# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1624892480 -10800
# Node ID b87b7092cedb742477fbcffb879e9ab7a6e55bef
# Parent  41f4bd4c51f132204aaabf8d6ffd6bc2f1a6e1ad
Improved logging of invalid headers.

In 71edd9192f24 logging of invalid headers which were rejected with the
NGX_HTTP_PARSE_INVALID_HEADER error was restricted to just the "client
sent invalid header line" message, without any attempts to log the header
itself.

This patch returns logging of the header up to the invalid character and
the character itself.  The r->header_end pointer is now properly set
in all cases to make logging possible.

The same logging is also introduced when parsing headers from upstream
servers.

diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -2019,10 +2019,12 @@ ngx_http_fastcgi_process_header(ngx_http
                 break;
             }
 
-            /* there was error while a header line parsing */
-
-            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                          "upstream sent invalid header");
+            /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
+
+            ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
+                          "upstream sent invalid header: \"%*s\\x%02xd...\"",
+                          r->header_end - r->header_name_start,
+                          r->header_name_start, *r->header_end);
 
             return NGX_HTTP_UPSTREAM_INVALID_HEADER;
         }
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -2019,10 +2019,12 @@ ngx_http_proxy_process_header(ngx_http_r
             return NGX_AGAIN;
         }
 
-        /* there was error while a header line parsing */
-
-        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                      "upstream sent invalid header");
+        /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
+
+        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
+                      "upstream sent invalid header: \"%*s\\x%02xd...\"",
+                      r->header_end - r->header_name_start,
+                      r->header_name_start, *r->header_end);
 
         return NGX_HTTP_UPSTREAM_INVALID_HEADER;
     }
diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -1140,10 +1140,12 @@ ngx_http_scgi_process_header(ngx_http_re
             return NGX_AGAIN;
         }
 
-        /* there was error while a header line parsing */
-
-        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                      "upstream sent invalid header");
+        /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
+
+        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
+                      "upstream sent invalid header: \"%*s\\x%02xd...\"",
+                      r->header_end - r->header_name_start,
+                      r->header_name_start, *r->header_end);
 
         return NGX_HTTP_UPSTREAM_INVALID_HEADER;
     }
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -1361,10 +1361,12 @@ ngx_http_uwsgi_process_header(ngx_http_r
             return NGX_AGAIN;
         }
 
-        /* there was error while a header line parsing */
-
-        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                      "upstream sent invalid header");
+        /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
+
+        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
+                      "upstream sent invalid header: \"%*s\\x%02xd...\"",
+                      r->header_end - r->header_name_start,
+                      r->header_name_start, *r->header_end);
 
         return NGX_HTTP_UPSTREAM_INVALID_HEADER;
     }
diff --git a/src/http/ngx_http_parse.c b/src/http/ngx_http_parse.c
--- a/src/http/ngx_http_parse.c
+++ b/src/http/ngx_http_parse.c
@@ -894,6 +894,7 @@ ngx_http_parse_header_line(ngx_http_requ
                 }
 
                 if (ch <= 0x20 || ch == 0x7f || ch == ':') {
+                    r->header_end = p;
                     return NGX_HTTP_PARSE_INVALID_HEADER;
                 }
 
@@ -962,6 +963,7 @@ ngx_http_parse_header_line(ngx_http_requ
             }
 
             if (ch <= 0x20 || ch == 0x7f) {
+                r->header_end = p;
                 return NGX_HTTP_PARSE_INVALID_HEADER;
             }
 
@@ -984,6 +986,7 @@ ngx_http_parse_header_line(ngx_http_requ
                 r->header_end = p;
                 goto done;
             case '\0':
+                r->header_end = p;
                 return NGX_HTTP_PARSE_INVALID_HEADER;
             default:
                 r->header_start = p;
@@ -1007,6 +1010,7 @@ ngx_http_parse_header_line(ngx_http_requ
                 r->header_end = p;
                 goto done;
             case '\0':
+                r->header_end = p;
                 return NGX_HTTP_PARSE_INVALID_HEADER;
             }
             break;
@@ -1022,6 +1026,7 @@ ngx_http_parse_header_line(ngx_http_requ
             case LF:
                 goto done;
             case '\0':
+                r->header_end = p;
                 return NGX_HTTP_PARSE_INVALID_HEADER;
             default:
                 state = sw_value;
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -1522,7 +1522,9 @@ ngx_http_process_request_headers(ngx_eve
         /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
 
         ngx_log_error(NGX_LOG_INFO, c->log, 0,
-                      "client sent invalid header line");
+                      "client sent invalid header line: \"%*s\\x%02xd...\"",
+                      r->header_end - r->header_name_start,
+                      r->header_name_start, *r->header_end);
 
         ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
         break;