02 Mar, 2013
1 commit
-
Pull new ARC architecture from Vineet Gupta:
"Initial ARC Linux port with some fixes on top for 3.9-rc1:I would like to introduce the Linux port to ARC Processors (from
Synopsys) for 3.9-rc1. The patch-set has been discussed on the public
lists since Nov and has received a fair bit of review, specially from
Arnd, tglx, Al and other subsystem maintainers for DeviceTree, kgdb...The arch bits are in arch/arc, some asm-generic changes (acked by
Arnd), a minor change to PARISC (acked by Helge).The series is a touch bigger for a new port for 2 main reasons:
1. It enables a basic kernel in first sub-series and adds
ptrace/kgdb/.. later2. Some of the fallout of review (DeviceTree support, multi-platform-
image support) were added on top of orig series, primarily to
record the revision history.This updated pull request additionally contains
- fixes due to our GNU tools catching up with the new syscall/ptrace
ABI- some (minor) cross-arch Kconfig updates."
* tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (82 commits)
ARC: split elf.h into uapi and export it for userspace
ARC: Fixup the current ABI version
ARC: gdbserver using regset interface possibly broken
ARC: Kconfig cleanup tracking cross-arch Kconfig pruning in merge window
ARC: make a copy of flat DT
ARC: [plat-arcfpga] DT arc-uart bindings change: "baud" => "current-speed"
ARC: Ensure CONFIG_VIRT_TO_BUS is not enabled
ARC: Fix pt_orig_r8 access
ARC: [3.9] Fallout of hlist iterator update
ARC: 64bit RTSC timestamp hardware issue
ARC: Don't fiddle with non-existent caches
ARC: Add self to MAINTAINERS
ARC: Provide a default serial.h for uart drivers needing BASE_BAUD
ARC: [plat-arcfpga] defconfig for fully loaded ARC Linux
ARC: [Review] Multi-platform image #8: platform registers SMP callbacks
ARC: [Review] Multi-platform image #7: SMP common code to use callbacks
ARC: [Review] Multi-platform image #6: cpu-to-dma-addr optional
ARC: [Review] Multi-platform image #5: NR_IRQS defined by ARC core
ARC: [Review] Multi-platform image #4: Isolate platform headers
ARC: [Review] Multi-platform image #3: switch to board callback
...
28 Feb, 2013
1 commit
-
The existing SUID_DUMP_* defines duplicate the newer SUID_DUMPABLE_*
defines introduced in 54b501992dd2 ("coredump: warn about unsafe
suid_dumpable / core_pattern combo"). Remove the new ones, and use the
prior values instead.Signed-off-by: Kees Cook
Reported-by: Chen Gang
Cc: Alexander Viro
Cc: Alan Cox
Cc: "Eric W. Biederman"
Cc: Doug Ledford
Cc: Serge Hallyn
Cc: James Morris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
26 Feb, 2013
1 commit
-
Pull module update from Rusty Russell:
"The sweeping change is to make add_taint() explicitly indicate whether
to disable lockdep, but it's a mechanical change."* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
MODSIGN: Add option to not sign modules during modules_install
MODSIGN: Add -s option to sign-file
MODSIGN: Specify the hash algorithm on sign-file command line
MODSIGN: Simplify Makefile with a Kconfig helper
module: clean up load_module a little more.
modpost: Ignore ARC specific non-alloc sections
module: constify within_module_*
taint: add explicit flag to show whether lock dep is still OK.
module: printk message when module signature fail taints kernel.
24 Feb, 2013
1 commit
-
When calculating amount of dirtyable memory, min_free_kbytes should be
subtracted because it is not intended for dirty pages.Addresses http://bugs.debian.org/695182
[akpm@linux-foundation.org: fix up min_free_kbytes extern declarations]
[akpm@linux-foundation.org: fix min() warning]
Signed-off-by: Paul Szabo
Acked-by: Rik van Riel
Cc: Wu Fengguang
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
22 Feb, 2013
1 commit
-
Pull misc ia64 bits from Tony Luck.
