For performance reasons, when SMAP is in use, SMAP is left open for an
entire put_user_try { ... } put_user_catch(); block, however, calling
__put_user() in the middle of that block will close SMAP as the
STAC..CLAC constructs intentionally do not nest.
Furthermore, using __put_user() rather than put_user_ex() here is bad
for performance.
Thus, introduce new [compat_]save_altstack_ex() helpers that replace
__[compat_]save_altstack() for x86, being currently the only
architecture which supports put_user_try { ... } put_user_catch().
Reported-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # v3.8+
Link: http://lkml.kernel.org/n/tip-es5p6y64if71k8p5u08agv9n@git.kernel.org
Since all architectures have been converted to use vm_unmapped_area(),
there is no remaining use for the free_area_cache.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf updates from Ingo Molnar:
"Kernel improvements:
- watchdog driver improvements by Li Zefan
- Power7 CPI stack events related improvements by Sukadev Bhattiprolu
- event multiplexing via hrtimers and other improvements by Stephane
Eranian
- kernel stack use optimization by Andrew Hunter
- AMD IOMMU uncore PMU support by Suravee Suthikulpanit
- NMI handling rate-limits by Dave Hansen
- various hw_breakpoint fixes by Oleg Nesterov
- hw_breakpoint overflow period sampling and related signal handling
fixes by Jiri Olsa
- Intel Haswell PMU support by Andi Kleen
Tooling improvements:
- Reset SIGTERM handler in workload child process, fix from David
Ahern.
- Makefile reorganization, prep work for Kconfig patches, from Jiri
Olsa.
- Add automated make test suite, from Jiri Olsa.
- Add --percent-limit option to 'top' and 'report', from Namhyung
Kim.
- Sorting improvements, from Namhyung Kim.
- Expand definition of sysfs format attribute, from Michael Ellerman.
Tooling fixes:
- 'perf tests' fixes from Jiri Olsa.
- Make Power7 CPI stack events available in sysfs, from Sukadev
Bhattiprolu.
- Handle death by SIGTERM in 'perf record', fix from David Ahern.
- Fix printing of perf_event_paranoid message, from David Ahern.
- Handle realloc failures in 'perf kvm', from David Ahern.
- Fix divide by 0 in variance, from David Ahern.
- Save parent pid in thread struct, from David Ahern.
- Handle JITed code in shared memory, from Andi Kleen.
- Fixes for 'perf diff', from Jiri Olsa.
- Remove some unused struct members, from Jiri Olsa.
- Add missing liblk.a dependency for python/perf.so, fix from Jiri
Olsa.
- Respect CROSS_COMPILE in liblk.a, from Rabin Vincent.
- No need to do locking when adding hists in perf report, only 'top'
needs that, from Namhyung Kim.
- Fix alignment of symbol column in in the hists browser (top,
report) when -v is given, from NAmhyung Kim.
- Fix 'perf top' -E option behavior, from Namhyung Kim.
- Fix bug in isupper() and islower(), from Sukadev Bhattiprolu.
- Fix compile errors in bp_signal 'perf test', from Sukadev
Bhattiprolu.
... and more things"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (102 commits)
perf/x86: Disable PEBS-LL in intel_pmu_pebs_disable()
perf/x86: Fix shared register mutual exclusion enforcement
perf/x86/intel: Support full width counting
x86: Add NMI duration tracepoints
perf: Drop sample rate when sampling is too slow
x86: Warn when NMI handlers take large amounts of time
hw_breakpoint: Introduce "struct bp_cpuinfo"
hw_breakpoint: Simplify *register_wide_hw_breakpoint()
hw_breakpoint: Introduce cpumask_of_bp()
hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() paths
hw_breakpoint: Simplify list/idx mess in toggle_bp_slot() paths
perf/x86/intel: Add mem-loads/stores support for Haswell
perf/x86/intel: Support Haswell/v4 LBR format
perf/x86/intel: Move NMI clearing to end of PMI handler
perf/x86/intel: Add Haswell PEBS support
perf/x86/intel: Add simple Haswell PMU support
perf/x86/intel: Add Haswell PEBS record support
perf/x86/intel: Fix sparse warning
perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation
perf/x86/amd: Add IOMMU Performance Counter resource management
...
dump_seek() does SEEK_CUR, not SEEK_SET; native binfmt_aout
handles it correctly (seeks by PAGE_SIZE - sizeof(struct user),
getting the current position to PAGE_SIZE), compat one seeks
by PAGE_SIZE and ends up at PAGE_SIZE + already written...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
While porting Vince's perf overflow tests I found perf event
breakpoint overflow does not work properly.
