Hello,
This installer sometimes sadly segfaults, most of the time in
libparted. To be able to catch this coredump[1], I ran those commands:
--8<---------------cut here---------------start------------->8---
echo /tmp/core > /proc/sys/kernel/core_pattern
prlimit --core=unlimited --pid=1234
--8<---------------cut here---------------end--------------->8---
The coredump I obtained did not seem to be exploitable, despite the fact
that it weights 155MB:
--8<---------------cut here---------------start------------->8---
mathieu@meije ~/guix [env]$ gdb
/gnu/store/1jgcbdzx2ss6xv59w55g3kr3x4935dfb-guile-3.0.8/bin/guile core
...
BFD: warning: /home/mathieu/guix/core has a segment extending past end of file
warning: core file may not match specified executable file.
...
Failed to read a valid object file image from memory.
Core was generated by
`/gnu/store/1jgcbdzx2ss6xv59w55g3kr3x4935dfb-guile-3.0.8/bin/guile
--no-auto-com'.
--8<---------------cut here---------------end--------------->8---
So I decided to adopt a new strategy and ran:
--8<---------------cut here---------------start------------->8---
$ gdb
$ attach 1234
...
$ gcore
--8<---------------cut here---------------end--------------->8---
to get a viable core dump, and those commands to exploit it (thanks
Josselin!):
--8<---------------cut here---------------start------------->8---
(gdb) info sharedlibrary
>From To Syms Read Shared Object Library
...
0x00007f892c59c850 0x00007f892c5d3d0b Yes (*)
/gnu/store/qz7qqrhgcs3ixv8f1k30gwiqr1prm7qs-parted-3.5/lib/libparted.so
(gdb) add-symbol-file
/gnu/store/b0ymz7vjfkcvhbci49q5yk1fi0l9lq49-parted-3.5/lib/libparted.so
0x00007f892c59c850
add symbol table from file
"/gnu/store/b0ymz7vjfkcvhbci49q5yk1fi0l9lq49-parted-3.5/lib/libparted.so" at
.text_addr = 0x7f892c59c850
(y or n) y
Reading symbols from
/gnu/store/b0ymz7vjfkcvhbci49q5yk1fi0l9lq49-parted-3.5/lib/libparted.so...
(gdb) bt
#0 linux_destroy (dev=0x1dc89e0) at arch/linux.c:1615
#1 0x00007f8941aecd37 in ?? () from
/gnu/store/1jgcbdzx2ss6xv59w55g3kr3x4935dfb-guile-3.0.8/lib/libguile-3.0.so.1
...
--8<---------------cut here---------------end--------------->8---
I think that it would be great if we could enable coredump generation
from the installer. This way, when a crash occurs and the installer
restarts, it would notice that there is an existing coredump in say
/tmp/coredump_xxx and propose to upload it using the existing dump
mechanism.
Thanks,
Mathieu
[1]: https://issues.guix.gnu.org/58732
