mirror of https://github.com/torvalds/linux.git
229 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Linus Torvalds
|
67850b7bdc |
While looking at the ptrace problems with PREEMPT_RT and the problems
of Peter Zijlstra was encountering with ptrace in his freezer rewrite I identified some cleanups to ptrace_stop that make sense on their own and move make resolving the other problems much simpler. The biggest issue is the habbit of the ptrace code to change task->__state from the tracer to suppress TASK_WAKEKILL from waking up the tracee. No other code in the kernel does that and it is straight forward to update signal_wake_up and friends to make that unnecessary. Peter's task freezer sets frozen tasks to a new state TASK_FROZEN and then it stores them by calling "wake_up_state(t, TASK_FROZEN)" relying on the fact that all stopped states except the special stop states can tolerate spurious wake up and recover their state. The state of stopped and traced tasked is changed to be stored in task->jobctl as well as in task->__state. This makes it possible for the freezer to recover tasks in these special states, as well as serving as a general cleanup. With a little more work in that direction I believe TASK_STOPPED can learn to tolerate spurious wake ups and become an ordinary stop state. The TASK_TRACED state has to remain a special state as the registers for a process are only reliably available when the process is stopped in the scheduler. Fundamentally ptrace needs acess to the saved register values of a task. There are bunch of semi-random ptrace related cleanups that were found while looking at these issues. One cleanup that deserves to be called out is from commit |
|
Peter Zijlstra
|
31cae1eaae |
sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state
Currently ptrace_stop() / do_signal_stop() rely on the special states
TASK_TRACED and TASK_STOPPED resp. to keep unique state. That is, this
state exists only in task->__state and nowhere else.
There's two spots of bother with this:
- PREEMPT_RT has task->saved_state which complicates matters,
meaning task_is_{traced,stopped}() needs to check an additional
variable.
- An alternative freezer implementation that itself relies on a
special TASK state would loose TASK_TRACED/TASK_STOPPED and will
result in misbehaviour.
As such, add additional state to task->jobctl to track this state
outside of task->__state.
NOTE: this doesn't actually fix anything yet, just adds extra state.
--EWB
* didn't add a unnecessary newline in signal.h
* Update t->jobctl in signal_wake_up and ptrace_signal_wake_up
instead of in signal_wake_up_state. This prevents the clearing
of TASK_STOPPED and TASK_TRACED from getting lost.
* Added warnings if JOBCTL_STOPPED or JOBCTL_TRACED are not cleared
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220421150654.757693825@infradead.org
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-12-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Eric W. Biederman
|
5b4197cb28 |
ptrace: Always take siglock in ptrace_resume
Make code analysis simpler and future changes easier by always taking siglock in ptrace_resume. Tested-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20220505182645.497868-11-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
2500ad1c7f |
ptrace: Don't change __state
Stop playing with tsk->__state to remove TASK_WAKEKILL while a ptrace command is executing. Instead remove TASK_WAKEKILL from the definition of TASK_TRACED, and implement a new jobctl flag TASK_PTRACE_FROZEN. This new flag is set in jobctl_freeze_task and cleared when ptrace_stop is awoken or in jobctl_unfreeze_task (when ptrace_stop remains asleep). In signal_wake_up add __TASK_TRACED to state along with TASK_WAKEKILL when the wake up is for a fatal signal. Skip adding __TASK_TRACED when TASK_PTRACE_FROZEN is not set. This has the same effect as changing TASK_TRACED to __TASK_TRACED as all of the wake_ups that use TASK_KILLABLE go through signal_wake_up. Handle a ptrace_stop being called with a pending fatal signal. Previously it would have been handled by schedule simply failing to sleep. As TASK_WAKEKILL is no longer part of TASK_TRACED schedule will sleep with a fatal_signal_pending. The code in signal_wake_up guarantees that the code will be awaked by any fatal signal that codes after TASK_TRACED is set. Previously the __state value of __TASK_TRACED was changed to TASK_RUNNING when woken up or back to TASK_TRACED when the code was left in ptrace_stop. Now when woken up ptrace_stop now clears JOBCTL_PTRACE_FROZEN and when left sleeping ptrace_unfreezed_traced clears JOBCTL_PTRACE_FROZEN. Tested-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20220505182645.497868-10-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
7b0fe1367e |
ptrace: Document that wait_task_inactive can't fail
After ptrace_freeze_traced succeeds it is known that the tracee has a __state value of __TASK_TRACED and that no __ptrace_unlink will happen because the tracer is waiting for the tracee, and the tracee is in ptrace_stop. The function ptrace_freeze_traced can succeed at any point after ptrace_stop has set TASK_TRACED and dropped siglock. The read_lock on tasklist_lock only excludes ptrace_attach. This means that the !current->ptrace which executes under a read_lock of tasklist_lock will never see a ptrace_freeze_trace as the tracer must have gone away before the tasklist_lock was taken and ptrace_attach can not occur until the read_lock is dropped. As ptrace_freeze_traced depends upon ptrace_attach running before it can run that excludes ptrace_freeze_traced until __state is set to TASK_RUNNING. This means that task_is_traced will fail in ptrace_freeze_attach and ptrace_freeze_attached will fail. On the current->ptrace branch of ptrace_stop which will be reached any time after ptrace_freeze_traced has succeed it is known that __state is __TASK_TRACED and schedule() will be called with that state. Use a WARN_ON_ONCE to document that wait_task_inactive(TASK_TRACED) should never fail. Remove the stale comment about may_ptrace_stop. Strictly speaking this is not true because if PREEMPT_RT is enabled wait_task_inactive can fail because __state can be changed. I don't see this as a problem as the ptrace code is currently broken on PREMPT_RT, and this is one of the issues. Failing and warning when the assumptions of the code are broken is good. Tested-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20220505182645.497868-8-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