* tag 'please-pull-misc-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
MAINTAINERS: update SGI & ia64 Altix stuff
sysctl: Enable IA64 "ignore-unaligned-usertrap" to be used cross-arch
16 Feb, 2013
1 commit
-
PARISC defines /proc/sys/kernel/unaligned-trap to runtime toggle
unaligned access emulation.The exact mechanics of enablig/disabling are still arch specific, we can
make the sysctl usable by other arches.Signed-off-by: Vineet Gupta
Acked-by: Helge Deller
Cc: "James E.J. Bottomley"
Cc: Helge Deller
Cc: "Eric W. Biederman"
Cc: Serge Hallyn
08 Feb, 2013
2 commits
-
Add a /proc/sys/kernel scheduler knob named
sched_rr_timeslice_ms that allows global changing of the
SCHED_RR timeslice value. User visable value is in milliseconds
but is stored as jiffies. Setting to 0 (zero) resets to the
default (currently 100ms).Signed-off-by: Clark Williams
Cc: Peter Zijlstra
Cc: Steven Rostedt
Link: http://lkml.kernel.org/r/20130207094704.13751796@riff.lan
Signed-off-by: Ingo Molnar -
Move the sysctl-related bits from include/linux/sched.h into
a new file: include/linux/sched/sysctl.h. Then update source
files requiring access to those bits by including the new
header file.Signed-off-by: Clark Williams
Cc: Peter Zijlstra
Cc: Steven Rostedt
Link: http://lkml.kernel.org/r/20130207094659.06dced96@riff.lan
Signed-off-by: Ingo Molnar
21 Jan, 2013
1 commit
-
Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.Signed-off-by: Rusty Russell
10 Jan, 2013
1 commit
-
IA64 defines /proc/sys/kernel/ignore-unaligned-usertrap to control
verbose warnings on unaligned access emulation.Although the exact mechanics of what to do with sysctl (ignore/shout)
are arch specific, this change enables the sysctl to be usable cross-arch.Signed-off-by: Vineet Gupta
Cc: Fenghua Yu
Cc: "Eric W. Biederman"
Cc: Serge Hallyn
Signed-off-by: Tony Luck
17 Dec, 2012
1 commit
-
Pull Automatic NUMA Balancing bare-bones from Mel Gorman:
"There are three implementations for NUMA balancing, this tree
(balancenuma), numacore which has been developed in tip/master and
autonuma which is in aa.git.In almost all respects balancenuma is the dumbest of the three because
its main impact is on the VM side with no attempt to be smart about
scheduling. In the interest of getting the ball rolling, it would be
desirable to see this much merged for 3.8 with the view to building
scheduler smarts on top and adapting the VM where required for 3.9.The most recent set of comparisons available from different people are
mel: https://lkml.org/lkml/2012/12/9/108
mingo: https://lkml.org/lkml/2012/12/7/331
tglx: https://lkml.org/lkml/2012/12/10/437
srikar: https://lkml.org/lkml/2012/12/10/397The results are a mixed bag. In my own tests, balancenuma does
reasonably well. It's dumb as rocks and does not regress against
mainline. On the other hand, Ingo's tests shows that balancenuma is
incapable of converging for this workloads driven by perf which is bad
but is potentially explained by the lack of scheduler smarts. Thomas'
results show balancenuma improves on mainline but falls far short of
numacore or autonuma. Srikar's results indicate we all suffer on a
large machine with imbalanced node sizes.My own testing showed that recent numacore results have improved
dramatically, particularly in the last week but not universally.
We've butted heads heavily on system CPU usage and high levels of
migration even when it shows that overall performance is better.
There are also cases where it regresses. Of interest is that for
specjbb in some configurations it will regress for lower numbers of
warehouses and show gains for higher numbers which is not reported by
the tool by default and sometimes missed in treports. Recently I
reported for numacore that the JVM was crashing with
NullPointerExceptions but currently it's unclear what the source of
this problem is. Initially I thought it was in how numacore batch
handles PTEs but I'm no longer think this is the case. It's possible
numacore is just able to trigger it due to higher rates of migration.These reports were quite late in the cycle so I/we would like to start
with this tree as it contains much of the code we can agree on and has
not changed significantly over the last 2-3 weeks."* tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits)
mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
mm: migrate: Account a transhuge page properly when rate limiting
mm: numa: Account for failed allocations and isolations as migration failures
mm: numa: Add THP migration for the NUMA working set scanning fault case build fix
mm: numa: Add THP migration for the NUMA working set scanning fault case.
mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node
mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG
mm: sched: numa: Control enabling and disabling of NUMA balancing
mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate
mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely tasknode relationships
mm: numa: migrate: Set last_nid on newly allocated page
mm: numa: split_huge_page: Transfer last_nid on tail page
mm: numa: Introduce last_nid to the page frame
sched: numa: Slowly increase the scanning period as NUMA faults are handled
mm: numa: Rate limit setting of pte_numa if node is saturated
mm: numa: Rate limit the amount of memory that is migrated between nodes
mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting
mm: numa: Migrate pages handled during a pmd_numa hinting fault
mm: numa: Migrate on reference policy
...
