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author | Daniel Borkmann <daniel@iogearbox.net> | 2016-07-22 02:19:42 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2016-07-25 20:34:11 +0300 |
commit | aa7145c16d6bf086538ad7eb20c807513bfa5efc (patch) | |
tree | dbaccc895163a74c9b87c71eeff8c1f59d4f2a9e /include/linux/bpf.h | |
parent | a1b43eddaec5a3fea55e1581caf217abda2d3147 (diff) | |
download | linux-aa7145c16d6bf086538ad7eb20c807513bfa5efc.tar.xz |
bpf, events: fix offset in skb copy handler
This patch fixes the __output_custom() routine we currently use with
bpf_skb_copy(). I missed that when len is larger than the size of the
current handle, we can issue multiple invocations of copy_func, and
__output_custom() advances destination but also source buffer by the
written amount of bytes. When we have __output_custom(), this is actually
wrong since in that case the source buffer points to a non-linear object,
in our case an skb, which the copy_func helper is supposed to walk.
Therefore, since this is non-linear we thus need to pass the offset into
the helper, so that copy_func can use it for extracting the data from
the source object.
Therefore, adjust the callback signatures properly and pass offset
into the skb_header_pointer() invoked from bpf_skb_copy() callback. The
__DEFINE_OUTPUT_COPY_BODY() is adjusted to accommodate for two things:
i) to pass in whether we should advance source buffer or not; this is
a compile-time constant condition, ii) to pass in the offset for
__output_custom(), which we do with help of __VA_ARGS__, so everything
can stay inlined as is currently. Both changes allow for adapting the
__output_* fast-path helpers w/o extra overhead.
Fixes: 555c8a8623a3 ("bpf: avoid stack copy and use skb ctx for event output")
Fixes: 7e3f977edd0b ("perf, events: add non-linear data support for raw records")
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 'include/linux/bpf.h')
-rw-r--r-- | include/linux/bpf.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 36da0749205a..11134238417d 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -211,7 +211,7 @@ bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *f const struct bpf_func_proto *bpf_get_trace_printk_proto(void); typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src, - unsigned long len); + unsigned long off, unsigned long len); u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy); |