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Groups > linux.kernel > #1608800
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.10 07/27] perf/core: Fix use-after-free in perf_release() |
| Date | 2017-03-24 19:20 +0100 |
| Message-ID | <toBYD-5oX-35@gated-at.bofh.it> (permalink) |
| References | <toBFf-50v-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra <peterz@infradead.org>
commit e552a8389aa409e257b7dcba74f67f128f979ccc upstream.
Dmitry reported syzcaller tripped a use-after-free in perf_release().
After much puzzlement Oleg spotted the below scenario:
Task1 Task2
fork()
perf_event_init_task()
/* ... */
goto bad_fork_$foo;
/* ... */
perf_event_free_task()
mutex_lock(ctx->lock)
perf_free_event(B)
perf_event_release_kernel(A)
mutex_lock(A->child_mutex)
list_for_each_entry(child, ...) {
/* child == B */
ctx = B->ctx;
get_ctx(ctx);
mutex_unlock(A->child_mutex);
mutex_lock(A->child_mutex)
list_del_init(B->child_list)
mutex_unlock(A->child_mutex)
/* ... */
mutex_unlock(ctx->lock);
put_ctx() /* >0 */
free_task();
mutex_lock(ctx->lock);
mutex_lock(A->child_mutex);
/* ... */
mutex_unlock(A->child_mutex);
mutex_unlock(ctx->lock)
put_ctx() /* 0 */
ctx->task && !TOMBSTONE
put_task_struct() /* UAF */
This patch closes the hole by making perf_event_free_task() destroy the
task <-> ctx relation such that perf_event_release_kernel() will no longer
observe the now dead task.
Spotted-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: fweisbec@gmail.com
Cc: oleg@redhat.com
Fixes: c6e5b73242d2 ("perf: Synchronously clean up child events")
Link: http://lkml.kernel.org/r/20170314155949.GE32474@worktop
Link: http://lkml.kernel.org/r/20170316125823.140295131@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/events/core.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10374,6 +10374,17 @@ void perf_event_free_task(struct task_st
continue;
mutex_lock(&ctx->mutex);
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * Destroy the task <-> ctx relation and mark the context dead.
+ *
+ * This is important because even though the task hasn't been
+ * exposed yet the context has been (through child_list).
+ */
+ RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
+ WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
+ put_task_struct(task); /* cannot be last */
+ raw_spin_unlock_irq(&ctx->lock);
again:
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
group_entry)
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[PATCH 4.10 00/27] 4.10.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:00 +0100
[PATCH 4.10 10/27] xprtrdma: Squelch kbuild sparse complaint Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:00 +0100
[PATCH 4.10 14/27] hwrng: omap - write registers after enabling the clock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 12/27] cpufreq: Fix and clean up show_cpuinfo_cur_freq() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 11/27] NFS prevent double free in async nfs4_exchange_id Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 15/27] hwrng: omap - use devm_clk_get() instead of of_clk_get() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 06/27] parisc: Fix system shutdown halt Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 23/27] isdn/gigaset: fix NULL-deref at probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 03/27] qla2xxx: Fix request queue corruption. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 25/27] percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 08/27] perf/core: Fix event inheritance on fork() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 16/27] hwrng: omap - Do not access INTMASK_REG on EIP76 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 17/27] md/raid1/10: fix potential deadlock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 13/27] powerpc/boot: Fix zImage TOC alignment Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 04/27] parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 09/27] md/r5cache: fix set_syndrome_sources() for data in cache Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 02/27] qla2xxx: Fix memory leak for abts processing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 01/27] give up on gcc ilog2() constant optimizations Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 19/27] scsi: lpfc: Add shutdown method for kexec Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:10 +0100
[PATCH 4.10 05/27] parisc: support R_PARISC_SECREL32 relocation in modules Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:20 +0100
[PATCH 4.10 07/27] perf/core: Fix use-after-free in perf_release() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:20 +0100
[PATCH 4.10 22/27] target: Fix VERIFY_16 handling in sbc_parse_cdb Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:30 +0100
[PATCH 4.10 20/27] scsi: libiscsi: add lock around task lists to fix list corruption regression Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:30 +0100
[PATCH 4.10 18/27] target/pscsi: Fix TYPE_TAPE + TYPE_MEDIMUM_CHANGER export Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:30 +0100
[PATCH 4.10 21/27] scsi: mpt3sas: Avoid sleeping in interrupt context Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:30 +0100
[PATCH 4.10 24/27] gfs2: Avoid alignment hole in struct lm_lockname Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:30 +0100
[PATCH 4.10 26/27] cgroup/pids: remove spurious suspicious RCU usage warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-24 19:30 +0100
Re: [PATCH 4.10 00/27] 4.10.6-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-03-25 01:10 +0100
Re: [PATCH 4.10 00/27] 4.10.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-26 10:30 +0200
Re: [PATCH 4.10 00/27] 4.10.6-stable review Guenter Roeck <linux@roeck-us.net> - 2017-03-25 05:20 +0100
Re: [PATCH 4.10 00/27] 4.10.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-03-26 11:10 +0200
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