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Wen Yang <wen.yang99@zte.com.cn> and majiang <ma.jiang@zte.com.cn>
report that a periodic signal received during fork can cause fork to
continually restart preventing an application from making progress.
The code was being overly pessimistic. Fork needs to guarantee that a
signal sent to multiple processes is logically delivered before the
fork and just to the forking process or logically delivered after the
fork to both the forking process and it's newly spawned child. For
signals like periodic timers that are always delivered to a single
process fork can safely complete and let them appear to logically
delivered after the fork().
While examining this issue I also discovered that fork today will miss
signals delivered to multiple processes during the fork and handled by
another thread. Similarly the current code will also miss blocked
signals that are delivered to multiple process, as those signals will
not appear pending during fork.
Add a list of each thread that is currently forking, and keep on that
list a signal set that records all of the signals sent to multiple
processes. When fork completes initialize the new processes
shared_pending signal set with it. The calculate_sigpending function
will see those signals and set TIF_SIGPENDING causing the new task to
take the slow path to userspace to handle those signals. Making it
appear as if those signals were received immediately after the fork.
It is not possible to send real time signals to multiple processes and
exceptions don't go to multiple processes, which means that that are
no signals sent to multiple processes that require siginfo. This
means it is safe to not bother collecting siginfo on signals sent
during fork.
The sigaction of a child of fork is initially the same as the
sigaction of the parent process. So a signal the parent ignores the
child will also initially ignore. Therefore it is safe to ignore
signals sent to multiple processes and ignored by the forking process.
Signals sent to only a single process or only a single thread and delivered
during fork are treated as if they are received after the fork, and generally
not dealt with. They won't cause any problems.
V2: Added removal from the multiprocess list on failure.
V3: Use -ERESTARTNOINTR directly
V4: - Don't queue both SIGCONT and SIGSTOP
- Initialize signal_struct.multiprocess in init_task
- Move setting of shared_pending to before the new task
is visible to signals. This prevents signals from comming
in before shared_pending.signal is set to delayed.signal
and being lost.
V5: - rework list add and delete to account for idle threads
v6: - Use sigdelsetmask when removing stop signals
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200447
Reported-by: Wen Yang <wen.yang99@zte.com.cn> and
Reported-by: majiang <ma.jiang@zte.com.cn>
Fixes: 4a2c7a7837da ("[PATCH] make fork() atomic wrt pgrp/session signals")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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There are only two signals that are delivered to every member of a
signal group: SIGSTOP and SIGKILL. Signal delivery requires every
signal appear to be delivered either before or after a clone syscall.
SIGKILL terminates the clone so does not need to be considered. Which
leaves only SIGSTOP that needs to be considered when creating new
threads.
Today in the event of a group stop TIF_SIGPENDING will get set and the
fork will restart ensuring the fork syscall participates in the group
stop.
A fork (especially of a process with a lot of memory) is one of the
most expensive system so we really only want to restart a fork when
necessary.
It is easy so check to see if a SIGSTOP is ongoing and have the new
thread join it immediate after the clone completes. Making it appear
the clone completed happened just before the SIGSTOP.
The calculate_sigpending function will see the bits set in jobctl and
set TIF_SIGPENDING to ensure the new task takes the slow path to userspace.
V2: The call to task_join_group_stop was moved before the new task is
added to the thread group list. This should not matter as
sighand->siglock is held over both the addition of the threads,
the call to task_join_group_stop and do_signal_stop. But the change
is trivial and it is one less thing to worry about when reading
the code.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The code in calculate_sigpending will now handle this so
it is just redundant and possibly a little confusing
to continue setting TIF_SIGPENDING in ptrace_init_task.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Add a function calculate_sigpending to test to see if any signals are
pending for a new task immediately following fork. Signals have to
happen either before or after fork. Today our practice is to push
all of the signals to before the fork, but that has the downside that
frequent or periodic signals can make fork take much much longer than
normal or prevent fork from completing entirely.