I found the x86 RF EFLAG bit not being set when returning
from debug exception after triggering signal handler. Which
is exactly what you get when you set perf breakpoint overflow
SIGIO handler.
This patch and the next two patches fix the underlying bugs.
This patch adds the RF EFLAGS bit to be restored on return from
signal from the original register context before the signal was
entered.
This will prevent the RF flag to disappear when returning
from exception due to the signal handler being executed.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Originally-Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1367421944-19082-2-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
Pull compat cleanup from Al Viro:
"Mostly about syscall wrappers this time; there will be another pile
with patches in the same general area from various people, but I'd
rather push those after both that and vfs.git pile are in."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
syscalls.h: slightly reduce the jungles of macros
get rid of union semop in sys_semctl(2) arguments
make do_mremap() static
sparc: no need to sign-extend in sync_file_range() wrapper
ppc compat wrappers for add_key(2) and request_key(2) are pointless
x86: trim sys_ia32.h
x86: sys32_kill and sys32_mprotect are pointless
get rid of compat_sys_semctl() and friends in case of ARCH_WANT_OLD_COMPAT_IPC
merge compat sys_ipc instances
consolidate compat lookup_dcookie()
convert vmsplice to COMPAT_SYSCALL_DEFINE
switch getrusage() to COMPAT_SYSCALL_DEFINE
switch epoll_pwait to COMPAT_SYSCALL_DEFINE
convert sendfile{,64} to COMPAT_SYSCALL_DEFINE
switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE
make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect
make HAVE_SYSCALL_WRAPPERS unconditional
consolidate cond_syscall and SYSCALL_ALIAS declarations
teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long
get rid of duplicate logics in __SC_....[1-6] definitions
switch binfmts that use ->read() to that (and to kernel_read()
in several cases in binfmt_flat - sure, it's nommu, but still,
doing ->read() into kmalloc'ed buffer...)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
their argument types are identical to those of sys_kill and sys_mprotect
resp., so we are not doing any kind of argument validation, etc. in those -
they turn into unconditional branches to corresponding syscalls.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull signal/compat fixes from Al Viro:
"Fixes for several regressions introduced in the last signal.git pile,
along with fixing bugs in truncate and ftruncate compat (on just about
anything biarch at least one of those two had been done wrong)."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
compat: restore timerfd settime and gettime compat syscalls
[regression] braino in "sparc: convert to ksignal"
fix compat truncate/ftruncate
switch lseek to COMPAT_SYSCALL_DEFINE
lseek() and truncate() on sparc really need sign extension
Pull vfs pile (part one) from Al Viro:
"Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent
locking violations, etc.
The most visible changes here are death of FS_REVAL_DOT (replaced with
"has ->d_weak_revalidate()") and a new helper getting from struct file
to inode. Some bits of preparation to xattr method interface changes.
Misc patches by various people sent this cycle *and* ocfs2 fixes from
several cycles ago that should've been upstream right then.
PS: the next vfs pile will be xattr stuff."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
saner proc_get_inode() calling conventions
proc: avoid extra pde_put() in proc_fill_super()
fs: change return values from -EACCES to -EPERM
fs/exec.c: make bprm_mm_init() static
ocfs2/dlm: use GFP_ATOMIC inside a spin_lock
ocfs2: fix possible use-after-free with AIO
ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path
get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero
target: writev() on single-element vector is pointless
export kernel_write(), convert open-coded instances
fs: encode_fh: return FILEID_INVALID if invalid fid_type
kill f_vfsmnt
vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op
nfsd: handle vfs_getattr errors in acl protocol
switch vfs_getattr() to struct path
default SET_PERSONALITY() in linux/elf.h
ceph: prepopulate inodes only when request is aborted
d_hash_and_lookup(): export, switch open-coded instances
9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate()
9p: split dropping the acls from v9fs_set_create_acl()
...
Pull signal handling cleanups from Al Viro:
"This is the first pile; another one will come a bit later and will
contain SYSCALL_DEFINE-related patches.
- a bunch of signal-related syscalls (both native and compat)
unified.
- a bunch of compat syscalls switched to COMPAT_SYSCALL_DEFINE
(fixing several potential problems with missing argument
validation, while we are at it)
- a lot of now-pointless wrappers killed
- a couple of architectures (cris and hexagon) forgot to save
altstack settings into sigframe, even though they used the
(uninitialized) values in sigreturn; fixed.
- microblaze fixes for delivery of multiple signals arriving at once
- saner set of helpers for signal delivery introduced, several
architectures switched to using those."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (143 commits)
x86: convert to ksignal
sparc: convert to ksignal
arm: switch to struct ksignal * passing
alpha: pass k_sigaction and siginfo_t using ksignal pointer
burying unused conditionals
make do_sigaltstack() static
arm64: switch to generic old sigaction() (compat-only)
arm64: switch to generic compat rt_sigaction()
arm64: switch compat to generic old sigsuspend
arm64: switch to generic compat rt_sigqueueinfo()
arm64: switch to generic compat rt_sigpending()
arm64: switch to generic compat rt_sigprocmask()
arm64: switch to generic sigaltstack
sparc: switch to generic old sigsuspend
sparc: COMPAT_SYSCALL_DEFINE does all sign-extension as well as SYSCALL_DEFINE
sparc: kill sign-extending wrappers for native syscalls
kill sparc32_open()
sparc: switch to use of generic old sigaction
sparc: switch sys_compat_rt_sigaction() to COMPAT_SYSCALL_DEFINE
mips: switch to generic sys_fork() and sys_clone()
...
For some reason they didn't get replaced so far by their
paravirt equivalents, resulting in code to be run with
interrupts disabled that doesn't expect so (causing, in the
observed case, a BUG_ON() to trigger) when syscall auditing is
enabled.
David (Cc-ed) came up with an identical fix, so likely this can
be taken to count as an ack from him.
Reported-by: Peter Moody <pmoody@google.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/5108E01902000078000BA9C5@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Tested-by: Peter Moody <pmoody@google.com>
Pull generic execve() changes from Al Viro:
"This introduces the generic kernel_thread() and kernel_execve()
functions, and switches x86, arm, alpha, um and s390 over to them."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
s390: convert to generic kernel_execve()
s390: switch to generic kernel_thread()
s390: fold kernel_thread_helper() into ret_from_fork()
s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
um: switch to generic kernel_thread()
x86, um/x86: switch to generic sys_execve and kernel_execve
x86: split ret_from_fork
alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
alpha: switch to generic kernel_thread()
alpha: switch to generic sys_execve()
arm: get rid of execve wrapper, switch to generic execve() implementation
arm: optimized current_pt_regs()
arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
generic sys_execve()
generic kernel_execve()
new helper: current_pt_regs()
preparation for generic kernel_thread()
um: kill thread->forking
um: let signal_delivered() do SIGTRAP on singlestepping into handler
...
32bit wrapper is lost on that; 64bit one is *not*, since
we need to arrange for full pt_regs on stack when we call
sys_execve() and we need to load callee-saved ones from
there afterwards.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reason for merge:
x86/fpu changed the structure of some of the code that x86/smap
changes; mostly fpu-internal.h but also minor changes to the
signal code.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Resolved Conflicts:
arch/x86/ia32/ia32_signal.c
arch/x86/include/asm/fpu-internal.h
arch/x86/kernel/signal.c
Signal handling contains a bunch of accesses to individual user space
items, which causes an excessive number of STAC and CLAC
instructions. Instead, let get/put_user_try ... get/put_user_catch()
contain the STAC and CLAC instructions.
