user/sven/linux.git/fs/exec.c, branch v5.10.32

exec: Transform exec_update_mutex into a rw_semaphore

2021-01-09T12:46:24Z

[ Upstream commit f7cfd871ae0c5008d94b6f66834e7845caa93c15 ] Recently syzbot reported[0] that there is a deadlock amongst the users of exec_update_mutex. The problematic lock ordering found by lockdep was: perf_event_open (exec_update_mutex -> ovl_i_mutex) chown (ovl_i_mutex -> sb_writes) sendfile (sb_writes -> p->lock) by reading from a proc file and writing to overlayfs proc_pid_syscall (p->lock -> exec_update_mutex) While looking at possible solutions it occured to me that all of the users and possible users involved only wanted to state of the given process to remain the same. They are all readers. The only writer is exec. There is no reason for readers to block on each other. So fix this deadlock by transforming exec_update_mutex into a rw_semaphore named exec_update_lock that only exec takes for writing. Cc: Jann Horn Cc: Vasiliy Kulikov Cc: Al Viro Cc: Bernd Edlinger Cc: Oleg Nesterov Cc: Christopher Yeoh Cc: Cyrill Gorcunov Cc: Sargun Dhillon Cc: Christian Brauner Cc: Arnd Bergmann Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Fixes: eea9673250db ("exec: Add exec_update_mutex to replace cred_guard_mutex") [0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org Signed-off-by: Eric W. Biederman Signed-off-by: Sasha Levin

Merge tag 'powerpc-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2020-10-16T19:21:15Z

Pull powerpc updates from Michael Ellerman: - A series from Nick adding ARCH_WANT_IRQS_OFF_ACTIVATE_MM & selecting it for powerpc, as well as a related fix for sparc. - Remove support for PowerPC 601. - Some fixes for watchpoints & addition of a new ptrace flag for detecting ISA v3.1 (Power10) watchpoint features. - A fix for kernels using 4K pages and the hash MMU on bare metal Power9 systems with > 16TB of RAM, or RAM on the 2nd node. - A basic idle driver for shallow stop states on Power10. - Tweaks to our sched domains code to better inform the scheduler about the hardware topology on Power9/10, where two SMT4 cores can be presented by firmware as an SMT8 core. - A series doing further reworks & cleanups of our EEH code. - Addition of a filter for RTAS (firmware) calls done via sys_rtas(), to prevent root from overwriting kernel memory. - Other smaller features, fixes & cleanups. Thanks to: Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Athira Rajeev, Biwen Li, Cameron Berkenpas, Cédric Le Goater, Christophe Leroy, Christoph Hellwig, Colin Ian King, Daniel Axtens, David Dai, Finn Thain, Frederic Barrat, Gautham R. Shenoy, Greg Kurz, Gustavo Romero, Ira Weiny, Jason Yan, Joel Stanley, Jordan Niethe, Kajol Jain, Konrad Rzeszutek Wilk, Laurent Dufour, Leonardo Bras, Liu Shixin, Luca Ceresoli, Madhavan Srinivasan, Mahesh Salgaonkar, Nathan Lynch, Nicholas Mc Guire, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Pedro Miraglia Franco de Carvalho, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Ravi Bangoria, Russell Currey, Satheesh Rajendran, Scott Cheloha, Segher Boessenkool, Srikar Dronamraju, Stan Johnson, Stephen Kitt, Stephen Rothwell, Thiago Jung Bauermann, Tyrel Datwyler, Vaibhav Jain, Vaidyanathan Srinivasan, Vasant Hegde, Wang Wensheng, Wolfram Sang, Yang Yingliang, zhengbin. * tag 'powerpc-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (228 commits) Revert "powerpc/pci: unmap legacy INTx interrupts when a PHB is removed" selftests/powerpc: Fix eeh-basic.sh exit codes cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_reboot_notifier powerpc/time: Make get_tb() common to PPC32 and PPC64 powerpc/time: Make get_tbl() common to PPC32 and PPC64 powerpc/time: Remove get_tbu() powerpc/time: Avoid using get_tbl() and get_tbu() internally powerpc/time: Make mftb() common to PPC32 and PPC64 powerpc/time: Rename mftbl() to mftb() powerpc/32s: Remove #ifdef CONFIG_PPC_BOOK3S_32 in head_book3s_32.S powerpc/32s: Rename head_32.S to head_book3s_32.S powerpc/32s: Setup the early hash table at all time. powerpc/time: Remove ifdef in get_dec() and set_dec() powerpc: Remove get_tb_or_rtc() powerpc: Remove __USE_RTC() powerpc: Tidy up a bit after removal of PowerPC 601. powerpc: Remove support for PowerPC 601 powerpc: Remove PowerPC 601 powerpc: Drop SYNC_601() ISYNC_601() and SYNC() powerpc: Remove CONFIG_PPC601_SYNC_FIX ...

Merge tag 'char-misc-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2020-10-15T17:01:51Z

