, +static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, + const struct bpf_insn *si, struct bpf_insn *insn_buf, struct bpf_prog *prog) { struct bpf_insn *insn = insn_buf; - switch (ctx_off) { + switch (si->off) { case offsetof(struct bpf_perf_event_data, sample_period): BUILD_BUG_ON(FIELD_SIZEOF(struct perf_sample_data, period) != sizeof(u64)); *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, - data), dst_reg, src_reg, + data), si->dst_reg, si->src_reg, offsetof(struct bpf_perf_event_data_kern, data)); - *insn++ = BPF_LDX_MEM(BPF_DW, dst_reg, dst_reg, + *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, offsetof(struct perf_sample_data, period)); break; default: *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, - regs), dst_reg, src_reg, + regs), si->dst_reg, si->src_reg, offsetof(struct bpf_perf_event_data_kern, regs)); - *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), dst_reg, dst_reg, ctx_off); + *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, + si->off); break; } @@ -606,7 +648,7 @@ static const struct bpf_verifier_ops perf_event_prog_ops = { .convert_ctx_access = pe_prog_convert_ctx_access, }; -static struct bpf_prog_type_list perf_event_tl = { +static struct bpf_prog_type_list perf_event_tl __ro_after_init = { .ops = &perf_event_prog_ops, .type = BPF_PROG_TYPE_PERF_EVENT, }; |