This means that get/put_user_try no longer nests, and furthermore that
it is no longer legal to use user space access functions other than
__get/put_user_ex() inside those blocks. However, these macros are
x86-specific anyway and are only used in the signal-handling paths; a
simple reordering of moving the larger subroutine calls out of the
try...catch blocks resolves that problem.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-12-git-send-email-hpa@linux.intel.com
When Supervisor Mode Access Prevention (SMAP) is enabled, access to
userspace from the kernel is controlled by the AC flag. To make the
performance of manipulating that flag acceptable, there are two new
instructions, STAC and CLAC, to set and clear it.
This patch adds those instructions, via alternative(), when the SMAP
feature is enabled. It also adds X86_EFLAGS_AC unconditionally to the
SYSCALL entry mask; there is simply no reason to make that one
conditional.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-9-git-send-email-hpa@linux.intel.com
Currently for x86 and x86_32 binaries, fpstate in the user sigframe is copied
to/from the fpstate in the task struct.
And in the case of signal delivery for x86_64 binaries, if the fpstate is live
in the CPU registers, then the live state is copied directly to the user
sigframe. Otherwise fpstate in the task struct is copied to the user sigframe.
During restore, fpstate in the user sigframe is restored directly to the live
CPU registers.
Historically, different code paths led to different bugs. For example,
x86_64 code path was not preemption safe till recently. Also there is lot
of code duplication for support of new features like xsave etc.
Unify signal handling code paths for x86 and x86_64 kernels.
New strategy is as follows:
Signal delivery: Both for 32/64-bit frames, align the core math frame area to
64bytes as needed by xsave (this where the main fpu/extended state gets copied
to and excludes the legacy compatibility fsave header for the 32-bit [f]xsave
frames). If the state is live, copy the register state directly to the user
frame. If not live, copy the state in the thread struct to the user frame. And
for 32-bit [f]xsave frames, construct the fsave header separately before
the actual [f]xsave area.
Signal return: As the 32-bit frames with [f]xstate has an additional
'fsave' header, copy everything back from the user sigframe to the
fpstate in the task structure and reconstruct the fxstate from the 'fsave'
header (Also user passed pointers may not be correctly aligned for
any attempt to directly restore any partial state). At the next fpstate usage,
everything will be restored to the live CPU registers.
For all the 64-bit frames and the 32-bit fsave frame, restore the state from
the user sigframe directly to the live CPU registers. 64-bit signals always
restored the math frame directly, so we can expect the math frame pointer
to be correctly aligned. For 32-bit fsave frames, there are no alignment
requirements, so we can restore the state directly.
"lat_sig catch" microbenchmark numbers (for x86, x86_64, x86_32 binaries) are
with in the noise range with this change.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1343171129-2747-4-git-send-email-suresh.b.siddha@intel.com
[ Merged in compilation fix ]
Link: http://lkml.kernel.org/r/1344544736.8326.17.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Fix the following sparse warnings:
sys_ia32.c:293:38: warning: incorrect type in argument 2 (different address spaces)
sys_ia32.c:293:38: expected unsigned int [noderef] [usertype] <asn:1>*stat_addr
sys_ia32.c:293:38: got unsigned int *stat_addr
Ironically, sys_ia32.h was introduced to fix sparse warnings but
missed that one.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Link: http://lkml.kernel.org/r/1346621506-30857-2-git-send-email-minipli@googlemail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signal delivery compat path may not have the 'TS_COMPAT' flag (that
flag indicates how we entered the kernel). So use
test_thread_flag(TIF_IA32) instead of is_ia32_task(): one of the
functions of TIF_IA32 is just what kind of signal frame we want.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1339722435.3475.57.camel@sbsiddha-desk.sc.intel.com
Cc: stable@kernel.org # v3.4
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Only 3 out of 63 do not. Renamed the current variant to __set_current_blocked(),
added set_current_blocked() that will exclude unblockable signals, switched
open-coded instances to it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull first series of signal handling cleanups from Al Viro:
"This is just the first part of the queue (about a half of it);
assorted fixes all over the place in signal handling.
This one ends with all sigsuspend() implementations switched to
generic one (->saved_sigmask-based).
