linux/fs/proc, branch v3.3

Fix race in process_vm_rw_core

2012-02-02T20:55:17Z

This fixes the race in process_vm_core found by Oleg (see http://article.gmane.org/gmane.linux.kernel/1235667/ for details). This has been updated since I last sent it as the creation of the new mm_access() function did almost exactly the same thing as parts of the previous version of this patch did. In order to use mm_access() even when /proc isn't enabled, we move it to kernel/fork.c where other related process mm access functions already are. Signed-off-by: Chris Yeoh Signed-off-by: Linus Torvalds

proc: make sure mem_open() doesn't pin the target's memory

2012-02-01T22:39:01Z

Once /proc/pid/mem is opened, the memory can't be released until mem_release() even if its owner exits. Change mem_open() to do atomic_inc(mm_count) + mmput(), this only pins mm_struct. Change mem_rw() to do atomic_inc_not_zero(mm_count) before access_remote_vm(), this verifies that this mm is still alive. I am not sure what should mem_rw() return if atomic_inc_not_zero() fails. With this patch it returns zero to match the "mm == NULL" case, may be it should return -EINVAL like it did before e268337d. Perhaps it makes sense to add the additional fatal_signal_pending() check into the main loop, to ensure we do not hold this memory if the target task was oom-killed. Cc: stable@kernel.org Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds

proc: unify mem_read() and mem_write()

2012-02-01T22:39:01Z

No functional changes, cleanup and preparation. mem_read() and mem_write() are very similar. Move this code into the new common helper, mem_rw(), which takes the additional "int write" argument. Cc: stable@kernel.org Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds

proc: mem_release() should check mm != NULL

2012-02-01T22:39:01Z

mem_release() can hit mm == NULL, add the necessary check. Cc: stable@kernel.org Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds

proc: clear_refs: do not clear reserved pages

2012-01-23T16:38:48Z

/proc/pid/clear_refs is used to clear the Referenced and YOUNG bits for pages and corresponding page table entries of the task with PID pid, which includes any special mappings inserted into the page tables in order to provide things like vDSOs and user helper functions. On ARM this causes a problem because the vectors page is mapped as a global mapping and since ec706dab ("ARM: add a vma entry for the user accessible vector page"), a VMA is also inserted into each task for this page to aid unwinding through signals and syscall restarts. Since the vectors page is required for handling faults, clearing the YOUNG bit (and subsequently writing a faulting pte) means that we lose the vectors page *globally* and cannot fault it back in. This results in a system deadlock on the next exception. To see this problem in action, just run: $ echo 1 > /proc/self/clear_refs on an ARM platform (as any user) and watch your system hang. I think this has been the case since 2.6.37 This patch avoids clearing the aforementioned bits for reserved pages, therefore leaving the vectors page intact on ARM. Since reserved pages are not candidates for swap, this change should not have any impact on the usefulness of clear_refs. Signed-off-by: Will Deacon Reported-by: Moussa Ba Acked-by: Hugh Dickins Cc: David Rientjes Cc: Russell King Acked-by: Nicolas Pitre Cc: Matt Mackall Cc: [2.6.37+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branches 'sched-urgent-for-linus', 'perf-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-01-19T22:53:06Z

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/accounting, proc: Fix /proc/stat interrupts sum * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tracepoints/module: Fix disabling tracepoints with taint CRAP or OOT x86/kprobes: Add arch/x86/tools/insn_sanity to .gitignore x86/kprobes: Fix typo transferred from Intel manual * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, syscall: Need __ARCH_WANT_SYS_IPC for 32 bits x86, tsc: Fix SMI induced variation in quick_pit_calibrate() x86, opcode: ANDN and Group 17 in x86-opcode-map.txt x86/kconfig: Move the ZONE_DMA entry under a menu x86/UV2: Add accounting for BAU strong nacks x86/UV2: Ack BAU interrupt earlier x86/UV2: Remove stale no-resources test for UV2 BAU x86/UV2: Work around BAU bug x86/UV2: Fix BAU destination timeout initialization x86/UV2: Fix new UV2 hardware by using native UV2 broadcast mode x86: Get rid of dubious one-bit signed bitfield

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit

2012-01-18T00:41:31Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit: (29 commits) audit: no leading space in audit_log_d_path prefix audit: treat s_id as an untrusted string audit: fix signedness bug in audit_log_execve_info() audit: comparison on interprocess fields audit: implement all object interfield comparisons audit: allow interfield comparison between gid and ogid audit: complex interfield comparison helper audit: allow interfield comparison in audit rules Kernel: Audit Support For The ARM Platform audit: do not call audit_getname on error audit: only allow tasks to set their loginuid if it is -1 audit: remove task argument to audit_set_loginuid audit: allow audit matching on inode gid audit: allow matching on obj_uid audit: remove audit_finish_fork as it can't be called audit: reject entry,always rules audit: inline audit_free to simplify the look of generic code audit: drop audit_set_macxattr as it doesn't do anything audit: inline checks for not needing to collect aux records audit: drop some potentially inadvisable likely notations ... Use evil merge to fix up grammar mistakes in Kconfig file. Bad speling and horrible grammar (and copious swearing) is to be expected, but let's keep it to commit messages and comments, rather than expose it to users in config help texts or printouts.

proc: clean up and fix /proc//mem handling

2012-01-17T23:21:19Z

Jüri Aedla reported that the /proc//mem handling really isn't very robust, and it also doesn't match the permission checking of any of the other related files. This changes it to do the permission checks at open time, and instead of tracking the process, it tracks the VM at the time of the open. That simplifies the code a lot, but does mean that if you hold the file descriptor open over an execve(), you'll continue to read from the _old_ VM. That is different from our previous behavior, but much simpler. If somebody actually finds a load where this matters, we'll need to revert this commit. I suspect that nobody will ever notice - because the process mapping addresses will also have changed as part of the execve. So you cannot actually usefully access the fd across a VM change simply because all the offsets for IO would have changed too. Reported-by: Jüri Aedla Cc: Al Viro Signed-off-by: Linus Torvalds

audit: only allow tasks to set their loginuid if it is -1

2012-01-17T21:17:00Z

At the moment we allow tasks to set their loginuid if they have CAP_AUDIT_CONTROL. In reality we want tasks to set the loginuid when they log in and it be impossible to ever reset. We had to make it mutable even after it was once set (with the CAP) because on update and admin might have to restart sshd. Now sshd would get his loginuid and the next user which logged in using ssh would not be able to set his loginuid. Systemd has changed how userspace works and allowed us to make the kernel work the way it should. With systemd users (even admins) are not supposed to restart services directly. The system will restart the service for them. Thus since systemd is going to loginuid==-1, sshd would get -1, and sshd would be allowed to set a new loginuid without special permissions. If an admin in this system were to manually start an sshd he is inserting himself into the system chain of trust and thus, logically, it's his loginuid that should be used! Since we have old systems I make this a Kconfig option. Signed-off-by: Eric Paris

audit: remove task argument to audit_set_loginuid

2012-01-17T21:17:00Z

The function always deals with current. Don't expose an option pretending one can use it for something. You can't. Signed-off-by: Eric Paris