Public bug reported:

After upgrading to groovy or installing fresh from the beta, schroot
fails to enter a source: chroot with std:bad_alloc:

$ schroot -c source:bionic-amd64
E: std::bad_alloc

Running this with debugging symbols under gdb we get the following
backtrace:

amurray@slate:~$ gdb --ex='break std::bad_alloc::bad_alloc()' --ex=run --args 
schroot -c source:bionic-amd64
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Reading symbols from schroot...
Reading symbols from 
/usr/lib/debug/.build-id/70/4469864df39ed3af1f8a23bd8d27adffeb8315.debug...
Catchpoint 1 (throw)
Function "std::bad_alloc::bad_alloc()" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (std::bad_alloc::bad_alloc()) pending.
Starting program: /usr/bin/schroot -c source:bionic-amd64
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Catchpoint 1 (exception thrown), 0x00007fd231965762 in __cxa_throw () from 
/lib/x86_64-linux-gnu/libstdc++.so.6
(gdb) bt full
#0  0x00007fd231965762 in __cxa_throw () from 
/lib/x86_64-linux-gnu/libstdc++.so.6
No symbol table info available.
#1  0x00007fd231959562 in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
No symbol table info available.
#2  0x00005596c26b8a2f in __gnu_cxx::new_allocator<char>::allocate 
(this=0x7ffd3b189dd0, __n=34359738368) at 
/usr/include/c++/9/ext/new_allocator.h:102
No locals.
#3  std::allocator_traits<std::allocator<char> >::allocate (__a=..., 
__n=34359738368) at /usr/include/c++/9/bits/alloc_traits.h:444
No locals.
#4  std::_Vector_base<char, std::allocator<char> >::_M_allocate 
(this=0x7ffd3b189dd0, __n=34359738368) at 
/usr/include/c++/9/bits/stl_vector.h:343
No locals.
#5  std::vector<char, std::allocator<char> >::reserve 
(this=this@entry=0x7ffd3b189dd0, __n=__n@entry=34359738368) at 
/usr/include/c++/9/bits/vector.tcc:78
        __old_size = 0
        __tmp = <optimised out>
#6  0x00005596c26b5996 in sbuild::group::query_name (this=0x7ffd3b189db0, 
name=0x5596c2c558c0 "admin") at ./sbuild/sbuild-util.cc:770
        size = 34359738368
        error = <optimised out>
        grp_result = 0x0
#7  0x00005596c26b5abf in sbuild::group::query_name (name=..., 
this=0x7ffd3b189db0) at /usr/include/c++/9/bits/basic_string.h:2300
No locals.
#8  sbuild::group::group (this=0x7ffd3b189db0, name=...) at 
./sbuild/sbuild-util.cc:717
No locals.
#9  0x00005596c26a463f in sbuild::session::is_group_member (this=<optimised 
out>, groupname="admin") at ./sbuild/sbuild-session.cc:390
        grp = {<group> = {gr_name = 0x7fd1b0416010 <error: Cannot access memory 
at address 0x7fd1b0416010>, gr_passwd = 0x7fd1b041601e <error: Cannot access 
memory at address 0x7fd1b041601e>, gr_gid = 138, 
            gr_mem = 0x7fd1b0416028}, buffer = std::vector of length 0, 
capacity 17179869184, valid = false}
        group_member = <optimised out>
        __PRETTY_FUNCTION__ = <optimised out>
#10 0x00005596c26a49eb in sbuild::session::get_chroot_membership 
(this=0x5596c2c329f0, chroot=..., in_users=@0x7ffd3b189e94: false, 
in_root_users=@0x7ffd3b189e95: false, in_groups=@0x7ffd3b189e96: false, 
    in_root_groups=@0x7ffd3b189e97: true) at ./sbuild/sbuild-session.cc:475
        gp = "admin"
        users = std::vector of length 0, capacity 0
        root_users = <optimised out>
        groups = <optimised out>
        root_groups = std::vector of length 3, capacity 3 = {"root", "sbuild", 
"admin"}
        upos = <optimised out>
        rupos = <optimised out>
#11 0x00005596c26a4cd1 in sbuild::session::get_chroot_auth_status 
(this=0x5596c2c329f0, status=sbuild::auth::STATUS_NONE, chroot=...) at 
./sbuild/sbuild-session.cc:496
        in_users = false
        in_root_users = false
        in_groups = false
        in_root_groups = true
#12 0x00005596c26a3ae1 in sbuild::session::get_auth_status 
(this=0x5596c2c329f0) at ./sbuild/sbuild-session.cc:554
        cur = {alias = "source:bionic-amd64", chroot = 
std::shared_ptr<sbuild::chroot> (use count 4, weak count 1) = {get() = 
0x5596c2c51b80}}
        status = sbuild::auth::STATUS_NONE
        __PRETTY_FUNCTION__ = <optimised out>
#13 0x00005596c26a3fba in sbuild::session::run (this=0x5596c2c329f0) at 
/usr/include/c++/9/bits/shared_ptr_base.h:1020
No locals.
#14 0x00005596c2731fb9 in schroot::main_base::run_impl (this=0x7ffd3b18a180) at 
/usr/include/c++/9/bits/shared_ptr_base.h:1020
        __PRETTY_FUNCTION__ = "virtual int schroot::main_base::run_impl()"
        sess_op = <optimised out>
#15 0x00005596c272b392 in schroot_base::main::run (this=0x7ffd3b18a180, 
argc=<optimised out>, argv=0x7ffd3b18a3a8) at 
./bin/schroot-base/schroot-base-main.cc:107
        status = <optimised out>
#16 0x00005596c269a2f0 in schroot_base::run<schroot::options, schroot::main> 
(argc=3, argv=0x7ffd3b18a3a8) at /usr/include/c++/9/bits/shared_ptr_base.h:1388
        opts = std::shared_ptr<schroot::options_base> (use count 3, weak count 
0) = {get() = 0x5596c2c2cce0}
        kit = {<schroot::main_base> = {<schroot_base::main> = {_vptr.main = 
0x5596c2778200 <vtable for schroot::main+16>, program_name = "schroot", 
              program_usage = "[OPTION…] [COMMAND] — run command or shell in a 
chroot", program_options = std::shared_ptr<schroot_base::options> (use count 3, 
weak count 0) = {get() = 0x5596c2c2cce0}, 
              use_syslog = true}, options = 
std::shared_ptr<schroot::options_base> (use count 3, weak count 0) = {get() = 
0x5596c2c2cce0}, config = 


