[Samba] smbd crashes: Segmentation fault in 4.15.0-Debian

[Jeremy Allison]

On Mon, Oct 18, 2021 at 12:43:14PM +0100, spindles seven via samba wrote:
>I have a domain member file server running Samba version 4.15.0 (from Louis' repo) on Debian Bullseye in a LXD container.    Has been running fine for some while then smbd crashed with these messages in syslog:
>
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.350765,  0] ../../lib/dbwrap/dbwrap.c:82(dbwrap_record_get_value)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   PANIC: assert failed at ../../lib/dbwrap/dbwrap.c(82): rec->value_valid
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.364364,  0] ../../lib/util/fault.c:172(smb_panic_log)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   ===============================================================
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.364399,  0] ../../lib/util/fault.c:173(smb_panic_log)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   INTERNAL ERROR: assert failed: rec->value_valid in pid 520846 (4.15.0-Debian)
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.364429,  0] ../../lib/util/fault.c:177(smb_panic_log)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   If you are running a recent Samba version, and if you think this problem is not yet fixed in the latest versions, please consider reporting this bug, see https://wiki.samba.org/index.php/Bug_Reporting
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.364461,  0] ../../lib/util/fault.c:182(smb_panic_log)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   ===============================================================
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.364488,  0] ../../lib/util/fault.c:183(smb_panic_log)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   PANIC (pid 520846): assert failed: rec->value_valid in 4.15.0-Debian
>Oct 18 11:38:16 lxd-m1 smbd[520846]: [2021/10/18 11:38:16.365002,  0] ../../lib/util/fault.c:287(log_stack_trace)
>Oct 18 11:38:16 lxd-m1 smbd[520846]:   BACKTRACE: 27 stack frames:
>Oct 18 11:38:16 lxd-m1 smbd[520846]:    #0 /usr/lib/x86_64-linux-gnu/libsamba-util.so.0(log_stack_trace+0x30) [0x7fe1c7cd2b70]
>Oct 18 11:38:16 lxd-m1 smbd[520846]:    #1 /usr/lib/x86_64-linux-gnu/libsamba-util.so.0(smb_panic+0x9) [0x7fe1c7cd2db9]
>Oct 18 11:38:16 lxd-m1 smbd[520846]:    #2 /usr/lib/x86_64-linux-gnu/samba/libdbwrap.so.0(dbwrap_record_get_value+0x27) [0x7fe1c7603997]
>Oct 18 11:38:16 lxd-m1 smbd[520846]:    #3 /usr/lib/x86_64-linux-gnu/samba/libsmbd-base.so.0(+0x21851a) [0x7fe1c7f5851a]
>Oct 18 11:38:16 lxd-m1 smbd[520846]:    #4 /usr/lib/x86_64-linux-gnu/samba/libsmbd-base.so.0(smb2srv_client_mc_negprot_send+0x6b) [0x7fe1c7f5951b]
>
>Restarting smbd has restored normal operation for now.    Should I report this as a bug or is there something else wrong?

This is being fixed as bug:

https://bugzilla.samba.org/show_bug.cgi?id=14882

Patch is in for review in gitlab now. Thanks for
reporting !