Bugs in nginx

[Igor Sysoev]

On Thu, Sep 10, 2009 at 03:10:05PM +0400, Maxim Dounin wrote:

> Hello!
> 
> On Thu, Sep 10, 2009 at 06:29:18AM -0400, gloomen wrote:
> 
> > Friends, help deal with nginx. I can not go to the site.
> > 
> > 502 Bad Gateway
> > nginx/0.7.61
> > 
> > ee /var/log/nginx-error.log
> > 
> > 2009/09/10 14:58:19  734#0: *3 upstream prematurely closed connection while reading response header from upstream, client: 10.10.10.10, server: xxx.net, request: "GET / HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "xxx.net"
> 
> So upstream probably just died.  Likely to be php-related issue, 
> try looking there.
> 
> Anyway it isn't "bugs in nginx".

There is one nginx fastcgi bug when fastcgi sends very large headers.
The attached patch fixes this. In other cases it's more like backend error.


-- 
Igor Sysoev
http://sysoev.ru/en/
-------------- next part --------------
Index: src/http/modules/ngx_http_fastcgi_module.c
===================================================================
--- src/http/modules/ngx_http_fastcgi_module.c	(revision 2379)
+++ src/http/modules/ngx_http_fastcgi_module.c	(working copy)
@@ -1072,9 +1072,10 @@
 static ngx_int_t
 ngx_http_fastcgi_process_header(ngx_http_request_t *r)
 {
-    u_char                         *p, *start, *last, *part_start;
+    u_char                         *p, *msg, *start, *last,
+                                   *part_start, *part_end;
     size_t                          size;
-    ngx_str_t                      *status_line, line, *pattern;
+    ngx_str_t                      *status_line, *pattern;
     ngx_int_t                       rc, status;
     ngx_buf_t                       buf;
     ngx_uint_t                      i;
@@ -1158,40 +1159,39 @@
         if (f->type == NGX_HTTP_FASTCGI_STDERR) {
 
             if (f->length) {
-                line.data = u->buffer.pos;
+                msg = u->buffer.pos;
 
                 if (u->buffer.pos + f->length <= u->buffer.last) {
-                    line.len = f->length;
                     u->buffer.pos += f->length;
                     f->length = 0;
                     f->state = ngx_http_fastcgi_st_padding;
 
                 } else {
-                    line.len = u->buffer.last - u->buffer.pos;
                     f->length -= u->buffer.last - u->buffer.pos;
                     u->buffer.pos = u->buffer.last;
                 }
 
-                while (line.data[line.len - 1] == LF
-                       || line.data[line.len - 1] == CR
-                       || line.data[line.len - 1] == '.'
-                       || line.data[line.len - 1] == ' ')
-                {
-                    line.len--;
+                for (p = u->buffer.pos - 1; msg < p; p--) {
+                    if (*p != LF && *p != CR && *p != '.' && *p != ' ') {
+                        break;
+                    }
                 }
 
+                p++;
+
                 ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                              "FastCGI sent in stderr: \"%V\"", &line);
+                              "FastCGI sent in stderr: \"%*s\"", p - msg, msg);
 
                 flcf = ngx_http_get_module_loc_conf(r, ngx_http_fastcgi_module);
 
                 if (flcf->catch_stderr) {
                     pattern = flcf->catch_stderr->elts;
 
-                    line.data[line.len - 1] = '\0';
-
                     for (i = 0; i < flcf->catch_stderr->nelts; i++) {
-                        if (ngx_strstr(line.data, pattern[i].data)) {
+                        if (ngx_strnstr(msg, (char *) pattern[i].data,
+                                        p - msg)
+                            != NULL)
+                        {
                             return NGX_HTTP_UPSTREAM_INVALID_HEADER;
                         }
                     }
@@ -1244,6 +1244,7 @@
         for ( ;; ) {
 
             part_start = u->buffer.pos;
+            part_end = u->buffer.last;
 
             rc = ngx_http_parse_header_line(r, &u->buffer, 1);
 
@@ -1444,8 +1445,12 @@
         part = ngx_array_push(f->split_parts);
 
         part->start = part_start;
-        part->end = u->buffer.last;
+        part->end = part_end;
 
+        if (u->buffer.pos < u->buffer.last) {
+            continue;
+        }
+
         return NGX_AGAIN;
     }
 }
@@ -1454,9 +1459,9 @@
 static ngx_int_t
 ngx_http_fastcgi_input_filter(ngx_event_pipe_t *p, ngx_buf_t *buf)
 {
+    u_char                  *m, *msg;
     ngx_int_t                rc;
     ngx_buf_t               *b, **prev;
-    ngx_str_t                line;
     ngx_chain_t             *cl;
     ngx_http_request_t      *r;
     ngx_http_fastcgi_ctx_t  *f;
@@ -1540,30 +1545,27 @@
                     break;
                 }
 
-                line.data = f->pos;
+                msg = f->pos;
 
                 if (f->pos + f->length <= f->last) {
-                    line.len = f->length;
                     f->pos += f->length;
                     f->length = 0;
                     f->state = ngx_http_fastcgi_st_padding;
 
                 } else {
-                    line.len = f->last - f->pos;
                     f->length -= f->last - f->pos;
                     f->pos = f->last;
                 }
 
-                while (line.data[line.len - 1] == LF
-                       || line.data[line.len - 1] == CR
-                       || line.data[line.len - 1] == '.'
-                       || line.data[line.len - 1] == ' ')
-                {
-                    line.len--;
+                for (m = f->pos - 1; msg < m; m--) {
+                    if (*m != LF && *m != CR && *m != '.' && *m != ' ') {
+                        break;
+                    }
                 }
 
                 ngx_log_error(NGX_LOG_ERR, p->log, 0,
-                              "FastCGI sent in stderr: \"%V\"", &line);
+                              "FastCGI sent in stderr: \"%*s\"",
+                              m + 1 - msg, msg);
 
                 if (f->pos == f->last) {
                     break;