redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity
alistair23-linux/kernel
History
Eric W. Biederman 117433236a exec: Transform exec_update_mutex into a rw_semaphore 
[ Upstream commit f7cfd871ae ]

Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex.  The problematic lock ordering found by lockdep
was:

   perf_event_open  (exec_update_mutex -> ovl_i_mutex)
   chown            (ovl_i_mutex       -> sb_writes)
   sendfile         (sb_writes         -> p->lock)
     by reading from a proc file and writing to overlayfs
   proc_pid_syscall (p->lock           -> exec_update_mutex)

While looking at possible solutions it occured to me that all of the
users and possible users involved only wanted to state of the given
process to remain the same.  They are all readers.  The only writer is
exec.

There is no reason for readers to block on each other.  So fix
this deadlock by transforming exec_update_mutex into a rw_semaphore
named exec_update_lock that only exec takes for writing.

Cc: Jann Horn <jannh@google.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christopher Yeoh <cyeoh@au1.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Fixes: eea9673250 ("exec: Add exec_update_mutex to replace cred_guard_mutex")
[0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com
Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2021-01-09 13:44:55 +01:00
..
bpf bpf: Zero-fill re-used per-cpu map element 2020-11-18 19:20:26 +01:00
cgroup cgroup: Fix memory leak when parsing multiple source parameters 2021-01-06 14:48:37 +01:00
configs
…
debug kgdb: Make "kgdbcon" work properly with "kgdb_earlycon" 2020-11-05 11:43:16 +01:00
dma swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb" 2020-11-18 19:20:32 +01:00
events exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:44:55 +01:00
gcov gcov: add support for GCC 10.1 2020-09-17 13:47:56 +02:00
irq genirq/irqdomain: Don't try to free an interrupt that has no mapping 2020-12-30 11:51:14 +01:00
livepatch livepatch: Nullify obj->mod in klp_module_coming()'s error path 2019-08-19 13:03:37 +02:00
locking exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:44:55 +01:00
power PM: hibernate: remove the bogus call to get_gendisk() in software_resume() 2020-10-29 09:58:04 +01:00
printk printk: handle blank console arguments passed in. 2020-10-01 13:18:04 +02:00
rcu arm64: smp: Tell RCU about CPUs that fail to come online 2020-11-24 13:29:01 +01:00
sched sched: Reenable interrupts in do_sched_yield() 2020-12-30 11:51:03 +01:00
time tick/sched: Remove bogus boot "safety" check 2021-01-06 14:48:40 +01:00
trace Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" 2020-12-30 11:51:47 +01:00
.gitignore Provide in-kernel headers to make extending kernel easier 2019-04-29 16:48:03 +02:00
Kconfig.freezer treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.hz treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.locks treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.preempt sched/rt, Kconfig: Unbreak def/oldconfig with CONFIG_PREEMPT=y 2019-07-22 18:05:11 +02:00
Makefile kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec() 2020-10-01 13:17:10 +02:00
acct.c
…
async.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
audit.c audit: fix a net reference leak in audit_list_rules_send() 2020-06-22 09:30:59 +02:00
audit.h audit: fix a net reference leak in audit_list_rules_send() 2020-06-22 09:30:59 +02:00
audit_fsnotify.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
audit_tree.c fsnotify: switch send_to_group() and ->handle_event to const struct qstr * 2019-04-26 13:51:03 -04:00
audit_watch.c audit: CONFIG_CHANGE don't log internal bookkeeping as an event 2020-10-01 13:17:32 +02:00
auditfilter.c audit: fix a net reference leak in audit_list_rules_send() 2020-06-22 09:30:59 +02:00
auditsc.c audit: enforce op for string fields 2019-05-28 17:46:43 -04:00
backtracetest.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
bounds.c
…
capability.c
…
compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
configs.c kernel/configs: Replace GPL boilerplate code with SPDX identifier 2019-07-30 18:34:15 +02:00
context_tracking.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
cpu.c kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling 2020-12-30 11:50:56 +01:00
cpu_pm.c kernel/cpu_pm: Fix uninitted local in cpu_pm 2020-06-22 09:31:22 +02:00
crash_core.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
crash_dump.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
cred.c keys: Fix request_key() cache 2020-01-17 19:48:42 +01:00
delayacct.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00
dma.c
…
elfcore.c kernel/elfcore.c: include proper prototypes 2019-09-25 17:51:39 -07:00
exec_domain.c
…
exit.c don't dump the threads that had been already exiting when zapped. 2020-11-18 19:20:31 +01:00
extable.c extable: Add function to search only kernel exception table 2019-08-21 22:23:48 +10:00
fail_function.c fail_function: Remove a redundant mutex unlock 2020-11-24 13:29:18 +01:00
fork.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:44:55 +01:00
freezer.c Revert "libata, freezer: avoid block device removal while system is frozen" 2019-10-06 09:11:37 -06:00
futex.c futex: Don't enable IRQs unconditionally in put_pi_state() 2020-11-18 19:20:30 +01:00
