[PATCH] Perl: NULL-terminate argument list

[Piotr Sikora]

# HG changeset patch
# User Piotr Sikora <piotr at cloudflare.com>
# Date 1403176596 25200
#      Thu Jun 19 04:16:36 2014 -0700
# Node ID 290f3fcb9cf552c235b9807cf0af3830b5add5af
# Parent  675bda8dcfdbf66e4a17017839f39ed6c8cbb9f5
Perl: NULL-terminate argument list.

perl_parse() function expects argv/argc-style argument list,
which according to the C standard must be NULL-terminated,
that is: argv[argc] == NULL.

This change fixes a crash (SIGSEGV) that could happen because
of the buffer overrun during perl module initialization.

Signed-off-by: Piotr Sikora <piotr at cloudflare.com>

diff -r 675bda8dcfdb -r 290f3fcb9cf5 src/http/modules/perl/ngx_http_perl_module.c
--- a/src/http/modules/perl/ngx_http_perl_module.c	Thu Jun 19 13:55:59 2014 +0400
+++ b/src/http/modules/perl/ngx_http_perl_module.c	Thu Jun 19 04:16:36 2014 -0700
@@ -577,7 +577,7 @@ ngx_http_perl_create_interpreter(ngx_con
 
     n = (pmcf->modules != NGX_CONF_UNSET_PTR) ? pmcf->modules->nelts * 2 : 0;
 
-    embedding = ngx_palloc(cf->pool, (4 + n) * sizeof(char *));
+    embedding = ngx_palloc(cf->pool, (5 + n) * sizeof(char *));
     if (embedding == NULL) {
         goto fail;
     }
@@ -595,6 +595,7 @@ ngx_http_perl_create_interpreter(ngx_con
     embedding[n++] = "-Mnginx";
     embedding[n++] = "-e";
     embedding[n++] = "0";
+    embedding[n] = NULL;
 
     n = perl_parse(perl, ngx_http_perl_xs_init, n, embedding, NULL);