diff options
author | Maxim Dounin <mdounin@mdounin.ru> | 2016-05-31 05:13:30 +0300 |
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committer | Maxim Dounin <mdounin@mdounin.ru> | 2016-05-31 05:13:30 +0300 |
commit | 969105accdcc3df885082a90012eb5cc8f31d5b7 (patch) | |
tree | 1f18de9d677f480cfd8882106c27d2d7ecf4a420 | |
parent | 91c1a88b46aad82eeaf3adefb632320c10284791 (diff) |
Core: skip special buffers on writing (ticket #981).
A special last buffer with cl->buf->pos set to NULL can be present in
a chain when writing request body if chunked encoding was used. This
resulted in a NULL pointer dereference if it happened to be the only
buffer left after a do...while loop iteration in ngx_write_chain_to_file().
The problem originally appeared in nginx 1.3.9 with chunked encoding
support. Additionally, rev. 3832b608dc8d (nginx 1.9.13) changed the
minimum number of buffers to trigger this from IOV_MAX (typically 1024)
to NGX_IOVS_PREALLOCATE (typically 64).
Fix is to skip such buffers in ngx_chain_to_iovec(), much like it is
done in other places.
-rw-r--r-- | src/os/unix/ngx_files.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/os/unix/ngx_files.c b/src/os/unix/ngx_files.c index 65c79a241..7fbb7c9a7 100644 --- a/src/os/unix/ngx_files.c +++ b/src/os/unix/ngx_files.c @@ -356,6 +356,11 @@ ngx_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *cl) n = 0; for ( /* void */ ; cl; cl = cl->next) { + + if (ngx_buf_special(cl->buf)) { + continue; + } + size = cl->buf->last - cl->buf->pos; if (prev == cl->buf->pos) { |