linux/kernel
Eric W. Biederman 526c3ddb6a signal/arm64: Document conflicts with SI_USER and SIGFPE,SIGTRAP,SIGBUS
Setting si_code to 0 results in a userspace seeing an si_code of 0.
This is the same si_code as SI_USER.  Posix and common sense requires
that SI_USER not be a signal specific si_code.  As such this use of 0
for the si_code is a pretty horribly broken ABI.

Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a
value of __SI_KILL and now sees a value of SIL_KILL with the result
that uid and pid fields are copied and which might copying the si_addr
field by accident but certainly not by design.  Making this a very
flakey implementation.

Utilizing FPE_FIXME, BUS_FIXME, TRAP_FIXME siginfo_layout will now return
SIL_FAULT and the appropriate fields will be reliably copied.

But folks this is a new and unique kind of bad.  This is massively
untested code bad.  This is inventing new and unique was to get
siginfo wrong bad.  This is don't even think about Posix or what
siginfo means bad.  This is lots of eyeballs all missing the fact
that the code does the wrong thing bad.  This is getting stuck
and keep making the same mistake bad.

I really hope we can find a non userspace breaking fix for this on a
port as new as arm64.

Possible ABI fixes include:
- Send the signal without siginfo
- Don't generate a signal
- Possibly assign and use an appropriate si_code
- Don't handle cases which can't happen