11 Dec, 2012
4 commits
-
The PTE scanning rate and fault rates are two of the biggest sources of
system CPU overhead with automatic NUMA placement. Ideally a proper policy
would detect if a workload was properly placed, schedule and adjust the
PTE scanning rate accordingly. We do not track the necessary information
to do that but we at least know if we migrated or not.This patch scans slower if a page was not migrated as the result of a
NUMA hinting fault up to sysctl_numa_balancing_scan_period_max which is
now higher than the previous default. Once every minute it will reset
the scanner in case of phase changes.This is hilariously crude and the numbers are arbitrary. Workloads will
converge quite slowly in comparison to what a proper policy should be able
to do. On the plus side, we will chew up less CPU for workloads that have
no need for automatic balancing.Signed-off-by: Mel Gorman
-
Add a 1 second delay before starting to scan the working set of
a task and starting to balance it amongst nodes.[ note that before the constant per task WSS sampling rate patch
the initial scan would happen much later still, in effect that
patch caused this regression. ]The theory is that short-run tasks benefit very little from NUMA
placement: they come and go, and they better stick to the node
they were started on. As tasks mature and rebalance to other CPUs
and nodes, so does their NUMA placement have to change and so
does it start to matter more and more.In practice this change fixes an observable kbuild regression:
# [ a perf stat --null --repeat 10 test of ten bzImage builds to /dev/shm ]
!NUMA:
45.291088843 seconds time elapsed ( +- 0.40% )
45.154231752 seconds time elapsed ( +- 0.36% )+NUMA, no slow start:
46.172308123 seconds time elapsed ( +- 0.30% )
46.343168745 seconds time elapsed ( +- 0.25% )+NUMA, 1 sec slow start:
45.224189155 seconds time elapsed ( +- 0.25% )
45.160866532 seconds time elapsed ( +- 0.17% )and it also fixes an observable perf bench (hackbench) regression:
# perf stat --null --repeat 10 perf bench sched messaging
-NUMA:
-NUMA: 0.246225691 seconds time elapsed ( +- 1.31% )
+NUMA no slow start: 0.252620063 seconds time elapsed ( +- 1.13% )+NUMA 1sec delay: 0.248076230 seconds time elapsed ( +- 1.35% )
The implementation is simple and straightforward, most of the patch
deals with adding the /proc/sys/kernel/numa_balancing_scan_delay_ms tunable
knob.Signed-off-by: Peter Zijlstra
Cc: Linus Torvalds
Cc: Andrew Morton
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Rik van Riel
[ Wrote the changelog, ran measurements, tuned the default. ]
Signed-off-by: Ingo Molnar
Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel -
Previously, to probe the working set of a task, we'd use
a very simple and crude method: mark all of its address
space PROT_NONE.That method has various (obvious) disadvantages:
- it samples the working set at dissimilar rates,
giving some tasks a sampling quality advantage
over others.- creates performance problems for tasks with very
large working sets- over-samples processes with large address spaces but
which only very rarely executeImprove that method by keeping a rotating offset into the
address space that marks the current position of the scan,
and advance it by a constant rate (in a CPU cycles execution
proportional manner). If the offset reaches the last mapped
address of the mm then it then it starts over at the first
address.The per-task nature of the working set sampling functionality in this tree
allows such constant rate, per task, execution-weight proportional sampling
of the working set, with an adaptive sampling interval/frequency that
goes from once per 100ms up to just once per 8 seconds. The current
sampling volume is 256 MB per interval.As tasks mature and converge their working set, so does the
sampling rate slow down to just a trickle, 256 MB per 8
seconds of CPU time executed.This, beyond being adaptive, also rate-limits rarely
executing systems and does not over-sample on overloaded
systems.[ In AutoNUMA speak, this patch deals with the effective sampling
rate of the 'hinting page fault'. AutoNUMA's scanning is
currently rate-limited, but it is also fundamentally
single-threaded, executing in the knuma_scand kernel thread,
so the limit in AutoNUMA is global and does not scale up with
the number of CPUs, nor does it scan tasks in an execution
proportional manner.So the idea of rate-limiting the scanning was first implemented
in the AutoNUMA tree via a global rate limit. This patch goes
beyond that by implementing an execution rate proportional