This shows sbuild is querying for the group 'admin' - however this does not 
exist on my groovy install:

amurray@slate:~$ getent group | grep ^admin
amurray@slate:~$ 

The reason it is checking for admin comes from the following 2
references for setting up schroot etc -
https://wiki.ubuntu.com/SimpleSbuild and
https://wiki.ubuntu.com/SecurityTeam/BuildEnvironment#Creating_the_schroots
- these both suggest creating a ~/.mk-sbuild.rc with the following
entry:

SCHROOT_CONF_SUFFIX="source-root-users=root,sbuild,admin
source-root-groups=root,sbuild,admin
preserve-environment=true"

So in this case, sbuild will allow users in the root, sbuild or admin
groups to be root in the source schroot.

The actual failure seems to be because the sbuild code does not check
for appropriate errors from getpwnam_r / getpwuid_r - in sbuild-utilc.cc
there is 4 variants of code like:

  while ((error = getgrnam_r(name, this,
                             &buffer[0], buffer.capacity(),
                             &grp_result)))
    {
      size <<= 1;
      buffer.reserve(size);
    }

However, this should only try and reallocate a larger buffer if these
return ERANGE. Otherwise, if it fails for some other reason (like the
group does not exist) it will continue to try and allocate a larger and
larger buffer until it fails due to lack of memory.

This would appear to be the same bug as https://bugs.debian.org/cgi-
bin/bugreport.cgi?bug=763896 and whilst according to that bug it was
fixed in schroot git upstream, perhaps this never made it into a debian
and hence Ubuntu release?

** Affects: schroot (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1899414

Title:
  schroot fails for source chroots with 'std:bad_alloc' on groovy

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