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2020-08-05Merge branch 'exec-linus' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull execve updates from Eric Biederman: "During the development of v5.7 I ran into bugs and quality of implementation issues related to exec that could not be easily fixed because of the way exec is implemented. So I have been diggin into exec and cleaning up what I can. This cycle I have been looking at different ideas and different implementations to see what is possible to improve exec, and cleaning the way exec interfaces with in kernel users. Only cleaning up the interfaces of exec with rest of the kernel has managed to stabalize and make it through review in time for v5.9-rc1 resulting in 2 sets of changes this cycle. - Implement kernel_execve - Make the user mode driver code a better citizen With kernel_execve the code size got a little larger as the copying of parameters from userspace and copying of parameters from userspace is now separate. The good news is kernel threads no longer need to play games with set_fs to use exec. Which when combined with the rest of Christophs set_fs changes should security bugs with set_fs much more difficult" * 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits) exec: Implement kernel_execve exec: Factor bprm_stack_limits out of prepare_arg_pages exec: Factor bprm_execve out of do_execve_common exec: Move bprm_mm_init into alloc_bprm exec: Move initialization of bprm->filename into alloc_bprm exec: Factor out alloc_bprm exec: Remove unnecessary spaces from binfmts.h umd: Stop using split_argv umd: Remove exit_umh bpfilter: Take advantage of the facilities of struct pid exit: Factor thread_group_exited out of pidfd_poll umd: Track user space drivers with struct pid bpfilter: Move bpfilter_umh back into init data exec: Remove do_execve_file umh: Stop calling do_execve_file umd: Transform fork_usermode_blob into fork_usermode_driver umd: Rename umd_info.cmdline umd_info.driver_name umd: For clarity rename umh_info umd_info umh: Separate the user mode driver and the user mode helper support umh: Remove call_usermodehelper_setup_file. ...
2020-08-05Merge tag 'seccomp-v5.9-rc1' of ↵Linus Torvalds1-0/+3
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull seccomp updates from Kees Cook: "There are a bunch of clean ups and selftest improvements along with two major updates to the SECCOMP_RET_USER_NOTIF filter return: EPOLLHUP support to more easily detect the death of a monitored process, and being able to inject fds when intercepting syscalls that expect an fd-opening side-effect (needed by both container folks and Chrome). The latter continued the refactoring of __scm_install_fd() started by Christoph, and in the process found and fixed a handful of bugs in various callers. - Improved selftest coverage, timeouts, and reporting - Add EPOLLHUP support for SECCOMP_RET_USER_NOTIF (Christian Brauner) - Refactor __scm_install_fd() into __receive_fd() and fix buggy callers - Introduce 'addfd' command for SECCOMP_RET_USER_NOTIF (Sargun Dhillon)" * tag 'seccomp-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (30 commits) selftests/seccomp: Test SECCOMP_IOCTL_NOTIF_ADDFD seccomp: Introduce addfd ioctl to seccomp user notifier fs: Expand __receive_fd() to accept existing fd pidfd: Replace open-coded receive_fd() fs: Add receive_fd() wrapper for __receive_fd() fs: Move __scm_install_fd() to __receive_fd() net/scm: Regularize compat handling of scm_detach_fds() pidfd: Add missing sock updates for pidfd_getfd() net/compat: Add missing sock updates for SCM_RIGHTS selftests/seccomp: Check ENOSYS under tracing selftests/seccomp: Refactor to use fixture variants selftests/harness: Clean up kern-doc for fixtures seccomp: Use -1 marker for end of mode 1 syscall list seccomp: Fix ioctl number for SECCOMP_IOCTL_NOTIF_ID_VALID selftests/seccomp: Rename user_trap_syscall() to user_notif_syscall() selftests/seccomp: Make kcmp() less required seccomp: Use pr_fmt selftests/seccomp: Improve calibration loop selftests/seccomp: use 90s as timeout selftests/seccomp: Expand benchmark to per-filter measurements ...