So we need move signals that we can after the fork to prevent that.
This updates the code to set TIF_SIGPENDING on a new task if there
are signals or other activities that have moved so that they appear
to happen after the fork.
As the code today restarts if it sees any such activity this won't
immediately have an effect, as there will be no reason for it
to set TIF_SIGPENDING immediately after the fork.
Adding calculate_sigpending means the code in fork can safely be
changed to not always restart if a signal is pending.
The new calculate_sigpending function sets sigpending if there
are pending bits in jobctl, pending signals, the freezer needs
to freeze the new task or the live kernel patching framework
need the new thread to take the slow path to userspace.
I have verified that setting TIF_SIGPENDING does make a new process
take the slow path to userspace before it executes it's first userspace
instruction.
I have looked at the callers of signal_wake_up and the code paths
setting TIF_SIGPENDING and I don't see anything else that needs to be
handled. The code probably doesn't need to set TIF_SIGPENDING for the
kernel live patching as it uses a separate thread flag as well. But
at this point it seems safer reuse the recalc_sigpending logic and get
the kernel live patching folks to sort out their story later.
V2: I have moved the test into schedule_tail where siglock can
be grabbed and recalc_sigpending can be reused directly.
Further as the last action of setting up a new task this
guarantees that TIF_SIGPENDING will be properly set in the
new process.
The helper calculate_sigpending takes the siglock and
uncontitionally sets TIF_SIGPENDING and let's recalc_sigpending
clear TIF_SIGPENDING if it is unnecessary. This allows reusing
the existing code and keeps maintenance of the conditions simple.
Oleg Nesterov <oleg@redhat.com> suggested the movement
and pointed out the need to take siglock if this code
was going to be called while the new task is discoverable.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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In practice this does not change anything as testing for fatal_signal_pending
and exiting for with an error code duplicates the work of the next clause
which recalculates pending signals and then exits fork if any are pending.
In both cases the pending signal will trigger the slow path when existing
to userspace, and the fatal signal will cause do_exit to be called.
The advantage of making this a separate test is that it makes it clear
processing the fatal signal will terminate the fork, and it allows the
rest of the signal logic to be updated without fear that this important
case will be lost.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Normally this would be something that would be handled by handling
signals that are sent to a group of processes but in this case the
forking process is not a member of the group being signaled. Thus
special code is needed to prevent a race with pid namespaces exiting,
and fork adding new processes within them.
Move this test up before the signal restart just in case signals are
also pending. Fatal conditions should take presedence over restarts.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This is the bottom and by pushing this down it simplifies the callers
and otherwise leaves things as is. This is in preparation for allowing
fork to implement better handling of signals set to groups of processes.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This information is already available in the callers and by pushing it
down it makes the code a little clearer, and allows implementing
better handling of signales set to a group of processes in fork.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This information is already available in the callers and by pushing it
down it makes the code a little clearer, and allows better group
signal behavior in fork.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This passes the information we already have at the call sight into
do_send_sig_info. Ultimately allowing for better handling of signals
sent to a group of processes during fork.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This information is already present and using it directly simplifies the logic
of the code.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This passes the information we already have at the call sight
into group_send_sig_info. Ultimatelly allowing for to better handle
signals sent to a group of processes.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Make the code more maintainable by performing more of the signal
related work in send_sigqueue.
A quick inspection of do_timer_create will show that this code path
does not lookup a thread group by a thread's pid. Making it safe
to find the task pointed to by it_pid with "pid_task(it_pid, type)";
This supports the changes needed in fork to tell if a signal was sent
to a single process or a group of processes.
Having the pid to task transition in signal.c will also make it easier
to sort out races with de_thread and and the thread group leader
exiting when it comes time to address that.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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In good_sigevent directly compute the default return value as
"task_tgid(current)". This is exactly the same as
"task_pid(current->group_leader)" but written more clearly.
In the thread case first compute the thread's pid. Then veify that
attached to that pid is a thread of the current thread group.
