package/nginx-naxsi: fix build with pcre2

Fix the following build failure raised since bump of nginx to version
1.22.1 in commit 722b84eafa5e3d9540e0a80bae0c971a3a778358:

/home/buildroot/autobuild/run/instance-2/output-1/build/nginx-naxsi-1.3/naxsi_src/naxsi_runtime.c: In function 'ngx_http_process_basic_rule_buffer':
/home/buildroot/autobuild/run/instance-2/output-1/build/nginx-naxsi-1.3/naxsi_src/naxsi_runtime.c:205:61: error: invalid use of incomplete typedef 'ngx_regex_t' {aka 'struct pcre2_real_code_8'}
  205 |       (tmp_idx < len && (match = pcre_exec(rl->br->rx->regex->code,
      |                                                             ^~

Fixes:
 - http://autobuild.buildroot.org/results/7fff888bd36710e2d2f5bb39a38597e8c04305ce

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/nginx-naxsi/0002-PCRE2-compatibility.patch

@@ -0,0 +1,221 @@
+From 2937c44276cba21601ade4e265d32515f570d68c Mon Sep 17 00:00:00 2001
+From: Danila Vershinin <ciapnz@gmail.com>
+Date: Thu, 16 Jun 2022 01:22:23 +0300
+Subject: [PATCH] PCRE2 compatibility (#587)
+
+* Fix: use pcre2 when building with nginx >= 1.21.5
+
+I've tried to compile naxsi 1.3 as module for nginx 1.21.6, and got the error:
+
+error: invalid use of incomplete typedef 'ngx_regex_t' {aka 'struct pcre2_real_code_8'}
+  205 |       (tmp_idx < len && (match = pcre_exec(rl->br->rx->regex->code,
+
+I found this issue report: Ref: https://github.com/nbs-system/naxsi/issues/580
+then i tried to solve the pcre2 compatibility issue.
+
+I've included an helper function that is 'copied' from: https://github.com/nginx/nginx/blob/master/src/core/ngx_regex.c#L393
+that it is called in place of 'pcre_exec' when nginx_version >= 1021005
+
+Not sure if this is the best solution, but I managed to build naxsi 1.3 as module for nginx 1.21.6 succesfully, and it seems to work well.
+
+I'm not used to develop in C anymore (since 25 years ago, at least!), but I hope that this patch I made can help anybody else.
+
+* Added a check for nginx_version >= 1021005
+
+Added a check for nginx_version >= 1021005 to avoid helper function definition on older versions
+
+* Use NGX_PCRE2 conditional
+
+Update naxsi.h
+
+Don't include pcre.h in order for compilation to work both against pcre and pcre2
+
+Fix pcre vs pcre2 compilation
+
+Co-authored-by: laluigino <99279306+laluigino@users.noreply.github.com>
+[Retrieved from:
+https://github.com/nbs-system/naxsi/commit/2937c44276cba21601ade4e265d32515f570d68c]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ naxsi_src/naxsi.h         |  1 -
+ naxsi_src/naxsi_config.c  |  9 ++++-
+ naxsi_src/naxsi_runtime.c | 82 ++++++++++++++++++++++++++++++++++++++-
+ naxsi_src/naxsi_utils.c   |  8 ++++
+ 4 files changed, 96 insertions(+), 4 deletions(-)
+
+diff --git a/naxsi_src/naxsi.h b/naxsi_src/naxsi.h
+index 53df1bd8..b2f5c1a5 100644
+--- a/naxsi_src/naxsi.h
++++ b/naxsi_src/naxsi.h
+@@ -19,7 +19,6 @@
+ #include <ngx_http.h>
+ #include <ngx_http_core_module.h>
+ #include <ngx_md5.h>
+-#include <pcre.h>
+ 
+ extern ngx_module_t ngx_http_naxsi_module;
+ 
+diff --git a/naxsi_src/naxsi_config.c b/naxsi_src/naxsi_config.c