With this, a bunch of assorted old buglets are fixed and most of the
missing bits of NOTIFY_RESUME hookup are in place. Two more fixes sit
in arm and um trees respectively, and there's a couple of broken ones
that need obvious fixes - parisc and avr32 check TIF_NOTIFY_RESUME
only on one of two codepaths; fixes for that will happen in the next
series"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (55 commits)
unicore32: if there's no handler we need to restore sigmask, syscall or no syscall
xtensa: add handling of TIF_NOTIFY_RESUME
microblaze: drop 'oldset' argument of do_notify_resume()
microblaze: handle TIF_NOTIFY_RESUME
score: add handling of NOTIFY_RESUME to do_notify_resume()
m68k: add TIF_NOTIFY_RESUME and handle it.
sparc: kill ancient comment in sparc_sigaction()
h8300: missing checks of __get_user()/__put_user() return values
frv: missing checks of __get_user()/__put_user() return values
cris: missing checks of __get_user()/__put_user() return values
powerpc: missing checks of __get_user()/__put_user() return values
sh: missing checks of __get_user()/__put_user() return values
sparc: missing checks of __get_user()/__put_user() return values
avr32: struct old_sigaction is never used
m32r: struct old_sigaction is never used
xtensa: xtensa_sigaction doesn't exist
alpha: tidy signal delivery up
score: don't open-code force_sigsegv()
cris: don't open-code force_sigsegv()
blackfin: don't open-code force_sigsegv()
...
Pull user namespace enhancements from Eric Biederman:
"This is a course correction for the user namespace, so that we can
reach an inexpensive, maintainable, and reasonably complete
implementation.
Highlights:
- Config guards make it impossible to enable the user namespace and
code that has not been converted to be user namespace safe.
- Use of the new kuid_t type ensures the if you somehow get past the
config guards the kernel will encounter type errors if you enable
user namespaces and attempt to compile in code whose permission
checks have not been updated to be user namespace safe.
- All uids from child user namespaces are mapped into the initial
user namespace before they are processed. Removing the need to add
an additional check to see if the user namespace of the compared
uids remains the same.
- With the user namespaces compiled out the performance is as good or
better than it is today.
- For most operations absolutely nothing changes performance or
operationally with the user namespace enabled.
- The worst case performance I could come up with was timing 1
billion cache cold stat operations with the user namespace code
enabled. This went from 156s to 164s on my laptop (or 156ns to
164ns per stat operation).
- (uid_t)-1 and (gid_t)-1 are reserved as an internal error value.
Most uid/gid setting system calls treat these value specially
anyway so attempting to use -1 as a uid would likely cause
entertaining failures in userspace.
- If setuid is called with a uid that can not be mapped setuid fails.
I have looked at sendmail, login, ssh and every other program I
could think of that would call setuid and they all check for and
handle the case where setuid fails.
- If stat or a similar system call is called from a context in which
we can not map a uid we lie and return overflowuid. The LFS
experience suggests not lying and returning an error code might be
better, but the historical precedent with uids is different and I
can not think of anything that would break by lying about a uid we
can't map.
- Capabilities are localized to the current user namespace making it
safe to give the initial user in a user namespace all capabilities.
My git tree covers all of the modifications needed to convert the core
kernel and enough changes to make a system bootable to runlevel 1."
Fix up trivial conflicts due to nearby independent changes in fs/stat.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
userns: Silence silly gcc warning.
cred: use correct cred accessor with regards to rcu read lock
userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
userns: Convert cgroup permission checks to use uid_eq
userns: Convert tmpfs to use kuid and kgid where appropriate
userns: Convert sysfs to use kgid/kuid where appropriate
userns: Convert sysctl permission checks to use kuid and kgids.
userns: Convert proc to use kuid/kgid where appropriate
userns: Convert ext4 to user kuid/kgid where appropriate
userns: Convert ext3 to use kuid/kgid where appropriate
userns: Convert ext2 to use kuid/kgid where appropriate.
userns: Convert devpts to use kuid/kgid where appropriate
userns: Convert binary formats to use kuid/kgid where appropriate
userns: Add negative depends on entries to avoid building code that is userns unsafe
userns: signal remove unnecessary map_cred_ns
userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
userns: Fail exec for suid and sgid binaries with ids outside our user namespace.
userns: Convert stat to return values mapped from kuids and kgids
userns: Convert user specfied uids and gids in chown into kuids and kgid
userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
...