gen_kheaders.sh kbuild: add variables for compression tools 2020-09-03 11:27:10 +02:00
groups.c
…
hung_task.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
iomem.c mm/nvdimm: add is_ioremap_addr and use that to check ioremap address 2019-07-12 11:05:40 -07:00
irq_work.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
jump_label.c jump_label: Don't warn on __exit jump entries 2019-08-29 15:10:10 +01:00
kallsyms.c kallsyms: Refactor kallsyms_show_value() to take cred 2020-07-16 08:16:44 +02:00
kcmp.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:44:55 +01:00
kcov.c
…
kexec.c kexec_load: Disable at runtime if the kernel is locked down 2019-08-19 21:54:15 -07:00
kexec_core.c kexec: bail out upon SIGKILL when allocating memory. 2019-09-25 17:51:40 -07:00
kexec_elf.c kexec_elf: support 32 bit ELF files 2019-09-06 23:58:44 +02:00
kexec_file.c Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
kexec_internal.h
…
kheaders.c kheaders: Move from proc to sysfs 2019-05-24 20:16:01 +02:00
kmod.c kmod: make request_module() return an error when autoloading is disabled 2020-04-17 10:50:22 +02:00
kprobes.c kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE 2020-10-01 13:18:25 +02:00
ksysfs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 170 2019-05-30 11:26:39 -07:00
kthread.c kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled 2020-11-10 12:37:27 +01:00
latencytop.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
module-internal.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
module.c module: delay kobject uevent until after module init call 2021-01-06 14:48:40 +01:00
module_signature.c MODSIGN: Export module signature definitions 2019-08-05 18:39:56 -04:00
module_signing.c MODSIGN: Export module signature definitions 2019-08-05 18:39:56 -04:00
notifier.c kernel/notifier.c: intercept duplicate registrations to avoid infinite loops 2020-10-01 13:17:23 +02:00
nsproxy.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
padata.c padata: add separate cpuhp node for CPUHP_PADATA_DEAD 2020-06-17 16:40:22 +02:00
panic.c panic: ensure preemption is disabled during panic() 2019-10-07 15:47:19 -07:00
params.c lockdown: Lock down module params that specify hardware parameters (eg. ioport) 2019-08-19 21:54:16 -07:00
pid.c kernel/pid.c: convert struct pid count to refcount_t 2019-07-16 19:23:24 -07:00
pid_namespace.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
profile.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
ptrace.c ptrace: Set PF_SUPERPRIV when checking capability 2020-11-24 13:29:24 +01:00
range.c
…
reboot.c reboot: fix overflow parsing reboot cpu number 2020-11-18 19:20:30 +01:00
relay.c kernel/relay.c: fix memleak on destroy relay channel 2020-08-26 10:40:51 +02:00
resource.c /dev/mem: Revoke mappings when a driver claims the region 2020-06-24 17:50:35 +02:00
rseq.c signal: Remove task parameter from force_sig 2019-05-27 09:36:28 -05:00
seccomp.c seccomp: Set PF_SUPERPRIV when checking capability 2020-11-24 13:29:24 +01:00
signal.c ptrace: fix task_join_group_stop() for the case when current is traced 2020-11-10 12:37:24 +01:00
smp.c smp: Warn on function calls from softirq context 2019-07-20 11:27:16 +02:00
smpboot.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
smpboot.h
…
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 11:01:13 -07:00
stackleak.c
…
stacktrace.c stacktrace: Don't skip first entry on noncurrent tasks 2019-11-04 21:19:25 +01:00
stop_machine.c stop_machine: Avoid potential race behaviour 2019-10-17 12:47:12 +02:00
sys.c kernel/sys.c: avoid copying possible padding bytes in copy_to_user 2020-10-01 13:17:23 +02:00
sys_ni.c arch: handle arches who do not yet define clone3 2019-06-21 01:54:53 +02:00
sysctl-test.c kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec() 2020-10-01 13:17:10 +02:00
sysctl.c kernel: sysctl: make drop_caches write-only 2020-01-04 19:18:32 +01:00
sysctl_binary.c
…
task_work.c
…
taskstats.c taskstats: fix data-race 2020-01-09 10:19:54 +01:00
test_kprobes.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00
torture.c torture: Remove exporting of internal functions 2019-08-01 14:30:22 -07:00
tracepoint.c The main changes in this release include: 2019-07-18 11:51:00 -07:00
tsacct.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
ucount.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
uid16.c
…
uid16.h
…
umh.c usermodehelper: reset umask to default before executing user process 2020-10-14 10:32:58 +02:00
up.c smp: Remove smp_call_function() and on_each_cpu() return values 2019-06-23 14:26:26 +02:00
user-return-notifier.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
user.c Keyrings namespacing 2019-07-08 19:36:47 -07:00
user_namespace.c Keyrings namespacing 2019-07-08 19:36:47 -07:00
utsname.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
utsname_sysctl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
watchdog.c watchdog/softlockup: Enforce that timestamp is valid on boot 2020-02-24 08:36:52 +01:00
watchdog_hld.c kernel/watchdog_hld.c: hard lockup message should end with a newline 2019-04-19 09:46:05 -07:00
workqueue.c workqueue: Remove the warning in wq_worker_sleeping() 2020-10-01 13:17:54 +02:00
workqueue_internal.h
…