2020-08-04bootconfig: Fix to find the initargs correctlyMasami Hiramatsu1-6/+8
Since the parse_args() stops parsing at '--', bootconfig_params() will never get the '--' as param and initargs_found never be true. In the result, if we pass some init arguments via the bootconfig, those are always appended to the kernel command line with '--' even if the kernel command line already has '--'. To fix this correctly, check the return value of parse_args() and set initargs_found true if the return value is not an error but a valid address. Link: https://lkml.kernel.org/r/159650953285.270383.14822353843556363851.stgit@devnote2 Fixes: f61872bb58a1 ("bootconfig: Use parse_args() to find bootconfig and '--'") Cc: stable@vger.kernel.org Reported-by: Arvind Sankar <nivedita@alum.mit.edu> Suggested-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-08-04Merge tag 'var-init-v5.9-rc1' of ↵Linus Torvalds1-5/+7
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull automatic variable initialization updates from Kees Cook: "This adds the "zero" init option from Clang, which is being used widely in production builds of Android and Chrome OS (though it also keeps the "pattern" init, which is better for debug builds). - Introduce CONFIG_INIT_STACK_ALL_ZERO (Alexander Potapenko)" * tag 'var-init-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: security: allow using Clang's zero initialization for stack variables
2020-08-04init: Align init_task to avoid conflict with MUTEX_FLAGSStafford Horne1-0/+1
When booting on 32-bit machines (seen on OpenRISC) I saw this warning with CONFIG_DEBUG_MUTEXES turned on. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:1242 __mutex_unlock_slowpath+0x328/0x3ec DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current) Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.8.0-rc1-simple-smp-00005-g2864e2171db4-dirty #179 Call trace: [<(ptrval)>] dump_stack+0x34/0x48 [<(ptrval)>] __warn+0x104/0x158 [<(ptrval)>] ? __mutex_unlock_slowpath+0x328/0x3ec [<(ptrval)>] warn_slowpath_fmt+0x7c/0x94 [<(ptrval)>] __mutex_unlock_slowpath+0x328/0x3ec [<(ptrval)>] mutex_unlock+0x18/0x28 [<(ptrval)>] __cpuhp_setup_state_cpuslocked.part.0+0x29c/0x2f4 [<(ptrval)>] ? page_alloc_cpu_dead+0x0/0x30 [<(ptrval)>] ? start_kernel+0x0/0x684 [<(ptrval)>] __cpuhp_setup_state+0x4c/0x5c [<(ptrval)>] page_alloc_init+0x34/0x68 [<(ptrval)>] ? start_kernel+0x1a0/0x684 [<(ptrval)>] ? early_init_dt_scan_nodes+0x60/0x70 irq event stamp: 0 I traced this to kernel/locking/mutex.c storing 3 bits of MUTEX_FLAGS in the task_struct pointer (mutex.owner). There is a comment saying that task_structs are always aligned to L1_CACHE_BYTES. This is not true for the init_task. On 64-bit machines this is not a problem because symbol addresses are naturally aligned to 64-bits providing 3 bits for MUTEX_FLAGS. Howerver, for 32-bit machines the symbol address only has 2 bits available. Fix this by setting init_task alignment to at least L1_CACHE_BYTES. Signed-off-by: Stafford Horne <shorne@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-08-04Merge tag 'x86-cleanups-2020-08-03' of ↵Linus Torvalds1-5/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc cleanups all around the place" * tag 'x86-cleanups-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/ioperm: Initialize pointer bitmap with NULL rather than 0 x86: uv: uv_hub.h: Delete duplicated word x86: cmpxchg_32.h: Delete duplicated word x86: bootparam.h: Delete duplicated word x86/mm: Remove the unused mk_kernel_pgd() #define x86/tsc: Remove unused "US_SCALE" and "NS_SCALE" leftover macros x86/ioapic: Remove unused "IOAPIC_AUTO" define x86/mm: Drop unused MAX_PHYSADDR_BITS x86/msr: Move the F15h MSRs where they belong x86/idt: Make idt_descr static initrd: Remove erroneous comment x86/mm/32: Fix -Wmissing prototypes warnings for init.c cpu/speculation: Add prototype for cpu_show_srbds() x86/mm: Fix -Wmissing-prototypes warnings for arch/x86/mm/init.c x86/asm: Unify __ASSEMBLY__ blocks x86/cpufeatures: Mark two free bits in word 3 x86/msr: Lift AMD family 0x15 power-specific MSRs
2020-08-04Merge tag 'x86-boot-2020-08-03' of ↵Linus Torvalds1-1/+14
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot updates from Ingo Molnar: "The main change in this cycle was to add support for ZSTD-compressed kernel and initrd images. ZSTD has a very fast decompressor, yet it compresses better than gzip" * tag 'x86-boot-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation: dontdiff: Add zstd compressed files .gitignore: Add ZSTD-compressed files x86: Add support for ZSTD compressed kernel x86: Bump ZO_z_extra_bytes margin for zstd usr: Add support for zstd compressed initramfs init: Add support for zstd compressed kernel lib: Add zstd support to decompress lib: Prepare zstd for preboot environment, improve performance
