- 24 Jan, 2014 40 commits
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Vivek Goyal authored
/sys/kernel/vmcoreinfo was introduced long back but there is no ABI documentation. This patch adds the documentation. Signed-off-by:
Vivek Goyal <vgoyal@redhat.com> Cc: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp> Cc: Dan Aloni <da-x@monatomic.org> Cc: Greg KH <greg@kroah.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Vivek Goyal authored
Right now we seem to be exporting the max data size contained inside vmcoreinfo note. But this does not include the size of meta data around vmcore info data. Like name of the note and starting and ending elf_note. I think user space expects total size and that size is put in PT_NOTE elf header. Things seem to be fine so far because we are not using vmcoreinfo note to the maximum capacity. But as it starts filling up, to capacity, at some point of time, problem will be visible. I don't think user space will be broken with this change. So there is no need to introduce vmcoreinfo2. This change is safe and backward compatible. More explanation on why this change is safe is below. vmcoreinfo contains information about kernel which user space needs to know to do things like filtering. For example, various kernel config options or information about size or offset of some data structures etc. All this information is commmunicated to user space with an ELF note present in ELF /proc/vmcore file. Currently vmcoreinfo data size is 4096. With some elf note meta data around it, actual size is 4132 bytes. But we are using barely 25% of that size. Rest is empty. So even if we tell user space that size of ELf note is 4096 and not 4132, nothing will be broken becase after around 1000 bytes, everything is zero anyway. But once we start filling up the note to the capacity, and not report the full size of note, bad things will start happening. Either some data will be lost or tools will be confused that they did not fine the zero note at the end. So I think this change is safe and should not break existing tools. Signed-off-by:
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Kees Cook authored
For general-purpose (i.e. distro) kernel builds it makes sense to build with CONFIG_KEXEC to allow end users to choose what kind of things they want to do with kexec. However, in the face of trying to lock down a system with such a kernel, there needs to be a way to disable kexec_load (much like module loading can be disabled). Without this, it is too easy for the root user to modify kernel memory even when CONFIG_STRICT_DEVMEM and modules_disabled are set. With this change, it is still possible to load an image for use later, then disable kexec_load so the image (or lack of image) can't be altered. The intention is for using this in environments where "perfect" enforcement is hard. Without a verified boot, along with verified modules, and along with verified kexec, this is trying to give a system a better chance to defend itself (or at least grow the window of discoverability) against attack in the face of a privilege escalation. In my mind, I consider several boot scenarios: 1) Verified boot of read-only verified root fs loading fd-based verification of kexec images. 2) Secure boot of writable root fs loading signed kexec images. 3) Regular boot loading kexec (e.g. kcrash) image early and locking it. 4) Regular boot with no control of kexec image at all. 1 and 2 don't exist yet, but will soon once the verified kexec series has landed. 4 is the state of things now. The gap between 2 and 4 is too large, so this change creates scenario 3, a middle-ground above 4 when 2 and 1 are not possible for a system. Signed-off-by:
Kees Cook <keescook@chromium.org> Acked-by:
Rik van Riel <riel@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by:
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Richard Weinberger authored
Currently both setup_new_exec() and flush_old_exec() issue a call to arch_pick_mmap_layout(). As setup_new_exec() and flush_old_exec() are always called pairwise arch_pick_mmap_layout() is called twice. This patch removes one call from setup_new_exec() to have it only called once. Signed-off-by:
Richard Weinberger <richard@nod.at> Tested-by:
Pat Erley <pat-lkml@erley.org> Signed-off-by:
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Zhang Yi authored
Userspace process doesn't want the PF_NO_SETAFFINITY, but its parent may be a kernel worker thread which has PF_NO_SETAFFINITY set, and this worker thread can do kernel_thread() to create the child. Clearing this flag in usersapce child to enable its migrating capability. Signed-off-by:
Zhang Yi <zhang.yi20@zte.com.cn> Acked-by:
Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
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Oleg Nesterov authored
Change do_signal_stop() and do_sigaction() to avoid next_thread() and use while_each_thread() instead. Signed-off-by:
