Description of problem:

"Require dbm-file-group" causes a segfault in dbmfilegroup_check_authorization in mod_authz_dbm.c.


You can see a segfault running it under gdb with a breakpoint:-

# gdb /usr/sbin/httpd
Reading symbols from /usr/sbin/httpd...Reading symbols from /usr/lib/debug/usr/sbin/httpd.debug...done.
done.
(gdb) b dbmfilegroup_check_authorization
Function "dbmfilegroup_check_authorization" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (dbmfilegroup_check_authorization) pending.
(gdb) run -X -DFOREGROUND
Starting program: /usr/sbin/httpd -X -DFOREGROUND
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
warning: Temporarily disabling breakpoints for unloaded shared library "/etc/httpd/modules/mod_authz_dbm.so"

(access a protected resource and submit username/password)

Breakpoint 1, dbmfilegroup_check_authorization (r=0x7f851f1c02d0, require_args=0x7f851ee87e56 "", parsed_require_args=0x0)
    at mod_authz_dbm.c:207
207     {
(gdb) 
210         char *user = r->user;
(gdb) 
207     {
(gdb) 
208         authz_dbm_config_rec *conf = ap_get_module_config(r->per_dir_config,
(gdb) 
211         const char *realm = ap_auth_name(r);
(gdb) 
218         if (!user) {
(gdb) 
219             return AUTHZ_DENIED_NO_USER;
(gdb) 
218         if (!user) {
(gdb) 
222         if (!conf->grpfile) {
(gdb) 
229         status = get_dbm_grp(r, apr_pstrcat(r->pool, user, ":", realm, NULL),
(gdb) 
232         if (status != APR_SUCCESS) {
(gdb) 
239         if (groups == NULL) {
(gdb) 
250         filegroup = authz_owner_get_file_group(r);
(gdb) print authz_owner_get_file_group 
$1 = (apr_OFN_authz_owner_get_file_group_t *) 0x0
(gdb) n

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()

(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x00007f7d041ee079 in dbmfilegroup_check_authorization (r=0x7f7d0a31e310, require_args=<optimized out>, 
    parsed_require_args=<optimized out>) at mod_authz_dbm.c:250
#2  0x00007f7d045f6da2 in apply_authz_sections (r=r@entry=0x7f7d0a31e310, section=section@entry=0x7f7d0a01e568, 
    parent_op=<optimized out>) at mod_authz_core.c:737
#3  0x00007f7d045f6f58 in apply_authz_sections (r=r@entry=0x7f7d0a31e310, section=section@entry=0x7f7d0a01e4c8, 
    parent_op=<optimized out>) at mod_authz_core.c:751
#4  0x00007f7d045f6f58 in apply_authz_sections (r=r@entry=0x7f7d0a31e310, section=0x7f7d0a01e5c0, 
    parent_op=parent_op@entry=AUTHZ_LOGIC_AND) at mod_authz_core.c:751
#5  0x00007f7d045f70da in authorize_user_core (r=0x7f7d0a31e310, after_authn=1) at mod_authz_core.c:840
#6  0x00007f7d0818da60 in ap_run_auth_checker (r=0x7f7d0a31e310) at request.c:90
#7  0x00007f7d08190358 in ap_process_request_internal (r=r@entry=0x7f7d0a31e310) at request.c:294
#8  0x00007f7d081ab628 in ap_process_async_request (r=r@entry=0x7f7d0a31e310) at http_request.c:315
#9  0x00007f7d081ab914 in ap_process_request (r=r@entry=0x7f7d0a31e310) at http_request.c:363
#10 0x00007f7d081a82a2 in ap_process_http_sync_connection (c=0x7f7d0a253af0) at http_core.c:190
#11 ap_process_http_connection (c=0x7f7d0a253af0) at http_core.c:231
#12 0x00007f7d081a0340 in ap_run_process_connection (c=0x7f7d0a253af0) at connection.c:41
#13 0x00007f7d081a0728 in ap_process_connection (c=c@entry=0x7f7d0a253af0, csd=<optimized out>) at connection.c:202
#14 0x00007f7cfdb7280f in child_main (child_num_arg=child_num_arg@entry=0) at prefork.c:707
#15 0x00007f7cfdb72a0c in make_child (s=0x7f7d09f5b340, slot=slot@entry=0) at prefork.c:749
#16 0x00007f7cfdb73791 in prefork_run (_pconf=<optimized out>, plog=0x7f7d09f5f378, s=0x7f7d09f5b340) at prefork.c:966
#17 0x00007f7d0817d2ce in ap_run_mpm (pconf=0x7f7d09f32158, plog=0x7f7d09f5f378, s=0x7f7d09f5b340) at mpm_common.c:96
#18 0x00007f7d081768f6 in main (argc=3, argv=0x7fff14a9f608) at main.c:777
(gdb) 



Version-Release number of selected component (if applicable):

httpd-2.4.6-31.el7.x86_64


How reproducible:


Steps to Reproduce:
1. append the following lines to httpd.conf


<Directory "/var/www/html/test2/">
    AuthName test
    AuthType Basic
    AuthBasicProvider dbm
    AuthDBMUserFile /etc/httpd/conf/users
    AuthDBMGroupFile /etc/httpd/conf/groups
    AuthzDBMType SDBM
    Require dbm-file-group
</Directory>

2. create html file

[root@host11 conf]# mkdir /var/www/html/test
[root@host11 conf]# cat > /var/www/html/test/index.html
hi
(Ctrl-D)
[root@host11 conf]#


3. create db

[root@host11 conf]# htdbm -c -TSDBM /etc/httpd/conf/users user1
New password: 
Re-type new password: 
Database /etc/httpd/conf/users created.
[root@host11 conf]# cat > groups.txt
user1 root
(Ctrl-D)
[root@host11 conf]# httxt2dbm -v -f SDBM -i ./groups.txt -o /etc/httpd/conf/groups
DBM Format: SDBM
Input File: ./groups.txt
DBM File: /etc/httpd/conf/groups
    'user1' -> 'root'
Conversion Complete.


4. start httpd

[root@host11 conf]# systemctl start httpd.service


5. access http://localhost/test/, then you will see the segfault.

Actual results:


Expected results:


Additional info: