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Takashi Iwai a91d66129f ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal
The commit 99b5c5bb9a ("ALSA: hda - Remove the use of set_fs()")
converted the get_kctl_0dB_offset() call for killing set_fs() usage in
HD-audio codec code.  The conversion assumed that the TLV callback
used in HD-audio code is only snd_hda_mixer_amp() and applies the TLV
calculation locally.

Although this assumption is correct, and all slave kctls are actually
with that callback, the current code is still utterly buggy; it
doesn't hit this condition and falls back to the next check.  It's
because the function gets called after adding slave kctls to vmaster.
By assigning a slave kctl, the slave kctl object is faked inside
vmaster code, and the whole kctl ops are overridden.  Thus the
callback op points to a different value from what we've assumed.

More badly, as reported by the KERNEXEC and UDEREF features of PaX,
the code flow turns into the unexpected pitfall.  The next fallback
check is SNDRV_CTL_ELEM_ACCESS_TLV_READ access bit, and this always
hits for each kctl with TLV.  Then it evaluates the callback function
pointer wrongly as if it were a TLV array.  Although currently its
side-effect is fairly limited, this incorrect reference may lead to an
unpleasant result.

For addressing the regression, this patch introduces a new helper to
vmaster code, snd_ctl_apply_vmaster_slaves().  This works similarly
like the existing map_slaves() in hda_codec.c: it loops over the slave
list of the given master, and applies the given function to each
slave.  Then the initializer function receives the right kctl object
and we can compare the correct pointer instead of the faked one.

Also, for catching the similar breakage in future, give an error
message when the unexpected TLV callback is found and bail out
immediately.

Fixes: 99b5c5bb9a ("ALSA: hda - Remove the use of set_fs()")
Reported-by: PaX Team <pageexec@freemail.hu>
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-18 12:27:00 +02:00
arch ARC udpates for 4.14-rc4 2017-10-06 15:57:08 -07:00
block bsg-lib: fix use-after-free under memory-pressure 2017-10-04 08:35:04 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: af_alg - update correct dst SGL entry 2017-09-20 17:42:42 +08:00
Documentation Merge branch 'i2c/for-current-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2017-10-07 10:07:51 -07:00
drivers SCSI fixes on 20171007 2017-10-07 12:34:16 -07:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Changes since last update: 2017-10-06 15:53:36 -07:00
include ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal 2017-10-18 12:27:00 +02:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel Merge branch 'core-watchdog-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-06 08:36:41 -07:00
lib lib/ratelimit.c: use deferred printk() version 2017-10-03 17:54:26 -07:00
mm mm/memory_hotplug: define find_{smallest|biggest}_section_pfn as unsigned long 2017-10-03 17:54:26 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-05 08:40:09 -07:00
samples media updates for v4.14-rc1 2017-09-07 12:53:14 -07:00
scripts checkpatch: fix ignoring cover-letter logic 2017-10-03 17:54:26 -07:00
security lsm: fix smack_inode_removexattr and xattr_getsecurity memleak 2017-10-04 18:03:15 +11:00
sound ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal 2017-10-18 12:27:00 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:06:31 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update James Hogan's email address 2017-10-04 17:11:53 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS ARC udpates for 4.14-rc4 2017-10-06 15:57:08 -07:00
Makefile Linux 4.14-rc4 2017-10-08 20:53:29 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.