Seg fault with "net sam mapunixgroup"

[Abhidnya Joshi]

Hi,

Below is our smb.conf

[global]
    realm =
    netbios name = test_nas
    workgroup = WORKGROUP
    max protocol = SMB3
    security = user
    preferred master = no
    domain master = no
    local master = no
    encrypt passwords = yes
    password server =
    idmap backend = tdb
    allow trusted domains = no
    load printers = no
    printcap name = /dev/null
    disable spoolss = yes
    winbind enum users = no
    winbind enum groups = no
    winbind use default domain = no
    log level = 2 passdb:3 auth:3 winbind:3
    log file = /var/log/samba/log.%m
    browseable = yes
    lanman auth = no
    ntlm auth = yes
    client ntlmv2 auth = no
    obey pam restrictions = no
    kernel change notify = no
    ea support = no
    store dos attributes = no
    host msdfs = yes
    ldap admin dn =
    ldap suffix =
    map to guest = Bad User
    machine password timeout = 2147483647
    unix extensions = no
    deadtime = 6
    vfs objects =
    aio read size = 0
    aio write size = 0
    strict allocate = yes
    wide links = yes
    create mask =  0775
    directory mask =  0775
    idmap config WORKGROUP:default = Yes
    idmap config WORKGROUP:range = 10000-1000000
    idmap config WORKGROUP:backend = rid
interfaces =
wins support = no
  passdb backend = smbpasswd
  kernel oplocks = no
netbios aliases =
  include = /etc/samba/%i.smb.conf

We want to allow adding groups locally and then map it to get SID.

Thanks and Regards
Abhidnya Joshi


-----Original Message-----
From: samba-technical-bounces at lists.samba.org [mailto:samba-technical-bounces at lists.samba.org] On Behalf Of Rowland Penny
Sent: Wednesday, May 27, 2015 1:23 PM
To: samba-technical at lists.samba.org
Subject: Re: Seg fault with "net sam mapunixgroup"

On 27/05/15 06:27, Abhidnya Joshi wrote:
> Hi,
>
> We are using Samba-4.1.16. We are getting seg fault always with "net sam mapunixgroup".
>
> The gdb shows stack as follows:
> (gdb)
> #0  0x00007f2fe4276451 in __strlen_sse2 () from /lib64/libc.so.6
> #1  0x00007f2fe5d87187 in tdb_pack_va (buf=0x8 <Address 0x8 out of 
> bounds>,bufsize=0, fmt=0x7f2fe6c7666c "f", ap=0x7fffaefbe7a0) at 
> ../source3/lib/util_tdb.c:98
> #2  0x00007f2fe5d87743 in tdb_pack (buf=<value optimized out>, 
> bufsize=<value optimized out>, fmt=<value optimized out>) at 
> ../source3/lib/util_tdb.c:138
> #3  0x00007f2fe6c54828 in add_mapping_entry (map=0x7f2fee274f60, 
> flag=<value optimized out>) at ../source3/groupdb/mapping_tdb.c:148
> #4  0x00007f2fe6c51c82 in pdb_default_add_group_mapping_entry 
> (methods=<value optimized out>, map=0x7f2fee274f60) at 
> ../source3/groupdb/mapping.c:459
> #5  0x00007f2fe6c4e695 in pdb_add_group_mapping_entry 
> (map=0x7f2fee274f60) at ../source3/passdb/pdb_interface.c:849
> #6  0x00007f2fec101aba in map_unix_group (c=<value optimized out>, 
> argc=<value optimized out>, argv=0x7f2fee26f928) at 
> ../source3/utils/net_sam.c:865
> #7  net_sam_mapunixgroup (c=<value optimized out>, argc=<value 
> optimized out>, argv=0x7f2fee26f928) at ../source3/utils/net_sam.c:893
> #8  0x00007f2fec0fd3cc in net_sam (c=0x7f2fee26d360, 
> argc=2,argv=0x7f2fee26f920) at ../source3/utils/net_sam.c:2280
> #9  0x00007f2fec0cbb56 in main (argc=5, argv=0x7fffaefbf648) at 
> ../source3/utils/net.c:960
> (gdb) f 3
> #3  0x00007f2fe6c54828 in add_mapping_entry (map=0x7f2fee274f60, flag=<value optimized out>) at ../source3/groupdb/mapping_tdb.c:148
> 148     ../source3/groupdb/mapping_tdb.c: No such file or directory. in ../source3/groupdb/mapping_tdb.c
> (gdb) p map->sid_name_use
> $1 = SID_NAME_DOM_GRP
> (gdb) p map->comment
> $2 = 0x7f2fee2766d0 "Unix Group nogroup"
> (gdb) p map->gid
> $3 = 1004
> (gdb) p map->nt_name
> $4 = 0x0
> (gdb)
>
> It seems that strlen dumps core as map->nt_name is a NULL pointer.  I rerun this by populating nt_name the way earlier samba version (3.6.24) populates and it works.
> In map_unix_group function as:
>         if (map->nt_name == NULL) {
>                 map->nt_name = talloc_asprintf(map, "%s", grp->gr_name);
>                 DEBUG(10, ("Populate map->nt_name with %s\n", grp->gr_name));
>         }
>
> May I know if I am missing anything?
>
> Thanks and Regards
> Abhidnya Joshi
>

Well, apart from telling us what version of samba you are using, showing us your smb.conf and telling us why you are trying to map a group, no

Rowland