This has the net effect of making the code a little clearer, and
making it obvious that posix timers never look up a process by a the
pid of a thread.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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When f_setown is called a pid and a pid type are stored. Replace the use
of PIDTYPE_PID with PIDTYPE_TGID as PIDTYPE_TGID goes to the entire thread
group. Replace the use of PIDTYPE_MAX with PIDTYPE_PID as PIDTYPE_PID now
is only for a thread.
Update the users of __f_setown to use PIDTYPE_TGID instead of
PIDTYPE_PID.
For now the code continues to capture task_pid (when task_tgid would
really be appropriate), and iterate on PIDTYPE_PID (even when type ==
PIDTYPE_TGID) out of an abundance of caution to preserve existing
behavior.
Oleg Nesterov suggested using the test to ensure we use PIDTYPE_PID
for tgid lookup also be used to avoid taking the tasklist lock.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Everywhere except in the pid array we distinguish between a tasks pid and
a tasks tgid (thread group id). Even in the enumeration we want that
distinction sometimes so we have added __PIDTYPE_TGID. With leader_pid
we almost have an implementation of PIDTYPE_TGID in struct signal_struct.
Add PIDTYPE_TGID as a first class member of the pid_type enumeration and
into the pids array. Then remove the __PIDTYPE_TGID special case and the
leader_pid in signal_struct.
The net size increase is just an extra pointer added to struct pid and
an extra pair of pointers of an hlist_node added to task_struct.
The effect on code maintenance is the removal of a number of special
cases today and the potential to remove many more special cases as
PIDTYPE_TGID gets used to it's fullest. The long term potential
is allowing zombie thread group leaders to exit, which will remove
a lot more special cases in the code.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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To access these fields the code always has to go to group leader so
going to signal struct is no loss and is actually a fundamental simplification.
This saves a little bit of memory by only allocating the pid pointer array
once instead of once for every thread, and even better this removes a
few potential races caused by the fact that group_leader can be changed
by de_thread, while signal_struct can not.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The cost is the the same and this removes the need
to worry about complications that come from de_thread
and group_leader changing.
__task_pid_nr_ns has been updated to take advantage of this change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The function is general and inline so there is no need
to hide it inside of exit.c
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This is cheap and no cost so we might as well.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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As files move around, their previous links break. Fix the
references for them.
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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The old HOWTO was removed a long time ago. The flat table
version is not metioned elsewhere, so just get rid of the
text.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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This file doesn't exist anymore:
Documentation/cpu-freq/user-guide.txt
As the ABI already points to Documentation/cpu-freq, just
remove the broken link and the associated text.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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As files got renamed, their references broke.
Manually fix a series of broken refs at the DT bindings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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Rename:
pinctrl-binding.txt -> pinctrl-bindings.txt
In order to match the current name of this file.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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There were some file movements that changed the location for
some DT bindings. Fix them with:
scripts/documentation-file-ref-check --fix
After manually checking if the new file makes sense.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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The specified locations are not right. Fix the wildcard logic
to point to the correct directories.
Without that, get-maintainer won't get things right:
$ ./scripts/get_maintainer.pl --no-git-fallback --no-r --no-n --no-l -f Documentation/devicetree/bindings/arm/cpu-enable-method/nuvoton,npcm750-smp
robh+dt@kernel.org (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
mark.rutland@arm.com (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
After the patch, it will properly point to NPCM arch maintainers:
$ ./scripts/get_maintainer.pl --no-git-fallback --no-r --no-n --no-l -f Documentation/devicetree/bindings/arm/cpu-enable-method/nuvoton,npcm750-smp
avifishman70@gmail.com (supporter:ARM/NUVOTON NPCM ARCHITECTURE)
tmaimon77@gmail.com (supporter:ARM/NUVOTON NPCM ARCHITECTURE)
robh+dt@kernel.org (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
mark.rutland@arm.com (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
Cc: Avi Fishman <avifishman70@gmail.com>
Cc: Tomer Maimon <tmaimon77@gmail.com>
Cc: Patrick Venture <venture@google.com>
Cc: Nancy Yuen <yuenn@google.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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Those files got a manufacturer's name prepended and were moved around.
