[Bug network/15048] New: getaddrinfo() leaks memory when /etc/nssswitch.conf is not present.

["jiji.vinitha at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=15048

             Bug #: 15048
           Summary: getaddrinfo() leaks memory when /etc/nssswitch.conf is
                    not present.
           Product: glibc
           Version: 2.11
            Status: NEW
          Severity: normal
          Priority: P2
         Component: network
        AssignedTo: unassigned@sourceware.org
        ReportedBy: jiji.vinitha@gmail.com
    Classification: Unclassified


Created attachment 6829
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6829
patch which fixes the leak

Hi,
 Found in glibc-2.11.2 on arm-*-linux-gnueabi target.
 The scenario:
  When
    * /etc/nsswitch.conf is not existing
    * gethostbyname() has not been called
    * dns server is reachable
    * "localhost.localdomain" is not resisted to dns 

   In the above scenario, getaddrinfo("localhost.localdomain"); is leaking
memory.
   The testcase to reproduce this issue

   [nsstest.c]
    #include <stdlib.h>
    #include <stdio.h>
    int main(int argc, char **argv)
      {
     int i;
     struct addrinfo *res;
     int cnt = 2500;
    #if 0
        if (gethostbyname("localhost.localdomain") == 0) {
        }
    #endif
    for( i = 0; i < cnt; i++ ) {
    if( getaddrinfo("localhost.localdomain", NULL, NULL, &res ) == 0 ){
         freeaddrinfo(res);
    }
    write(1, ".", 1);
    }
    write(1, "done\n", 5);
    while(1){sleep(62);}
    return 0;
    }

   How to reproduce the leak 

    # strace -e open ./nsstest
    ...
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory) <- cause of leak
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory)
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory)
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory)
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory)
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory)
    .open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or
directory)
    ...


   RSS is increasing as shown below while executed the binary



   # ./nsstest
............................................................................................................................................................................................................................................................................................................................................................................................................................................................................^Z

[1]+  Stopped                 ./nsstest
# ps
  PID TTY          TIME CMD
  167 pts/0    00:00:00 bash
  284 pts/0    00:00:00 nsstest
  285 pts/0    00:00:00 ps
# ps -p 284 u
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root       284  0.9  0.5   1960   668 pts/0    T    00:29   0:00 ./nsstest
# fg
./nsstest
..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................^Z
[1]+  Stopped                 ./nsstest
# ps -p 284 u
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root       284  1.3  0.6   2088   768 pts/0    T    00:29   0:00 ./nsstest
# fg
./nsstest
...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................^Z
[1]+  Stopped                 ./nsstest
# ps -p 284 u
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root       284  1.1  0.7   2216   912 pts/0    T    00:29   0:00 ./nsstest
#

   The attached patch  solved this issue in glibc-2.11.2.

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