+index 4ea15567..6d2f0e23 100644
+--- a/naxsi_src/naxsi_config.c
++++ b/naxsi_src/naxsi_config.c
+@@ -322,8 +322,11 @@ naxsi_zone(ngx_conf_t* r, ngx_str_t* tmp, ngx_http_rule_t* rule)
+ 
+         custom_rule->target_rx = ngx_pcalloc(r->pool, sizeof(ngx_regex_compile_t));
+         return_value_if(!custom_rule->target_rx, NGX_CONF_ERROR);
+-
++#if (NGX_PCRE2)
++        custom_rule->target_rx->options  = PCRE2_CASELESS | PCRE2_MULTILINE;
++#else
+         custom_rule->target_rx->options  = PCRE_CASELESS | PCRE_MULTILINE;
++#endif
+         custom_rule->target_rx->pattern  = custom_rule->target;
+         custom_rule->target_rx->pool     = r->pool;
+         custom_rule->target_rx->err.len  = 0;
+@@ -442,7 +445,11 @@ naxsi_rx(ngx_conf_t* r, ngx_str_t* tmp, ngx_http_rule_t* rule)
+   ha.len  = tmp->len - strlen(RX_T);
+   rgc     = ngx_pcalloc(r->pool, sizeof(ngx_regex_compile_t));
+   return_value_if(!rgc, NGX_CONF_ERROR);
++#if (NGX_PCRE2)
++  rgc->options  = PCRE2_CASELESS | PCRE2_MULTILINE;
++#else
+   rgc->options  = PCRE_CASELESS | PCRE_MULTILINE;
++#endif
+   rgc->pattern  = ha;
+   rgc->pool     = r->pool;
+   rgc->err.len  = 0;
+diff --git a/naxsi_src/naxsi_runtime.c b/naxsi_src/naxsi_runtime.c
+index d548ce37..784852b0 100644
+--- a/naxsi_src/naxsi_runtime.c
++++ b/naxsi_src/naxsi_runtime.c
+@@ -181,6 +181,75 @@ ngx_http_naxsi_rawbody_parse(ngx_http_request_ctx_t* ctx,
+ unsigned char*
+ ngx_utf8_check(ngx_str_t* str);
+ 
++#if defined nginx_version && (nginx_version >= 1021005)
++/*
++ * variables to use pcre2
++ */
++static pcre2_match_data       *ngx_pcre2_match_data;
++static ngx_uint_t              ngx_pcre2_match_data_size;
++
++/*
++ * helper function to use pcre2
++ */
++ngx_int_t
++ngx_pcre2_exec(ngx_regex_t *re, unsigned char* str, unsigned int len, ngx_int_t tmp_idx, int *captures, ngx_uint_t size)
++{
++    size_t      *ov;
++    ngx_int_t    rc;
++    ngx_uint_t   n, i;
++
++    /*
++     * The pcre2_match() function might allocate memory for backtracking
++     * frames, typical allocations are from 40k and above.  So the allocator
++     * is configured to do direct allocations from heap during matching.
++     */
++
++    if (ngx_pcre2_match_data == NULL
++        || size > ngx_pcre2_match_data_size)
++    {
++        /*
++         * Allocate a match data if not yet allocated or smaller than
++         * needed.
++         */
++
++        if (ngx_pcre2_match_data) {
++            pcre2_match_data_free(ngx_pcre2_match_data);
++        }
++
++        ngx_pcre2_match_data_size = size;
++        ngx_pcre2_match_data = pcre2_match_data_create(size / 3, NULL);
++
++        if (ngx_pcre2_match_data == NULL) {
++            rc = PCRE2_ERROR_NOMEMORY;
++            goto failed;
++        }
++    }
++
++    rc = pcre2_match(re, str, len, tmp_idx, 0, ngx_pcre2_match_data, NULL);
++
++    if (rc < 0) {
++        goto failed;
++    }
++
++    n = pcre2_get_ovector_count(ngx_pcre2_match_data);
++    ov = pcre2_get_ovector_pointer(ngx_pcre2_match_data);
++
++    if (n > size / 3) {
++        n = size / 3;
++    }
++
++    for (i = 0; i < n; i++) {
++        captures[i * 2] = ov[i * 2];
++        captures[i * 2 + 1] = ov[i * 2 + 1];
++    }
++
++failed:
++
++    return rc;
++
++}
++#endif
++
+ /*
+ ** in : string to inspect, associated rule
+ ** does : apply the rule on the string, return 1 if matched,
+@@ -201,7 +270,14 @@ ngx_http_process_basic_rule_buffer(ngx_str_t* str, ngx_http_rule_t* rl, ngx_int_
+     tmp_idx = 0;
+     len     = str->len;
+     while
+-#if defined   nginx_version && (nginx_version >= 1002002 && nginx_version != 1003000)
++#if (NGX_PCRE2)
++      (tmp_idx < len && (match = ngx_pcre2_exec(rl->br->rx->regex,                         
++                                           str->data,
++                                           str->len,
++                                           tmp_idx,
++                                           captures,
++                                           30)) >= 0)
++#elif defined nginx_version && (nginx_version >= 1002002 && nginx_version != 1003000)
+       (tmp_idx < len && (match = pcre_exec(rl->br->rx->regex->code,
+                                            0,
+                                            (const char*)str->data,
+@@ -496,7 +572,9 @@ ngx_http_naxsi_pcre_wrapper(ngx_regex_compile_t* rx, unsigned char* str, unsigne
+   int match;
+   int captures[30];
+ 
+-#if defined   nginx_version && (nginx_version >= 1002002 && nginx_version != 1003000)
++#if (NGX_PCRE2)
++  match = ngx_pcre2_exec(rx->regex, str, len, 0, captures, 1);
++#elif defined nginx_version && (nginx_version >= 1002002 && nginx_version != 1003000)
+   match = pcre_exec(rx->regex->code, 0, (const char*)str, len, 0, 0, captures, 1);
+ #elif defined nginx_version && (nginx_version > 1001011)
+   match = pcre_exec(rx->regex->pcre, 0, (const char*)str, len, 0, 0, captures, 1);
+diff --git a/naxsi_src/naxsi_utils.c b/naxsi_src/naxsi_utils.c
+index e3d6f185..d2ecedec 100644
+--- a/naxsi_src/naxsi_utils.c
++++ b/naxsi_src/naxsi_utils.c
+@@ -800,7 +800,11 @@ ngx_http_naxsi_create_hashtables_n(ngx_http_naxsi_loc_conf_t* dlc, ngx_conf_t* c
+             ngx_pcalloc(cf->pool, sizeof(ngx_regex_compile_t));
+           rgc = custloc_array(curr_r->br->custom_locations->elts)[name_idx].target_rx;
+           if (rgc) {
++#if (NGX_PCRE2)
++            rgc->options  = PCRE2_CASELESS | PCRE2_MULTILINE;
++#else
+             rgc->options  = PCRE_CASELESS | PCRE_MULTILINE;
++#endif
+             rgc->pattern  = custloc_array(curr_r->br->custom_locations->elts)[name_idx].target;
+             rgc->pool     = cf->pool;
+             rgc->err.len  = 0;
+@@ -816,7 +820,11 @@ ngx_http_naxsi_create_hashtables_n(ngx_http_naxsi_loc_conf_t* dlc, ngx_conf_t* c
+             ngx_pcalloc(cf->pool, sizeof(ngx_regex_compile_t));
+           rgc = custloc_array(curr_r->br->custom_locations->elts)[uri_idx].target_rx;
+           if (rgc) {
++#if (NGX_PCRE2)
++            rgc->options  = PCRE2_CASELESS | PCRE2_MULTILINE;
++#else
+             rgc->options  = PCRE_CASELESS | PCRE_MULTILINE;
++#endif
+             rgc->pattern  = custloc_array(curr_r->br->custom_locations->elts)[uri_idx].target;
+             rgc->pool     = cf->pool;
+             rgc->err.len  = 0;