linux/include
Eric W. Biederman 311fc65c9f pty: Repair TIOCGPTPEER
The implementation of TIOCGPTPEER has two issues.

When /dev/ptmx (as opposed to /dev/pts/ptmx) is opened the wrong
vfsmount is passed to dentry_open.  Which results in the kernel displaying
the wrong pathname for the peer.

The second is simply by caching the vfsmount and dentry of the peer it leaves
them open, in a way they were not previously Which because of the inreased
reference counts can cause unnecessary behaviour differences resulting in
regressions.

To fix these move the ioctl into tty_io.c at a generic level allowing
the ioctl to have access to the struct file on which the ioctl is
being called.  This allows the path of the slave to be derived when
opening the slave through TIOCGPTPEER instead of requiring the path to
the slave be cached.  Thus removing the need for caching the path.

A new function devpts_ptmx_path is factored out of devpts_acquire and
used to implement a function devpts_mntget.   The new function devpts_mntget
takes a filp to perform the lookup on and fsi so that it can confirm
that the superblock that is found by devpts_ptmx_path is the proper superblock.

v2: Lots of fixes to make the code actually work
v3: Suggestions by Linus
    - Removed the unnecessary initialization of filp in ptm_open_peer
    - Simplified devpts_ptmx_path as gotos are no longer required

[ This is the fix for the issue that was reverted in commit
  143c97cc65, but this time without breaking 'pbuilder' due to
  increased reference counts   - Linus ]

Fixes: 54ebbfb160 ("tty: add TIOCGPTPEER ioctl")
Reported-by: Christian Brauner <christian.brauner@canonical.com>
Reported-and-tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-24 13:23:03 -07:00
..
acpi ACPI: NUMA: add missing include in acpi_numa.h 2017-07-24 22:27:43 +02:00
asm-generic mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem 2017-08-10 15:54:07 -07:00
clocksource
crypto
drm i915, amd and some core fixes + mediatek color support 2017-07-13 11:26:18 -07:00
dt-bindings Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-07-15 10:59:54 -07:00
keys
kvm KVM: arm/arm64: PMU: Fix overflow interrupt injection 2017-07-25 14:18:01 +01:00
linux pty: Repair TIOCGPTPEER 2017-08-24 13:23:03 -07:00
math-emu
media media: platform: davinci: drop VPFE_CMD_S_CCDC_RAW_PARAMS 2017-07-26 06:14:33 -04:00
memory
misc
net net_sched: fix order of queue length updates in qdisc_replace() 2017-08-20 20:02:00 -07:00
pcmcia
ras
rdma IB/cma: Fix reference count leak when no ipv4 addresses are set 2017-07-20 11:24:13 -04:00
rxrpc
scsi SCSI fixes on 20170823 2017-08-23 11:34:40 -07:00
soc
sound ASoC: fix pcm-creation regression 2017-07-17 15:50:32 +01:00
target iscsi-target: Fix iscsi_np reset hung task during parallel delete 2017-08-06 14:41:41 -07:00
trace ext4: remove unused metadata accounting variables 2017-07-30 22:30:11 -04:00
uapi drm/msm: Remove __user from __u64 data types 2017-08-01 19:11:48 -04:00
video
xen xen/balloon: don't online new memory initially 2017-07-23 08:13:18 +02:00