Segfault while reloading/stopping nginx

[zimmerle]

This problem was originally reported by @defanator. @defanator also investigated the issue, nailing down the problem to the exactly point where the code is crashing.

Bellow is a simple configuration that will lead to the crash:

    server {
        listen 80;

        modsecurity on;
        modsecurity_rules '
           SecDefaultAction "phase:2,deny"
        ';

        location / {
            proxy_pass http://backend;
        }

        location /another/one {
            proxy_pass http://backend;
        }

        location /and/third/one/ {
            proxy_pass http://backend;
        }
    }

Here crash stack trace:

#0  0x0000000000000061 in ?? ()
#1  0x00007fbeb7867376 in modsecurity::Rules::~Rules (this=0x23f4440, __in_chrg=<optimized out>) at rules.cc:97
#2  0x00007fbeb786739e in modsecurity::msc_rules_cleanup (rules=0x23f4440) at rules.cc:357
#3  0x00007fbeb7b45645 in ngx_http_modsecurity_config_cleanup (data=0x23f1438) at ../ModSecurity-nginx/src/ngx_http_modsecurity_module.c:611
#4  0x000000000040df2c in ngx_destroy_pool (pool=0x236c4f0) at src/core/ngx_palloc.c:57
#5  0x000000000043031a in ngx_worker_process_exit (cycle=cycle@entry=0x236c540) at src/os/unix/ngx_process_cycle.c:1001
#6  0x0000000000430407 in ngx_worker_process_cycle (cycle=cycle@entry=0x236c540, data=data@entry=0x0) at src/os/unix/ngx_process_cycle.c:758
#7  0x000000000042ee60 in ngx_spawn_process (cycle=cycle@entry=0x236c540, proc=proc@entry=0x430352 <ngx_worker_process_cycle>, data=data@entry=0x0, 
    name=name@entry=0x481297 "worker process", respawn=respawn@entry=-3) at src/os/unix/ngx_process.c:198
#8  0x000000000043053b in ngx_start_worker_processes (cycle=cycle@entry=0x236c540, n=8, type=type@entry=-3) at src/os/unix/ngx_process_cycle.c:358
#9  0x0000000000430e0f in ngx_master_process_cycle (cycle=cycle@entry=0x236c540) at src/os/unix/ngx_process_cycle.c:130
#10 0x000000000040c94e in main (argc=<optimized out>, argv=<optimized out>) at src/core/nginx.c:367

[defanator]

The following patch seems to fix this issue: owasp-modsecurity/ModSecurity@3ee7b24#diff-e221cb70032281cab47059fcdde13418

Thanks!

[zimmerle]

Thanks @defanator ;)

This issue is now closed.