user/sven/linux.git/kernel/pid_namespace.c, branch v5.4.250

memcg: enable accounting for pids in nested pid namespaces

2021-09-22T10:26:37Z

commit fab827dbee8c2e06ca4ba000fa6c48bcf9054aba upstream. Commit 5d097056c9a0 ("kmemcg: account certain kmem allocations to memcg") enabled memcg accounting for pids allocated from init_pid_ns.pid_cachep, but forgot to adjust the setting for nested pid namespaces. As a result, pid memory is not accounted exactly where it is really needed, inside memcg-limited containers with their own pid namespaces. Pid was one the first kernel objects enabled for memcg accounting. init_pid_ns.pid_cachep marked by SLAB_ACCOUNT and we can expect that any new pids in the system are memcg-accounted. Though recently I've noticed that it is wrong. nested pid namespaces creates own slab caches for pid objects, nested pids have increased size because contain id both for all parent and for own pid namespaces. The problem is that these slab caches are _NOT_ marked by SLAB_ACCOUNT, as a result any pids allocated in nested pid namespaces are not memcg-accounted. Pid struct in nested pid namespace consumes up to 500 bytes memory, 100000 such objects gives us up to ~50Mb unaccounted memory, this allow container to exceed assigned memcg limits. Link: https://lkml.kernel.org/r/8b6de616-fd1a-02c6-cbdb-976ecdcfa604@virtuozzo.com Fixes: 5d097056c9a0 ("kmemcg: account certain kmem allocations to memcg") Cc: stable@vger.kernel.org Signed-off-by: Vasily Averin Reviewed-by: Michal Koutný Reviewed-by: Shakeel Butt Acked-by: Christian Brauner Acked-by: Roman Gushchin Cc: Michal Hocko Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

proc/sysctl: add shared variables for range check

2019-07-19T00:08:07Z

In the sysctl code the proc_dointvec_minmax() function is often used to validate the user supplied value between an allowed range. This function uses the extra1 and extra2 members from struct ctl_table as minimum and maximum allowed value. On sysctl handler declaration, in every source file there are some readonly variables containing just an integer which address is assigned to the extra1 and extra2 members, so the sysctl range is enforced. The special values 0, 1 and INT_MAX are very often used as range boundary, leading duplication of variables like zero=0, one=1, int_max=INT_MAX in different source files: $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l 248 Add a const int array containing the most commonly used values, some macros to refer more easily to the correct array member, and use them instead of creating a local one for every object file. This is the bloat-o-meter output comparing the old and new binary compiled with the default Fedora config: # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164) Data old new delta sysctl_vals - 12 +12 __kstrtab_sysctl_vals - 12 +12 max 14 10 -4 int_max 16 - -16 one 68 - -68 zero 128 28 -100 Total: Before=20583249, After=20583085, chg -0.00% [mcroce@redhat.com: tipc: remove two unused variables] Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com [akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c] [arnd@arndb.de: proc/sysctl: make firmware loader table conditional] Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de [akpm@linux-foundation.org: fix fs/eventpoll.c] Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com Signed-off-by: Matteo Croce Signed-off-by: Arnd Bergmann Acked-by: Kees Cook Reviewed-by: Aaron Tomlin Cc: Matthew Wilcox Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2019-07-09T04:48:15Z

Pull force_sig() argument change from Eric Biederman: "A source of error over the years has been that force_sig has taken a task parameter when it is only safe to use force_sig with the current task. The force_sig function is built for delivering synchronous signals such as SIGSEGV where the userspace application caused a synchronous fault (such as a page fault) and the kernel responded with a signal. Because the name force_sig does not make this clear, and because the force_sig takes a task parameter the function force_sig has been abused for sending other kinds of signals over the years. Slowly those have been fixed when the oopses have been tracked down. This set of changes fixes the remaining abusers of force_sig and carefully rips out the task parameter from force_sig and friends making this kind of error almost impossible in the future" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits) signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus signal: Remove the signal number and task parameters from force_sig_info signal: Factor force_sig_info_to_task out of force_sig_info signal: Generate the siginfo in force_sig signal: Move the computation of force into send_signal and correct it. signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal signal: Remove the task parameter from force_sig_fault signal: Use force_sig_fault_to_task for the two calls that don't deliver to current signal: Explicitly call force_sig_fault on current signal/unicore32: Remove tsk parameter from __do_user_fault signal/arm: Remove tsk parameter from __do_user_fault signal/arm: Remove tsk parameter from ptrace_break signal/nds32: Remove tsk parameter from send_sigtrap signal/riscv: Remove tsk parameter from do_trap signal/sh: Remove tsk parameter from force_sig_info_fault signal/um: Remove task parameter from send_sigtrap signal/x86: Remove task parameter from send_sigtrap signal: Remove task parameter from force_sig_mceerr signal: Remove task parameter from force_sig signal: Remove task parameter from force_sigsegv ...

signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig

2019-05-27T14:36:28Z

The locking in force_sig_info is not prepared to deal with a task that exits or execs (as sighand may change). The is not a locking problem in force_sig as force_sig is only built to handle synchronous exceptions. Further the function force_sig_info changes the signal state if the signal is ignored, or blocked or if SIGNAL_UNKILLABLE will prevent the delivery of the signal. The signal SIGKILL can not be ignored and can not be blocked and SIGNAL_UNKILLABLE won't prevent it from being delivered. So using force_sig rather than send_sig for SIGKILL is confusing and pointless. Because it won't impact the sending of the signal and and because using force_sig is wrong, replace force_sig with send_sig. Cc: Daniel Lezcano Cc: Serge Hallyn Cc: Oleg Nesterov Fixes: cf3f89214ef6 ("pidns: add reboot_pid_ns() to handle the reboot syscall") Signed-off-by: "Eric W. Biederman"

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45Z

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 Signed-off-by: Greg Kroah-Hartman

signal: Use group_send_sig_info to kill all processes in a pid namespace

2018-09-16T14:08:25Z

Replace send_sig_info in zap_pid_ns_processes with group_send_sig_info. This makes more sense as the entire process group is being killed. More importantly this allows the kill of those processes with PIDTYPE_MAX to indicate all of the process in the pid namespace are being signaled. This is needed for fork to detect when signals are sent to a group of processes. Admittedly fork has another case to catch SIGKILL but the principle remains that it is desirable to know when a group of processes is being signaled. Signed-off-by: "Eric W. Biederman"

signal: Use SEND_SIG_PRIV not SEND_SIG_FORCED with SIGKILL and SIGSTOP

2018-09-11T19:19:35Z

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 Signed-off-by: "Eric W. Biederman"

Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2018-04-04T02:15:32Z

Pull namespace updates from Eric Biederman: "There was a lot of work this cycle fixing bugs that were discovered after the merge window and getting everything ready where we can reasonably support fully unprivileged fuse. The bug fixes you already have and much of the unprivileged fuse work is coming in via other trees. Still left for fully unprivileged fuse is figuring out how to cleanly handle .set_acl and .get_acl in the legacy case, and properly handling of evm xattrs on unprivileged mounts. Included in the tree is a cleanup from Alexely that replaced a linked list with a statically allocated fix sized array for the pid caches, which simplifies and speeds things up. Then there is are some cleanups and fixes for the ipc namespace. The motivation was that in reviewing other code it was discovered that access ipc objects from different pid namespaces recorded pids in such a way that when asked the wrong pids were returned. In the worst case there has been a measured 30% performance impact for sysvipc semaphores. Other test cases showed no measurable performance impact. Manfred Spraul and Davidlohr Bueso who tend to work on sysvipc performance both gave the nod that this is good enough. Casey Schaufler and James Morris have given their approval to the LSM side of the changes. I simplified the types and the code dealing with sysvipc to pass just kern_ipc_perm for all three types of ipc. Which reduced the header dependencies throughout the kernel and simplified the lsm code. Which let me work on the pid fixes without having to worry about trivial changes causing complete kernel recompiles" * 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ipc/shm: Fix pid freeing. ipc/shm: fix up for struct file no longer being available in shm.h ipc/smack: Tidy up from the change in type of the ipc security hooks ipc: Directly call the security hook in ipc_ops.associate ipc/sem: Fix semctl(..., GETPID, ...) between pid namespaces ipc/msg: Fix msgctl(..., IPC_STAT, ...) between pid namespaces ipc/shm: Fix shmctl(..., IPC_STAT, ...) between pid namespaces. ipc/util: Helpers for making the sysvipc operations pid namespace aware ipc: Move IPCMNI from include/ipc.h into ipc/util.h msg: Move struct msg_queue into ipc/msg.c shm: Move struct shmid_kernel into ipc/shm.c sem: Move struct sem and struct sem_array into ipc/sem.c msg/security: Pass kern_ipc_perm not msg_queue into the msg_queue security hooks shm/security: Pass kern_ipc_perm not shmid_kernel into the shm security hooks sem/security: Pass kern_ipc_perm not sem_array into the sem security hooks pidns: simpler allocation of pid_* caches

kernel: use kernel_wait4() instead of sys_wait4()

2018-04-02T18:14:51Z

All call sites of sys_wait4() set *rusage to NULL. Therefore, there is no need for the copy_to_user() handling of *rusage, and we can use kernel_wait4() directly. This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Acked-by: Luis R. Rodriguez Cc: Al Viro Cc: Andrew Morton Signed-off-by: Dominik Brodowski

pidns: simpler allocation of pid_* caches

2018-03-21T14:40:17Z

Those pid_* caches are created on demand when a process advances to the new level of pid namespace. Which means pointers are stable, write only and thus can be packed into an array instead of spreading them over and using lists(!) to find them. Both first and subsequent clone/unshare(CLONE_NEWPID) become faster. Signed-off-by: Alexey Dobriyan Signed-off-by: Eric W. Biederman