6a2d90ba02 |
ptrace: Reimplement PTRACE_KILL by always sending SIGKILL
The current implementation of PTRACE_KILL is buggy and has been for many years as it assumes it's target has stopped in ptrace_stop. At a quick skim it looks like this assumption has existed since ptrace support was added in linux v1.0. While PTRACE_KILL has been deprecated we can not remove it as a quick search with google code search reveals many existing programs calling it. When the ptracee is not stopped at ptrace_stop some fields would be set that are ignored except in ptrace_stop. Making the userspace visible behavior of PTRACE_KILL a noop in those case. As the usual rules are not obeyed it is not clear what the consequences are of calling PTRACE_KILL on a running process. Presumably userspace does not do this as it achieves nothing. Replace the implementation of PTRACE_KILL with a simple send_sig_info(SIGKILL) followed by a return 0. This changes the observable user space behavior only in that PTRACE_KILL on a process not stopped in ptrace_stop will also kill it. As that has always been the intent of the code this seems like a reasonable change. Cc: stable@vger.kernel.org Reported-by: Al Viro <viro@zeniv.linux.org.uk> Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20220505182645.497868-7-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
16cc1bc67d |
ptrace: Remove arch_ptrace_attach
The last remaining implementation of arch_ptrace_attach is ia64's ptrace_attach_sync_user_rbs which was added at the end of 2007 in commit |
|
Tiezhu Yang
|
f26b2afd53 |
ptrace: remove redudant check of #ifdef PTRACE_SINGLESTEP
Patch series "ptrace: do some cleanup". This patch (of 3): PTRACE_SINGLESTEP is always defined as 9 in include/uapi/linux/ptrace.h, remove redudant check of #ifdef PTRACE_SINGLESTEP. Link: https://lkml.kernel.org/r/1649240981-11024-2-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
|
Jann Horn
|
ee1fee9005 |
ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
Setting PTRACE_O_SUSPEND_SECCOMP is supposed to be a highly privileged
operation because it allows the tracee to completely bypass all seccomp
filters on kernels with CONFIG_CHECKPOINT_RESTORE=y. It is only supposed to
be settable by a process with global CAP_SYS_ADMIN, and only if that
process is not subject to any seccomp filters at all.
However, while these permission checks were done on the PTRACE_SETOPTIONS
path, they were missing on the PTRACE_SEIZE path, which also sets
user-specified ptrace flags.
Move the permissions checks out into a helper function and let both
ptrace_attach() and ptrace_setoptions() call it.
Cc: stable@kernel.org
Fixes:
|
|
|
Eric W. Biederman
|
6707d0fc60 |
ptrace: Remove second setting of PT_SEIZED in ptrace_attach
The code is totally redundant remove it. Link: https://lkml.kernel.org/r/20220103213312.9144-6-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Peter Zijlstra
|
2f064a59a1 |
sched: Change task_struct::state
Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org |
|
Oleg Nesterov
|
dbb5afad10 |
ptrace: make ptrace() fail if the tracee changed its pid unexpectedly
Suppose we have 2 threads, the group-leader L and a sub-theread T,
both parked in ptrace_stop(). Debugger tries to resume both threads
and does
ptrace(PTRACE_CONT, T);
ptrace(PTRACE_CONT, L);
If the sub-thread T execs in between, the 2nd PTRACE_CONT doesn not
resume the old leader L, it resumes the post-exec thread T which was
actually now stopped in PTHREAD_EVENT_EXEC. In this case the
PTHREAD_EVENT_EXEC event is lost, and the tracer can't know that the
tracee changed its pid.
This patch makes ptrace() fail in this case until debugger does wait()
and consumes PTHREAD_EVENT_EXEC which reports old_pid. This affects all
ptrace requests except the "asynchronous" PTRACE_INTERRUPT/KILL.
The patch doesn't add the new PTRACE_ option to not complicate the API,
and I _hope_ this won't cause any noticeable regression:
- If debugger uses PTRACE_O_TRACEEXEC and the thread did an exec
and the tracer does a ptrace request without having consumed
the exec event, it's 100% sure that the thread the ptracer
thinks it is targeting does not exist anymore, or isn't the
same as the one it thinks it is targeting.
- To some degree this patch adds nothing new. In the scenario
above ptrace(L) can fail with -ESRCH if it is called after the
execing sub-thread wakes the leader up and before it "steals"
the leader's pid.
Test-case:
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <errno.h>
#include <pthread.h>
#include <assert.h>
void *tf(void *arg)
{
execve("/usr/bin/true", NULL, NULL);
assert(0);
return NULL;
}
int main(void)
{
int leader = fork();
if (!leader) {
kill(getpid(), SIGSTOP);
pthread_t th;
pthread_create(&th, NULL, tf, NULL);
for (;;)
pause();
return 0;
}
waitpid(leader, NULL, WSTOPPED);
ptrace(PTRACE_SEIZE, leader, 0,
PTRACE_O_TRACECLONE | PTRACE_O_TRACEEXEC);
waitpid(leader, NULL, 0);
ptrace(PTRACE_CONT, leader, 0,0);
waitpid(leader, NULL, 0);
int status, thread = waitpid(-1, &status, 0);
assert(thread > 0 && thread != leader);
assert(status == 0x80137f);
ptrace(PTRACE_CONT, thread, 0,0);
/*
* waitid() because waitpid(leader, &status, WNOWAIT) does not
* report status. Why ????
