diff options
author | Alexei Starovoitov <ast@kernel.org> | 2018-08-29 10:47:17 -0700 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2018-08-29 10:47:18 -0700 |
commit | d65e6c80c6bb72ced46ce90dea4016d913a8ddd4 (patch) | |
tree | daa8c87faa188cf123e905140f1ab3e995439fc4 | |
parent | 5b24109b0563d45094c470684c1f8cea1af269f8 (diff) | |
parent | a8cf76a9023bc6709b1361d06bb2fae5227b9d68 (diff) |
Merge branch 'bpf_msg_pull_data-fixes'
Daniel Borkmann says:
====================
This set contains three more fixes for the bpf_msg_pull_data()
mainly for correcting scatterlist ring wrap-arounds as well as
fixing up data pointers. For details please see individual patches.
Thanks!
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r-- | net/core/filter.c | 36 |
1 files changed, 19 insertions, 17 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index ec4d67c0cf0c..2c7801f6737a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2282,6 +2282,13 @@ static const struct bpf_func_proto bpf_msg_cork_bytes_proto = { .arg2_type = ARG_ANYTHING, }; +#define sk_msg_iter_var(var) \ + do { \ + var++; \ + if (var == MAX_SKB_FRAGS) \ + var = 0; \ + } while (0) + BPF_CALL_4(bpf_msg_pull_data, struct sk_msg_buff *, msg, u32, start, u32, end, u64, flags) { @@ -2302,14 +2309,13 @@ BPF_CALL_4(bpf_msg_pull_data, if (start < offset + len) break; offset += len; - i++; - if (i == MAX_SKB_FRAGS) - i = 0; + sk_msg_iter_var(i); } while (i != msg->sg_end); if (unlikely(start >= offset + len)) return -EINVAL; + first_sg = i; /* The start may point into the sg element so we need to also * account for the headroom. */ @@ -2317,8 +2323,6 @@ BPF_CALL_4(bpf_msg_pull_data, if (!msg->sg_copy[i] && bytes_sg_total <= len) goto out; - first_sg = i; - /* At this point we need to linearize multiple scatterlist * elements or a single shared page. Either way we need to * copy into a linear buffer exclusively owned by BPF. Then @@ -2331,9 +2335,7 @@ BPF_CALL_4(bpf_msg_pull_data, */ do { copy += sg[i].length; - i++; - if (i == MAX_SKB_FRAGS) - i = 0; + sk_msg_iter_var(i); if (bytes_sg_total <= copy) break; } while (i != msg->sg_end); @@ -2359,9 +2361,7 @@ BPF_CALL_4(bpf_msg_pull_data, sg[i].length = 0; put_page(sg_page(&sg[i])); - i++; - if (i == MAX_SKB_FRAGS) - i = 0; + sk_msg_iter_var(i); } while (i != last_sg); sg[first_sg].length = copy; @@ -2371,11 +2371,15 @@ BPF_CALL_4(bpf_msg_pull_data, * had a single entry though we can just replace it and * be done. Otherwise walk the ring and shift the entries. */ - shift = last_sg - first_sg - 1; + WARN_ON_ONCE(last_sg == first_sg); + shift = last_sg > first_sg ? + last_sg - first_sg - 1 : + MAX_SKB_FRAGS - first_sg + last_sg - 1; if (!shift) goto out; - i = first_sg + 1; + i = first_sg; + sk_msg_iter_var(i); do { int move_from; @@ -2392,15 +2396,13 @@ BPF_CALL_4(bpf_msg_pull_data, sg[move_from].page_link = 0; sg[move_from].offset = 0; - i++; - if (i == MAX_SKB_FRAGS) - i = 0; + sk_msg_iter_var(i); } while (1); msg->sg_end -= shift; if (msg->sg_end < 0) msg->sg_end += MAX_SKB_FRAGS; out: - msg->data = sg_virt(&sg[i]) + start - offset; + msg->data = sg_virt(&sg[first_sg]) + start - offset; msg->data_end = msg->data + bytes; return 0; |