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path: root/include/linux/ns_common.h
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2025-11-14nsproxy: fix free_nsproxy() and simplify create_new_namespaces()Christian Brauner
Make it possible to handle NULL being passed to the reference count helpers instead of forcing the caller to handle this. Afterwards we can nicely allow a cleanup guard to handle nsproxy freeing. Active reference count handling is not done in nsproxy_free() but rather in free_nsproxy() as nsproxy_free() is also called from setns() failure paths where a new nsproxy has been prepared but has not been marked as active via switch_task_namespaces(). Link: https://lore.kernel.org/690bfb9e.050a0220.2e3c35.0013.GAE@google.com Link: https://patch.msgid.link/20251111-sakralbau-guthaben-7dcc277d337f@brauner Fixes: 3c9820d5c64a ("ns: add active reference count") Reported-by: syzbot+0b2e79f91ff6579bfa5b@syzkaller.appspotmail.com Reported-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: drop custom reference count initialization for initial namespacesChristian Brauner
Initial namespaces don't modify their reference count anymore. They remain fixed at one so drop the custom refcount initializations. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-16-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: add asserts for initial namespace active reference countsChristian Brauner
They always remain fixed at one. Notice when that assumptions is broken. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-14-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: add asserts for initial namespace reference countsChristian Brauner
They always remain fixed at one. Notice when that assumptions is broken. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-13-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: make all reference counts on initial namespace a nopChristian Brauner
They are always active so no need to needlessly cacheline ping-pong. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-12-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: rename is_initial_namespace()Christian Brauner
Rename is_initial_namespace() to ns_init_inum() and make it symmetrical with the ns id variant. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-9-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: make is_initial_namespace() argument constChristian Brauner
We don't modify the data structure at all so pass it as const. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-8-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11nstree: switch to new structuresChristian Brauner
Switch the nstree management to the new combined structures. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-5-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-11ns: move namespace types into separate headerChristian Brauner
Add a dedicated header for namespace types. Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-1-e8a9264e0fb9@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-10ns: add asserts for active refcount underflowChristian Brauner
Add a few more assert to detect active reference count underflows. Link: https://patch.msgid.link/20251109-namespace-6-19-fixes-v1-6-ae8a4ad5a3b3@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-10ns: handle setns(pidfd, ...) cleanlyChristian Brauner
The setns() system call supports: (1) namespace file descriptors (nsfd) (2) process file descriptors (pidfd) When using nsfds the namespaces will remain active because they are pinned by the vfs. However, when pidfds are used things are more complicated. When the target task exits and passes through exit_nsproxy_namespaces() or is reaped and thus also passes through exit_cred_namespaces() after the setns()'ing task has called prepare_nsset() but before the active reference count of the set of namespaces it wants to setns() to might have been dropped already: P1 P2 pid_p1 = clone(CLONE_NEWUSER | CLONE_NEWNET | CLONE_NEWNS) pidfd = pidfd_open(pid_p1) setns(pidfd, CLONE_NEWUSER | CLONE_NEWNET | CLONE_NEWNS) prepare_nsset() exit(0) // ns->__ns_active_ref == 1 // parent_ns->__ns_active_ref == 1 -> exit_nsproxy_namespaces() -> exit_cred_namespaces() // ns_active_ref_put() will also put // the reference on the owner of the // namespace. If the only reason the // owning namespace was alive was // because it was a parent of @ns // it's active reference count now goes // to zero... -------------------------------- // | // ns->__ns_active_ref == 0 | // parent_ns->__ns_active_ref == 0 | | commit_nsset() -----------------> // If setns() // now manages to install the namespaces // it will call ns_active_ref_get() // on them thus bumping the active reference // count from zero again but without also // taking the required reference on the owner. // Thus we get: // // ns->__ns_active_ref == 1 // parent_ns->__ns_active_ref == 0 When later someone does ns_active_ref_put() on @ns it will underflow parent_ns->__ns_active_ref leading to a splat from our asserts thinking there are still active references when in fact the counter just