working set sampling rate that is not implemented via a single
global scanning daemon. ][ Dan Carpenter pointed out a possible NULL pointer dereference in the
first version of this patch. ]Based-on-idea-by: Andrea Arcangeli
Bug-Found-By: Dan Carpenter
Signed-off-by: Peter Zijlstra
Cc: Linus Torvalds
Cc: Andrew Morton
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Rik van Riel
[ Wrote changelog and fixed bug. ]
Signed-off-by: Ingo Molnar
Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel -
NOTE: This patch is based on "sched, numa, mm: Add fault driven
placement and migration policy" but as it throws away all the policy
to just leave a basic foundation I had to drop the signed-offs-by.This patch creates a bare-bones method for setting PTEs pte_numa in the
context of the scheduler that when faulted later will be faulted onto the
node the CPU is running on. In itself this does nothing useful but any
placement policy will fundamentally depend on receiving hints on placement
from fault context and doing something intelligent about it.Signed-off-by: Mel Gorman
Acked-by: Rik van Riel
29 Nov, 2012
1 commit
-
Remove conditional code based on CONFIG_HOTPLUG being false. It's
always on now in preparation of it going away as an option.Signed-off-by: Bill Pemberton
Signed-off-by: Greg Kroah-Hartman
09 Oct, 2012
1 commit
-
Introduce SYSCTL_EXCEPTION_TRACE config option and selec it in the
architectures requiring support for the "exception-trace" debug_table
entry in kernel/sysctl.c.Signed-off-by: Catalin Marinas
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: "David S. Miller"
Cc: Chris Metcalf
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: "H. Peter Anvin"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
06 Oct, 2012
1 commit
-
Adds an expert Kconfig option, CONFIG_COREDUMP, which allows disabling of
core dump. This saves approximately 2.6k in the compiled kernel, and
complements CONFIG_ELF_CORE, which now depends on it.CONFIG_COREDUMP also disables coredump-related sysctls, except for
suid_dumpable and related functions, which are necessary for ptrace.[akpm@linux-foundation.org: fix binfmt_aout.c build]
Signed-off-by: Alex Kelly
Reviewed-by: Josh Triplett
Acked-by: Serge Hallyn
Acked-by: Kees Cook
Cc: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Oct, 2012
1 commit
-
Pull arm64 support from Catalin Marinas:
"Linux support for the 64-bit ARM architecture (AArch64)Features currently supported:
- 39-bit address space for user and kernel (each)
- 4KB and 64KB page configurations
- Compat (32-bit) user applications (ARMv7, EABI only)
- Flattened Device Tree (mandated for all AArch64 platforms)
- ARM generic timers"* tag 'arm64-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64: (35 commits)
arm64: ptrace: remove obsolete ptrace request numbers from user headers
arm64: Do not set the SMP/nAMP processor bit
arm64: MAINTAINERS update
arm64: Build infrastructure
arm64: Miscellaneous header files
arm64: Generic timers support
arm64: Loadable modules
arm64: Miscellaneous library functions
arm64: Performance counters support
arm64: Add support for /proc/sys/debug/exception-trace
arm64: Debugging support
arm64: Floating point and SIMD
arm64: 32-bit (compat) applications support
arm64: User access library functions
arm64: Signal handling support
arm64: VDSO support
arm64: System calls handling
arm64: ELF definitions
arm64: SMP support
arm64: DMA mapping API
...
17 Sep, 2012
1 commit
-
This patch allows setting of the show_unhandled_signals variable via
/proc/sys/debug/exception-trace. The default value is currently 1
showing unhandled user faults (undefined instructions, data aborts) and
invalid signal stack frames.Signed-off-by: Catalin Marinas
Acked-by: Tony Lindgren
Acked-by: Arnd Bergmann
Acked-by: Nicolas Pitre
Acked-by: Olof Johansson
Acked-by: Santosh Shilimkar
04 Sep, 2012
1 commit
-
Unlike others, sched_migration_cost, sched_time_avg and
sched_shares_window doesn't have time unit as suffix. Add them.Signed-off-by: Namhyung Kim
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1345083330-19486-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar
02 Aug, 2012
1 commit
-
Pull second vfs pile from Al Viro:
"The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
deadlock reproduced by xfstests 068), symlink and hardlink restriction
patches, plus assorted cleanups and fixes.Note that another fsfreeze deadlock (emergency thaw one) is *not*
dealt with - the series by Fernando conflicts a lot with Jan's, breaks
userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
for massive vfsmount leak; this is going to be handled next cycle.
