diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-04-13 00:10:52 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-04-15 03:40:41 +0200 |
| commit | 074f528eed408b467516e142fa4c45e5b0d2ba16 (patch) | |
| tree | e42352604c4f0db159881faff4b7cef49393d878 /kernel/trace | |
| parent | bpf, verifier: add ARG_PTR_TO_RAW_STACK type (diff) | |
| download | linux-074f528eed408b467516e142fa4c45e5b0d2ba16.tar.xz linux-074f528eed408b467516e142fa4c45e5b0d2ba16.zip | |
bpf: convert relevant helper args to ARG_PTR_TO_RAW_STACK
This patch converts all helpers that can use ARG_PTR_TO_RAW_STACK as argument
type. For tc programs this is bpf_skb_load_bytes(), bpf_skb_get_tunnel_key(),
bpf_skb_get_tunnel_opt(). For tracing, this optimizes bpf_get_current_comm()
and bpf_probe_read(). The check in bpf_skb_load_bytes() for MAX_BPF_STACK can
also be removed since the verifier already makes sure we stay within bounds
on stack buffers.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 413ec5614180..685587885374 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -62,17 +62,21 @@ EXPORT_SYMBOL_GPL(trace_call_bpf); static u64 bpf_probe_read(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { void *dst = (void *) (long) r1; - int size = (int) r2; + int ret, size = (int) r2; void *unsafe_ptr = (void *) (long) r3; - return probe_kernel_read(dst, unsafe_ptr, size); + ret = probe_kernel_read(dst, unsafe_ptr, size); + if (unlikely(ret < 0)) + memset(dst, 0, size); + + return ret; } 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_STACK, + .arg1_type = ARG_PTR_TO_RAW_STACK, .arg2_type = ARG_CONST_STACK_SIZE, .arg3_type = ARG_ANYTHING, }; |