underflowed. So resurrect the ownership chain if necessary as well. If the caller succeeded to grab passive references to the set of namespaces the setns() should simply succeed even if the target task exists or gets reaped in the meantime and thus has dropped all active references to its namespaces. The race is rare and can only be triggered when using pidfs to setns() to namespaces. Also note that active reference on initial namespaces are nops. Since we now always handle parent references directly we can drop ns_ref_active_get_owner() when adding a namespace to a namespace tree. This is now all handled uniformly in the places where the new namespaces actually become active. Link: https://patch.msgid.link/20251109-namespace-6-19-fixes-v1-5-ae8a4ad5a3b3@kernel.org Fixes: 3c9820d5c64a ("ns: add active reference count") Reported-by: syzbot+1957b26299cf3ff7890c@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-10ns: don't increment or decrement initial namespacesChristian Brauner
There's no need to bump the active reference counts of initial namespaces as they're always active and can simply remain at 1. Link: https://patch.msgid.link/20251109-namespace-6-19-fixes-v1-2-ae8a4ad5a3b3@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03nstree: add listns()Christian Brauner
Add a new listns() system call that allows userspace to iterate through namespaces in the system. This provides a programmatic interface to discover and inspect namespaces, enhancing existing namespace apis. Currently, there is no direct way for userspace to enumerate namespaces in the system. Applications must resort to scanning /proc/<pid>/ns/ across all processes, which is: 1. Inefficient - requires iterating over all processes 2. Incomplete - misses inactive namespaces that aren't attached to any running process but are kept alive by file descriptors, bind mounts, or parent namespace references 3. Permission-heavy - requires access to /proc for many processes 4. No ordering or ownership. 5. No filtering per namespace type: Must always iterate and check all namespaces. The list goes on. The listns() system call solves these problems by providing direct kernel-level enumeration of namespaces. It is similar to listmount() but obviously tailored to namespaces. /* * @req: Pointer to struct ns_id_req specifying search parameters * @ns_ids: User buffer to receive namespace IDs * @nr_ns_ids: Size of ns_ids buffer (maximum number of IDs to return) * @flags: Reserved for future use (must be 0) */ ssize_t listns(const struct ns_id_req *req, u64 *ns_ids, size_t nr_ns_ids, unsigned int flags); Returns: - On success: Number of namespace IDs written to ns_ids - On error: Negative error code /* * @size: Structure size * @ns_id: Starting point for iteration; use 0 for first call, then * use the last returned ID for subsequent calls to paginate * @ns_type: Bitmask of namespace types to include (from enum ns_type): * 0: Return all namespace types * MNT_NS: Mount namespaces * NET_NS: Network namespaces * USER_NS: User namespaces * etc. Can be OR'd together * @user_ns_id: Filter results to namespaces owned by this user namespace: * 0: Return all namespaces (subject to permission checks) * LISTNS_CURRENT_USER: Namespaces owned by caller's user namespace * Other value: Namespaces owned by the specified user namespace ID */ struct ns_id_req { __u32 size; /* sizeof(struct ns_id_req) */ __u32 spare; /* Reserved, must be 0 */ __u64 ns_id; /* Last seen namespace ID (for pagination) */ __u32 ns_type; /* Filter by namespace type(s) */ __u32 spare2; /* Reserved, must be 0 */ __u64 user_ns_id; /* Filter by owning user namespace */ }; Example 1: List all namespaces void list_all_namespaces(void) { struct ns_id_req req = { .size = sizeof(req), .ns_id = 0, /* Start from beginning */ .ns_type = 0, /* All types */ .user_ns_id = 0, /* All user namespaces */ }; uint64_t ids[100]; ssize_t ret; printf("All namespaces in the system:\n"); do { ret = listns(&req, ids, 100, 0); if (ret < 0) { perror("listns"); break; } for (ssize_t i = 0; i < ret; i++) printf(" Namespace ID: %llu\n", (unsigned long long)ids[i]); /* Continue from last seen ID */ if (ret > 0) req.ns_id = ids[ret - 1]; } while (ret == 100); /* Buffer was full, more may exist */ } Example 2: List network namespaces only void list_network_namespaces(void) { struct ns_id_req req = { .size = sizeof(req), .ns_id = 0, .ns_type = NET_NS, /* Only network namespaces */ .user_ns_id = 0, }; uint64_t ids[100]; ssize_t ret; ret = listns(&req, ids, 100, 0); if (ret < 0) { perror("listns"); return; } printf("Network namespaces: %zd found\n", ret); for (ssize_t i = 0; i < ret; i++) printf(" netns ID: %llu\n", (unsigned long long)ids[i]); } Example 3: List namespaces owned by current user namespace void list_owned_namespaces(void) { struct ns_id_req req = { .size = sizeof(req), .ns_id = 0, .ns_type = 0, /* All types */ .user_ns_id = LISTNS_CURRENT_USER, /* Current userns */ }; uint64_t ids[100]; ssize_t ret; ret = listns(&req, ids, 100, 0); if (ret < 0) { perror("listns"); return; } printf("Namespaces owned by my user namespace: %zd\n", ret); for (ssize_t i = 0; i < ret; i++) printf(" ns ID: %llu\n", (unsigned long long)ids[i]); } Example 4: List multiple namespace types void list_network_and_mount_namespaces(void) { struct ns_id_req req = { .size = sizeof(req), .ns_id = 0, .ns_type = NET_NS | MNT_NS, /* Network and mount */ .user_ns_id = 0, }; uint64_t ids[100]; ssize_t ret; ret = listns(&req, ids, 100, 0); printf("Network and mount namespaces: %zd found\n", ret); } Example 5: Pagination through large namespace sets void list_all_with_pagination(void) { struct ns_id_req req = { .size = sizeof(req), .ns_id = 0, .ns_type = 0, .user_ns_id = 0, }; uint64_t ids[50]; size_t total = 0; ssize_t ret; printf("Enumerating all namespaces with pagination:\n"); while (1) { ret = listns(&req, ids, 50, 0); if (ret < 0) { perror("listns"); break; } if (ret == 0) break; /* No more namespaces */ total += ret; printf(" Batch: %zd namespaces\n", ret); /* Last ID in this batch becomes start of next batch */ req.ns_id = ids[ret - 1]; if (ret < 50) break; /* Partial batch = end of results */ } printf("Total: %zu namespaces\n", total); } Permission Model listns() respects namespace isolation and capabilities: (1) Global listing (user_ns_id = 0): - Requires CAP_SYS_ADMIN in the namespace's owning user namespace - OR the namespace must be in the caller's namespace context (e.g., a namespace the caller is currently using) - User namespaces additionally allow listing if the caller has CAP_SYS_ADMIN in that user namespace itself (2) Owner-filtered listing (user_ns_id != 0): - Requires CAP_SYS_ADMIN in the specified owner user namespace - OR the namespace must be in the caller's namespace context - This allows unprivileged processes to enumerate namespaces they own (3) Visibility: - Only "active" namespaces are listed - A namespace is active if it has a non-zero __ns_ref_active count - This includes namespaces used by running processes, held by open file descriptors, or kept active by bind mounts - Inactive namespaces (kept alive only by internal kernel references) are not visible via listns() Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-19-2e6f823ebdc0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03nstree: add unified namespace listChristian Brauner
Allow to walk the unified namespace list completely locklessly. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-18-2e6f823ebdc0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03nstree: maintain list of owned namespacesChristian Brauner
The namespace tree doesn't express the ownership concept of namespace appropriately. Maintain a list of directly owned namespaces per user namespace. This will allow userspace and the kernel to use the listns() system call to walk the namespace tree by owning user namespace. The rbtree is used to find the relevant namespace entry point which allows to continue iteration and the owner list can be used to walk the tree completely lock free. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-16-2e6f823ebdc0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03nstree: assign fixed ids to the initial namespacesChristian Brauner
The initial set of namespace comes with fixed inode numbers making it easy for userspace to identify them solely based on that information. This has long preceeded anything here. Similarly, let's assign fixed namespace ids for the initial namespaces. Kill the cookie and use a sequentially increasing number. This has the nice side-effect that the owning user namespace will always have a namespace id that is smaller than any of it's descendant namespaces. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-15-2e6f823ebdc0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03nstree: introduce a unified treeChristian Brauner
This will allow userspace to lookup and stat a namespace simply by its identifier without having to know what type of namespace it is. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-13-2e6f823ebdc0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03ns: use anonymous struct to group list memberChristian Brauner
Make it easier to spot that they belong together conceptually. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-12-2e6f823ebdc0@kernel.org Tested-by: syzbot@syzkaller.appspotmail.com Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03ns: add active reference countChristian Brauner