*
* Why WEXITED? because we have another kernel problem connected
* to mt-exec.
*/
siginfo_t info;
assert(waitid(P_PID, leader, &info, WSTOPPED|WEXITED|WNOWAIT) == 0);
assert(info.si_pid == leader && info.si_status == 0x0405);
/* OK, it sleeps in ptrace(PTRACE_EVENT_EXEC == 0x04) */
assert(ptrace(PTRACE_CONT, leader, 0,0) == -1);
assert(errno == ESRCH);
assert(leader == waitpid(leader, &status, WNOHANG));
assert(status == 0x04057f);
assert(ptrace(PTRACE_CONT, leader, 0,0) == 0);
return 0;
}
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Simon Marchi <simon.marchi@efficios.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Pedro Alves <palves@redhat.com>
Acked-by: Simon Marchi <simon.marchi@efficios.com>
Acked-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Ingo Molnar
|
d0d252b8ca |
Linux 5.12-rc8
-----BEGIN PGP SIGNATURE----- iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmB8qHweHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGEXIIAILUbsTJsNsvZIkZ uQ6SY6gnsPFkRiSRjY0YsZLUnqjTuiiHeTz4gzkonddwdnAp/9g6OIHIEBaeTqBh sTUMU/61Fgtrt/IvkA1yJ3rlawqgwdMe2VdimB+EFhufcSKq+5vpd3MVP4IuGx4E J3psoTU4gVltFs5t+1QjvI3XmByN0Qm8FMRXR7iL+zov1QTmGwR3G6Rn4AymG+QT pdruKboyZPfsrFGSVx7wd3HpFyQcrclEX9rKmBNZqets9d9JGWnqnEN4vQKmwO86 4MV29ucdMXH0AMB3kzGdVp0Ji2Ykt5W0K+MUWbFLtcSxnpu1OyBKGsEAMlRbD7ik gm0bMSw= =qHI0 -----END PGP SIGNATURE----- Merge tag 'v5.12-rc8' into sched/core, to pick up fixes Signed-off-by: Ingo Molnar <mingo@kernel.org> |
|
Jens Axboe
|
e8b33b8cfa |
Revert "kernel: treat PF_IO_WORKER like PF_KTHREAD for ptrace/signals"
This reverts commit
|
|
Piotr Figiel
|
90f093fa8e |
rseq, ptrace: Add PTRACE_GET_RSEQ_CONFIGURATION request
For userspace checkpoint and restore (C/R) a way of getting process state containing RSEQ configuration is needed. There are two ways this information is going to be used: - to re-enable RSEQ for threads which had it enabled before C/R - to detect if a thread was in a critical section during C/R Since C/R preserves TLS memory and addresses RSEQ ABI will be restored using the address registered before C/R. Detection whether the thread is in a critical section during C/R is needed to enforce behavior of RSEQ abort during C/R. Attaching with ptrace() before registers are dumped itself doesn't cause RSEQ abort. Restoring the instruction pointer within the critical section is problematic because rseq_cs may get cleared before the control is passed to the migrated application code leading to RSEQ invariants not being preserved. C/R code will use RSEQ ABI address to find the abort handler to which the instruction pointer needs to be set. To achieve above goals expose the RSEQ ABI address and the signature value with the new ptrace request PTRACE_GET_RSEQ_CONFIGURATION. This new ptrace request can also be used by debuggers so they are aware of stops within restartable sequences in progress. Signed-off-by: Piotr Figiel <figiel@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michal Miroslaw <emmir@google.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20210226135156.1081606-1-figiel@google.com |
|
|
Jens Axboe
|
6fb8f43ced |
kernel: treat PF_IO_WORKER like PF_KTHREAD for ptrace/signals
Signed-off-by: Jens Axboe <axboe@kernel.dk> |
|
|
Linus Torvalds
|
ac73e3dc8a |
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:
- a few random little subsystems
- almost all of the MM patches which are staged ahead of linux-next
material. I'll trickle to post-linux-next work in as the dependents
get merged up.
Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
mm: cleanup kstrto*() usage
mm: fix fall-through warnings for Clang
mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
mm:backing-dev: use sysfs_emit in macro defining functions
mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
mm: use sysfs_emit for struct kobject * uses
mm: fix kernel-doc markups
zram: break the strict dependency from lzo
zram: add stat to gather incompressible pages since zram set up
zram: support page writeback
mm/process_vm_access: remove redundant initialization of iov_r
mm/zsmalloc.c: rework the list_add code in insert_zspage()
mm/zswap: move to use crypto_acomp API for hardware acceleration
mm/zswap: fix passing zero to 'PTR_ERR' warning
mm/zswap: make struct kernel_param_ops definitions const
userfaultfd/selftests: hint the test runner on required privilege
userfaultfd/selftests: fix retval check for userfaultfd_open()
userfaultfd/selftests: always dump something in modes
userfaultfd: selftests: make __{s,u}64 format specifiers portable
...