Pull char/misc driver updates from Greg KH: "Here is the big set of char, misc, and other assorted driver subsystem patches for 5.10-rc1. There's a lot of different things in here, all over the drivers/ directory. Some summaries: - soundwire driver updates - habanalabs driver updates - extcon driver updates - nitro_enclaves new driver - fsl-mc driver and core updates - mhi core and bus updates - nvmem driver updates - eeprom driver updates - binder driver updates and fixes - vbox minor bugfixes - fsi driver updates - w1 driver updates - coresight driver updates - interconnect driver updates - misc driver updates - other minor driver updates All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (396 commits) binder: fix UAF when releasing todo list docs: w1: w1_therm: Fix broken xref, mistakes, clarify text misc: Kconfig: fix a HISI_HIKEY_USB dependency LSM: Fix type of id parameter in kernel_post_load_data prototype misc: Kconfig: add a new dependency for HISI_HIKEY_USB firmware_loader: fix a kernel-doc markup w1: w1_therm: make w1_poll_completion static binder: simplify the return expression of binder_mmap test_firmware: Test partial read support firmware: Add request_partial_firmware_into_buf() firmware: Store opt_flags in fw_priv fs/kernel_file_read: Add "offset" arg for partial reads IMA: Add support for file reads without contents LSM: Add "contents" flag to kernel_read_file hook module: Call security_kernel_post_load_data() firmware_loader: Use security_post_load_data() LSM: Introduce kernel_post_load_data() hook fs/kernel_read_file: Add file_size output argument fs/kernel_read_file: Switch buffer size arg to size_t fs/kernel_read_file: Remove redundant size argument ...

fs/kernel_read_file: Split into separate source file

2020-10-05T11:34:18Z

These routines are used in places outside of exec(2), so in preparation for refactoring them, move them into a separate source file, fs/kernel_read_file.c. Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Acked-by: Scott Branden Link: https://lore.kernel.org/r/20201002173828.2099543-5-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

fs/kernel_read_file: Split into separate include file

2020-10-05T11:34:18Z

Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h include file. That header gets pulled in just about everywhere and doesn't really need functions not related to the general fs interface. Suggested-by: Christoph Hellwig Signed-off-by: Scott Branden Signed-off-by: Kees Cook Reviewed-by: Christoph Hellwig Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Acked-by: Greg Kroah-Hartman Acked-by: James Morris Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com Link: https://lore.kernel.org/r/20201002173828.2099543-4-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum

2020-10-05T11:34:18Z

FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs that are interested in filtering between types of things. The "how" should be an internal detail made uninteresting to the LSMs. Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Acked-by: Scott Branden Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

io_uring: don't rely on weak ->files references

2020-10-01T02:32:32Z

Grab actual references to the files_struct. To avoid circular references issues due to this, we add a per-task note that keeps track of what io_uring contexts a task has used. When the tasks execs or exits its assigned files, we cancel requests based on this tracking. With that, we can grab proper references to the files table, and no longer need to rely on stashing away ring_fd and ring_file to check if the ring_fd may have been closed. Cc: stable@vger.kernel.org # v5.5+ Reviewed-by: Pavel Begunkov Signed-off-by: Jens Axboe

mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

2020-09-16T02:24:31Z

Reading and modifying current->mm and current->active_mm and switching mm should be done with irqs off, to prevent races seeing an intermediate state. This is similar to commit 38cf307c1f20 ("mm: fix kthread_use_mm() vs TLB invalidate"). At exec-time when the new mm is activated, the old one should usually be single-threaded and no longer used, unless something else is holding an mm_users reference (which may be possible). Absent other mm_users, there is also a race with preemption and lazy tlb switching. Consider the kernel_execve case where the current thread is using a lazy tlb active mm: call_usermodehelper() kernel_execve() old_mm = current->mm; active_mm = current->active_mm; *** preempt *** --------------------> schedule() prev->active_mm = NULL; mmdrop(prev active_mm); ... <-------------------- schedule() current->mm = mm; current->active_mm = mm; if (!old_mm) mmdrop(active_mm); If we switch back to the kernel thread from a different mm, there is a double free of the old active_mm, and a missing free of the new one. Closing this race only requires interrupts to be disabled while ->mm and ->active_mm are being switched, but the TLB problem requires also holding interrupts off over activate_mm. Unfortunately not all archs can do that yet, e.g., arm defers the switch if irqs are disabled and expects finish_arch_post_lock_switch() to be called to complete the flush; um takes a blocking lock in activate_mm(). So as a first step, disable interrupts across the mm/active_mm updates to close the lazy tlb preempt race, and provide an arch option to extend that to activate_mm which allows architectures doing IPI based TLB shootdowns to close the second race. This is a bit ugly, but in the interest of fixing the bug and backporting before all architectures are converted this is a compromise. Signed-off-by: Nicholas Piggin Acked-by: Peter Zijlstra (Intel) Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200914045219.3736466-2-npiggin@gmail.com

mm/gup: remove task_struct pointer for all gup code

2020-08-12T17:58:04Z

After the cleanup of page fault accounting, gup does not need to pass task_struct around any more. Remove that parameter in the whole gup stack. Signed-off-by: Peter Xu Signed-off-by: Andrew Morton Reviewed-by: John Hubbard Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com Signed-off-by: Linus Torvalds

exec: move path_noexec() check earlier

2020-08-12T17:58:01Z

The path_noexec() check, like the regular file check, was happening too late, letting LSMs see impossible execve()s. Check it earlier as well in may_open() and collect the redundant fs/exec.c path_noexec() test under the same robustness comment as the S_ISREG() check. My notes on the call path, and related arguments, checks, etc: do_open_execat() struct open_flags open_exec_flags = { .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, .acc_mode = MAY_EXEC, ... do_filp_open(dfd, filename, open_flags) path_openat(nameidata, open_flags, flags) file = alloc_empty_file(open_flags, current_cred()); do_open(nameidata, file, open_flags) may_open(path, acc_mode, open_flag) /* new location of MAY_EXEC vs path_noexec() test */ inode_permission(inode, MAY_OPEN | acc_mode) security_inode_permission(inode, acc_mode) vfs_open(path, file) do_dentry_open(file, path->dentry->d_inode, open) security_file_open(f) open() /* old location of path_noexec() test */ Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Cc: Alexander Viro Cc: Aleksa Sarai Cc: Christian Brauner Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Tetsuo Handa Link: http://lkml.kernel.org/r/20200605160013.3954297-4-keescook@chromium.org Signed-off-by: Linus Torvalds