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Patch "ALSA: seq: Fix possible UAF in snd_seq_check_queue()" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: seq: Fix possible UAF in snd_seq_check_queue() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From d0f833065221cbfcbadf19fd4102bcfa9330006a Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Fri, 9 Mar 2018 21:58:28 +0100 Subject: ALSA: seq: Fix possible UAF in snd_seq_check_queue() From: Takashi Iwai <tiwai(a)suse.de> commit d0f833065221cbfcbadf19fd4102bcfa9330006a upstream. Although we've covered the races between concurrent write() and ioctl() in the previous patch series, there is still a possible UAF in the following scenario: A: user client closed B: timer irq -> snd_seq_release() -> snd_seq_timer_interrupt() -> snd_seq_free_client() -> snd_seq_check_queue() -> cell = snd_seq_prioq_cell_peek() -> snd_seq_prioq_leave() .... removing all cells -> snd_seq_pool_done() .... vfree() -> snd_seq_compare_tick_time(cell) ... Oops So the problem is that a cell is peeked and accessed without any protection until it's retrieved from the queue again via snd_seq_prioq_cell_out(). This patch tries to address it, also cleans up the code by a slight refactoring. snd_seq_prioq_cell_out() now receives an extra pointer argument. When it's non-NULL, the function checks the event timestamp with the given pointer. The caller needs to pass the right reference either to snd_seq_tick or snd_seq_realtime depending on the event timestamp type. A good news is that the above change allows us to remove the snd_seq_prioq_cell_peek(), too, thus the patch actually reduces the code size. Reviewed-by: Nicolai Stange <nstange(a)suse.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/seq/seq_prioq.c | 28 ++++++++++++++-------------- sound/core/seq/seq_prioq.h | 6 ++---- sound/core/seq/seq_queue.c | 28 +++++++++------------------- 3 files changed, 25 insertions(+), 37 deletions(-) --- a/sound/core/seq/seq_prioq.c +++ b/sound/core/seq/seq_prioq.c @@ -87,7 +87,7 @@ void snd_seq_prioq_delete(struct snd_seq if (f->cells > 0) { /* drain prioQ */ while (f->cells > 0) - snd_seq_cell_free(snd_seq_prioq_cell_out(f)); + snd_seq_cell_free(snd_seq_prioq_cell_out(f, NULL)); } kfree(f); @@ -214,8 +214,18 @@ int snd_seq_prioq_cell_in(struct snd_seq return 0; } +/* return 1 if the current time >= event timestamp */ +static int event_is_ready(struct snd_seq_event *ev, void *current_time) +{ + if ((ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) + return snd_seq_compare_tick_time(current_time, &ev->time.tick); + else + return snd_seq_compare_real_time(current_time, &ev->time.time); +} + /* dequeue cell from prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f) +struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f, + void *current_time) { struct snd_seq_event_cell *cell; unsigned long flags; @@ -227,6 +237,8 @@ struct snd_seq_event_cell *snd_seq_prioq spin_lock_irqsave(&f->lock, flags); cell = f->head; + if (cell && current_time && !event_is_ready(&cell->event, current_time)) + cell = NULL; if (cell) { f->head = cell->next; @@ -252,18 +264,6 @@ int snd_seq_prioq_avail(struct snd_seq_p return f->cells; } - -/* peek at cell at the head of the prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_peek(struct snd_seq_prioq * f) -{ - if (f == NULL) { - pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n"); - return NULL; - } - return f->head; -} - - static inline int prioq_match(struct snd_seq_event_cell *cell, int client, int timestamp) { --- a/sound/core/seq/seq_prioq.h +++ b/sound/core/seq/seq_prioq.h @@ -44,14 +44,12 @@ void snd_seq_prioq_delete(struct snd_seq int snd_seq_prioq_cell_in(struct snd_seq_prioq *f, struct snd_seq_event_cell *cell); /* dequeue cell from prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f); +struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f, + void *current_time); /* return number of events available in prioq */ int snd_seq_prioq_avail(struct snd_seq_prioq *f); -/* peek at cell at the head of the prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_peek(struct snd_seq_prioq *f); - /* client left queue */ void snd_seq_prioq_leave(struct snd_seq_prioq *f, int client, int timestamp); --- a/sound/core/seq/seq_queue.c +++ b/sound/core/seq/seq_queue.c @@ -277,30 +277,20 @@ void snd_seq_check_queue(struct snd_seq_ __again: /* Process tick queue... */ - while ((cell = snd_seq_prioq_cell_peek(q->tickq)) != NULL) { - if (snd_seq_compare_tick_time(&q->timer->tick.cur_tick, - &cell->event.time.tick)) { - cell = snd_seq_prioq_cell_out(q->tickq); - if (cell) - snd_seq_dispatch_event(cell, atomic, hop); - } else { - /* event remains in the queue */ + for (;;) { + cell = snd_seq_prioq_cell_out(q->tickq, + &q->timer->tick.cur_tick); + if (!cell) break; - } + snd_seq_dispatch_event(cell, atomic, hop); } - /* Process time queue... */ - while ((cell = snd_seq_prioq_cell_peek(q->timeq)) != NULL) { - if (snd_seq_compare_real_time(&q->timer->cur_time, - &cell->event.time.time)) { - cell = snd_seq_prioq_cell_out(q->timeq); - if (cell) - snd_seq_dispatch_event(cell, atomic, hop); - } else { - /* event remains in the queue */ + for (;;) { + cell = snd_seq_prioq_cell_out(q->timeq, &q->timer->cur_time); + if (!cell) break; - } + snd_seq_dispatch_event(cell, atomic, hop); } /* free lock */ Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-4.14/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-4.14/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-4.14/alsa-hda-revert-power_save-option-default-value.patch queue-4.14/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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Patch "ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 01c0b4265cc16bc1f43f475c5944c55c10d5768f Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Sat, 10 Mar 2018 23:04:23 +0100 Subject: ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats() From: Takashi Iwai <tiwai(a)suse.de> commit 01c0b4265cc16bc1f43f475c5944c55c10d5768f upstream. snd_pcm_oss_get_formats() has an obvious use-after-free around snd_mask_test() calls, as spotted by syzbot. The passed format_mask argument is a pointer to the hw_params object that is freed before the loop. What a surprise that it has been present since the original code of decades ago... Reported-by: syzbot+4090700a4f13fccaf648(a)syzkaller.appspotmail.com Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/oss/pcm_oss.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1762,10 +1762,9 @@ static int snd_pcm_oss_get_formats(struc return -ENOMEM; _snd_pcm_hw_params_any(params); err = snd_pcm_hw_refine(substream, params); - format_mask = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT); - kfree(params); if (err < 0) - return err; + goto error; + format_mask = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT); for (fmt = 0; fmt < 32; ++fmt) { if (snd_mask_test(format_mask, fmt)) { int f = snd_pcm_oss_format_to(fmt); @@ -1773,7 +1772,10 @@ static int snd_pcm_oss_get_formats(struc formats |= f; } } - return formats; + + error: + kfree(params); + return err < 0 ? err : formats; } static int snd_pcm_oss_set_format(struct snd_pcm_oss_file *pcm_oss_file, int format) Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-4.14/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-4.14/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-4.14/alsa-hda-revert-power_save-option-default-value.patch queue-4.14/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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Patch "ALSA: seq: Clear client entry before deleting else at closing" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: seq: Clear client entry before deleting else at closing to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From a2ff19f7b70118ced291a28d5313469914de451b Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Fri, 9 Mar 2018 22:23:31 +0100 Subject: ALSA: seq: Clear client entry before deleting else at closing From: Takashi Iwai <tiwai(a)suse.de> commit a2ff19f7b70118ced291a28d5313469914de451b upstream. When releasing a client, we need to clear the clienttab[] entry at first, then call snd_seq_queue_client_leave(). Otherwise, the in-flight cell in the queue might be picked up by the timer interrupt via snd_seq_check_queue() before calling snd_seq_queue_client_leave(), and it's delivered to another queue while the client is clearing queues. This may eventually result in an uncleared cell remaining in a queue, and the later snd_seq_pool_delete() may need to wait for a long time until the event gets really processed. By moving the clienttab[] clearance at the beginning of release, any event delivery of a cell belonging to this client will fail at a later point, since snd_seq_client_ptr() returns NULL. Thus the cell that was picked up by the timer interrupt will be returned immediately without further delivery, and the long stall of snd_seq_delete_pool() can be avoided, too. Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/seq/seq_clientmgr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -255,12 +255,12 @@ static int seq_free_client1(struct snd_s if (!client) return 0; - snd_seq_delete_all_ports(client); - snd_seq_queue_client_leave(client->number); spin_lock_irqsave(&clients_lock, flags); clienttablock[client->number] = 1; clienttab[client->number] = NULL; spin_unlock_irqrestore(&clients_lock, flags); + snd_seq_delete_all_ports(client); + snd_seq_queue_client_leave(client->number); snd_use_lock_sync(&client->use_lock); snd_seq_queue_client_termination(client->number); if (client->pool) Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-4.14/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-4.14/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-4.14/alsa-hda-revert-power_save-option-default-value.patch queue-4.14/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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Patch "ALSA: hda - Revert power_save option default value" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: hda - Revert power_save option default value to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-hda-revert-power_save-option-default-value.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 40088dc4e1ead7df31728c73f5b51d71da18831d Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Mon, 12 Mar 2018 13:55:48 +0100 Subject: ALSA: hda - Revert power_save option default value From: Takashi Iwai <tiwai(a)suse.de> commit 40088dc4e1ead7df31728c73f5b51d71da18831d upstream. With the commit 1ba8f9d30817 ("ALSA: hda: Add a power_save blacklist"), we changed the default value of power_save option to -1 for processing the power-save blacklist. Unfortunately, this seems breaking user-space applications that actually read the power_save parameter value via sysfs and judge / adjust the power-saving status. They see the value -1 as if the power-save is turned off, although the actual value is taken from CONFIG_SND_HDA_POWER_SAVE_DEFAULT and it can be a positive. So, overall, passing -1 there was no good idea. Let's partially revert it -- at least for power_save option default value is restored again to CONFIG_SND_HDA_POWER_SAVE_DEFAULT. Meanwhile, in this patch, we keep the blacklist behavior and make is adjustable via the new option, pm_blacklist. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199073 Fixes: 1ba8f9d30817 ("ALSA: hda: Add a power_save blacklist") Acked-by: Hans de Goede <hdegoede(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/pci/hda/hda_intel.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -181,11 +181,15 @@ static const struct kernel_param_ops par }; #define param_check_xint param_check_int -static int power_save = -1; +static int power_save = CONFIG_SND_HDA_POWER_SAVE_DEFAULT; module_param(power_save, xint, 0644); MODULE_PARM_DESC(power_save, "Automatic power-saving timeout " "(in second, 0 = disable)."); +static bool pm_blacklist = true; +module_param(pm_blacklist, bool, 0644); +MODULE_PARM_DESC(pm_blacklist, "Enable power-management blacklist"); + /* reset the HD-audio controller in power save mode. * this may give more power-saving, but will take longer time to * wake up. @@ -2300,10 +2304,9 @@ static int azx_probe_continue(struct azx val = power_save; #ifdef CONFIG_PM - if (val == -1) { + if (pm_blacklist) { const struct snd_pci_quirk *q; - val = CONFIG_SND_HDA_POWER_SAVE_DEFAULT; q = snd_pci_quirk_lookup(chip->pci, power_save_blacklist); if (q && val) { dev_info(chip->card->dev, "device %04x:%04x is on the power_save blacklist, forcing power_save to 0\n", Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-4.14/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-4.14/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-4.14/alsa-hda-revert-power_save-option-default-value.patch queue-4.14/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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Patch "lock_parent() needs to recheck if dentry got __dentry_kill'ed under it" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled lock_parent() needs to recheck if dentry got __dentry_kill'ed under it to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: lock_parent-needs-to-recheck-if-dentry-got-__dentry_kill-ed-under-it.