There probably will be another pull request, but that stuff won't be
in it."Fix up trivial conflicts due to unrelated changes next to each other in
drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
delousing target_core_file a bit
Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
fs: Remove old freezing mechanism
ext2: Implement freezing
btrfs: Convert to new freezing mechanism
nilfs2: Convert to new freezing mechanism
ntfs: Convert to new freezing mechanism
fuse: Convert to new freezing mechanism
gfs2: Convert to new freezing mechanism
ocfs2: Convert to new freezing mechanism
xfs: Convert to new freezing code
ext4: Convert to new freezing mechanism
fs: Protect write paths by sb_start_write - sb_end_write
fs: Skip atime update on frozen filesystem
fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
fs: Improve filesystem freezing handling
switch the protection of percpu_counter list to spinlock
nfsd: Push mnt_want_write() outside of i_mutex
btrfs: Push mnt_want_write() outside of i_mutex
fat: Push mnt_want_write() outside of i_mutex
...
01 Aug, 2012
1 commit
-
Since per-BDI flusher threads were introduced in 2.6, the pdflush
mechanism is not used any more. But the old interface exported through
/proc/sys/vm/nr_pdflush_threads still exists and is obviously useless.For back-compatibility, printk warning information and return 2 to notify
the users that the interface is removed.Signed-off-by: Wanpeng Li
Cc: Wu Fengguang
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
31 Jul, 2012
2 commits
-
register_sysctl_table() is a strange function, as it makes internal
allocations (a header) to register a sysctl_table. This header is a
handle to the table that is created, and can be used to unregister the
table. But if the table is permanent and never unregistered, the header
acts the same as a static variable.Unfortunately, this allocation of memory that is never expected to be
freed fools kmemleak in thinking that we have leaked memory. For those
sysctl tables that are never unregistered, and have no pointer referencing
them, kmemleak will think that these are memory leaks:unreferenced object 0xffff880079fb9d40 (size 192):
comm "swapper/0", pid 0, jiffies 4294667316 (age 12614.152s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[] kmemleak_alloc+0x73/0x98
[] kmemleak_alloc_recursive.constprop.42+0x16/0x18
[] __kmalloc+0x107/0x153
[] kzalloc.constprop.8+0xe/0x10
[] __register_sysctl_paths+0xe1/0x160
[] register_sysctl_paths+0x1b/0x1d
[] register_sysctl_table+0x18/0x1a
[] sysctl_init+0x10/0x14
[] proc_sys_init+0x2f/0x31
[] proc_root_init+0xa5/0xa7
[] start_kernel+0x3d0/0x40a
[] x86_64_start_reservations+0xae/0xb2
[] x86_64_start_kernel+0x102/0x111
[] 0xffffffffffffffffThe sysctl_base_table used by sysctl itself is one such instance that
registers the table to never be unregistered.Use kmemleak_not_leak() to suppress the kmemleak false positive.
Signed-off-by: Steven Rostedt
Acked-by: Catalin Marinas
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When suid_dumpable=2, detect unsafe core_pattern settings and warn when
they are seen.Signed-off-by: Kees Cook
Suggested-by: Andrew Morton
Cc: Alexander Viro
Cc: Alan Cox
Cc: "Eric W. Biederman"
Cc: Doug Ledford
Cc: Serge Hallyn
Cc: James Morris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Jul, 2012
1 commit
-
This adds symlink and hardlink restrictions to the Linux VFS.
Symlinks:
A long-standing class of security issues is the symlink-based
time-of-check-time-of-use race, most commonly seen in world-writable
directories like /tmp. The common method of exploitation of this flaw
is to cross privilege boundaries when following a given symlink (i.e. a
root process follows a symlink belonging to another user). For a likely
incomplete list of hundreds of examples across the years, please see:
http://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=/tmpThe solution is to permit symlinks to only be followed when outside
a sticky world-writable directory, or when the uid of the symlink and
follower match, or when the directory owner matches the symlink's owner.Some pointers to the history of earlier discussion that I could find:
1996 Aug, Zygo Blaxell
http://marc.info/?l=bugtraq&m=87602167419830&w=2
1996 Oct, Andrew Tridgell
http://lkml.indiana.edu/hypermail/linux/kernel/9610.2/0086.html
1997 Dec, Albert D Cahalan
http://lkml.org/lkml/1997/12/16/4
2005 Feb, Lorenzo Hernández García-Hierro
http://lkml.indiana.edu/hypermail/linux/kernel/0502.0/1896.html
2010 May, Kees Cook
https://lkml.org/lkml/2010/5/30/144Past objections and rebuttals could be summarized as:
- Violates POSIX.
