linux-stable.git/Documentation, branch linux-3.10.y Linux kernel stable tree mm: larger stack guard gap, between vmas 2017-06-21T13:42:43+00:00 Hugh Dickins hughd@google.com 2017-06-19T11:03:24+00:00 1ad9a25dd06fda9bdc27875e1cedb8277accb212 commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> [wt: backport to 4.11: adjust context] [wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide] [wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes] [wt: backport to 3.18: adjust context ; no FOLL_POPULATE ; s390 uses generic arch_get_unmapped_area()] [wt: backport to 3.16: adjust context] [wt: backport to 3.10: adjust context ; code logic in PARISC's arch_get_unmapped_area() wasn't found ; code inserted into expand_upwards() and expand_downwards() runs under anon_vma lock; changes for gup.c:faultin_page go to memory.c:__get_user_pages(); included Hugh Dickins' fixes] Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
[wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes]
[wt: backport to 3.18: adjust context ; no FOLL_POPULATE ;
     s390 uses generic arch_get_unmapped_area()]
[wt: backport to 3.16: adjust context]
[wt: backport to 3.10: adjust context ; code logic in PARISC's
     arch_get_unmapped_area() wasn't found ; code inserted into
     expand_upwards() and expand_downwards() runs under anon_vma lock;
     changes for gup.c:faultin_page go to memory.c:__get_user_pages();
     included Hugh Dickins' fixes]
Signed-off-by: Willy Tarreau <w@1wt.eu>
x86/platform/goldfish: Prevent unconditional loading 2017-06-07T22:47:00+00:00 Thomas Gleixner tglx@linutronix.de 2017-02-15T10:11:50+00:00 d3926e196305a4075aaf3da82e5fbd5bc192a58d commit 47512cfd0d7a8bd6ab71d01cd89fca19eb2093eb upstream. The goldfish platform code registers the platform device unconditionally which causes havoc in several ways if the goldfish_pdev_bus driver is enabled: - Access to the hardcoded physical memory region, which is either not available or contains stuff which is completely unrelated. - Prevents that the interrupt of the serial port can be requested - In case of a spurious interrupt it goes into a infinite loop in the interrupt handler of the pdev_bus driver (which needs to be fixed seperately). Add a 'goldfish' command line option to make the registration opt-in when the platform is compiled in. I'm seriously grumpy about this engineering trainwreck, which has seven SOBs from Intel developers for 50 lines of code. And none of them figured out that this is broken. Impressive fail! Fixes: ddd70cf93d78 ("goldfish: platform device for x86") Reported-by: Gabriel C <nix.or.die@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 47512cfd0d7a8bd6ab71d01cd89fca19eb2093eb upstream.

The goldfish platform code registers the platform device unconditionally
which causes havoc in several ways if the goldfish_pdev_bus driver is
enabled:

 - Access to the hardcoded physical memory region, which is either not
   available or contains stuff which is completely unrelated.

 - Prevents that the interrupt of the serial port can be requested

 - In case of a spurious interrupt it goes into a infinite loop in the
   interrupt handler of the pdev_bus driver (which needs to be fixed
   seperately).

Add a 'goldfish' command line option to make the registration opt-in when
the platform is compiled in.

I'm seriously grumpy about this engineering trainwreck, which has seven
SOBs from Intel developers for 50 lines of code. And none of them figured
out that this is broken. Impressive fail!

Fixes: ddd70cf93d78 ("goldfish: platform device for x86")
Reported-by: Gabriel C <nix.or.die@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
ARM: dts: imx31: fix clock control module interrupts description 2017-06-07T22:46:56+00:00 Vladimir Zapolskiy vz@mleia.com 2016-09-26T00:03:40+00:00 2024f68a981fdf9301e01a43fbdec193a9e5181e commit 2e575cbc930901718cc18e084566ecbb9a4b5ebb upstream. The type of AVIC interrupt controller found on i.MX31 is one-cell, namely 31 for CCM DVFS and 53 for CCM, however for clock control module its interrupts are specified as 3-cells, fix it. Fixes: ef0e4a606fb6 ("ARM: mx31: Replace clk_register_clkdev with clock DT lookup") Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Vladimir Zapolskiy <vz@mleia.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 2e575cbc930901718cc18e084566ecbb9a4b5ebb upstream.

The type of AVIC interrupt controller found on i.MX31 is one-cell,
namely 31 for CCM DVFS and 53 for CCM, however for clock control
module its interrupts are specified as 3-cells, fix it.