Adjust their references accordingly.
Also, due those movements, Documentation/devicetree/bindings/video
doesn't exist anymore.
Cc: David Airlie <airlied@linux.ie>
Cc: David Lechner <david@lechnology.com>
Cc: Peter Senna Tschudin <peter.senna@collabora.com>
Cc: Martin Donnelly <martin.donnelly@ge.com>
Cc: Martyn Welch <martyn.welch@collabora.co.uk>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Alison Wang <alison.wang@nxp.com>
Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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The alsa parameters file was renamed to alsa-configuration.rst.
With regards to OSS, it got retired as a hole by at changeset
727dede0ba8a ("sound: Retire OSS"). So, it doesn't make sense
to keep mentioning it at kernel-parameters.txt.
Fixes: 727dede0ba8a ("sound: Retire OSS")
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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The location pointed there is missing "bindings/" on its path.
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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As we move stuff around, some doc references are broken. Fix some of
them via this script:
./scripts/documentation-file-ref-check --fix
Manually checked that produced results are valid.
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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Some files, like tools/memory-model/README has references to
a Documentation file that is locale to it. Handle references
that are relative to them too.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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Now that the number of broken refs are smaller, improve the logic
that gets rid of false-positives.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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Sometimes, people use dash instead of underline or vice-versa.
Try to autocorrect it.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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There are several links broken due to DT file movements. Add
a hint logic to seek for those changes.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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at MAINTAINERS, some filename paths use '?' and things like [7,9].
So, accept more wildcards, in order to avoid false-positives.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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The name of the --fix option was renamed, but it was not
changed at the quick help message.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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There's a missing ".rst" at the doc's file name.
Acked-by: Ramesh Shanmugasundaram <Ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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There are several places pointing to old documentation files:
Documentation/video4linux/API.html
Documentation/video4linux/bttv/
Documentation/video4linux/cx2341x/fw-encoder-api.txt
Documentation/video4linux/m5602.txt
Documentation/video4linux/v4l2-framework.txt
Documentation/video4linux/videobuf
Documentation/video4linux/Zoran
Make them point to the new location where available, removing
otherwise.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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This file got renamed, but the references still point to the
old place.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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This script was moved out of Documentation/dvb, but the
links weren't updated.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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As we move stuff around, some doc references are broken. Fix some of
them via this script:
./scripts/documentation-file-ref-check --fix
Manually checked if the produced result is valid, removing a few
false-positives.
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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The script:
./scripts/documentation-file-ref-check --fix
Gives multiple hints for broken references on some files.
Manually use the one that applies for some files.
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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Currently we were running HWIF quirks before getting HW capabilities.
This is not right because some HWIF callbacks depend on HW caps.
Lets save the quirks callback and use it in a later stage.
This fixes Altera socfpga.
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Fixes: 5f0456b43140 ("net: stmmac: Implement logic to automatically select HW Interface")
Reported-by: Dinh Nguyen <dinh.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Vitor Soares <soares@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Dinh Nguyen <dinh.linux@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Commit 9ce33e46531d ("neighbour: support for NTF_EXT_LEARNED flag")
added support for NTF_EXT_LEARNED for neighbour entries.
NTF_EXT_LEARNED entries are neigh entries managed by control
plane (eg: Ethernet VPN implementation in FRR routing suite).
Periodic gc already excludes these entries. This patch extends
it to forced gc which the earlier patch missed.
Fixes: 9ce33e46531d ("neighbour: support for NTF_EXT_LEARNED flag")
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When sysfs_create_group fails, the lack of error-handling code may
cause unexpected results.
This patch adds error-handling code after calling sysfs_create_group.
Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Current behavior in tls_sw_recvmsg() is to wait for incoming tls
messages and copy up to exactly len bytes of data that the user
provided. This is problematic in the sense that i) if no packet
is currently queued in strparser we keep waiting until one has been
processed and pushed into tls receive layer for tls_wait_data() to
wake up and push the decrypted bits to user space. Given after
tls decryption, we're back at streaming data, use sock_rcvlowat()
hint from tcp socket instead. Retain current behavior with MSG_WAITALL
flag and otherwise use the hint target for breaking the loop and
returning to application. This is done if currently no ctx->recv_pkt
is ready, otherwise continue to process it from our strparser
backlog.
Fixes: c46234ebb4d1 ("tls: RX path for ktls")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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syzkaller managed to trigger a use-after-free in tls like the
following:
BUG: KASAN: use-after-free in tls_push_record.constprop.15+0x6a2/0x810 [tls]
Write of size 1 at addr ffff88037aa08000 by task a.out/2317
CPU: 3 PID: 2317 Comm: a.out Not tainted 4.17.0+ #144
Hardware name: LENOVO 20FBCTO1WW/20FBCTO1WW, BIOS N1FET47W (1.21 ) 11/28/2016
Call Trace:
dump_stack+0x71/0xab
print_address_description+0x6a/0x280
kasan_report+0x258/0x380
? tls_push_record.constprop.15+0x6a2/0x810 [tls]
tls_push_record.constprop.15+0x6a2/0x810 [tls]
tls_sw_push_pending_record+0x2e/0x40 [tls]
tls_sk_proto_close+0x3fe/0x710 [tls]
? tcp_check_oom+0x4c0/0x4c0
? tls_write_space+0x260/0x260 [tls]
? kmem_cache_free+0x88/0x1f0
inet_release+0xd6/0x1b0
__sock_release+0xc0/0x240
sock_close+0x11/0x20
__fput+0x22d/0x660
task_work_run+0x114/0x1a0
do_exit+0x71a/0x2780
? mm_update_next_owner+0x650/0x650
? handle_mm_fault+0x2f5/0x5f0
? __do_page_fault+0x44f/0xa50
? mm_fault_error+0x2d0/0x2d0
do_group_exit+0xde/0x300
__x64_sys_exit_group+0x3a/0x50
do_syscall_64+0x9a/0x300
? page_fault+0x8/0x30
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This happened through fault injection where aead_req allocation in
tls_do_encryption() eventually failed and we returned -ENOMEM from
the function. Turns out that the use-after-free is triggered from
tls_sw_sendmsg() in the second tls_push_record(). The error then
triggers a jump to waiting for memory in sk_stream_wait_memory()
resp. returning immediately in case of MSG_DONTWAIT. What follows is
the trim_both_sgl(sk, orig_size), which drops elements from the sg
list added via tls_sw_sendmsg(). Now the use-after-free gets triggered
when the socket is being closed, where tls_sk_proto_close() callback
is invoked. The tls_complete_pending_work() will figure that there's
a pending closed tls record to be flushed and thus calls into the
tls_push_pending_closed_record() from there. ctx->push_pending_record()
is called from the latter, which is the tls_sw_push_pending_record()
from sw path. This again calls into tls_push_record(). And here the
tls_fill_prepend() will panic since the buffer address has been freed
earlier via trim_both_sgl(). One way to fix it is to move the aead
request allocation out of tls_do_encryption() early into tls_push_record().
This means we don't prep the tls header and advance state to the
TLS_PENDING_CLOSED_RECORD before allocation which could potentially
fail happened. That fixes the issue on my side.
Fixes: 3c4d7559159b ("tls: kernel TLS support")
Reported-by: syzbot+5c74af81c547738e1684@syzkaller.appspotmail.com
Reported-by: syzbot+709f2810a6a05f11d4d3@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric W. Biederman
Linus Torvalds
Mauro Carvalho Chehab
Jose Abreu
Roopa Prabhu
Zhouyang Jia
Daniel Borkmann