- POSIX didn't consider this situation and it's not useful to follow
a broken specification at the cost of security.
- Might break unknown applications that use this feature.
- Applications that break because of the change are easy to spot and
fix. Applications that are vulnerable to symlink ToCToU by not having
the change aren't. Additionally, no applications have yet been found
that rely on this behavior.
- Applications should just use mkstemp() or O_CREATE|O_EXCL.
- True, but applications are not perfect, and new software is written
all the time that makes these mistakes; blocking this flaw at the
kernel is a single solution to the entire class of vulnerability.
- This should live in the core VFS.
- This should live in an LSM. (https://lkml.org/lkml/2010/5/31/135)
- This should live in an LSM.
- This should live in the core VFS. (https://lkml.org/lkml/2010/8/2/188)Hardlinks:
On systems that have user-writable directories on the same partition
as system files, a long-standing class of security issues is the
hardlink-based time-of-check-time-of-use race, most commonly seen in
world-writable directories like /tmp. The common method of exploitation
of this flaw is to cross privilege boundaries when following a given
hardlink (i.e. a root process follows a hardlink created by another
user). Additionally, an issue exists where users can "pin" a potentially
vulnerable setuid/setgid file so that an administrator will not actually
upgrade a system fully.The solution is to permit hardlinks to only be created when the user is
already the existing file's owner, or if they already have read/write
access to the existing file.Many Linux users are surprised when they learn they can link to files
they have no access to, so this change appears to follow the doctrine
of "least surprise". Additionally, this change does not violate POSIX,
which states "the implementation may require that the calling process
has permission to access the existing file"[1].This change is known to break some implementations of the "at" daemon,
though the version used by Fedora and Ubuntu has been fixed[2] for
a while. Otherwise, the change has been undisruptive while in use in
Ubuntu for the last 1.5 years.[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/linkat.html
[2] http://anonscm.debian.org/gitweb/?p=collab-maint/at.git;a=commitdiff;h=f4114656c3a6c6f6070e315ffdf940a49eda3279This patch is based on the patches in Openwall and grsecurity, along with
suggestions from Al Viro. I have added a sysctl to enable the protected
behavior, and documentation.Signed-off-by: Kees Cook
Acked-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro
05 Apr, 2012
1 commit
-
Commit bfdc0b4 adds code to restrict access to dmesg_restrict,
however, it incorrectly alters kptr_restrict rather than
dmesg_restrict.The original patch from Richard Weinberger
(https://lkml.org/lkml/2011/3/14/362) alters dmesg_restrict as
expected, and so the patch seems to have been misapplied.This adds the CAP_SYS_ADMIN check to both dmesg_restrict and
kptr_restrict, since both are sensitive.Reported-by: Phillip Lougher
Signed-off-by: Kees Cook
Acked-by: Serge Hallyn
Acked-by: Richard Weinberger
Cc: stable@vger.kernel.org
Signed-off-by: James Morris
29 Mar, 2012
5 commits
-
Merge third batch of patches from Andrew Morton:
- Some MM stragglers
- core SMP library cleanups (on_each_cpu_mask)
- Some IPI optimisations
- kexec
- kdump
- IPMI
- the radix-tree iterator work
- various other misc bits."That'll do for -rc1. I still have ~10 patches for 3.4, will send
those along when they've baked a little more."* emailed from Andrew Morton : (35 commits)
backlight: fix typo in tosa_lcd.c
crc32: add help text for the algorithm select option
mm: move hugepage test examples to tools/testing/selftests/vm
mm: move slabinfo.c to tools/vm
mm: move page-types.c from Documentation to tools/vm
selftests/Makefile: make `run_tests' depend on `all'
selftests: launch individual selftests from the main Makefile
radix-tree: use iterators in find_get_pages* functions
radix-tree: rewrite gang lookup using iterator
radix-tree: introduce bit-optimized iterator
fs/proc/namespaces.c: prevent crash when ns_entries[] is empty
nbd: rename the nbd_device variable from lo to nbd
pidns: add reboot_pid_ns() to handle the reboot syscall
sysctl: use bitmap library functions
ipmi: use locks on watchdog timeout set on reboot
ipmi: simplify locking
ipmi: fix message handling during panics
ipmi: use a tasklet for handling received messages
ipmi: increase KCS timeouts
ipmi: decrease the IPMI message transaction time in interrupt mode
... -
Use bitmap_set() instead of using set_bit() for each bit. This conversion
is valid because the bitmap is private in the function call and atomic
bitops were unnecessary.This also includes minor change.
