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[nginx] SCGI: combining headers with identical names (ticket #1724).

Sergey Kandaurov
May 30, 2022 06:34PM
details: https://hg.nginx.org/nginx/rev/75af96daee97
branches:
changeset: 8021:75af96daee97
user: Maxim Dounin <mdounin@mdounin.ru>
date: Mon May 30 21:25:28 2022 +0300
description:
SCGI: combining headers with identical names (ticket #1724).

SCGI specification explicitly forbids headers with duplicate names
(section "3. Request Format"): "Duplicate names are not allowed in
the headers".

Further, provided headers are expected to follow CGI specification,
which also requires to combine headers (RFC 3875, section "4.1.18.
Protocol-Specific Meta-Variables"): "If multiple header fields with
the same field-name are received then the server MUST rewrite them
as a single value having the same semantics".

diffstat:

src/http/modules/ngx_http_scgi_module.c | 50 +++++++++++++++++++++++++++++---
1 files changed, 45 insertions(+), 5 deletions(-)

diffs (106 lines):

diff -r f8f6b9fee66a -r 75af96daee97 src/http/modules/ngx_http_scgi_module.c
--- a/src/http/modules/ngx_http_scgi_module.c Mon May 30 21:25:27 2022 +0300
+++ b/src/http/modules/ngx_http_scgi_module.c Mon May 30 21:25:28 2022 +0300
@@ -633,14 +633,14 @@ static ngx_int_t
ngx_http_scgi_create_request(ngx_http_request_t *r)
{
off_t content_length_n;
- u_char ch, *key, *val, *lowcase_key;
+ u_char ch, sep, *key, *val, *lowcase_key;
size_t len, key_len, val_len, allocated;
ngx_buf_t *b;
ngx_str_t content_length;
ngx_uint_t i, n, hash, skip_empty, header_params;
ngx_chain_t *cl, *body;
ngx_list_part_t *part;
- ngx_table_elt_t *header, **ignored;
+ ngx_table_elt_t *header, *hn, **ignored;
ngx_http_scgi_params_t *params;
ngx_http_script_code_pt code;
ngx_http_script_engine_t e, le;
@@ -707,7 +707,11 @@ ngx_http_scgi_create_request(ngx_http_re
allocated = 0;
lowcase_key = NULL;

- if (params->number) {
+ if (ngx_http_link_multi_headers(r) != NGX_OK) {
+ return NGX_ERROR;
+ }
+
+ if (params->number || r->headers_in.multi) {
n = 0;
part = &r->headers_in.headers.part;

@@ -737,6 +741,12 @@ ngx_http_scgi_create_request(ngx_http_re
i = 0;
}

+ for (n = 0; n < header_params; n++) {
+ if (&header[i] == ignored[n]) {
+ goto next_length;
+ }
+ }
+
if (params->number) {
if (allocated < header[i].key.len) {
allocated = header[i].key.len + 16;
@@ -770,6 +780,15 @@ ngx_http_scgi_create_request(ngx_http_re

len += sizeof("HTTP_") - 1 + header[i].key.len + 1
+ header[i].value.len + 1;
+
+ for (hn = header[i].next; hn; hn = hn->next) {
+ len += hn->value.len + 2;
+ ignored[header_params++] = hn;
+ }
+
+ next_length:
+
+ continue;
}
}

@@ -869,7 +888,7 @@ ngx_http_scgi_create_request(ngx_http_re

for (n = 0; n < header_params; n++) {
if (&header[i] == ignored[n]) {
- goto next;
+ goto next_value;
}
}

@@ -893,12 +912,33 @@ ngx_http_scgi_create_request(ngx_http_re

val = b->last;
b->last = ngx_copy(val, header[i].value.data, header[i].value.len);
+
+ if (header[i].next) {
+
+ if (header[i].key.len == sizeof("Cookie") - 1
+ && ngx_strncasecmp(header[i].key.data, (u_char *) "Cookie",
+ sizeof("Cookie") - 1)
+ == 0)
+ {
+ sep = ';';
+
+ } else {
+ sep = ',';
+ }
+
+ for (hn = header[i].next; hn; hn = hn->next) {
+ *b->last++ = sep;
+ *b->last++ = ' ';
+ b->last = ngx_copy(b->last, hn->value.data, hn->value.len);
+ }
+ }
+
*b->last++ = (u_char) 0;

ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"scgi param: \"%s: %s\"", key, val);

- next:
+ next_value:

continue;
}
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Subject Author Views Posted

[nginx] SCGI: combining headers with identical names (ticket #1724).

Sergey Kandaurov 110 May 30, 2022 06:34PM



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