2020-07-31init: Add support for zstd compressed kernelNick Terrell1-1/+14
- Add the zstd and zstd22 cmds to scripts/Makefile.lib - Add the HAVE_KERNEL_ZSTD and KERNEL_ZSTD options Architecture specific support is still needed for decompression. Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200730190841.2071656-4-nickrterrell@gmail.com
2020-07-31init: add an init_utimes helperChristoph Hellwig1-2/+1
Add a simple helper to set timestamps with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_stat helperChristoph Hellwig1-1/+2
Add a simple helper to stat with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mknod helperChristoph Hellwig3-4/+3
Add a simple helper to mknod with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_mknod. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mkdir helperChristoph Hellwig3-4/+5
Add a simple helper to mkdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_mkdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_symlink helperChristoph Hellwig1-1/+1
Add a simple helper to symlink with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_symlink. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_link helperChristoph Hellwig1-1/+1
Add a simple helper to link with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_link. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_eaccess helperChristoph Hellwig1-2/+2
Add a simple helper to check if a file exists based on kernel space file name and switch the early init code over to it. Note that this theoretically changes behavior as it always is based on the effective permissions. But during early init that doesn't make a difference. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chmod helperChristoph Hellwig1-2/+2
Add a simple helper to chmod with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chown helperChristoph Hellwig1-3/+3
Add a simple helper to chown with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chroot helperChristoph Hellwig2-3/+3
Add a simple helper to chroot with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chroot. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chdir helperChristoph Hellwig2-5/+5
Add a simple helper to chdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_rmdir helperChristoph Hellwig1-1/+1
Add a simple helper to rmdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_rmdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_unlink helperChristoph Hellwig4-5/+6
Add a simple helper to unlink with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_unlink. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_umount helperChristoph Hellwig1-1/+1
Like ksys_umount, but takes a kernel pointer for the destination path. Switch over the umount in the init code, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mount helperChristoph Hellwig3-7/+8
Like do_mount, but takes a kernel pointer for the destination path. Switch over the mounts in the init code and devtmpfs to it, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: mark create_dev as __initChristoph Hellwig1-1/+1
This helper is only used for the early init code. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: mark console_on_rootfs as __initChristoph Hellwig1-1/+1
This helper is only used for the early init code. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: initialize ramdisk_execute_command at compile timeChristoph Hellwig1-5/+1
Set ramdisk_execute_command to "/init" at compile time. The command line can still override it, but this saves a few instructions and removes a NULL check. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31initramfs: use vfs_utimes in do_copyChristoph Hellwig1-4/+6
Don't bother saving away the pathname and just use the new struct path based utimes helper instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31init: open code setting up stdin/stdout/stderrChristoph Hellwig1-6/+10
Don't rely on the implicit set_fs(KERNEL_DS) for ksys_open to work, but instead open a struct file for /dev/console and then install it as FD 0/1/2 manually. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31initramfs: switch initramfs unpacking to struct file based APIsChristoph Hellwig1-21/+26
There is no good reason to mess with file descriptors from in-kernel code, switch the initramfs unpacking to struct file based write instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initramfs: remove clean_rootfsChristoph Hellwig1-48/+1
There is no point in trying to clean up after unpacking the initramfs failed, as it should never get past the magic number check. In addition the current code only removes file that are direct children of the root entry, which wasn't complete anyway Fixes: df52092f3c97 ("fastboot: remove duplicate unpack_to_rootfs()") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-30initramfs: remove the populate_initrd_image and clean_rootfs stubsChristoph Hellwig1-11/+4