- Use bitmap_copy() for shorter typingSigned-off-by: Akinobu Mita
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
…m/linux/kernel/git/dhowells/linux-asm_system
Pull "Disintegrate and delete asm/system.h" from David Howells:
"Here are a bunch of patches to disintegrate asm/system.h into a set of
separate bits to relieve the problem of circular inclusion
dependencies.I've built all the working defconfigs from all the arches that I can
and made sure that they don't break.The reason for these patches is that I recently encountered a circular
dependency problem that came about when I produced some patches to
optimise get_order() by rewriting it to use ilog2().This uses bitops - and on the SH arch asm/bitops.h drags in
asm-generic/get_order.h by a circuituous route involving asm/system.h.The main difficulty seems to be asm/system.h. It holds a number of
low level bits with no/few dependencies that are commonly used (eg.
memory barriers) and a number of bits with more dependencies that
aren't used in many places (eg. switch_to()).These patches break asm/system.h up into the following core pieces:
(1) asm/barrier.h
Move memory barriers here. This already done for MIPS and Alpha.
(2) asm/switch_to.h
Move switch_to() and related stuff here.
(3) asm/exec.h
Move arch_align_stack() here. Other process execution related bits
could perhaps go here from asm/processor.h.(4) asm/cmpxchg.h
Move xchg() and cmpxchg() here as they're full word atomic ops and
frequently used by atomic_xchg() and atomic_cmpxchg().(5) asm/bug.h
Move die() and related bits.
(6) asm/auxvec.h
Move AT_VECTOR_SIZE_ARCH here.
Other arch headers are created as needed on a per-arch basis."
Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that. We'll find out anything that got broken and fix it..* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
Delete all instances of asm/system.h
Remove all #inclusions of asm/system.h
Add #includes needed to permit the removal of asm/system.h
Move all declarations of free_initmem() to linux/mm.h
Disintegrate asm/system.h for OpenRISC
Split arch_align_stack() out from asm-generic/system.h
Split the switch_to() wrapper out of asm-generic/system.h
Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
Create asm-generic/barrier.h
Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
Disintegrate asm/system.h for Xtensa
Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
Disintegrate asm/system.h for Tile
Disintegrate asm/system.h for Sparc
Disintegrate asm/system.h for SH
Disintegrate asm/system.h for Score
Disintegrate asm/system.h for S390
Disintegrate asm/system.h for PowerPC
Disintegrate asm/system.h for PA-RISC
Disintegrate asm/system.h for MN10300
... -
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it. Performed with the following command:perl -p -i -e 's!^#\s*include\s*.*\n!!' `grep -Irl '^#\s*include\s*' *`
Signed-off-by: David Howells
-
Disintegrate asm/system.h for Sparc.
Signed-off-by: David Howells
cc: sparclinux@vger.kernel.org
24 Mar, 2012
1 commit
-
Pull sysctl updates from Eric Biederman:
- Rewrite of sysctl for speed and clarity.
Insert/remove/Lookup in sysctl are all now O(NlogN) operations, and
are no longer bottlenecks in the process of adding and removing
network devices.sysctl is now focused on being a filesystem instead of system call
and the code can all be found in fs/proc/proc_sysctl.c. Hopefully
this means the code is now approachable.Much thanks is owed to Lucian Grinjincu for keeping at this until
something was found that was usable.- The recent proc_sys_poll oops found by the fuzzer during hibernation
is fixed.* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl: (36 commits)
sysctl: protect poll() in entries that may go away
sysctl: Don't call sysctl_follow_link unless we are a link.
sysctl: Comments to make the code clearer.
sysctl: Correct error return from get_subdir
sysctl: An easier to read version of find_subdir
sysctl: fix memset parameters in setup_sysctl_set()
sysctl: remove an unused variable
sysctl: Add register_sysctl for normal sysctl users
sysctl: Index sysctl directories with rbtrees.
sysctl: Make the header lists per directory.
sysctl: Move sysctl_check_dups into insert_header
sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy
sysctl: Replace root_list with links between sysctl_table_sets.
sysctl: Add sysctl_print_dir and use it in get_subdir
sysctl: Stop requiring explicit management of sysctl directories
sysctl: Add a root pointer to ctl_table_set
sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry
sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry.
sysctl: Normalize the root_table data structure.
sysctl: Factor out insert_header and erase_header
...