|
|
John Hubbard
|
d3f5ffcacd |
mm: cleanup: remove unused tsk arg from __access_remote_vm
Despite a comment that said that page fault accounting would be charged to whatever task_struct* was passed into __access_remote_vm(), the tsk argument was actually unused. Making page fault accounting actually use this task struct is quite a project, so there is no point in keeping the tsk argument. Delete both the comment, and the argument. [rppt@linux.ibm.com: changelog addition] Link: https://lkml.kernel.org/r/20201026074137.4147787-1-jhubbard@nvidia.com Signed-off-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Linus Torvalds
|
1ac0884d54 |
A set of updates for entry/exit handling:
- More generalization of entry/exit functionality
- The consolidation work to reclaim TIF flags on x86 and also for non-x86
specific TIF flags which are solely relevant for syscall related work
and have been moved into their own storage space. The x86 specific part
had to be merged in to avoid a major conflict.
- The TIF_NOTIFY_SIGNAL work which replaces the inefficient signal
delivery mode of task work and results in an impressive performance
improvement for io_uring. The non-x86 consolidation of this is going to
come seperate via Jens.
- The selective syscall redirection facility which provides a clean and
efficient way to support the non-Linux syscalls of WINE by catching them
at syscall entry and redirecting them to the user space emulation. This
can be utilized for other purposes as well and has been designed
carefully to avoid overhead for the regular fastpath. This includes the
core changes and the x86 support code.
- Simplification of the context tracking entry/exit handling for the users
of the generic entry code which guarantee the proper ordering and
protection.
- Preparatory changes to make the generic entry code accomodate S390
specific requirements which are mostly related to their syscall restart
mechanism.
-----BEGIN PGP SIGNATURE-----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=hsjV
-----END PGP SIGNATURE-----
Merge tag 'core-entry-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core entry/exit updates from Thomas Gleixner:
"A set of updates for entry/exit handling:
- More generalization of entry/exit functionality
- The consolidation work to reclaim TIF flags on x86 and also for
non-x86 specific TIF flags which are solely relevant for syscall
related work and have been moved into their own storage space. The
x86 specific part had to be merged in to avoid a major conflict.
- The TIF_NOTIFY_SIGNAL work which replaces the inefficient signal
delivery mode of task work and results in an impressive performance
improvement for io_uring. The non-x86 consolidation of this is
going to come seperate via Jens.
- The selective syscall redirection facility which provides a clean
and efficient way to support the non-Linux syscalls of WINE by
catching them at syscall entry and redirecting them to the user
space emulation. This can be utilized for other purposes as well
and has been designed carefully to avoid overhead for the regular
fastpath. This includes the core changes and the x86 support code.
- Simplification of the context tracking entry/exit handling for the
users of the generic entry code which guarantee the proper ordering
and protection.
- Preparatory changes to make the generic entry code accomodate S390
specific requirements which are mostly related to their syscall
restart mechanism"
* tag 'core-entry-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
entry: Add syscall_exit_to_user_mode_work()
entry: Add exit_to_user_mode() wrapper
entry_Add_enter_from_user_mode_wrapper
entry: Rename exit_to_user_mode()
entry: Rename enter_from_user_mode()
docs: Document Syscall User Dispatch
selftests: Add benchmark for syscall user dispatch
selftests: Add kselftest for syscall user dispatch
entry: Support Syscall User Dispatch on common syscall entry
kernel: Implement selective syscall userspace redirection
signal: Expose SYS_USER_DISPATCH si_code type
x86: vdso: Expose sigreturn address on vdso to the kernel
MAINTAINERS: Add entry for common entry code
entry: Fix boot for !CONFIG_GENERIC_ENTRY
x86: Support HAVE_CONTEXT_TRACKING_OFFSTACK
context_tracking: Only define schedule_user() on !HAVE_CONTEXT_TRACKING_OFFSTACK archs
sched: Detect call to schedule from critical entry code
context_tracking: Don't implement exception_enter/exit() on CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK
context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK
x86: Reclaim unused x86 TI flags
...
|
|
Mickaël Salaün
|
cf23705244 |
ptrace: Set PF_SUPERPRIV when checking capability
Commit |
|
Gabriel Krisman Bertazi
|
64eb35f701 |
ptrace: Migrate TIF_SYSCALL_EMU to use SYSCALL_WORK flag
On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SYSCALL_EMU, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-8-krisman@collabora.com |
|
|
Gabriel Krisman Bertazi
|
64c19ba29b |
ptrace: Migrate to use SYSCALL_TRACE flag
On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SYSCALL_TRACE, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20201116174206.2639648-7-krisman@collabora.com |
|
Christian Brauner
|
6b3ad6649a
|
ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()
Commit |
|
Elvira Khabirova
|
201766a20e |
ptrace: add PTRACE_GET_SYSCALL_INFO request
PTRACE_GET_SYSCALL_INFO is a generic ptrace API that lets ptracer obtain
details of the syscall the tracee is blocked in.
There are two reasons for a special syscall-related ptrace request.
Firstly, with the current ptrace API there are cases when ptracer cannot
retrieve necessary information about syscalls. Some examples include:
* The notorious int-0x80-from-64-bit-task issue. See [1] for details.