Fixes: ef0e4a606fb6 ("ARM: mx31: Replace clk_register_clkdev with clock DT lookup")
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
scsi: fix race between simultaneous decrements of ->host_failed 2016-08-27T09:40:28+00:00 Wei Fang fangwei1@huawei.com 2016-06-07T06:53:56+00:00 ec032b74164fab3dabeceb37362f2a58227c51b8 commit 72d8c36ec364c82bf1bf0c64dfa1041cfaf139f7 upstream. sas_ata_strategy_handler() adds the works of the ata error handler to system_unbound_wq. This workqueue asynchronously runs work items, so the ata error handler will be performed concurrently on different CPUs. In this case, ->host_failed will be decreased simultaneously in scsi_eh_finish_cmd() on different CPUs, and become abnormal. It will lead to permanently inequality between ->host_failed and ->host_busy, and scsi error handler thread won't start running. IO errors after that won't be handled. Since all scmds must have been handled in the strategy handler, just remove the decrement in scsi_eh_finish_cmd() and zero ->host_busy after the strategy handler to fix this race. Fixes: 50824d6c5657 ("[SCSI] libsas: async ata-eh") Cc: stable@vger.kernel.org Signed-off-by: Wei Fang <fangwei1@huawei.com> Reviewed-by: James Bottomley <jejb@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 72d8c36ec364c82bf1bf0c64dfa1041cfaf139f7 upstream.

sas_ata_strategy_handler() adds the works of the ata error handler to
system_unbound_wq. This workqueue asynchronously runs work items, so the
ata error handler will be performed concurrently on different CPUs. In
this case, ->host_failed will be decreased simultaneously in
scsi_eh_finish_cmd() on different CPUs, and become abnormal.

It will lead to permanently inequality between ->host_failed and
->host_busy, and scsi error handler thread won't start running. IO
errors after that won't be handled.

Since all scmds must have been handled in the strategy handler, just
remove the decrement in scsi_eh_finish_cmd() and zero ->host_busy after
the strategy handler to fix this race.

Fixes: 50824d6c5657 ("[SCSI] libsas: async ata-eh")
Cc: stable@vger.kernel.org
Signed-off-by: Wei Fang <fangwei1@huawei.com>
Reviewed-by: James Bottomley <jejb@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
pipe: limit the per-user amount of pages allocated in pipes 2016-08-21T21:22:36+00:00 Willy Tarreau w@1wt.eu 2016-07-15T18:26:27+00:00 f474c525b4f412522cd092b6c8bffb6a0fd9a4de commit 759c01142a5d0f364a462346168a56de28a80f52 upstream. On no-so-small systems, it is possible for a single process to cause an OOM condition by filling large pipes with data that are never read. A typical process filling 4000 pipes with 1 MB of data will use 4 GB of memory. On small systems it may be tricky to set the pipe max size to prevent this from happening. This patch makes it possible to enforce a per-user soft limit above which new pipes will be limited to a single page, effectively limiting them to 4 kB each, as well as a hard limit above which no new pipes may be created for this user. This has the effect of protecting the system against memory abuse without hurting other users, and still allowing pipes to work correctly though with less data at once. The limit are controlled by two new sysctls : pipe-user-pages-soft, and pipe-user-pages-hard. Both may be disabled by setting them to zero. The default soft limit allows the default number of FDs per process (1024) to create pipes of the default size (64kB), thus reaching a limit of 64MB before starting to create only smaller pipes. With 256 processes limited to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = 1084 MB of memory allocated for a user. The hard limit is disabled by default to avoid breaking existing applications that make intensive use of pipes (eg: for splicing). CVE-2016-2847 Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> Signed-off-by: Chas Williams <3chas3@gmail.com> 
commit 759c01142a5d0f364a462346168a56de28a80f52 upstream.

On no-so-small systems, it is possible for a single process to cause an
OOM condition by filling large pipes with data that are never read. A
typical process filling 4000 pipes with 1 MB of data will use 4 GB of
memory. On small systems it may be tricky to set the pipe max size to
prevent this from happening.

This patch makes it possible to enforce a per-user soft limit above
which new pipes will be limited to a single page, effectively limiting
them to 4 kB each, as well as a hard limit above which no new pipes may
be created for this user. This has the effect of protecting the system
against memory abuse without hurting other users, and still allowing
pipes to work correctly though with less data at once.

The limit are controlled by two new sysctls : pipe-user-pages-soft, and
pipe-user-pages-hard. Both may be disabled by setting them to zero. The
default soft limit allows the default number of FDs per process (1024)
to create pipes of the default size (64kB), thus reaching a limit of 64MB
before starting to create only smaller pipes. With 256 processes limited
to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB =
1084 MB of memory allocated for a user. The hard limit is disabled by
default to avoid breaking existing applications that make intensive use
of pipes (eg: for splicing).

CVE-2016-2847

Reported-by: socketpair@gmail.com
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Mitigates: CVE-2013-4312 (Linux 2.0+)
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Chas Williams <3chas3@gmail.com>
efi: Make efivarfs entries immutable by default 2016-03-16T15:41:37+00:00 Peter Jones pjones@redhat.com 2016-02-08T19:48:15+00:00 7b35014c77e1ba732617c83ab6705298302bd09f commit ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879 upstream. "rm -rf" is bricking some peoples' laptops because of variables being used to store non-reinitializable firmware driver data that's required to POST the hardware. These are 100% bugs, and they need to be fixed, but in the mean time it shouldn't be easy to *accidentally* brick machines. We have to have delete working, and picking which variables do and don't work for deletion is quite intractable, so instead make everything immutable by default (except for a whitelist), and make tools that aren't quite so broad-spectrum unset the immutable flag. Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879 upstream.