14 Feb, 2012
1 commit
-
Trim security.h
Signed-off-by: Al Viro
Signed-off-by: James Morris
25 Jan, 2012
3 commits
-
Move the core sysctl code from kernel/sysctl.c and kernel/sysctl_check.c
into fs/proc/proc_sysctl.c.Currently sysctl maintenance is hampered by the sysctl implementation
being split across 3 files with artificial layering between them.
Consolidate the entire sysctl implementation into 1 file so that
it is easier to see what is going on and hopefully allowing for
simpler maintenance.For functions that are now only used in fs/proc/proc_sysctl.c remove
their declarations from sysctl.h and make them static in fs/proc/proc_sysctl.cSigned-off-by: Eric W. Biederman
-
Simplify the code by treating the base sysctl table like any other
sysctl table and register it with register_sysctl_table.To ensure this table is registered early enough to avoid problems
call sysctl_init from proc_sys_init.Rename sysctl_net.c:sysctl_init() to net_sysctl_init() to avoid
name conflicts now that kernel/sysctl.c:sysctl_init() is no longer
static.Signed-off-by: Eric W. Biederman
-
- In sysctl.h move functions only available if CONFIG_SYSCL
is defined inside of #ifdef CONFIG_SYSCTL- Move the stub function definitions for !CONFIG_SYSCTL
into sysctl.h and make them static inlines.Signed-off-by: Eric W. Biederman
05 Dec, 2011
1 commit
-
Currently, messages are just output on the detection of stack
overflow, which is not sufficient for systems that need a
high reliability. This is because in general the overflow may
corrupt data, and the additional corruption may occur due to
reading them unless systems stop.This patch adds the sysctl parameter
kernel.panic_on_stackoverflow and causes a panic when detecting
the overflows of kernel, IRQ and exception stacks except user
stack according to the parameter. It is disabled by default.Signed-off-by: Mitsuo Hayasaka
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Randy Dunlap
Cc: "H. Peter Anvin"
Link: http://lkml.kernel.org/r/20111129060836.11076.12323.stgit@ltc219.sdl.hitachi.co.jp
Signed-off-by: Ingo Molnar
01 Nov, 2011
2 commits
-
Quoth Andrew:
- Most of MM. Still waiting for the poweroc guys to get off their
butts and review some threaded hugepages patches.- alpha
- vfs bits
- drivers/misc
- a few core kerenl tweaks
- printk() features
- MAINTAINERS updates
- backlight merge
- leds merge
- various lib/ updates
- checkpatch updates
* akpm: (127 commits)
epoll: fix spurious lockdep warnings
checkpatch: add a --strict check for utf-8 in commit logs
kernel.h/checkpatch: mark strict_strto and simple_strto as obsolete
llist-return-whether-list-is-empty-before-adding-in-llist_add-fix
wireless: at76c50x: follow rename pack_hex_byte to hex_byte_pack
fat: follow rename pack_hex_byte() to hex_byte_pack()
security: follow rename pack_hex_byte() to hex_byte_pack()
kgdb: follow rename pack_hex_byte() to hex_byte_pack()
lib: rename pack_hex_byte() to hex_byte_pack()
lib/string.c: fix strim() semantics for strings that have only blanks
lib/idr.c: fix comment for ida_get_new_above()
lib/percpu_counter.c: enclose hotplug only variables in hotplug ifdef
lib/bitmap.c: quiet sparse noise about address space
lib/spinlock_debug.c: print owner on spinlock lockup
lib/kstrtox: common code between kstrto*() and simple_strto*() functions
drivers/leds/leds-lp5521.c: check if reset is successful
leds: turn the blink_timer off before starting to blink
leds: save the delay values after a successful call to blink_set()
drivers/leds/leds-gpio.c: use gpio_get_value_cansleep() when initializing
drivers/leds/leds-lm3530.c: add __devexit_p where needed
... -
Userspace needs to know the highest valid capability of the running
kernel, which right now cannot reliably be retrieved from the header files
only. The fact that this value cannot be determined properly right now
creates various problems for libraries compiled on newer header files
which are run on older kernels. They assume capabilities are available
which actually aren't. libcap-ng is one example. And we ran into the
same problem with systemd too.Now the capability is exported in /proc/sys/kernel/cap_last_cap.
[akpm@linux-foundation.org: make cap_last_cap const, per Ulrich]
Signed-off-by: Dan Ballard
Cc: Randy Dunlap
Cc: Ingo Molnar
Cc: Lennart Poettering
Cc: Kay Sievers
Cc: Ulrich Drepper
Cc: James Morris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