If initrd support is not enable just print the warning directly instead of hiding the fact that we just failed behind two stub functions. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initrd: mark initrd support as deprecatedChristoph Hellwig1-0/+2
The classic initial ramdisk has been replaced by the much more flexible and efficient initramfs a long time. Warn about it being removed soon. Includes a spelling fix from Colin Ian King <colin.king@canonical.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initrd: mark init_linuxrc as __initChristoph Hellwig1-1/+1
Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initrd: switch initrd loading to struct file based APIsChristoph Hellwig1-40/+39
There is no good reason to mess with file descriptors from in-kernel code, switch the initrd loading to struct file based read and writes instead. Also Pass an explicit offset instead of ->f_pos, and to make that easier, use file scope file structs and offsets everywhere except for identify_ramdisk_image instead of the current strange mix. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initrd: remove the BLKFLSBUF call in handle_initrdChristoph Hellwig1-9/+0
BLKFLSBUF used to be overloaded for the ramdisk driver to free the whole ramdisk, which was completely different behavior compared to all other drivers. But this magic overload got removed in commit ff26956875c2 ("brd: remove support for BLKFLSBUF"), so this call is entirely pointless now. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initrd: remove support for multiple floppiesChristoph Hellwig3-78/+12
Remove the special handling for multiple floppies in the initrd code. No one should be using floppies for booting these days. (famous last words..) Includes a spelling fix from Colin Ian King <colin.king@canonical.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-29sched: tasks: Use sequence counter with associated spinlockAhmed S. Darwish1-1/+2
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-14-a.darwish@linutronix.de
2020-07-29arm, arm64: Fix selection of CONFIG_SCHED_THERMAL_PRESSUREValentin Schneider1-0/+2
Qian reported that the current setup forgoes the Kconfig dependencies and results in warnings such as: WARNING: unmet direct dependencies detected for SCHED_THERMAL_PRESSURE Depends on [n]: SMP [=y] && CPU_FREQ_THERMAL [=n] Selected by [y]: - ARM64 [=y] Revert commit e17ae7fea871 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE") and re-implement it by making the option default to 'y' for arm64 and arm, which respects Kconfig dependencies (i.e. will remain 'n' if CPU_FREQ_THERMAL=n). Fixes: e17ae7fea871 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE") Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200729135718.1871-1-valentin.schneider@arm.com
2020-07-26Merge branch 'x86/urgent' into x86/cleanupsIngo Molnar1-4/+4
Refresh the branch for a dependent commit. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-22sched: Cleanup SCHED_THERMAL_PRESSURE kconfig entryValentin Schneider1-1/+14
As Russell pointed out [1], this option is severely lacking in the documentation department, and figuring out if one has the required dependencies to benefit from turning it on is not straightforward. Make it non user-visible, and add a bit of help to it. While at it, make it depend on CPU_FREQ_THERMAL. [1]: https://lkml.kernel.org/r/20200603173150.GB1551@shell.armlinux.org.uk Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200712165917.9168-3-valentin.schneider@arm.com
2020-07-21exec: Implement kernel_execveEric W. Biederman1-3/+1
To allow the kernel not to play games with set_fs to call exec implement kernel_execve. The function kernel_execve takes pointers into kernel memory and copies the values pointed to onto the new userspace stack. The calls with arguments from kernel space of do_execve are replaced with calls to kernel_execve. The calls do_execve and do_execveat are made static as there are now no callers outside of exec. The comments that mention do_execve are updated to refer to kernel_execve or execve depending on the circumstances. In addition to correcting the comments, this makes it easy to grep for do_execve and verify it is not used. Inspired-by: https://lkml.kernel.org/r/20200627072704.2447163-1-hch@lst.de Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/87wo365ikj.fsf@x220.int.ebiederm.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-07-16md: move the early init autodetect code to drivers/md/Christoph Hellwig4-315/+1
Just like the NFS and CIFS root code this better lives with the driver it is tightly integrated with. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Song Liu <song@kernel.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-16init: remove the bstat helperChristoph Hellwig2-14/+4