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 3b821409632ab778d46e807516b457dfa72736ed Mon Sep 17 00:00:00 2001 From: Al Viro <viro(a)zeniv.linux.org.uk> Date: Fri, 23 Feb 2018 20:47:17 -0500 Subject: lock_parent() needs to recheck if dentry got __dentry_kill'ed under it From: Al Viro <viro(a)zeniv.linux.org.uk> commit 3b821409632ab778d46e807516b457dfa72736ed upstream. In case when dentry passed to lock_parent() is protected from freeing only by the fact that it's on a shrink list and trylock of parent fails, we could get hit by __dentry_kill() (and subsequent dentry_kill(parent)) between unlocking dentry and locking presumed parent. We need to recheck that dentry is alive once we lock both it and parent *and* postpone rcu_read_unlock() until after that point. Otherwise we could return a pointer to struct dentry that already is rcu-scheduled for freeing, with ->d_lock held on it; caller's subsequent attempt to unlock it can end up with memory corruption. Cc: stable(a)vger.kernel.org # 3.12+, counting backports Signed-off-by: Al Viro <viro(a)zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- fs/dcache.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/fs/dcache.c +++ b/fs/dcache.c @@ -581,11 +581,16 @@ again: spin_unlock(&parent->d_lock); goto again; } - rcu_read_unlock(); - if (parent != dentry) + if (parent != dentry) { spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); - else + if (unlikely(dentry->d_lockref.count < 0)) { + spin_unlock(&parent->d_lock); + parent = NULL; + } + } else { parent = NULL; + } + rcu_read_unlock(); return parent; } Patches currently in stable-queue which might be from viro(a)zeniv.linux.org.uk are queue-3.18/lock_parent-needs-to-recheck-if-dentry-got-__dentry_kill-ed-under-it.patch

7 years, 7 months

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Patch "fs/aio: Use RCU accessors for kioctx_table->table[]" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled fs/aio: Use RCU accessors for kioctx_table->table[] to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: fs-aio-use-rcu-accessors-for-kioctx_table-table.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From d0264c01e7587001a8c4608a5d1818dba9a4c11a Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj(a)kernel.org> Date: Wed, 14 Mar 2018 12:10:17 -0700 Subject: fs/aio: Use RCU accessors for kioctx_table->table[] From: Tejun Heo <tj(a)kernel.org> commit d0264c01e7587001a8c4608a5d1818dba9a4c11a upstream. While converting ioctx index from a list to a table, db446a08c23d ("aio: convert the ioctx list to table lookup v3") missed tagging kioctx_table->table[] as an array of RCU pointers and using the appropriate RCU accessors. This introduces a small window in the lookup path where init and access may race. Mark kioctx_table->table[] with __rcu and use the approriate RCU accessors when using the field. Signed-off-by: Tejun Heo <tj(a)kernel.org> Reported-by: Jann Horn <jannh(a)google.com> Fixes: db446a08c23d ("aio: convert the ioctx list to table lookup v3") Cc: Benjamin LaHaise <bcrl(a)kvack.org> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: stable(a)vger.kernel.org # v3.12+ Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- fs/aio.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) --- a/fs/aio.c +++ b/fs/aio.c @@ -68,9 +68,9 @@ struct aio_ring { #define AIO_RING_PAGES 8 struct kioctx_table { - struct rcu_head rcu; - unsigned nr; - struct kioctx *table[]; + struct rcu_head rcu; + unsigned nr; + struct kioctx __rcu *table[]; }; struct kioctx_cpu { @@ -583,9 +583,9 @@ static int ioctx_add_table(struct kioctx while (1) { if (table) for (i = 0; i < table->nr; i++) - if (!table->table[i]) { + if (!rcu_access_pointer(table->table[i])) { ctx->id = i; - table->table[i] = ctx; + rcu_assign_pointer(table->table[i], ctx); spin_unlock(&mm->ioctx_lock); /* While kioctx setup is in progress, @@ -760,8 +760,8 @@ static int kill_ioctx(struct mm_struct * spin_lock(&mm->ioctx_lock); table = rcu_dereference_raw(mm->ioctx_table); - WARN_ON(ctx != table->table[ctx->id]); - table->table[ctx->id] = NULL; + WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id])); + RCU_INIT_POINTER(table->table[ctx->id], NULL); spin_unlock(&mm->ioctx_lock); /* free_ioctx_reqs() will do the necessary RCU synchronization */ @@ -817,7 +817,8 @@ void exit_aio(struct mm_struct *mm) return; for (i = 0; i < table->nr; ++i) { - struct kioctx *ctx = table->table[i]; + struct kioctx *ctx = + rcu_dereference_protected(table->table[i], true); struct completion requests_done = COMPLETION_INITIALIZER_ONSTACK(requests_done); @@ -1003,7 +1004,7 @@ static struct kioctx *lookup_ioctx(unsig if (!table || id >= table->nr) goto out; - ctx = table->table[id]; + ctx = rcu_dereference(table->table[id]); if (ctx && ctx->user_id == ctx_id) { percpu_ref_get(&ctx->users); ret = ctx; Patches currently in stable-queue which might be from tj(a)kernel.org are queue-3.18/fs-aio-add-explicit-rcu-grace-period-when-freeing-kioctx.patch queue-3.18/fs-aio-use-rcu-accessors-for-kioctx_table-table.patch

