[Pkg-samba-maint] Bug#946419: samba-vfs-modules: Resource forks are truncated when written to fruit-enabled share

[Keith Kaisershot]

Package: samba-vfs-modules
Version: 2:4.11.1+dfsg-3
Severity: important

I use vfs_fruit with a Samba share serving various older versions of Mac OS X, from 10.6 up through 10.11, archiving classic Mac files dating back to the mid 80s. With the latest Samba 4.11.1 in Debian testing, writing one of these older files with a resource fork larger than 64K results in the resource fork portion getting truncated to 65454 bytes on the server end. This corrupts old Mac files with resource forks larger than 64K-- executables are the most affected by this, but graphic files such as PICT are too.

Looks like this is a regression, as this issue does not occur in 4.9.5 from Debian stable.

Repro steps:
1) Copy a classic 68K Mac OS application > 65K from a Mac OS X 10.11 client to a Samba 4.9.5 host. (I used ircle 1.5.6 as a test case here.)
2) Get Info on the newly-copied file on the 4.9.5 server and observe that the application's size matches that of the original file on the client.
 - Screenshot here: https://blitter.net/etc/rsrc_bug/Screen%20Shot%202019-12-08%20at%2012.13.23%20PM.png
3) Observe the same in Finder.
 - Screenshot here: https://blitter.net/etc/rsrc_bug/Screen%20Shot%202019-12-08%20at%2012.12.15%20PM.png
4) Copy the same application from the same Mac OS X 10.11 client to a Samba 4.11.1 host.
5) Get Info on the newly-copied file on the 4.11.1 server and observe that the application's size has been truncated.
 - Screenshot here: https://blitter.net/etc/rsrc_bug/Screen%20Shot%202019-12-08%20at%2012.13.26%20PM.png
6) Observe the same in Finder.
 - Screenshot here: https://blitter.net/etc/rsrc_bug/Screen%20Shot%202019-12-08%20at%2012.12.35%20PM.png

My smb.conf from testparm (identical on both test hosts above except for the name of the share which should reflect the Samba version)-- /srv/test is 0777 on both host filesystems (ext4):

# Global parameters
[global]
	log file = /var/log/samba/log.%m
	logging = file
	map to guest = Bad User
	max log size = 1000
	obey pam restrictions = Yes
	pam password change = Yes
	panic action = /usr/share/samba/panic-action %d
	passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
	passwd program = /usr/bin/passwd %u
	server role = standalone server
	unix password sync = Yes
	usershare allow guests = Yes
	idmap config * : backend = tdb
	vfs objects = catia fruit streams_xattr


[4.11.1]
	guest ok = Yes
	path = /srv/test
	read only = No


-- System Information:
Debian Release: bullseye/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 5.2.0-3-amd64 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages samba-vfs-modules depends on:
ii  libbsd0       0.10.0-1
ii  libc6         2.29-2
ii  libgnutls30   3.6.10-4
ii  libtalloc2    2.3.0-2
ii  libtdb1       1.4.2-2
ii  libtevent0    0.10.1-3
ii  libwbclient0  2:4.11.1+dfsg-3
ii  samba-libs    2:4.11.1+dfsg-3

Versions of packages samba-vfs-modules recommends:
ii  libcephfs2   12.2.11+dfsg1-2.1+b2
ii  libdbus-1-3  1.12.16-2
ii  libgfapi0    7.0-1

samba-vfs-modules suggests no packages.

-- no debconf information