In short, if a 64-bit task performs a syscall through int 0x80, its
tracer has no reliable means to find out that the syscall was, in
fact, a compat syscall, and misidentifies it.
* Syscall-enter-stop and syscall-exit-stop look the same for the
tracer. Common practice is to keep track of the sequence of
ptrace-stops in order not to mix the two syscall-stops up. But it is
not as simple as it looks; for example, strace had a (just recently
fixed) long-standing bug where attaching strace to a tracee that is
performing the execve system call led to the tracer identifying the
following syscall-exit-stop as syscall-enter-stop, which messed up
all the state tracking.
* Since the introduction of commit
|
|
|
Linus Torvalds
|
dfd437a257 |
arm64 updates for 5.3:
- arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}
- Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
manage the permissions of executable vmalloc regions more strictly
- Slight performance improvement by keeping softirqs enabled while
touching the FPSIMD/SVE state (kernel_neon_begin/end)
- Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new XAFLAG
and AXFLAG instructions for floating point comparison flags
manipulation) and FRINT (rounding floating point numbers to integers)
- Re-instate ARM64_PSEUDO_NMI support which was previously marked as
BROKEN due to some bugs (now fixed)
- Improve parking of stopped CPUs and implement an arm64-specific
panic_smp_self_stop() to avoid warning on not being able to stop
secondary CPUs during panic
- perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
platforms
- perf: DDR performance monitor support for iMX8QXP
- cache_line_size() can now be set from DT or ACPI/PPTT if provided to
cope with a system cache info not exposed via the CPUID registers
- Avoid warning on hardware cache line size greater than
ARCH_DMA_MINALIGN if the system is fully coherent
- arm64 do_page_fault() and hugetlb cleanups
- Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)
- Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the 'arm_boot_flags'
introduced in 5.1)
- CONFIG_RANDOMIZE_BASE now enabled in defconfig
- Allow the selection of ARM64_MODULE_PLTS, currently only done via
RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
over into the vmalloc area
- Make ZONE_DMA32 configurable
-----BEGIN PGP SIGNATURE-----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=0TDT
-----END PGP SIGNATURE-----
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}
- Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
manage the permissions of executable vmalloc regions more strictly
- Slight performance improvement by keeping softirqs enabled while
touching the FPSIMD/SVE state (kernel_neon_begin/end)
- Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new
XAFLAG and AXFLAG instructions for floating point comparison flags
manipulation) and FRINT (rounding floating point numbers to integers)
- Re-instate ARM64_PSEUDO_NMI support which was previously marked as
BROKEN due to some bugs (now fixed)
- Improve parking of stopped CPUs and implement an arm64-specific
panic_smp_self_stop() to avoid warning on not being able to stop
secondary CPUs during panic
- perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
platforms
- perf: DDR performance monitor support for iMX8QXP
- cache_line_size() can now be set from DT or ACPI/PPTT if provided to
cope with a system cache info not exposed via the CPUID registers
- Avoid warning on hardware cache line size greater than
ARCH_DMA_MINALIGN if the system is fully coherent
- arm64 do_page_fault() and hugetlb cleanups
- Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)
- Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the
'arm_boot_flags' introduced in 5.1)
- CONFIG_RANDOMIZE_BASE now enabled in defconfig
- Allow the selection of ARM64_MODULE_PLTS, currently only done via
RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
over into the vmalloc area
- Make ZONE_DMA32 configurable
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (54 commits)
perf: arm_spe: Enable ACPI/Platform automatic module loading
arm_pmu: acpi: spe: Add initial MADT/SPE probing
ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
ACPI/PPTT: Modify node flag detection to find last IDENTICAL
x86/entry: Simplify _TIF_SYSCALL_EMU handling
arm64: rename dump_instr as dump_kernel_instr
arm64/mm: Drop [PTE|PMD]_TYPE_FAULT
arm64: Implement panic_smp_self_stop()
arm64: Improve parking of stopped CPUs
arm64: Expose FRINT capabilities to userspace
arm64: Expose ARMv8.5 CondM capability to userspace
arm64: defconfig: enable CONFIG_RANDOMIZE_BASE
arm64: ARM64_MODULES_PLTS must depend on MODULES
arm64: bpf: do not allocate executable memory
arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages
arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP
arm64: module: create module allocations without exec permissions
arm64: Allow user selection of ARM64_MODULE_PLTS
acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
arm64: Allow selecting Pseudo-NMI again
...
|
|
|
Jann Horn
|
6994eefb00 |
ptrace: Fix ->ptracer_cred handling for PTRACE_TRACEME
Fix two issues:
When called for PTRACE_TRACEME, ptrace_link() would obtain an RCU
reference to the parent's objective credentials, then give that pointer
to get_cred(). However, the object lifetime rules for things like
struct cred do not permit unconditionally turning an RCU reference into
a stable reference.
PTRACE_TRACEME records the parent's credentials as if the parent was
acting as the subject, but that's not the case. If a malicious
unprivileged child uses PTRACE_TRACEME and the parent is privileged, and
at a later point, the parent process becomes attacker-controlled
(because it drops privileges and calls execve()), the attacker ends up
with control over two processes with a privileged ptrace relationship,
which can be abused to ptrace a suid binary and obtain root privileges.
Fix both of these by always recording the credentials of the process
that is requesting the creation of the ptrace relationship:
current_cred() can't change under us, and current is the proper subject
for access control.