7 years, 7 months

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Patch "fs/aio: Add explicit RCU grace period when freeing kioctx" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled fs/aio: Add explicit RCU grace period when freeing kioctx to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: fs-aio-add-explicit-rcu-grace-period-when-freeing-kioctx.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From a6d7cff472eea87d96899a20fa718d2bab7109f3 Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj(a)kernel.org> Date: Wed, 14 Mar 2018 12:10:17 -0700 Subject: fs/aio: Add explicit RCU grace period when freeing kioctx From: Tejun Heo <tj(a)kernel.org> commit a6d7cff472eea87d96899a20fa718d2bab7109f3 upstream. While fixing refcounting, e34ecee2ae79 ("aio: Fix a trinity splat") incorrectly removed explicit RCU grace period before freeing kioctx. The intention seems to be depending on the internal RCU grace periods of percpu_ref; however, percpu_ref uses a different flavor of RCU, sched-RCU. This can lead to kioctx being freed while RCU read protected dereferences are still in progress. Fix it by updating free_ioctx() to go through call_rcu() explicitly. v2: Comment added to explain double bouncing. Signed-off-by: Tejun Heo <tj(a)kernel.org> Reported-by: Jann Horn <jannh(a)google.com> Fixes: e34ecee2ae79 ("aio: Fix a trinity splat") Cc: Kent Overstreet <kent.overstreet(a)gmail.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: stable(a)vger.kernel.org # v3.13+ Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- fs/aio.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) --- a/fs/aio.c +++ b/fs/aio.c @@ -110,7 +110,8 @@ struct kioctx { struct page **ring_pages; long nr_pages; - struct work_struct free_work; + struct rcu_head free_rcu; + struct work_struct free_work; /* see free_ioctx() */ /* * signals when all in-flight requests are done @@ -505,6 +506,12 @@ static int kiocb_cancel(struct kiocb *ki return cancel(kiocb); } +/* + * free_ioctx() should be RCU delayed to synchronize against the RCU + * protected lookup_ioctx() and also needs process context to call + * aio_free_ring(), so the double bouncing through kioctx->free_rcu and + * ->free_work. + */ static void free_ioctx(struct work_struct *work) { struct kioctx *ctx = container_of(work, struct kioctx, free_work); @@ -518,6 +525,14 @@ static void free_ioctx(struct work_struc kmem_cache_free(kioctx_cachep, ctx); } +static void free_ioctx_rcufn(struct rcu_head *head) +{ + struct kioctx *ctx = container_of(head, struct kioctx, free_rcu); + + INIT_WORK(&ctx->free_work, free_ioctx); + schedule_work(&ctx->free_work); +} + static void free_ioctx_reqs(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, reqs); @@ -526,8 +541,8 @@ static void free_ioctx_reqs(struct percp if (ctx->requests_done) complete(ctx->requests_done); - INIT_WORK(&ctx->free_work, free_ioctx); - schedule_work(&ctx->free_work); + /* Synchronize against RCU protected table->table[] dereferences */ + call_rcu(&ctx->free_rcu, free_ioctx_rcufn); } /* @@ -749,7 +764,7 @@ static int kill_ioctx(struct mm_struct * table->table[ctx->id] = NULL; spin_unlock(&mm->ioctx_lock); - /* percpu_ref_kill() will do the necessary call_rcu() */ + /* free_ioctx_reqs() will do the necessary RCU synchronization */ wake_up_all(&ctx->wait); /* Patches currently in stable-queue which might be from tj(a)kernel.org are queue-3.18/fs-aio-add-explicit-rcu-grace-period-when-freeing-kioctx.patch queue-3.18/fs-aio-use-rcu-accessors-for-kioctx_table-table.patch

7 years, 7 months

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Patch "ALSA: seq: Fix possible UAF in snd_seq_check_queue()" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: seq: Fix possible UAF in snd_seq_check_queue() to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From d0f833065221cbfcbadf19fd4102bcfa9330006a Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Fri, 9 Mar 2018 21:58:28 +0100 Subject: ALSA: seq: Fix possible UAF in snd_seq_check_queue() From: Takashi Iwai <tiwai(a)suse.de> commit d0f833065221cbfcbadf19fd4102bcfa9330006a upstream. Although we've covered the races between concurrent write() and ioctl() in the previous patch series, there is still a possible UAF in the following scenario: A: user