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tyler Baicar <tbaicar@codeaurora.org>
Cc: James Morse <james.morse@arm.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Ref: 53631b54c8 ("arm64: Floating point and SIMD")
Ref: 32015c2356 ("arm64: exception: handle Synchronous External Abort")
Ref: 1d18c47c73 ("arm64: MMU fault handling and page table management")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-12 14:21:05 -06:00
..
bpf bpf: do not allow root to mangle valid pointers 2017-12-21 02:26:29 +01:00
cgroup Revert "cgroup/cpuset: remove circular dependency deadlock" 2017-12-04 14:55:59 -08:00
configs ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES. 2017-08-22 18:43:23 -07:00
debug signal: Simplify and fix kdb_send_sig 2018-01-03 18:01:08 -06:00
events locking/barriers: Convert users of lockless_dereference() to READ_ONCE() 2017-12-17 13:57:15 +01:00
gcov License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq genirq/msi, x86/vector: Prevent reservation mode for non maskable MSI 2017-12-29 21:13:05 +01:00
livepatch Merge branch 'for-linus' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2017-11-15 10:21:58 -08:00
locking locking/lockdep: Remove the cross-release locking checks 2017-12-12 12:38:51 +01:00
power Revert "cpuset: Make cpuset hotplug synchronous" 2017-12-04 14:41:11 -08:00
printk remove task and stack pointer printout from oops dump 2017-12-05 08:23:20 -08:00
rcu Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 17:56:58 -08:00
sched cpufreq: schedutil: Use idle_calls counter of the remote CPU 2017-12-28 12:26:54 +01:00
time Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 12:30:34 -08:00
trace tracing: Fix possible double free on failure of allocating trace buffer 2017-12-27 14:21:27 -05:00
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
acct.c Merge branch 'linus' into locking/core, to resolve conflicts 2017-11-07 10:32:44 +01:00
async.c async: Adjust system_state checks 2017-05-23 10:01:37 +02:00
audit.c Audit: remove unused audit_log_secctx function 2017-11-10 16:08:47 -05:00
audit.h audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
audit_fsnotify.c Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2017-05-03 11:05:15 -07:00
audit_tree.c Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2017-11-14 14:08:20 -08:00
audit_watch.c audit/stable-4.13 PR 20170816 2017-08-16 16:48:34 -07:00
auditfilter.c audit: filter PATH records keyed on filesystem magic 2017-11-10 16:08:56 -05:00
auditsc.c audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
backtracetest.c
bounds.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
capability.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat.c sched_rr_get_interval(): move compat to native, get rid of set_fs() 2017-09-20 00:30:57 -04:00
configs.c
context_tracking.c
cpu.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 12:30:34 -08:00
cpu_pm.c PM / CPU: replace raw_notifier with atomic_notifier 2017-07-31 13:09:49 +02:00
crash_core.c kdump: print a message in case parse_crashkernel_mem resulted in zero bytes 2017-11-17 16:10:03 -08:00
crash_dump.c
cred.c doc: ReSTify credentials.txt 2017-05-18 10:30:19 -06:00
delayacct.c
dma.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
elfcore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exec_domain.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exit.c arch: define weak abort() 2017-12-14 16:00:49 -08:00
extable.c kprobes, x86/alternatives: Use text_mutex to protect smp_alt_modules 2017-11-07 12:20:09 +01:00
fork.c Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-23 11:53:04 -08:00
freezer.c
futex.c futex: futex_wake_op, fix sign_extend32 sign bits 2017-12-10 12:50:57 -08:00
futex_compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
groups.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
hung_task.c kernel/hung_task.c: defer showing held locks 2017-05-08 17:15:10 -07:00
irq_work.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 17:33:11 -08:00
jump_label.c jump_label: Invoke jump_label_test() via early_initcall() 2017-11-14 08:41:41 +01:00
kallsyms.c kallsyms: take advantage of the new '%px' format 2017-11-29 10:30:13 -08:00
kcmp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kcov.c kcov: fix comparison callback signature 2017-12-14 16:00:48 -08:00
kexec.c kdump: protect vmcoreinfo data under the crash memory 2017-07-12 16:26:00 -07:00
kexec_core.c x86/mm, kexec: Allow kexec to be used with SME 2017-07-18 11:38:04 +02:00
kexec_file.c resource: Provide resource struct in resource walk callback 2017-11-07 15:35:57 +01:00
kexec_internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kmod.c kmod: move #ifdef CONFIG_MODULES wrapper to Makefile 2017-09-08 18:26:51 -07:00
kprobes.c kprobes: Disable the jprobes APIs 2017-10-20 11:02:29 +02:00
ksysfs.c kexec: move vmcoreinfo out of the kernel's .bss section 2017-07-12 16:25:59 -07:00
kthread.c treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
latencytop.c
memremap.c memremap: add scheduling point to devm_memremap_pages 2017-10-03 17:54:25 -07:00
module-internal.h
module.c kallsyms: take advantage of the new '%px' format 2017-11-29 10:30:13 -08:00
module_signing.c
notifier.c
nsproxy.c
padata.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
panic.c kernel/panic.c: add TAINT_AUX 2017-11-17 16:10:04 -08:00
params.c kernel/params.c: improve STANDARD_PARAM_DEF readability 2017-10-03 17:54:26 -07:00
pid.c pid: remove pidhash 2017-11-17 16:10:04 -08:00
pid_namespace.c pid: remove pidhash 2017-11-17 16:10:04 -08:00
profile.c
ptrace.c signal: Remove kernel interal si_code magic 2017-07-24 14:30:28 -05:00
range.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reboot.c kernel/reboot.c: add devm_register_reboot_notifier() 2017-11-17 16:10:04 -08:00
relay.c Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-02 11:38:06 -07:00
resource.c x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory pages 2017-11-07 15:35:58 +01:00
seccomp.c locking/barriers: Convert users of lockless_dereference() to READ_ONCE() 2017-12-17 13:57:15 +01:00
signal.c signal/arm64: Document conflicts with SI_USER and SIGFPE,SIGTRAP,SIGBUS 2018-01-12 14:21:05 -06:00
smp.c smp/core: Use lockdep to assert IRQs are disabled/enabled 2017-11-08 11:13:50 +01:00
smpboot.c watchdog/core, powerpc: Lock cpus across reconfiguration 2017-10-04 10:53:54 +02:00
smpboot.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
softirq.c kmemcheck: rip it out 2017-11-15 18:21:05 -08:00
stacktrace.c
stop_machine.c stop_machine: Provide stop_machine_cpuslocked() 2017-05-26 10:10:36 +02:00
sys.c arm64 updates for 4.15 2017-11-15 10:56:56 -08:00
sys_ni.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sysctl.c kernel/sysctl.c: code cleanups 2017-11-17 16:10:03 -08:00
sysctl_binary.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
task_work.c locking/barriers: Convert users of lockless_dereference() to READ_ONCE() 2017-12-17 13:57:15 +01:00
taskstats.c taskstats: add e/u/stime for TGID command 2017-05-08 17:15:12 -07:00
test_kprobes.c kprobes: Disable the jprobes test code 2017-10-20 11:02:54 +02:00
torture.c torture: Fix typo suppressing CPU-hotplug statistics 2017-07-25 13:04:45 -07:00
tracepoint.c
tsacct.c
ucount.c
uid16.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
umh.c kernel/umh.c: optimize 'proc_cap_handler()' 2017-11-17 16:10:01 -08:00
up.c smp: Avoid using two cache lines for struct call_single_data 2017-08-29 15:14:38 +02:00
user-return-notifier.c
user.c userns: use union in {g,u}idmap struct 2017-10-31 17:22:58 -05:00
user_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2017-11-16 12:20:15 -08:00
utsname.c
utsname_sysctl.c
watchdog.c Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
watchdog_hld.c Merge branch 'linus' into core/urgent, to pick up dependent commits 2017-11-04 08:53:04 +01:00
workqueue.c workqueue: remove unneeded kallsyms include 2017-12-11 07:15:43 -08:00
workqueue_internal.h Merge branch 'for-4.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2017-11-06 12:26:49 -08:00