Sameer Nanda <snanda@chromium.org> Signed-off-by:
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Oleg Nesterov authored
Change k_getrusage() to use while_each_thread(), no changes in the compiled code. Signed-off-by:
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Oleg Nesterov authored
Change the remaining next_thread (ab)users to use while_each_thread(). The last user which should be changed is next_tid(), but we can't do this now. __exit_signal() and complete_signal() are fine, they actually need next_thread() logic. This patch (of 3): do_task_stat() can use while_each_thread(), no changes in the compiled code. Signed-off-by:
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Oleg Nesterov authored
We can kill either task->did_exec or PF_FORKNOEXEC, they are mutually exclusive. The patch kills ->did_exec because it has a single user. Signed-off-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
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Oleg Nesterov authored
Both success/failure paths cleanup bprm->file, we can move this code into free_bprm() to simlify and cleanup this logic. Signed-off-by:
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Oleg Nesterov authored
fs_struct->in_exec == T means that this ->fs is used by a single process (thread group), and one of the treads does do_execve(). To avoid the mt-exec races this code has the following complications: 1. check_unsafe_exec() returns -EBUSY if ->in_exec was already set by another thread. 2. do_execve_common() records "clear_in_exec" to ensure that the error path can only clear ->in_exec if it was set by current. However, after 9b1bf12d "signals: move cred_guard_mutex from task_struct to signal_struct" we do not need these complications: 1. We can't race with our sub-thread, this is called under per-process ->cred_guard_mutex. And we can't race with another CLONE_FS task, we already checked that this fs is not shared. We can remove the dead -EAGAIN logic. 2. "out_unmark:" in do_execve_common() is either called under ->cred_guard_mutex, or after de_thread() which kills other threads, so we can't race with sub-thread which could set ->in_exec. And if ->fs is shared with another process ->in_exec should be false anyway. We can clear in_exec unconditionally. This also means that check_unsafe_exec() can be void. Signed-off-by:
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Oleg Nesterov authored
next_thread() should be avoided, change check_unsafe_exec() to use while_each_thread(). Nobody except signal->curr_target actually needs next_thread-like code, and we need to change (fix) this interface. This particular code is fine, p == current. But in general the code like this can loop forever if p exits and next_thread(t) can't reach the unhashed thread. This also saves 32 bytes. Signed-off-by:
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Daeseok Youn authored
current->mm doesn't need a NULL check in dup_mm(). Becasue dup_mm() is used only in copy_mm() and current->mm is checked whether it is NULL or not in copy_mm() before calling dup_mm(). Signed-off-by:
Daeseok Youn <daeseok.youn@gmail.com> Acked-by:
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Daeseok Youn authored
Fix errors reported by checkpatch.pl. One error is parentheses, the other is a whitespace issue. Signed-off-by:
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DaeSeok Youn authored
dup_mm() is used only in kernel/fork.c Signed-off-by:
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Paul Gortmaker authored
PROC_FS is a bool, so this code is either present or absent. It will never be modular, so using module_init as an alias for __initcall is rather misleading. Fix this up now, so that we can relocate module_init from init.h into module.h in the future. If we don't do this, we'd have to add module.h to obviously non-modular code, and that would be ugly at best. Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of fs_initcall (which makes sense for fs code) will thus change these registrations from level 6-device to level 5-fs (i.e. slightly earlier). However no observable impact of that small difference has been observed during testing, or is expected. Also note that this change uncovers a missing semicolon bug in the registration of vmcore_init as an initcall. Signed-off-by:
Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by:
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Axel Lin authored
Trivial cleanup to eliminate a goto. Signed-off-by:
Axel Lin <axel.lin@ingics.com> Signed-off-by:
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Dave Jones authored