This change is theoretically userspace-visible, but I am not aware of
any code that it will actually break.
Fixes:
|
|
|
Linus Torvalds
|
aa7235483a |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ptrace fixes from Eric Biederman:
"This is just two very minor fixes:
- prevent ptrace from reading unitialized kernel memory found twice
by syzkaller
- restore a missing smp_rmb in ptrace_may_access and add comment tp
it so it is not removed by accident again.
Apologies for being a little slow about getting this to you, I am
still figuring out how to develop with a little baby in the house"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ptrace: restore smp_rmb() in __ptrace_may_access()
signal/ptrace: Don't leak unitialized kernel memory with PTRACE_PEEK_SIGINFO
|
|
|
Jann Horn
|
f6581f5b55 |
ptrace: restore smp_rmb() in __ptrace_may_access()
Restore the read memory barrier in __ptrace_may_access() that was deleted
a couple years ago. Also add comments on this barrier and the one it pairs
with to explain why they're there (as far as I understand).
Fixes:
|
|
Sudeep Holla
|
15532fd6f5 |
ptrace: move clearing of TIF_SYSCALL_EMU flag to core
While the TIF_SYSCALL_EMU is set in ptrace_resume independent of any architecture, currently only powerpc and x86 unset the TIF_SYSCALL_EMU flag in ptrace_disable which gets called from ptrace_detach. Let's move the clearing of TIF_SYSCALL_EMU flag to __ptrace_unlink which gets executed from ptrace_detach and also keep it along with or close to clearing of TIF_SYSCALL_TRACE. Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
|
|
Eric W. Biederman
|
f6e2aa91a4 |
signal/ptrace: Don't leak unitialized kernel memory with PTRACE_PEEK_SIGINFO
Recently syzbot in conjunction with KMSAN reported that
ptrace_peek_siginfo can copy an uninitialized siginfo to userspace.
Inspecting ptrace_peek_siginfo confirms this.
The problem is that off when initialized from args.off can be
initialized to a negaive value. At which point the "if (off >= 0)"
test to see if off became negative fails because off started off
negative.
Prevent the core problem by adding a variable found that is only true
if a siginfo is found and copied to a temporary in preparation for
being copied to userspace.
Prevent args.off from being truncated when being assigned to off by
testing that off is <= the maximum possible value of off. Convert off
to an unsigned long so that we should not have to truncate args.off,
we have well defined overflow behavior so if we add another check we
won't risk fighting undefined compiler behavior, and so that we have a
type whose maximum value is easy to test for.
Cc: Andrei Vagin <avagin@gmail.com>
Cc: stable@vger.kernel.org
Reported-by: syzbot+0d602a1b0d8c95bdf299@syzkaller.appspotmail.com
Fixes:
|
|
Thomas Gleixner
|
457c899653 |
treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|
Andrei Vagin
|
fcfc2aa018 |
ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK
There are a few system calls (pselect, ppoll, etc) which replace a task
sigmask while they are running in a kernel-space
When a task calls one of these syscalls, the kernel saves a current
sigmask in task->saved_sigmask and sets a syscall sigmask.
On syscall-exit-stop, ptrace traps a task before restoring the
saved_sigmask, so PTRACE_GETSIGMASK returns the syscall sigmask and
PTRACE_SETSIGMASK does nothing, because its sigmask is replaced by
saved_sigmask, when the task returns to user-space.
This patch fixes this problem. PTRACE_GETSIGMASK returns saved_sigmask
if it's set. PTRACE_SETSIGMASK drops the TIF_RESTORE_SIGMASK flag.
Link: http://lkml.kernel.org/r/20181120060616.6043-1-avagin@gmail.com
Fixes:
|
|
|
Linus Torvalds
|
96d4f267e4 |
Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
|
Thomas Gleixner
|
46f7ecb1e7 |
ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS
The IBPB control code in x86 removed the usage. Remove the functionality which was introduced for this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Casey Schaufler <casey.schaufler@intel.com> Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Jon Masters <jcm@redhat.com> Cc: Waiman Long <longman9394@gmail.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Dave Stewart <david.c.stewart@intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185005.559149393@linutronix.de |
|
|
Linus Torvalds
|
ba9f6f8954 |
Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull siginfo updates from Eric Biederman: "I have been slowly sorting out siginfo and this is the culmination of that work. The primary result is in several ways the signal infrastructure has been made less error prone. The code has been updated so that manually specifying SEND_SIG_FORCED is never necessary. The conversion to the new siginfo sending functions is now complete, which makes it difficult to send a signal without filling in the proper siginfo fields. At the tail end of the patchset comes the optimization of decreasing the size of struct siginfo in the kernel from 128 bytes to about 48 bytes on 64bit. The fundamental observation that enables this is by definition none of the known ways to use struct siginfo uses the extra bytes. This comes at the cost of a small user space observable difference. For the rare case of siginfo being injected into the kernel only what can be copied into kernel_siginfo is delivered to the destination, the rest of the bytes are set to 0. For cases where the signal and the si_code are known this is safe, because we know those bytes are not used. For cases where the signal and si_code combination is unknown the bits that won't fit into struct kernel_siginfo are tested to verify they are zero, and the send fails if they are not. I made an extensive search through userspace code and I could not find anything that would break because of the above change. If it turns out I did break something it will take just the revert of a single change to restore kernel_siginfo to the same size as userspace siginfo. Testing did reveal dependencies on preferring the signo passed to sigqueueinfo over si->signo, so bit the bullet and added the complexity necessary to