"rm -rf" is bricking some peoples' laptops because of variables being
used to store non-reinitializable firmware driver data that's required
to POST the hardware.

These are 100% bugs, and they need to be fixed, but in the mean time it
shouldn't be easy to *accidentally* brick machines.

We have to have delete working, and picking which variables do and don't
work for deletion is quite intractable, so instead make everything
immutable by default (except for a whitelist), and make tools that
aren't quite so broad-spectrum unset the immutable flag.

Signed-off-by: Peter Jones <pjones@redhat.com>
Tested-by: Lee, Chun-Yi <jlee@suse.com>
Acked-by: Matthew Garrett <mjg59@coreos.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pinctrl: mvebu: armada-xp: fix functions of MPP48 2015-08-03T16:29:42+00:00 Thomas Petazzoni thomas.petazzoni@free-electrons.com 2015-06-09T16:46:58+00:00 91d0d491518984502fd02fe28fb229856f6112d8 commit ea78b9511a54d0de026e04b5da86b30515072f31 upstream. There was a mistake in the definition of the functions for MPP48 on Marvell Armada XP. The second function is dev(clkout), and not tclk. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Fixes: 463e270f766a ("pinctrl: mvebu: add pinctrl driver for Armada XP") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ea78b9511a54d0de026e04b5da86b30515072f31 upstream.

There was a mistake in the definition of the functions for MPP48 on
Marvell Armada XP. The second function is dev(clkout), and not tclk.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Fixes: 463e270f766a ("pinctrl: mvebu: add pinctrl driver for Armada XP")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pinctrl: mvebu: armada-xp: remove non-existing VDD cpu_pd functions 2015-08-03T16:29:42+00:00 Thomas Petazzoni thomas.petazzoni@free-electrons.com 2015-06-09T16:46:57+00:00 d150690472aed58d3208c8a46356c09bff6ca064 commit 80b3d04feab5e69d51cb2375eb989a7165e43e3b upstream. The latest version of the Armada XP datasheet no longer documents the VDD cpu_pd functions, which might indicate they are not working and/or not supported. This commit ensures the pinctrl driver matches the datasheet. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Fixes: 463e270f766a ("pinctrl: mvebu: add pinctrl driver for Armada XP") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 80b3d04feab5e69d51cb2375eb989a7165e43e3b upstream.

The latest version of the Armada XP datasheet no longer documents the
VDD cpu_pd functions, which might indicate they are not working and/or
not supported. This commit ensures the pinctrl driver matches the
datasheet.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Fixes: 463e270f766a ("pinctrl: mvebu: add pinctrl driver for Armada XP")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pinctrl: mvebu: armada-xp: remove non-existing NAND pins 2015-08-03T16:29:42+00:00 Thomas Petazzoni thomas.petazzoni@free-electrons.com 2015-06-09T16:46:56+00:00 74806d71a4449dd8e6dedc921b979108da34fa8b commit bc99357f3690c11817756adfee0ece811a3db2e7 upstream. After updating to a more recent version of the Armada XP datasheet, we realized that some of the pins documented as having a NAND-related functionality in fact did not have such functionality. This commit updates the pinctrl driver accordingly. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Fixes: 463e270f766a ("pinctrl: mvebu: add pinctrl driver for Armada XP") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit bc99357f3690c11817756adfee0ece811a3db2e7 upstream.

After updating to a more recent version of the Armada XP datasheet, we
realized that some of the pins documented as having a NAND-related
functionality in fact did not have such functionality. This commit
updates the pinctrl driver accordingly.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Fixes: 463e270f766a ("pinctrl: mvebu: add pinctrl driver for Armada XP")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pinctrl: mvebu: armada-370: fix spi0 pin description 2015-08-03T16:29:42+00:00 Thomas Petazzoni thomas.petazzoni@free-electrons.com 2015-06-09T16:46:54+00:00 eef15dcc8010b6bde54f8b20ff876581e0fd2760 commit 438881dfddb9107ef0eb30b49368e91e092f0b3e upstream. Due to a mistake, the CS0 and CS1 SPI0 functions were incorrectly named "spi0-1" instead of just "spi0". This commit fixes that. This DT binding change does not affect any of the in-tree users. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Fixes: 5f597bb2be57 ("pinctrl: mvebu: add pinctrl driver for Armada 370") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 438881dfddb9107ef0eb30b49368e91e092f0b3e upstream.

Due to a mistake, the CS0 and CS1 SPI0 functions were incorrectly
named "spi0-1" instead of just "spi0". This commit fixes that.

This DT binding change does not affect any of the in-tree users.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Fixes: 5f597bb2be57 ("pinctrl: mvebu: add pinctrl driver for Armada 370")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>