Mercurial > hg > nginx
changeset 7545:0ef2bc0ec9c9
Gzip: fixed "zero size buf" alerts after ac5a741d39cf.
After ac5a741d39cf it is now possible that after zstream.avail_out
reaches 0 and we allocate additional buffer, there will be no more data
to put into this buffer, triggering "zero size buf" alert. Fix is to
reset b->temporary flag in this case.
Additionally, an optimization added to avoid allocating additional buffer
in this case, by checking if last deflate() call returned Z_STREAM_END.
Note that checking for Z_STREAM_END by itself is not enough to fix alerts,
as deflate() can return Z_STREAM_END without producing any output if the
buffer is smaller than gzip trailer.
Reported by Witold Filipczyk,
http://mailman.nginx.org/pipermail/nginx-devel/2019-July/012469.html.
| author | Maxim Dounin <mdounin@mdounin.ru> |
|---|---|
| date | Wed, 31 Jul 2019 17:29:00 +0300 |
| parents | e1a3fa4c054f |
| children | fcd92ad76b7b |
| files | src/http/modules/ngx_http_gzip_filter_module.c |
| diffstat | 1 files changed, 11 insertions(+), 4 deletions(-) [+] |
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line diff
--- a/src/http/modules/ngx_http_gzip_filter_module.c +++ b/src/http/modules/ngx_http_gzip_filter_module.c @@ -778,7 +778,7 @@ ngx_http_gzip_filter_deflate(ngx_http_re ctx->out_buf->last = ctx->zstream.next_out; - if (ctx->zstream.avail_out == 0) { + if (ctx->zstream.avail_out == 0 && rc != Z_STREAM_END) { /* zlib wants to output some more gzipped data */ @@ -868,6 +868,7 @@ ngx_http_gzip_filter_deflate_end(ngx_htt ngx_http_gzip_ctx_t *ctx) { int rc; + ngx_buf_t *b; ngx_chain_t *cl; ctx->zin = ctx->zstream.total_in; @@ -888,13 +889,19 @@ ngx_http_gzip_filter_deflate_end(ngx_htt return NGX_ERROR; } - cl->buf = ctx->out_buf; + b = ctx->out_buf; + + if (ngx_buf_size(b) == 0) { + b->temporary = 0; + } + + b->last_buf = 1; + + cl->buf = b; cl->next = NULL; *ctx->last_out = cl; ctx->last_out = &cl->next; - ctx->out_buf->last_buf = 1; - ctx->zstream.avail_in = 0; ctx->zstream.avail_out = 0;