The only caller of the bstat function becomes cleaner and simpler when open coding the function. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: NeilBrown <neilb@suse.de> Acked-by: Song Liu <song@kernel.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-11seccomp: Report number of loaded filters in /proc/$pid/statusKees Cook1-0/+3
A common question asked when debugging seccomp filters is "how many filters are attached to your process?" Provide a way to easily answer this question through /proc/$pid/status with a "Seccomp_filters" line. Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-01kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with ClangMasahiro Yamada1-4/+4
scripts/cc-can-link.sh tests if the compiler can link userspace programs. When $(CC) is GCC, it is checked against the target architecture because the toolchain prefix is specified as a part of $(CC). When $(CC) is Clang, it is checked against the host architecture because --target option is missing. Pass $(CLANG_FLAGS) to scripts/cc-can-link.sh to evaluate the link capability for the target architecture. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
2020-06-26docs: move nommu-mmap.txt to admin-guide and rename to ReSTMauro Carvalho Chehab1-1/+1
The nommu-mmap.txt file provides description of user visible behaviuour. So, move it to the admin-guide. As it is already at the ReST, also rename it. Suggested-by: Mike Rapoport <rppt@linux.ibm.com> Suggested-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/3a63d1833b513700755c85bf3bda0a6c4ab56986.1592918949.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-19initrd: Remove erroneous commentTom Rini1-5/+0
Most architectures have been passing the location of an initrd via the initrd= option since their inception. Remove the comment as it's both wrong and unrelated to the commit that introduced it. For a bit more context, I assume there's been some confusion between "initrd" being a keyword in things like extlinux.conf and also that for quite a long time now initrd information is passed via device tree and not the command line on relevant architectures. But it's still true that it's been a valid command line option to the kernel since the 90s. It's just the case that in 2018 the code was consolidated from under arch/ and in to this file. [ bp: Move the context clarification up into the commit message proper. ] Fixes: 694cfd87b0c8 ("x86/setup: Add an initrdmem= option to specify initrd physical address") Signed-off-by: Tom Rini <trini@konsulko.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200619143056.24538-1-trini@konsulko.com
2020-06-16security: allow using Clang's zero initialization for stack variablesglider@google.com1-5/+7
In addition to -ftrivial-auto-var-init=pattern (used by CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for locals enabled by -ftrivial-auto-var-init=zero. The future of this flag is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497). Right now it is guarded by another flag, -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang, which means it may not be supported by future Clang releases. Another possible resolution is that -ftrivial-auto-var-init=zero will persist (as certain users have already started depending on it), but the name of the guard flag will change. In the meantime, zero initialization has proven itself as a good production mitigation measure against uninitialized locals. Unlike pattern initialization, which has a higher chance of triggering existing bugs, zero initialization provides safe defaults for strings, pointers, indexes, and sizes. On the other hand, pattern initialization remains safer for return values. Chrome OS and Android are moving to using zero initialization for production builds. Performance-wise, the difference between pattern and zero initialization is usually negligible, although the generated code for zero initialization is more compact. This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that enables zero initialization for locals if the corresponding flags are supported by Clang. Cc: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-13Merge tag 'kbuild-v5.8-2' of ↵Linus Torvalds1-7/+7
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - fix build rules in binderfs sample - fix build errors when Kbuild recurses to the top Makefile - covert '---help---' in Kconfig to 'help' * tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: treewide: replace '---help---' in Kconfig files with 'help' kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables samples: binderfs: really compile this sample and fix build issues
2020-06-13treewide: replace '---help---' in Kconfig files with 'help'Masahiro Yamada1-7/+7
Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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