client closed B: timer irq -> snd_seq_release() -> snd_seq_timer_interrupt() -> snd_seq_free_client() -> snd_seq_check_queue() -> cell = snd_seq_prioq_cell_peek() -> snd_seq_prioq_leave() .... removing all cells -> snd_seq_pool_done() .... vfree() -> snd_seq_compare_tick_time(cell) ... Oops So the problem is that a cell is peeked and accessed without any protection until it's retrieved from the queue again via snd_seq_prioq_cell_out(). This patch tries to address it, also cleans up the code by a slight refactoring. snd_seq_prioq_cell_out() now receives an extra pointer argument. When it's non-NULL, the function checks the event timestamp with the given pointer. The caller needs to pass the right reference either to snd_seq_tick or snd_seq_realtime depending on the event timestamp type. A good news is that the above change allows us to remove the snd_seq_prioq_cell_peek(), too, thus the patch actually reduces the code size. Reviewed-by: Nicolai Stange <nstange(a)suse.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/seq/seq_prioq.c | 28 ++++++++++++++-------------- sound/core/seq/seq_prioq.h | 6 ++---- sound/core/seq/seq_queue.c | 28 +++++++++------------------- 3 files changed, 25 insertions(+), 37 deletions(-) --- a/sound/core/seq/seq_prioq.c +++ b/sound/core/seq/seq_prioq.c @@ -87,7 +87,7 @@ void snd_seq_prioq_delete(struct snd_seq if (f->cells > 0) { /* drain prioQ */ while (f->cells > 0) - snd_seq_cell_free(snd_seq_prioq_cell_out(f)); + snd_seq_cell_free(snd_seq_prioq_cell_out(f, NULL)); } kfree(f); @@ -214,8 +214,18 @@ int snd_seq_prioq_cell_in(struct snd_seq return 0; } +/* return 1 if the current time >= event timestamp */ +static int event_is_ready(struct snd_seq_event *ev, void *current_time) +{ + if ((ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) + return snd_seq_compare_tick_time(current_time, &ev->time.tick); + else + return snd_seq_compare_real_time(current_time, &ev->time.time); +} + /* dequeue cell from prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f) +struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f, + void *current_time) { struct snd_seq_event_cell *cell; unsigned long flags; @@ -227,6 +237,8 @@ struct snd_seq_event_cell *snd_seq_prioq spin_lock_irqsave(&f->lock, flags); cell = f->head; + if (cell && current_time && !event_is_ready(&cell->event, current_time)) + cell = NULL; if (cell) { f->head = cell->next; @@ -252,18 +264,6 @@ int snd_seq_prioq_avail(struct snd_seq_p return f->cells; } - -/* peek at cell at the head of the prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_peek(struct snd_seq_prioq * f) -{ - if (f == NULL) { - pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n"); - return NULL; - } - return f->head; -} - - static inline int prioq_match(struct snd_seq_event_cell *cell, int client, int timestamp) { --- a/sound/core/seq/seq_prioq.h +++ b/sound/core/seq/seq_prioq.h @@ -44,14 +44,12 @@ void snd_seq_prioq_delete(struct snd_seq int snd_seq_prioq_cell_in(struct snd_seq_prioq *f, struct snd_seq_event_cell *cell); /* dequeue cell from prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f); +struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f, + void *current_time); /* return number of events available in prioq */ int snd_seq_prioq_avail(struct snd_seq_prioq *f); -/* peek at cell at the head of the prioq */ -struct snd_seq_event_cell *snd_seq_prioq_cell_peek(struct snd_seq_prioq *f); - /* client left queue */ void snd_seq_prioq_leave(struct snd_seq_prioq *f, int client, int timestamp); --- a/sound/core/seq/seq_queue.c +++ b/sound/core/seq/seq_queue.c @@ -271,30 +271,20 @@ void snd_seq_check_queue(struct snd_seq_ __again: /* Process tick queue... */ - while ((cell = snd_seq_prioq_cell_peek(q->tickq)) != NULL) { - if (snd_seq_compare_tick_time(&q->timer->tick.cur_tick, - &cell->event.time.tick)) { - cell = snd_seq_prioq_cell_out(q->tickq); - if (cell) - snd_seq_dispatch_event(cell, atomic, hop); - } else { - /* event remains in the queue */ + for (;;) { + cell = snd_seq_prioq_cell_out(q->tickq, + &q->timer->tick.cur_tick); + if (!cell) break; - } + snd_seq_dispatch_event(cell, atomic, hop); } - /* Process time queue... */ - while ((cell = snd_seq_prioq_cell_peek(q->timeq)) != NULL) { - if (snd_seq_compare_real_time(&q->timer->cur_time, - &cell->event.time.time)) { - cell = snd_seq_prioq_cell_out(q->timeq); - if (cell) - snd_seq_dispatch_event(cell, atomic, hop); - } else { - /* event remains in the queue */ + for (;;) { + cell = snd_seq_prioq_cell_out(q->timeq, &q->timer->cur_time); + if (!cell) break; - } + snd_seq_dispatch_event(cell, atomic, hop); } /* free lock */ Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-3.18/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-3.18/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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Patch "ALSA: seq: Clear client entry before deleting else at closing" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: seq: Clear client entry before deleting else at closing to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From a2ff19f7b70118ced291a28d5313469914de451b Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Fri, 9 Mar 2018 22:23:31 +0100 Subject: ALSA: seq: Clear client entry before deleting else at closing From: Takashi Iwai <tiwai(a)suse.de> commit a2ff19f7b70118ced291a28d5313469914de451b upstream. When releasing a client, we need to clear the clienttab[] entry at first, then call snd_seq_queue_client_leave(). Otherwise, the in-flight cell in the queue might be picked up by the timer interrupt via snd_seq_check_queue() before calling snd_seq_queue_client_leave(), and it's delivered to another queue while the client is clearing queues. This may eventually result in an uncleared cell remaining in a queue, and the later snd_seq_pool_delete() may need to wait for a long time until the event gets really processed. By moving the clienttab[] clearance at the beginning of release, any event delivery of a cell belonging to this client will fail at a later point, since snd_seq_client_ptr() returns NULL. Thus the cell that was picked up by the timer interrupt will be returned immediately without further delivery, and the long stall of snd_seq_delete_pool() can be avoided, too. Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/seq/seq_clientmgr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -270,12 +270,12 @@ static int seq_free_client1(struct snd_s if (!client) return 0; - snd_seq_delete_all_ports(client); - snd_seq_queue_client_leave(client->number); spin_lock_irqsave(&clients_lock, flags); clienttablock[client->number] = 1; clienttab[client->number] = NULL; spin_unlock_irqrestore(&clients_lock, flags); + snd_seq_delete_all_ports(client); + snd_seq_queue_client_leave(client->number); snd_use_lock_sync(&client->use_lock); snd_seq_queue_client_termination(client->number); if (client->pool) Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-3.18/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-3.18/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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Patch "ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats() to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 01c0b4265cc16bc1f43f475c5944c55c10d5768f Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Sat, 10 Mar 2018 23:04:23 +0100 Subject: ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats() From: Takashi Iwai <tiwai(a)suse.de> commit 01c0b4265cc16bc1f43f475c5944c55c10d5768f upstream. snd_pcm_oss_get_formats() has an obvious use-after-free around snd_mask_test() calls, as spotted by syzbot. The passed format_mask argument is a pointer to the hw_params object that is freed before the loop. What a surprise that it has been present since the original code of decades ago... Reported-by: syzbot+4090700a4f13fccaf648(a)syzkaller.appspotmail.com Cc: <stable(a)vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/oss/pcm_oss.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1815,10 +1815,9 @@ static int snd_pcm_oss_get_formats(struc return -ENOMEM; _snd_pcm_hw_params_any(params); err = snd_pcm_hw_refine(substream, params); - format_mask = *hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); - kfree(params); if (err < 0) - return err; + goto error; + format_mask = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT); for (fmt = 0; fmt < 32; ++fmt) { if (snd_mask_test(&format_mask, fmt)) { int f = snd_pcm_oss_format_to(fmt); @@ -1826,7 +1825,10 @@ static int snd_pcm_oss_get_formats(struc formats |= f; } } - return formats; + + error: + kfree(params); + return err < 0 ? err : formats; } static int snd_pcm_oss_set_format(struct snd_pcm_oss_file *pcm_oss_file, int format) Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-fix-uaf-in-snd_pcm_oss_get_formats.patch queue-3.18/alsa-seq-fix-possible-uaf-in-snd_seq_check_queue.patch queue-3.18/alsa-seq-clear-client-entry-before-deleting-else-at-closing.patch

7 years, 7 months

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