handle that case. Testing also revealed bad things can happen if a negative signal number is passed into the system calls. Something no sane application will do but something a malicious program or a fuzzer might do. So I have fixed the code that performs the bounds checks to ensure negative signal numbers are handled" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits) signal: Guard against negative signal numbers in copy_siginfo_from_user32 signal: Guard against negative signal numbers in copy_siginfo_from_user signal: In sigqueueinfo prefer sig not si_signo signal: Use a smaller struct siginfo in the kernel signal: Distinguish between kernel_siginfo and siginfo signal: Introduce copy_siginfo_from_user and use it's return value signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Fail sigqueueinfo if si_signo != sig signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal/unicore32: Use force_sig_fault where appropriate signal/unicore32: Generate siginfo in ucs32_notify_die signal/unicore32: Use send_sig_fault where appropriate signal/arc: Use force_sig_fault where appropriate signal/arc: Push siginfo generation into unhandled_exception signal/ia64: Use force_sig_fault where appropriate signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn signal/ia64: Use the generic force_sigsegv in setup_frame signal/arm/kvm: Use send_sig_mceerr signal/arm: Use send_sig_fault where appropriate signal/arm: Use force_sig_fault where appropriate ... |
|
|
Eric W. Biederman
|
ae7795bc61 |
signal: Distinguish between kernel_siginfo and siginfo
Linus recently observed that if we did not worry about the padding member in struct siginfo it is only about 48 bytes, and 48 bytes is much nicer than 128 bytes for allocating on the stack and copying around in the kernel. The obvious thing of only adding the padding when userspace is including siginfo.h won't work as there are sigframe definitions in the kernel that embed struct siginfo. So split siginfo in two; kernel_siginfo and siginfo. Keeping the traditional name for the userspace definition. While the version that is used internally to the kernel and ultimately will not be padded to 128 bytes is called kernel_siginfo. The definition of struct kernel_siginfo I have put in include/signal_types.h A set of buildtime checks has been added to verify the two structures have the same field offsets. To make it easy to verify the change kernel_siginfo retains the same size as siginfo. The reduction in size comes in a following change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
4cd2e0e70a |
signal: Introduce copy_siginfo_from_user and use it's return value
In preparation for using a smaller version of siginfo in the kernel introduce copy_siginfo_from_user and use it when siginfo is copied from userspace. Make the pattern for using copy_siginfo_from_user and copy_siginfo_from_user32 to capture the return value and return that value on error. This is a necessary prerequisite for using a smaller siginfo in the kernel than the kernel exports to userspace. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
Jiri Kosina
|
dbfe2953f6 |
x86/speculation: Apply IBPB more strictly to avoid cross-process data leak
Currently, IBPB is only issued in cases when switching into a non-dumpable
process, the rationale being to protect such 'important and security
sensitive' processess (such as GPG) from data leaking into a different
userspace process via spectre v2.
This is however completely insufficient to provide proper userspace-to-userpace
spectrev2 protection, as any process can poison branch buffers before being
scheduled out, and the newly scheduled process immediately becomes spectrev2
victim.
In order to minimize the performance impact (for usecases that do require
spectrev2 protection), issue the barrier only in cases when switching between
processess where the victim can't be ptraced by the potential attacker (as in
such cases, the attacker doesn't have to bother with branch buffers at all).
[ tglx: Split up PTRACE_MODE_NOACCESS_CHK into PTRACE_MODE_SCHED and
PTRACE_MODE_IBPB to be able to do ptrace() context tracking reasonably
fine-grained ]
Fixes:
|
|
|
Eric W. Biederman
|
079b22dc9b |
signal: Use SEND_SIG_PRIV not SEND_SIG_FORCED with SIGKILL and SIGSTOP
Now that siginfo is never allocated for SIGKILL and SIGSTOP there is no difference between SEND_SIG_PRIV and SEND_SIG_FORCED for SIGKILL and SIGSTOP. This makes SEND_SIG_FORCED unnecessary and redundant in the presence of SIGKILL and SIGSTOP. Therefore change users of SEND_SIG_FORCED that are sending SIGKILL or SIGSTOP to use SEND_SIG_PRIV instead. This removes the last users of SEND_SIG_FORCED. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
Mike Rapoport
|
2ee0826085 |
pids: introduce find_get_task_by_vpid() helper
There are several functions that do find_task_by_vpid() followed by get_task_struct(). We can use a helper function instead. Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Linus Torvalds
|
3dbc4f5485 |
Merge branch 'next-seccomp' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull seccomp updates from James Morris: "Add support for retrieving seccomp metadata" * 'next-seccomp' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: ptrace, seccomp: add support for retrieving seccomp metadata seccomp: hoist out filter resolving logic |
|
|
Eric W. Biederman
|
0752d7bf62 |
ptrace: Use copy_siginfo in setsiginfo and getsiginfo
Now that copy_siginfo copies all of the fields this is safe, safer (as all of the bits are guaranteed to be copied), clearer, and less error prone than using a structure copy. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
eb5346c379 |
signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32
The new unified copy_siginfo_from_user32 takes care of this. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
Tycho Andersen
|
26500475ac |
ptrace, seccomp: add support for retrieving seccomp metadata