The namespace tree is, among other things, currently used to support file handles for namespaces. When a namespace is created it is placed on the namespace trees and when it is destroyed it is removed from the namespace trees. While a namespace is on the namespace trees with a valid reference count it is possible to reopen it through a namespace file handle. This is all fine but has some issues that should be addressed. On current kernels a namespace is visible to userspace in the following cases: (1) The namespace is in use by a task. (2) The namespace is persisted through a VFS object (namespace file descriptor or bind-mount). Note that (2) only cares about direct persistence of the namespace itself not indirectly via e.g., file->f_cred file references or similar. (3) The namespace is a hierarchical namespace type and is the parent of a single or multiple child namespaces. Case (3) is interesting because it is possible that a parent namespace might not fulfill any of (1) or (2), i.e., is invisible to userspace but it may still be resurrected through the NS_GET_PARENT ioctl(). Currently namespace file handles allow much broader access to namespaces than what is currently possible via (1)-(3). The reason is that namespaces may remain pinned for completely internal reasons yet are inaccessible to userspace. For example, a user namespace my remain pinned by get_cred() calls to stash the opener's credentials into file->f_cred. As it stands file handles allow to resurrect such a users namespace even though this should not be possible via (1)-(3). This is a fundamental uapi change that we shouldn't do if we don't have to. Consider the following insane case: Various architectures support the CONFIG_MMU_LAZY_TLB_REFCOUNT option which uses lazy TLB destruction. When this option is set a userspace task's struct mm_struct may be used for kernel threads such as the idle task and will only be destroyed once the cpu's runqueue switches back to another task. But because of ptrace() permission checks struct mm_struct stashes the user namespace of the task that struct mm_struct originally belonged to. The kernel thread will take a reference on the struct mm_struct and thus pin it. So on an idle system user namespaces can be persisted for arbitrary amounts of time which also means that they can be resurrected using namespace file handles. That makes no sense whatsoever. The problem is of course excarabted on large systems with a huge number of cpus. To handle this nicely we introduce an active reference count which tracks (1)-(3). This is easy to do as all of these things are already managed centrally. Only (1)-(3) will count towards the active reference count and only namespaces which are active may be opened via namespace file handles. The problem is that namespaces may be resurrected. Which means that they can become temporarily inactive and will be reactived some time later. Currently the only example of this is the SIOGCSKNS socket ioctl. The SIOCGSKNS ioctl allows to open a network namespace file descriptor based on a socket file descriptor. If a socket is tied to a network namespace that subsequently becomes inactive but that socket is persisted by another process in another network namespace (e.g., via SCM_RIGHTS of pidfd_getfd()) then the SIOCGSKNS ioctl will resurrect this network namespace. So calls to open_related_ns() and open_namespace() will end up resurrecting the corresponding namespace tree. Note that the active reference count does not regulate the lifetime of the namespace itself. This is still done by the normal reference count. The active reference count can only be elevated if the regular reference count is elevated. The active reference count also doesn't regulate the presence of a namespace on the namespace trees. It only regulates its visiblity to namespace file handles (and in later patches to listns()). A namespace remains on the namespace trees from creation until its actual destruction. This will allow the kernel to always reach any namespace trivially and it will also enable subsystems like bpf to walk the namespace lists on the system for tracing or general introspection purposes. Note that different namespaces have different visibility lifetimes on current kernels. While most namespace are immediately released when the last task using them exits, the user- and pid namespace are persisted and thus both remain accessible via /proc/<pid>/ns/<ns_type>. The user namespace lifetime is aliged with struct cred and is only released through exit_creds(). However, it becomes inaccessible to userspace once the last task using it is reaped, i.e., when release_task() is called and all proc entries are flushed. Similarly, the pid namespace is also visible until the last task using it has been reaped and the associated pid numbers are freed. The active reference counts of the user- and pid namespace are decremented once the task is reaped. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-11-2e6f823ebdc0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03ns: add __ns_ref_read()Christian Brauner
Implement ns_ref_read() the same way as ns_ref_{get,put}(). No point in making that any more special or different from the other helpers. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-9-2e6f823ebdc0@kernel.org Tested-by: syzbot@syzkaller.appspotmail.com Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03ns: initialize ns_list_node for initial namespacesChristian Brauner
Make sure that the list is always initialized for initial namespaces. Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-8-2e6f823ebdc0@kernel.org Fixes: 885fc8ac0a4d ("nstree: make iterator generic") Tested-by: syzbot@syzkaller.appspotmail.com Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-03ns: add NS_COMMON_INIT()Christian Brauner
