Mercurial > hg > nginx
comparison src/os/unix/ngx_files.c @ 6574:7eb19447b2de
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.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 31 May 2016 05:13:30 +0300 |
parents | f01ab2dbcfdc |
children | 577628e6b6a6 |
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6573:2d5d35409eba | 6574:7eb19447b2de |
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354 prev = NULL; | 354 prev = NULL; |
355 total = 0; | 355 total = 0; |
356 n = 0; | 356 n = 0; |
357 | 357 |
358 for ( /* void */ ; cl; cl = cl->next) { | 358 for ( /* void */ ; cl; cl = cl->next) { |
359 | |
360 if (ngx_buf_special(cl->buf)) { | |
361 continue; | |
362 } | |
363 | |
359 size = cl->buf->last - cl->buf->pos; | 364 size = cl->buf->last - cl->buf->pos; |
360 | 365 |
361 if (prev == cl->buf->pos) { | 366 if (prev == cl->buf->pos) { |
362 iov->iov_len += size; | 367 iov->iov_len += size; |
363 | 368 |