Pull exception table generation updates from Ingo Molnar:
"The biggest change here is to allow the build-time sorting of the
exception table, to speed up booting. This is achieved by the
architecture enabling BUILDTIME_EXTABLE_SORT. This option is enabled
for x86 and MIPS currently.
On x86 a number of fixes and changes were needed to allow build-time
sorting of the exception table, in particular a relocation invariant
exception table format was needed. This required the abstracting out
of exception table protocol and the removal of 20 years of accumulated
assumptions about the x86 exception table format.
While at it, this tree also cleans up various other aspects of
exception handling, such as early(er) exception handling for
rdmsr_safe() et al.
All in one, as the result of these changes the x86 exception code is
now pretty nice and modern. As an added bonus any regressions in this
code will be early and violent crashes, so if you see any of those,
you'll know whom to blame!"
Fix up trivial conflicts in arch/{mips,x86}/Kconfig files due to nearby
modifications of other core architecture options.
* 'x86-extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
Revert "x86, extable: Disable presorted exception table for now"
scripts/sortextable: Handle relative entries, and other cleanups
x86, extable: Switch to relative exception table entries
x86, extable: Disable presorted exception table for now
x86, extable: Add _ASM_EXTABLE_EX() macro
x86, extable: Remove open-coded exception table entries in arch/x86/ia32/ia32entry.S
x86, extable: Remove open-coded exception table entries in arch/x86/include/asm/xsave.h
x86, extable: Remove open-coded exception table entries in arch/x86/include/asm/kvm_host.h
x86, extable: Remove the now-unused __ASM_EX_SEC macros
x86, extable: Remove open-coded exception table entries in arch/x86/xen/xen-asm_32.S
x86, extable: Remove open-coded exception table entries in arch/x86/um/checksum_32.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/usercopy_32.c
x86, extable: Remove open-coded exception table entries in arch/x86/lib/putuser.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/getuser.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/csum-copy_64.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/copy_user_nocache_64.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/copy_user_64.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/checksum_32.S
x86, extable: Remove open-coded exception table entries in arch/x86/kernel/test_rodata.c
x86, extable: Remove open-coded exception table entries in arch/x86/kernel/entry_64.S
...
guts of saved_sigmask-based sigsuspend/rt_sigsuspend. Takes
kernel sigset_t *.
Open-coded instances replaced with calling it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull security subsystem updates from James Morris:
"New notable features:
- The seccomp work from Will Drewry
- PR_{GET,SET}_NO_NEW_PRIVS from Andy Lutomirski
- Longer security labels for Smack from Casey Schaufler
- Additional ptrace restriction modes for Yama by Kees Cook"
Fix up trivial context conflicts in arch/x86/Kconfig and include/linux/filter.h
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (65 commits)
apparmor: fix long path failure due to disconnected path
apparmor: fix profile lookup for unconfined
ima: fix filename hint to reflect script interpreter name
KEYS: Don't check for NULL key pointer in key_validate()
Smack: allow for significantly longer Smack labels v4
gfp flags for security_inode_alloc()?
Smack: recursive tramsmute
Yama: replace capable() with ns_capable()
TOMOYO: Accept manager programs which do not start with / .
KEYS: Add invalidation support
KEYS: Do LRU discard in full keyrings
KEYS: Permit in-place link replacement in keyring list
KEYS: Perform RCU synchronisation on keys prior to key destruction
KEYS: Announce key type (un)registration
KEYS: Reorganise keys Makefile
KEYS: Move the key config into security/keys/Kconfig
KEYS: Use the compat keyctl() syscall wrapper on Sparc64 for Sparc32 compat
Yama: remove an unused variable
samples/seccomp: fix dependencies on arch macros
Yama: add additional ptrace scopes
...
- Store uids and gids with kuid_t and kgid_t in struct kstat
- Convert uid and gids to userspace usable values with
from_kuid and from_kgid
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
