diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/LSM/SafeSetID.rst | 29 | ||||
| -rw-r--r-- | Documentation/admin-guide/cpu-load.rst | 63 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 15 | ||||
| -rw-r--r-- | Documentation/admin-guide/nfs/fault_injection.rst | 70 | ||||
| -rw-r--r-- | Documentation/admin-guide/nfs/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/vm.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/xfs.rst | 32 |
7 files changed, 101 insertions, 111 deletions
diff --git a/Documentation/admin-guide/LSM/SafeSetID.rst b/Documentation/admin-guide/LSM/SafeSetID.rst index 7bff07ce4fdd..17996c9070e2 100644 --- a/Documentation/admin-guide/LSM/SafeSetID.rst +++ b/Documentation/admin-guide/LSM/SafeSetID.rst @@ -3,9 +3,9 @@ SafeSetID ========= SafeSetID is an LSM module that gates the setid family of syscalls to restrict UID/GID transitions from a given UID/GID to only those approved by a -system-wide whitelist. These restrictions also prohibit the given UIDs/GIDs +system-wide allowlist. These restrictions also prohibit the given UIDs/GIDs from obtaining auxiliary privileges associated with CAP_SET{U/G}ID, such as -allowing a user to set up user namespace UID mappings. +allowing a user to set up user namespace UID/GID mappings. Background @@ -98,10 +98,21 @@ Directions for use ================== This LSM hooks the setid syscalls to make sure transitions are allowed if an applicable restriction policy is in place. Policies are configured through -securityfs by writing to the safesetid/add_whitelist_policy and -safesetid/flush_whitelist_policies files at the location where securityfs is -mounted. The format for adding a policy is '<UID>:<UID>', using literal -numbers, such as '123:456'. To flush the policies, any write to the file is -sufficient. Again, configuring a policy for a UID will prevent that UID from -obtaining auxiliary setid privileges, such as allowing a user to set up user -namespace UID mappings. +securityfs by writing to the safesetid/uid_allowlist_policy and +safesetid/gid_allowlist_policy files at the location where securityfs is +mounted. The format for adding a policy is '<UID>:<UID>' or '<GID>:<GID>', +using literal numbers, and ending with a newline character such as '123:456\n'. +Writing an empty string "" will flush the policy. Again, configuring a policy +for a UID/GID will prevent that UID/GID from obtaining auxiliary setid +privileges, such as allowing a user to set up user namespace UID/GID mappings. + +Note on GID policies and setgroups() +================== +In v5.9 we are adding support for limiting CAP_SETGID privileges as was done +previously for CAP_SETUID. However, for compatibility with common sandboxing +related code conventions in userspace, we currently allow arbitrary +setgroups() calls for processes with CAP_SETGID restrictions. Until we add +support in a future release for restricting setgroups() calls, these GID +policies add no meaningful security. setgroups() restrictions will be enforced +once we have the policy checking code in place, which will rely on GID policy +configuration code added in v5.9. diff --git a/Documentation/admin-guide/cpu-load.rst b/Documentation/admin-guide/cpu-load.rst index ebdecf864080..f3ada90e9ca8 100644 --- a/Documentation/admin-guide/cpu-load.rst +++ b/Documentation/admin-guide/cpu-load.rst @@ -61,43 +61,46 @@ will lead to quite erratic information inside ``/proc/stat``:: static volatile sig_atomic_t stop; - static void sighandler (int signr) + static void sighandler(int signr) { - (void) signr; - stop = 1; + (void) signr; + stop = 1; } + static unsigned long hog (unsigned long niters) { - stop = 0; - while (!stop && --niters); - return niters; + stop = 0; + while (!stop && --niters); + return niters; } + int main (void) { - int i; - struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 1 }, - .it_value = { .tv_sec = 0, .tv_usec = 1 } }; - sigset_t set; - unsigned long v[HIST]; - double tmp = 0.0; - unsigned long n; - signal (SIGALRM, &sighandler); - setitimer (ITIMER_REAL, &it, NULL); - - hog (ULONG_MAX); - for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog (ULONG_MAX); - for (i = 0; i < HIST; ++i) tmp += v[i]; - tmp /= HIST; - n = tmp - (tmp / 3.0); - - sigemptyset (&set); - sigaddset (&set, SIGALRM); - - for (;;) { - hog (n); - sigwait (&set, &i); - } - return 0; + int i; + struct itimerval it = { + .it_interval = { .tv_sec = 0, .tv_usec = 1 }, + .it_value = { .tv_sec = 0, .tv_usec = 1 } }; + sigset_t set; + unsigned long v[HIST]; + double tmp = 0.0; + unsigned long n; + signal(SIGALRM, &sighandler); + setitimer(ITIMER_REAL, &it, NULL); + + hog (ULONG_MAX); + for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog(ULONG_MAX); + for (i = 0; i < HIST; ++i) tmp += v[i]; + tmp /= HIST; + n = tmp - (tmp / 3.0); + + sigemptyset(&set); + sigaddset(&set, SIGALRM); + + for (;;) { + hog(n); + sigwait(&set, &i); + } + return 0; } diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f1eeba73d931..526d65d8573a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5970,6 +5970,21 @@ improve timer resolution at the expense of processing more timer interrupts. + xen.event_eoi_delay= [XEN] + How long to delay EOI handling in case of event + storms (jiffies). Default is 10. + + xen.event_loop_timeout= [XEN] + After which time (jiffies) the event handling loop + should start to delay EOI handling. Default is 2. + + xen.fifo_events= [XEN] + Boolean parameter to disable using fifo event handling + even if available. Normally fifo event handling is + preferred over the 2-level event handling, as it is + fairer and the number of possible event channels is + much higher. Default is on (use fifo events). + nopv= [X86,XEN,KVM,HYPER_V,VMWARE] Disables the PV optimizations forcing the guest to run as generic guest with no PV drivers. Currently support diff --git a/Documentation/admin-guide/nfs/fault_injection.rst b/Documentation/admin-guide/nfs/fault_injection.rst deleted file mode 100644 index eb029c0c15ce..000000000000 --- a/Documentation/admin-guide/nfs/fault_injection.rst +++ /dev/null @@ -1,70 +0,0 @@ -=================== -NFS Fault Injection -=================== - -Fault injection is a method for forcing errors that may not normally occur, or -may be difficult to reproduce. Forcing these errors in a controlled environment -can help the developer find and fix bugs before their code is shipped in a -production system. Injecting an error on the Linux NFS server will allow us to -observe how the client reacts and if it manages to recover its state correctly. - -NFSD_FAULT_INJECTION must be selected when configuring the kernel to use this -feature. - - -Using Fault Injection -===================== -On the client, mount the fault injection server through NFS v4.0+ and do some -work over NFS (open files, take locks, ...). - -On the server, mount the debugfs filesystem to <debug_dir> and ls -<debug_dir>/nfsd. This will show a list of files that will be used for -injecting faults on the NFS server. As root, write a number n to the file -corresponding to the action you want the server to take. The server will then -process the first n items it finds. So if you want to forget 5 locks, echo '5' -to <debug_dir>/nfsd/forget_locks. A value of 0 will tell the server to forget -all corresponding items. A log message will be created containing the number -of items forgotten (check dmesg). - -Go back to work on the client and check if the client recovered from the error -correctly. - - -Available Faults -================ -forget_clients: - The NFS server keeps a list of clients that have placed a mount call. If - this list is cleared, the server will have no knowledge of who the client - is, forcing the client to reauthenticate with the server. - -forget_openowners: - The NFS server keeps a list of what files are currently opened and who - they were opened by. Clearing this list will force the client to reopen - its files. - -forget_locks: - The NFS server keeps a list of what files are currently locked in the VFS. - Clearing this list will force the client to reclaim its locks (files are - unlocked through the VFS as they are cleared from this list). - -forget_delegations: - A delegation is used to assure the client that a file, or part of a file, - has not changed since the delegation was awarded. Clearing this list will - force the client to reacquire its delegation before accessing the file - again. - -recall_delegations: - Delegations can be recalled by the server when another client attempts to - access a file. This test will notify the client that its delegation has - been revoked, forcing the client to reacquire the delegation before using - the file again. - - -tools/nfs/inject_faults.sh script -================================= -This script has been created to ease the fault injection process. This script -will detect the mounted debugfs directory and write to the files located there -based on the arguments passed by the user. For example, running -`inject_faults.sh forget_locks 1` as root will instruct the server to forget -one lock. Running `inject_faults forget_locks` will instruct the server to -forgetall locks. diff --git a/Documentation/admin-guide/nfs/index.rst b/Documentation/admin-guide/nfs/index.rst index 6b5a3c90fac5..3601a708f333 100644 --- a/Documentation/admin-guide/nfs/index.rst +++ b/Documentation/admin-guide/nfs/index.rst @@ -12,4 +12,3 @@ NFS nfs-idmapper pnfs-block-server pnfs-scsi-server - fault_injection diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index 4b9d2e8e9142..f455fa00c00f 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm: - admin_reserve_kbytes - block_dump - compact_memory +- compaction_proactiveness - compact_unevictable_allowed - dirty_background_bytes - dirty_background_ratio @@ -37,6 +38,7 @@ Currently, these files are in /proc/sys/vm: - dirty_writeback_centisecs - drop_caches - extfrag_threshold +- highmem_is_dirtyable - hugetlb_shm_group - laptop_mode - legacy_va_layout diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst index f461d6c33534..86de8a1ad91c 100644 --- a/Documentation/admin-guide/xfs.rst +++ b/Documentation/admin-guide/xfs.rst @@ -210,6 +210,28 @@ When mounting an XFS filesystem, the following options are accepted. inconsistent namespace presentation during or after a failover event. +Deprecation of V4 Format +======================== + +The V4 filesystem format lacks certain features that are supported by +the V5 format, such as metadata checksumming, strengthened metadata +verification, and the ability to store timestamps past the year 2038. +Because of this, the V4 format is deprecated. All users should upgrade +by backing up their files, reformatting, and restoring from the backup. + +Administrators and users can detect a V4 filesystem by running xfs_info +against a filesystem mountpoint and checking for a string containing +"crc=". If no such string is found, please upgrade xfsprogs to the +latest version and try again. + +The deprecation will take place in two parts. Support for mounting V4 +filesystems can now be disabled at kernel build time via Kconfig option. +The option will default to yes until September 2025, at which time it +will be changed to default to no. In September 2030, support will be +removed from the codebase entirely. + +Note: Distributors may choose to withdraw V4 format support earlier than +the dates listed above. Deprecated Mount Options ======================== @@ -217,6 +239,9 @@ Deprecated Mount Options =========================== ================ Name Removal Schedule =========================== ================ +Mounting with V4 filesystem September 2030 +ikeep/noikeep September 2025 +attr2/noattr2 September 2025 =========================== ================ @@ -331,7 +356,12 @@ The following sysctls are available for the XFS filesystem: Deprecated Sysctls ================== -None at present. +=========================== ================ + Name Removal Schedule +=========================== ================ +fs.xfs.irix_sgid_inherit September 2025 +fs.xfs.irix_symlink_mode September 2025 +=========================== ================ Removed Sysctls |