Add an initializer that can be used for the ns common initialization for static namespace such as most init namespaces. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Link: https://patch.msgid.link/87ecqhy2y5.ffs@tglx Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-25ns: move ns type into struct ns_commonChristian Brauner
It's misplaced in struct proc_ns_operations and ns->ops might be NULL if the namespace is compiled out but we still want to know the type of the namespace for the initial namespace struct. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-22ns: simplify ns_common_init() furtherChristian Brauner
Simply derive the ns operations from the namespace type. Acked-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19ns: rename to __ns_refChristian Brauner
Make it easier to grep and rename to ns_count. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19ns: add reference count helpersChristian Brauner
Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19ns: add ns_common_free()Christian Brauner
And drop ns_free_inum(). Anything common that can be wasted centrally should be wasted in the new common helper. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19nscommon: simplify initializationChristian Brauner
There's a lot of information that namespace implementers don't need to know about at all. Encapsulate this all in the initialization helper. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19nscommon: move to separate fileChristian Brauner
It's really awkward spilling the ns common infrastructure into multiple headers. Move it to a separate file. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19nstree: make iterator genericChristian Brauner
Move the namespace iteration infrastructure originally introduced for mount namespaces into a generic library usable by all namespace types. Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19ns: move to_ns_common() to ns_common.hChristian Brauner
Move the helper to ns_common.h where it belongs. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-01nsfs: convert to path_from_stashed() helperChristian Brauner
Use the newly added path_from_stashed() helper for nsfs. Link: https://lore.kernel.org/r/20240218-neufahrzeuge-brauhaus-fb0eb6459771@brauner Signed-off-by: Christian Brauner <brauner@kernel.org>
2020-08-19ns: Add a common refcount into ns_commonChristian Brauner
Currently every namespace type has its own lifetime counter which is stored in the specific namespace struct. The lifetime counters are used identically for all namespaces types. Namespaces may of course have additional unrelated counters and these are not altered. This introduces a common lifetime counter into struct ns_common. The ns_common struct encompasses information that all namespaces share. That should include the lifetime counter since its common for all of them. It also allows us to unify the type of the counters across all namespaces. Most of them use refcount_t but one uses atomic_t and at least one uses kref. Especially the last one doesn't make much sense since it's just a wrapper around refcount_t since 2016 and actually complicates cleanup operations by having to use container_of() to cast the correct namespace struct out of struct ns_common. Having the lifetime counter for the namespaces in one place reduces maintenance cost. Not just because after switching all namespaces over we will have removed more code than we added but also because the logic is more easily understandable and we indicate to the user that the basic lifetime requirements for all namespaces are currently identical. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> [christian.brauner@ubuntu.com: rewrite commit & split into two patches] Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-12-10take the targets of /proc/*/ns/* symlinks to separate fsAl Viro
New pseudo-filesystem: nsfs. Targets of /proc/*/ns/* live there now. It's not mountable (not even registered, so it's not in /proc/filesystems, etc.). Files on it *are* bindable - we explicitly permit that in do_loopback(). This stuff lives in fs/nsfs.c now; proc_ns_fget() moved there as well. get_proc_ns() is a macro now (it's simply returning ->i_private; would have been an inline, if not for header ordering headache). proc_ns_inode() is an ex-parrot. The interface used in procfs is ns_get_path(path, task, ops) and ns_get_name(buf, size, task, ops). Dentries and inodes are never hashed; a non-counting reference to dentry is stashed in ns_common (removed by ->d_prune()) and reused by ns_get_path() if present. See ns_get_path()/ns_prune_dentry/nsfs_evict() for details of that mechanism. As the result, proc_ns_follow_link() has stopped poking in nd->path.mnt; it does nd_jump_link() on a consistent <vfsmount,dentry> pair it gets from ns_get_path(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-04copy address of proc_ns_ops into ns_commonAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-04common object embedded into various struct ....nsAl Viro
for now - just move corresponding ->proc_inum instances over there Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>