Distribution kernels might want to build in support for /proc/device-tree for kernels that might end up running on hardware that doesn't support openfirmware. This results in an empty /proc/device-tree existing. Remove it if the OFW root node doesn't exist. This situation actually confuses grub2, resulting in install failures. grub2 sees the /proc/device-tree and picks the wrong install target cf. http://bzr.savannah.gnu.org/lh/grub/trunk/grub/annotate/4300/util/grub-install.in#L311 grub should be more robust, but still, leaving an empty proc dir seems pointless. Addresses https://bugzilla.redhat.com/show_bug.cgi?id=818378. Signed-off-by:
Dave Jones <davej@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Josh Boyer <jwboyer@fedoraproject.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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Rui Xiang authored
Use existing accessors proc_set_user() and proc_set_size() to set attributes. Just a cleanup. Signed-off-by:
Rui Xiang <rui.xiang@huawei.com> Signed-off-by:
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Oleg Nesterov authored
1. proc_task_readdir()->first_tid() path truncates f_pos to int, this is wrong even on 64bit. We could check that f_pos < PID_MAX or even INT_MAX in proc_task_readdir(), but this patch simply checks the potential overflow in first_tid(), this check is nop on 64bit. We do not care if it was negative and the new unsigned value is huge, all we need to ensure is that we never wrongly return !NULL. 2. Remove the 2nd "nr != 0" check before get_nr_threads(), nr_threads == 0 is not distinguishable from !pid_task() above. Signed-off-by:
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Oleg Nesterov authored
proc_task_readdir() does not really need "leader", first_tid() has to revalidate it anyway. Just pass proc_pid(inode) to first_tid() instead, it can do pid_task(PIDTYPE_PID) itself and read ->group_leader only if necessary. The patch also extracts the "inode is dead" code from pid_delete_dentry(dentry) into the new trivial helper, proc_inode_is_dead(inode), proc_task_readdir() uses it to return -ENOENT if this dir was removed. This is a bit racy, but the race is very inlikely and the getdents() after openndir() can see the empty "." + ".." dir only once. Signed-off-by:
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Oleg Nesterov authored
Rerwrite the main loop to use while_each_thread() instead of next_thread(). We are going to fix or replace while_each_thread(), next_thread() should be avoided whenever possible. Signed-off-by:
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Oleg Nesterov authored
proc_task_readdir() verifies that the result of get_proc_task() is pid_alive() and thus its ->group_leader is fine too. However this is not necessarily true after rcu_read_unlock(), we need to recheck this again after first_tid() does rcu_read_lock(). Otherwise leader->thread_group.next (used by next_thread()) can be invalid if the rcu grace period expires in between. The race is subtle and unlikely, but still it is possible afaics. To simplify lets ignore the "likely" case when tid != 0, f_version can be cleared by proc_task_operations->llseek(). Suppose we have a main thread M and its subthread T. Suppose that f_pos == 3, iow first_tid() should return T. Now suppose that the following happens between rcu_read_unlock() and rcu_read_lock(): 1. T execs and becomes the new leader. This removes M from ->thread_group but next_thread(M) is still T. 2. T creates another thread X which does exec as well, T goes away. 3. X creates another subthread, this increments nr_threads. 4. first_tid() does next_thread(M) and returns the already dead T. Note also that we need 2. and 3. only because of get_nr_threads() check, and this check was supposed to be optimization only. Signed-off-by:
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Oleg Nesterov authored
get_task_state() and task_state_array[] look confusing and suboptimal, it is not clear what it can actually report to user-space and task_state_array[] blows .data for no reason. 1. state = (tsk->state & TASK_REPORT) | tsk->exit_state is not clear. TASK_REPORT is self-documenting but it is not clear what ->exit_state can add. Move the potential exit_state's (EXIT_ZOMBIE and EXIT_DEAD) into TASK_REPORT and use it to calculate the final result. 2. With the change above it is obvious that task_state_array[] has the unused entries just to make BUILD_BUG_ON() happy. Change this BUILD_BUG_ON() to use TASK_REPORT rather than TASK_STATE_MAX and shrink task_state_array[]. 3. Turn the "while (state)" loop into fls(state). Signed-off-by:
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Oleg Nesterov authored
1. Remove fs/coredump.h. It is not clear why do we need it, it only declares __get_dumpable(), signal.c includes it for no reason. 2. Now that get_dumpable() and __get_dumpable() are really trivial make them inline in linux/sched.h. Signed-off-by:
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Oleg Nesterov authored
Nobody actually needs MMF_DUMPABLE/MMF_DUMP_SECURELY, they are only used to enforce the encoding of SUID_DUMP_* enum in mm->flags & MMF_DUMPABLE_MASK. Now that set_dumpable() updates both bits atomically we can kill them and simply store the value "as is" in 2 lower bits. Signed-off-by:
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Oleg Nesterov authored
set_dumpable() updates MMF_DUMPABLE_MASK in a non-trivial way to ensure that get_dumpable() can't observe the intermediate state, but this all can't help if multiple threads call set_dumpable() at the same time. And in theory commit_creds()->set_dumpable(SUID_DUMP_ROOT) racing with sys_prctl()->set_dumpable(SUID_DUMP_DISABLE) can result in SUID_DUMP_USER. Change this code to update both bits atomically via cmpxchg(). Note: this assumes that it is safe to mix bitops and cmpxchg. IOW, if, say, an architecture implements cmpxchg() using the locking (like arch/parisc/lib/bitops.c does), then it should use the same locks for set_bit/etc. Signed-off-by:
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Sangjung Woo authored
As the notifier_block name (i.e. foobar_cpu_notifer) is different from the parameter (i.e.foobar_cpu_notifier) of register function, that is definitely error and it also makes readers confused. Signed-off-by:
Sangjung Woo <sangjung.woo@samsung.com> Reviewed-by:
Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by:
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Robert Graffham authored
Remove an outdated reference to "most personal computers" having only one CPU, and change the use of "singleprocessor" and "single processor" in CONFIG_SMP's documentation to "uniprocessor" across all arches where that documentation is present. Signed-off-by:
Robert Graffham <psquid@psquid.net> Signed-off-by:
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Fabian Frederick authored
Add the following documentation-files with description : -autofs4-mount-control.txt -btrfs.txt -debugfs.txt -devpts.txt -fiemap.txt -gfs2-glocks.txt -gfs2-uevents.txt -omfs.txt -path-lookup.txt -qnx6.txt -quota.txt -squashfs.txt -sysfs-tagging.txt -ubifs.txt -xfs-delayed-logging-design.txt -xfs-self-describing-metadata.txt Add the following documentation directories with description : -caching -cifs (replacing cifs.txt) -pohmelfs Remove the following documentation-files reference: -dentry-locking.txt -reiser4.txt Signed-off-by:
Fabian Frederick <fabf@skynet.be> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
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Fabian Frederick authored
- ramdisk_blocksize doesn't exist anymore - Module parameters added to documentation Signed-off-by:
Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
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Andre Richter authored
Fix a wrong device_attribute declaration example. Signed-off-by:
Andre Richter <andre.o.richter@gmail.com> Cc: Greg KH <greg@kroah.com> Signed-off-by:
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Sougata Santra authored
HFS+ resource fork lookup breaks opendir() library function. Since opendir first calls open() with O_DIRECTORY flag set. O_DIRECTORY means "refuse to open if not a directory". The open system call in the kernel does a check for inode->i_op->lookup and returns -ENOTDIR. So if hfsplus_file_lookup is set it allows opendir() for plain files. Also resource fork lookup in HFS+ does not work. Since it is never invoked after VFS permission checking. It will always return with -EACCES. When we call opendir() on a file, it does not return NULL. opendir() library call is based on open with O_DIRECTORY flag passed and then layered on top of getdents() system call. O_DIRECTORY means "refuse to open if not a directory". The open() system call in the kernel does a check for: do_sys_open() -->..--> can_lookup() i.e it only checks inode->i_op->lookup and returns ENOTDIR if this function pointer is not set. In OSX, we can open "file/rsrc" to get the resource fork of "file". This behavior is emulated inside hfsplus on Linux, which means that to some degree every file acts like a directory. That is the reason lookup() inode operations is supported for files, and it is possible to do a lookup on this specific name. As a result of this open succeeds without returning ENOTDIR for HFS+ Please see the LKML discussion thread on this issue: http://marc.info/?l=linux-fsdevel&m=122823343730412&w=2 I tried to test file/rsrc lookup in HFS+ driver and the feature does not work. From OSX: $ touch test $ echo "1234" > test/..namedfork/rsrc $ ls -l test..namedfork/rsrc --rw-r--r-- 1 tuxera staff 5 10 dec 12:59 test/..namedfork/rsrc [sougata@ultrabook tmp]$ id uid=1000(sougata) gid=1000(sougata) groups=1000(sougata),5(tty),18(dialout),1001(vboxusers) [sougata@ultrabook tmp]$ mount /dev/sdb1 on /mnt/tmp type hfsplus (rw,relatime,umask=0,uid=1000,gid=1000,nls=utf8) [sougata@ultrabook tmp]$ ls -l test/rsrc ls: cannot access test/rsrc: Permission denied According to this LKML thread it is expected behavior. http://marc.info/?t=121139033800008&r=1&w=4 I guess now that permission checking happens in vfs generic_permission() ? So it turns out that even though the lookup() inode_operation exists for HFS+ files. It cannot really get invoked ?. So if we can disable this feature to make opendir() work for HFS+. Signed-off-by:
Sougata Santra <sougata@tuxera.com> Acked-by:
Christoph Hellwig <hch@lst.de> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Anton Altaparmakov <aia21@cam.ac.uk> Signed-off-by:
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Vyacheslav Dubeyko authored
Add comments for ioctls in fs/nilfs2/ioctl.c file and describe NILFS2 specific ioctls in Documentation/filesystems/nilfs2.txt. Signed-off-by:
Vyacheslav Dubeyko <slava@dubeyko.com> Reviewed-by:
Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Wenliang Fan <fanwlexca@gmail.com> Signed-off-by:
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Wenliang Fan authored
The local variable 'pos' in nilfs_ioctl_wrap_copy function can overflow if a large number was passed to argv->v_index from userspace and the sum of argv->v_index and argv->v_nmembs exceeds the maximum value of __u64 type integer (= ~(__u64)0 = 18446744073709551615). Here, argv->v_index is a 64-bit width argument to specify the start position of target data items (such as segment number, checkpoint number, or virtual block address of nilfs), and argv->v_nmembs gives the total number of the items that userland programs (such as lssu, lscp, or cleanerd) want to get information about, which also gives the maximum element count of argv->v_base[] array. nilfs_ioctl_wrap_copy() calls dofunc() repeatedly and increments the position variable 'pos' at the end of each iteration if dofunc() itself didn't update 'pos': if (pos == ppos) pos += n; This patch prevents the overflow here by rejecting pairs of a start position (argv->v_index) and a total count (argv->v_nmembs) which leads to the overflow. [konishi.ryusuke@lab.ntt.co.jp: fix signedness issue] Signed-off-by:Wenliang Fan <fanwlexca@gmail.com> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Signed-off-by:
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Dmitry Monakhov authored
Pipe has no data associated with fs so it is not good idea to block pipe_write() if FS is frozen, but we can not update file's time on such filesystem. Let's use same idea as we use in touch_time(). Addresses https://bugzilla.kernel.org/show_bug.cgi?id=65701Signed-off-by:
Dmitry Monakhov <dmonakhov@openvz.org> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Andreas Werner authored
Add support for SMBus-only adapters (e.g. i2c-piix4). The driver has implemented only support for I2C adapters which implement the I2C_FUNC_SMBUS_I2C_BLOCK functionality before. With this patch it is possible to load and use the RTC driver with I2C and SMBUS adapters like the rtc-ds1307 does. Tested on AMD G Series Platform (i2c-piix4 adapter driver). Signed-off-by:
Andreas Werner <andreas.werner@men.de> Signed-off-by:
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Geert Uytterhoeven authored
If CONFIG_PM_SLEEP=n: drivers/rtc/rtc-s5m.c:643: warning: `s5m_rtc_resume' defined but not used drivers/rtc/rtc-s5m.c:654: warning: `s5m_rtc_suspend' defined but not used Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
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Stephen Warren authored
The current MAX8907 driver has two issues related to weekday value handling: 1) The HW WEEKDAY register has range 0..6 rather than 1..7 as documented. Note that I validated the actual HW range by observing the HW register roll from 6->0 rather than 6->7->1 as would otherwise be expected. This matches Linux's tm_wday range of 0..6. When the CMOS RAM content is lost, the date returned from the device is 2007-01-01 00:00:00, which is a Monday. The WEEKDAY register reads 1 in this case. This matches the numbering in Linux's tm_wday field. Hence we should write Linux's tm_wday value to the register without modifying it. Hence, remove the +1/-1 calculations for WEEKDAY/tm_wday. 2) There's no need to make alarms match on the WEEKDAY register, since the other fields together uniquely define the alarm date/time. Ignoring the WEEKDAY value in the match isolates the driver from any incorrect value in the current time copy of the WEEKDAY register. Each change individually, or both together, solves an issue that I observed; "hwclock -r" would time out waiting for its alarm to fire if the CMOS RAM content had been lost, and hence the WEEKDAY register value mismatched what the driver expected it to be. "hwclock -w" would solve this by over-writing the HW default WEEKDAY register value with what the driver expected. Signed-off-by:
Stephen Warren <swarren@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Sachin Kamat authored
'hym8563_clkout_ops' is used only in this file. Signed-off-by:
Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by:
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