With the new SECCOMP_FILTER_FLAG_LOG, we need to be able to extract these flags for checkpoint restore, since they describe the state of a filter. So, let's add PTRACE_SECCOMP_GET_METADATA, similar to ..._GET_FILTER, which returns the metadata of the nth filter (right now, just the flags). Hopefully this will be future proof, and new per-filter metadata can be added to this struct. Signed-off-by: Tycho Andersen <tycho@docker.com> CC: Kees Cook <keescook@chromium.org> CC: Andy Lutomirski <luto@amacapital.net> CC: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> |
|
|
Eric W. Biederman
|
cc731525f2 |
signal: Remove kernel interal si_code magic
struct siginfo is a union and the kernel since 2.4 has been hiding a union tag in the high 16bits of si_code using the values: __SI_KILL __SI_TIMER __SI_POLL __SI_FAULT __SI_CHLD __SI_RT __SI_MESGQ __SI_SYS While this looks plausible on the surface, in practice this situation has not worked well. - Injected positive signals are not copied to user space properly unless they have these magic high bits set. - Injected positive signals are not reported properly by signalfd unless they have these magic high bits set. - These kernel internal values leaked to userspace via ptrace_peek_siginfo - It was possible to inject these kernel internal values and cause the the kernel to misbehave. - Kernel developers got confused and expected these kernel internal values in userspace in kernel self tests. - Kernel developers got confused and set si_code to __SI_FAULT which is SI_USER in userspace which causes userspace to think an ordinary user sent the signal and that it was not kernel generated. - The values make it impossible to reorganize the code to transform siginfo_copy_to_user into a plain copy_to_user. As si_code must be massaged before being passed to userspace. So remove these kernel internal si codes and make the kernel code simpler and more maintainable. To replace these kernel internal magic si_codes introduce the helper function siginfo_layout, that takes a signal number and an si_code and computes which union member of siginfo is being used. Have siginfo_layout return an enumeration so that gcc will have enough information to warn if a switch statement does not handle all of union members. A couple of architectures have a messed up ABI that defines signal specific duplications of SI_USER which causes more special cases in siginfo_layout than I would like. The good news is only problem architectures pay the cost. Update all of the code that used the previous magic __SI_ values to use the new SIL_ values and to call siginfo_layout to get those values. Escept where not all of the cases are handled remove the defaults in the switch statements so that if a new case is missed in the future the lack will show up at compile time. Modify the code that copies siginfo si_code to userspace to just copy the value and not cast si_code to a short first. The high bits are no longer used to hold a magic union member. Fixup the siginfo header files to stop including the __SI_ values in their constants and for the headers that were missing it to properly update the number of si_codes for each signal type. The fixes to copy_siginfo_from_user32 implementations has the interesting property that several of them perviously should never have worked as the __SI_ values they depended up where kernel internal. With that dependency gone those implementations should work much better. The idea of not passing the __SI_ values out to userspace and then not reinserting them has been tested with criu and criu worked without changes. Ref: 2.4.0-test1 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
|
|
Eric W. Biederman
|
c70d9d809f |
ptrace: Properly initialize ptracer_cred on fork
When I introduced ptracer_cred I failed to consider the weirdness of
fork where the task_struct copies the old value by default. This
winds up leaving ptracer_cred set even when a process forks and
the child process does not wind up being ptraced.
Because ptracer_cred is not set on non-ptraced processes whose
parents were ptraced this has broken the ability of the enlightenment
window manager to start setuid children.
Fix this by properly initializing ptracer_cred in ptrace_init_task
This must be done with a little bit of care to preserve the current value
of ptracer_cred when ptrace carries through fork. Re-reading the
ptracer_cred from the ptracing process at this point is inconsistent
with how PT_PTRACE_CAP has been maintained all of these years.
Tested-by: Takashi Iwai <tiwai@suse.de>
Fixes:
|
|
bsegall@google.com
|
5402e97af6 |
ptrace: fix PTRACE_LISTEN race corrupting task->state
In PT_SEIZED + LISTEN mode STOP/CONT signals cause a wakeup against
__TASK_TRACED. If this races with the ptrace_unfreeze_traced at the end
of a PTRACE_LISTEN, this can wake the task /after/ the check against
__TASK_TRACED, but before the reset of state to TASK_TRACED. This
causes it to instead clobber TASK_WAKING, allowing a subsequent wakeup
against TRACED while the task is still on the rq wake_list, corrupting
it.
Oleg said:
"The kernel can crash or this can lead to other hard-to-debug problems.
In short, "task->state = TASK_TRACED" in ptrace_unfreeze_traced()
assumes that nobody else can wake it up, but PTRACE_LISTEN breaks the
contract. Obviusly it is very wrong to manipulate task->state if this
task is already running, or WAKING, or it sleeps again"
[akpm@linux-foundation.org: coding-style fixes]
Fixes:
|
|
|
Ingo Molnar
|
299300258d |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
|
|
Ingo Molnar
|
f7ccbae45c |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/coredump.h>
We are going to split <linux/sched/coredump.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/coredump.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
|
|
Ingo Molnar
|
6e84f31522 |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h>
We are going to split <linux/sched/mm.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/mm.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. The APIs that are going to be moved first are: mm_alloc() __mmdrop() mmdrop() mmdrop_async_fn() mmdrop_async() mmget_not_zero() mmput() mmput_async() get_task_mm() mm_access() mm_release() Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |