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2012-12-14userns: Require CAP_SYS_ADMIN for most uses of setns.Eric W. Biederman1-1/+2
Andy Lutomirski <luto@amacapital.net> found a nasty little bug in the permissions of setns. With unprivileged user namespaces it became possible to create new namespaces without privilege. However the setns calls were relaxed to only require CAP_SYS_ADMIN in the user nameapce of the targed namespace. Which made the following nasty sequence possible. pid = clone(CLONE_NEWUSER | CLONE_NEWNS); if (pid == 0) { /* child */ system("mount --bind /home/me/passwd /etc/passwd"); } else if (pid != 0) { /* parent */ char path[PATH_MAX]; snprintf(path, sizeof(path), "/proc/%u/ns/mnt"); fd = open(path, O_RDONLY); setns(fd, 0); system("su -"); } Prevent this possibility by requiring CAP_SYS_ADMIN in the current user namespace when joing all but the user namespace. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-12-11mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLBAndi Kleen1-1/+2
There was some desire in large applications using MAP_HUGETLB or SHM_HUGETLB to use 1GB huge pages on some mappings, and stay with 2MB on others. This is useful together with NUMA policy: use 2MB interleaving on some mappings, but 1GB on local mappings. This patch extends the IPC/SHM syscall interfaces slightly to allow specifying the page size. It borrows some upper bits in the existing flag arguments and allows encoding the log of the desired page size in addition to the *_HUGETLB flag. When 0 is specified the default size is used, this makes the change fully compatible. Extending the internal hugetlb code to handle this is straight forward. Instead of a single mount it just keeps an array of them and selects the right mount based on the specified page size. When no page size is specified it uses the mount of the default page size. The change is not visible in /proc/mounts because internal mounts don't appear there. It also has very little overhead: the additional mounts just consume a super block, but not more memory when not used. I also exported the new flags to the user headers (they were previously under __KERNEL__). Right now only symbols for x86 and some other architecture for 1GB and 2MB are defined. The interface should already work for all other architectures though. Only architectures that define multiple hugetlb sizes actually need it (that is currently x86, tile, powerpc). However tile and powerpc have user configurable hugetlb sizes, so it's not easy to add defines. A program on those architectures would need to query sysfs and use the appropiate log2. [akpm@linux-foundation.org: cleanups] [rientjes@google.com: fix build] [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-11-20proc: Usable inode numbers for the namespace file descriptors.Eric W. Biederman2-0/+18
Assign a unique proc inode to each namespace, and use that inode number to ensure we only allocate at most one proc inode for every namespace in proc. A single proc inode per namespace allows userspace to test to see if two processes are in the same namespace. This has been a long requested feature and only blocked because a naive implementation would put the id in a global space and would ultimately require having a namespace for the names of namespaces, making migration and certain virtualization tricks impossible. We still don't have per superblock inode numbers for proc, which appears necessary for application unaware checkpoint/restart and migrations (if the application is using namespace file descriptors) but that is now allowd by the design if it becomes important. I have preallocated the ipc and uts initial proc inode numbers so their structures can be statically initialized. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-11-20userns: Make create_new_namespaces take a user_ns parameterEric W. Biederman1-6/+4
Modify create_new_namespaces to explicitly take a user namespace parameter, instead of implicitly through the task_struct. This allows an implementation of unshare(CLONE_NEWUSER) where the new user namespace is not stored onto the current task_struct until after all of the namespaces are created. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-11-20userns: Allow unprivileged use of setns.Eric W. Biederman1-1/+5
- Push the permission check from the core setns syscall into the setns install methods where the user namespace of the target namespace can be determined, and used in a ns_capable call. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-10-12audit: make audit_inode take struct filenameJeff Layton1-2/+2
Keep a pointer to the audit_names "slot" in struct filename. Have all of the audit_inode callers pass a struct filename ponter to audit_inode instead of a string pointer. If the aname field is already populated, then we can skip walking the list altogether and just use it directly. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-12vfs: define struct filename and have getname() return itJeff Layton1-6/+7
getname() is intended to copy pathname strings from userspace into a kernel buffer. The result is just a string in kernel space. It would however be quite helpful to be able to attach some ancillary info to the string. For instance, we could attach some audit-related info to reduce the amount of audit-related processing needed. When auditing is enabled, we could also call getname() on the string more than once and not need to recopy it from userspace. This patchset converts the getname()/putname() interfaces to return a struct instead of a string. For now, the struct just tracks the string in kernel space and the original userland pointer for it. Later, we'll add other information to the struct as it becomes convenient. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-12audit: set the name_len in audit_inode for parent lookupsJeff Layton1-4/+4
Currently, this gets set mostly by happenstance when we call into audit_inode_child. While that might be a little more efficient, it seems wrong. If the syscall ends up failing before audit_inode_child ever gets called, then you'll have an audit_names record that shows the full path but has the parent inode info attached. Fix this by passing in a parent flag when we call audit_inode that gets set to the value of LOOKUP_PARENT. We can then fix up the pathname for the audit entry correctly from the get-go. While we're at it, clean up the no-op macro for audit_inode in the !CONFIG_AUDITSYSCALL case. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-09ipc/mqueue: remove unnecessary rb_init_node() callsMichel Lespinasse1-3/+0
Commit d6629859b36d ("ipc/mqueue: improve performance of send/recv") and ce2d52cc ("ipc/mqueue: add rbtree node caching support") introduced an rbtree of message priorities, and usage of rb_init_node() to initialize the corresponding nodes. As it turns out, rb_init_node() is unnecessary here, as the nodes are fully initialized on insertion by rb_link_node() and the code doesn't access nodes that aren't inserted on the rbtree. Removing the rb_init_node() calls as I removed that function during rbtree API cleanups (the only other use of it was in a place that similarly didn't require it). Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-26switch simple cases of fget_light to fdgetAl Viro1-43/+41
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26switch mqueue syscalls to fget_light()Al Viro1-12/+14
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-06userns: Convert ipc to use kuid and kgid where appropriateEric W. Biederman5-33/+50
- Store the ipc owner and creator with a kuid - Store the ipc group and the crators group with a kgid. - Add error handling to ipc_update_perms, allowing it to fail if the uids and gids can not be converted to kuids or kgids. - Modify the proc files to display the ipc creator and owner in the user namespace of the opener of the proc file. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-08-18mqueue: lift mnt_want_write() outside ->i_mutex, clean up a bitAl Viro1-33/+28
the way it abuses ->d_fsdata still needs to be killed, but that's a separate story. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-30ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSIONWill Deacon3-4/+4
Rather than #define the options manually in the architecture code, add Kconfig options for them and select them there instead. This also allows us to select the compat IPC version parsing automatically for platforms using the old compat IPC interface. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30ipc: compat: use signed size_t types for msgsnd and msgrcvWill Deacon1-4/+4
The msgsnd and msgrcv system calls use size_t to represent the size of the message being transferred. POSIX states that values of msgsz greater than SSIZE_MAX cause the result to be implementation-defined. On Linux, this equates to returning -EINVAL if (long) msgsz < 0. For compat tasks where !CONFIG_ARCH_WANT_OLD_COMPAT_IPC and compat_size_t is smaller than size_t, negative size values passed from userspace will be interpreted as positive values by do_msg{rcv,snd} and will fail to exit early with -EINVAL. This patch changes the compat prototypes for msg{rcv,snd} so that the message size is represented as a compat_ssize_t, which we cast to the native ssize_t type for the core IPC code. Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPCWill Deacon1-1/+1
Commit 48b25c43e6ee ("ipc: provide generic compat versions of IPC syscalls") added a new ARCH_WANT_OLD_COMPAT_IPC config option for architectures to select if their compat target requires the old IPC syscall interface. For architectures (such as AArch64) that do not require the internal calling conventions provided by this option, but have a compat target where the C library passes the IPC_64 flag explicitly, compat_ipc_parse_version no longer strips out the flag before calling the native system call implementation, resulting in unknown SHM/IPC commands and -EINVAL being returned to userspace. This patch separates the selection of the internal calling conventions for the IPC syscalls from the version parsing, allowing architectures to select __ARCH_WANT_COMPAT_IPC_PARSE_VERSION if they want to use version parsing whilst retaining the newer syscall calling conventions. Acked-by: Chris Metcalf <cmetcalf@tilera.com> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30ipc: add COMPAT_SHMLBA supportWill Deacon3-7/+12
If the SHMLBA definition for a native task differs from the definition for a compat task, the do_shmat() function would need to handle both. This patch introduces COMPAT_SHMLBA, which is used by the compat shmat syscall when calling the ipc code and allows architectures such as AArch64 (where the native SHMLBA is 64k but the compat (AArch32) definition is 16k) to provide the correct semantics for compat IPC system calls. Cc: David S. Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-23switch dentry_open() to struct path, make it grab references itselfAl Viro1-70/+47
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14don't pass nameidata * to vfs_create()Al Viro1-1/+1
all we want is a boolean flag, same as the method gets now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14don't pass nameidata to ->create()Al Viro1-1/+1
boolean "does it have to be exclusive?" flag is passed instead; Local filesystem should just ignore it - the object is guaranteed not to be there yet. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-07ipc: shm: restore MADV_REMOVE functionality on shared memory segmentsWill Deacon1-0/+12
Commit 17cf28afea2a ("mm/fs: remove truncate_range") removed the truncate_range inode operation in favour of the fallocate file operation. When using SYSV IPC shared memory segments, calling madvise with the MADV_REMOVE advice on an area of shared memory will attempt to invoke the .fallocate function for the shm_file_operations, which is NULL and therefore returns -EOPNOTSUPP to userspace. The previous behaviour would inherit the inode_operations from the underlying tmpfs file and invoke truncate_range there. This patch restores the previous behaviour by wrapping the underlying fallocate function in shm_fallocate, as we do for fsync. [hughd@google.com: use -ENOTSUPP in shm_fallocate()] Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-01switch aio and shm to do_mmap_pgoff(), make do_mmap() staticAl Viro1-1/+1
after all, 0 bytes and 0 pages is the same thing... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01take security_mmap_file() outside of ->mmap_semAl Viro1-0/+5
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-31ipc/mqueue: add rbtree node caching supportDoug Ledford1-23/+81
When I wrote the first patch that added the rbtree support for message queue insertion, it sped up the case where the queue was very full drastically from the original code. It, however, slowed down the case where the queue was empty (not drastically though). This patch caches the last freed rbtree node struct so we can quickly reuse it when we get a new message. This is the common path for any queue that very frequently goes from 0 to 1 then back to 0 messages in queue. Andrew Morton didn't like that we were doing a GFP_ATOMIC allocation in msg_insert, so this patch attempts to speculatively allocate a new node struct outside of the spin lock when we know we need it, but will still fall back to a GFP_ATOMIC allocation if it has to. Once I added the caching, the necessary various ret = ; spin_unlock gyrations in mq_timedsend were getting pretty ugly, so this also slightly refactors that function to streamline the flow of the code and the function exit. Finally, while working on getting performance back I made sure that all of the node structs were always fully initialized when they were first used, rendering the use of kzalloc unnecessary and a waste of CPU cycles. The net result of all of this is: 1) We will avoid a GFP_ATOMIC allocation when possible, but fall back on it when necessary. 2) We will speculatively allocate a node struct using GFP_KERNEL if our cache is empty (and save the struct to our cache if it's still empty after we have obtained the spin lock). 3) The performance of the common queue empty case has significantly improved and is now much more in line with the older performance for this case. The performance changes are: Old mqueue new mqueue new mqueue + caching queue empty send/recv 305/288ns 349/318ns 310/322ns I don't think we'll ever be able to get the recv performance back, but that's because the old recv performance was a direct result and consequence of the old methods abysmal send performance. The recv path simply must do more so that the send path does not incur such a penalty under higher queue depths. As it turns out, the new caching code also sped up the various queue full cases relative to my last patch. That could be because of the difference between the syscall path in 3.3.4-rc5 and 3.3.4-rc6, or because of the change in code flow in the mq_timedsend routine. Regardless, I'll take it. It wasn't huge, and I *would* say it was within the margin for error, but after many repeated runs what I'm seeing is that the old numbers trend slightly higher (about 10 to 20ns depending on which test is the one running). [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: strengthen checks on mqueue creationDoug Ledford1-9/+18
We already check the mq attr struct if it's passed in, but now that the admin can set system wide defaults separate from maximums, it's actually possible to set the defaults to something that would overflow. So, if there is no attr struct passed in to the open call, check the default values. While we are at it, simplify mq_attr_ok() by making it return 0 or an error condition, so that way if we add more tests to it later, we have the option of what error should be returned instead of the calling location having to pick a possibly inaccurate error code. [akpm@linux-foundation.org: s/ENOMEM/EOVERFLOW/] Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Manfred Spraul <manfred@colorfullife.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: correct mq_attr_ok testDoug Ledford1-3/+8
While working on the other parts of the mqueue stuff, I noticed that the calculation for overflow in mq_attr_ok didn't actually match reality (this is especially true since my last patch which changed how we account memory slightly). In particular, we used to test for overflow using: msgs * msgsize + msgs * sizeof(struct msg_msg *) That was never really correct because each message we allocate via load_msg() is actually a struct msg_msg followed by the data for the message (and if struct msg_msg + data exceeds PAGE_SIZE we end up allocating struct msg_msgseg structs too, but accounting for them would get really tedious, so let's ignore those...they're only a pointer in size anyway). This patch updates the calculation to be more accurate in regards to maximum possible memory consumption by the mqueue. [akpm@linux-foundation.org: add a local to simplify overflow-checking expression] Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Manfred Spraul <manfred@colorfullife.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: improve performance of send/recvDoug Ledford1-43/+130
The existing implementation of the POSIX message queue send and recv functions is, well, abysmal. Even worse than abysmal. I submitted a patch to increase the maximum POSIX message queue limit to 65536 due to customer needs, however, upon looking over the send/recv implementation, I realized that my customer needs help with that too even if they don't know it. The basic problem is that, given the fairly typical use case scenario for a large queue of queueing lots of messages all at the same priority (I verified with my customer that this is indeed what their app does), the msg_insert routine is basically a frikkin' bubble sort. I mean, whoa, that's *so* middle school. OK, OK, to not slam the original author too much, I'm sure they didn't envision a queue depth of 50,000+ messages. No one would think that moving elements in an array, one at a time, and dereferencing each pointer in that array to check priority of the message being pointed too, again one at a time, for 50,000+ times would be good. So let's assume that, as is typical, the users have found a way to break our code simply by using it in a way we didn't envision. Fair enough. "So, just how broken is it?", you ask. I wondered the same thing, so I wrote an app to let me know. It's my next patch. It gave me some interesting results. Here's what it tested: Interference with other apps - In continuous mode, the app just sits there and hits a message queue forever, while you go do something productive on another terminal using other CPUs. You then measure how long it takes you to do that something productive. Then you restart the app in fake continuous mode, and it sits in a tight loop on a CPU while you repeat your tests. The whole point of this is to keep one CPU tied up (so it can't be used in your other work) but in one case tied up hitting the mqueue code so we can see the effect of walking that 65,528 element array one pointer at a time on the global CPU cache. If it's bad, then it will slow down your app on the other CPUs just by polluting cache mercilessly. In the fake case, it will be in a tight loop, but not polluting cache. Testing the mqueue subsystem directly - Here we just run a number of tests to see how the mqueue subsystem performs under different conditions. A couple conditions are known to be worst case for the old system, and some routines, so this tests all of them. So, on to the results already: Subsystem/Test Old New Time to compile linux kernel (make -j12 on a 6 core CPU) Running mqueue test user 49m10.744s user 45m26.294s sys 5m51.924s sys 4m59.894s total 55m02.668s total 50m26.188s Running fake test user 45m32.686s user 45m18.552s sys 5m12.465s sys 4m56.468s total 50m45.151s total 50m15.020s % slowdown from mqueue cache thrashing ~8% ~.5% Avg time to send/recv (in nanoseconds per message) when queue empty 305/288 349/318 when queue full (65528 messages) constant priority 526589/823 362/314 increasing priority 403105/916 495/445 decreasing priority 73420/594 482/409 random priority 280147/920 546/436 Time to fill/drain queue (65528 messages, in seconds) constant priority 17.37/.12 .13/.12 increasing priority 4.14/.14 .21/.18 decreasing priority 12.93/.13 .21/.18 random priority 8.88/.16 .22/.17 So, I think the results speak for themselves. It's possible this implementation could be improved by cacheing at least one priority level in the node tree (that would bring the queue empty performance more in line with the old implementation), but this works and is *so* much better than what we had, especially for the common case of a single priority in use, that further refinements can be in follow on patches. [akpm@linux-foundation.org: fix typo in comment, remove stray semicolon] [levinsasha928@gmail.com: use correct gfp flags in msg_insert] Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Manfred Spraul <manfred@colorfullife.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31mqueue: separate mqueue default value from maximum valueKOSAKI Motohiro2-3/+24
Commit b231cca4381e ("message queues: increase range limits") changed mqueue default value when attr parameter is specified NULL from hard coded value to fs.mqueue.{msg,msgsize}_max sysctl value. This made large side effect. When user need to use two mqueue applications 1) using !NULL attr parameter and it require big message size and 2) using NULL attr parameter and only need small size message, app (1) require to raise fs.mqueue.msgsize_max and app (2) consume large memory size even though it doesn't need. Doug Ledford propsed to switch back it to static hard coded value. However it also has a compatibility problem. Some applications might started depend on the default value is tunable. The solution is to separate default value from maximum value. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Joe Korty <joe.korty@ccur.com> Cc: Amerigo Wang <amwang@redhat.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31mqueue: don't use kmalloc with KMALLOC_MAX_SIZEKOSAKI Motohiro1-2/+2
KMALLOC_MAX_SIZE is not a good threshold. It is extremely high and problematic. Unfortunately, some silly drivers depend on this and we can't change it. But any new code needn't use such extreme ugly high order allocations. It brings us awful fragmentation issues and system slowdown. Signed-off-by: KOSAKI Motohiro <mkosaki@jp.fujitsu.com> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Joe Korty <joe.korty@ccur.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Joe Korty <joe.korty@ccur.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: update maximums for the mqueue subsystemDoug Ledford1-2/+9
Commit b231cca4381e ("message queues: increase range limits") changed the maximum size of a message in a message queue from INT_MAX to 8192*128. Unfortunately, we had customers that relied on a size much larger than 8192*128 on their production systems. After reviewing POSIX, we found that it is silent on the maximum message size. We did find a couple other areas in which it was not silent. Fix up the mqueue maximums so that the customer's system can continue to work, and document both the POSIX and real world requirements in ipc_namespace.h so that we don't have this issue crop back up. Also, commit 9cf18e1dd74cd0 ("ipc: HARD_MSGMAX should be higher not lower on 64bit") fiddled with HARD_MSGMAX without realizing that the number was intentionally in place to limit the msg queue depth to one that was small enough to kmalloc an array of pointers (hence why we divided 128k by sizeof(long)). If we wish to meet POSIX requirements, we have no choice but to change our allocation to a vmalloc instead (at least for the large queue size case). With that, it's possible to increase our allowed maximum to the POSIX requirements (or more if we choose). [sfr@canb.auug.org.au: using vmalloc requires including vmalloc.h] Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Joe Korty <joe.korty@ccur.com> Cc: Jiri Slaby <jslaby@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: enforce hard limitsDoug Ledford1-3/+5
In two places we don't enforce the hard limits for CAP_SYS_RESOURCE apps. In preparation for making more reasonable hard limits, start enforcing them even on CAP_SYS_RESOURCE. Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Joe Korty <joe.korty@ccur.com> Cc: Jiri Slaby <jslaby@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: switch back to using non-max values on createDoug Ledford1-2/+3
Commit b231cca4381e ("message queues: increase range limits") changed how we create a queue that does not include an attr struct passed to open so that it creates the queue with whatever the maximum values are. However, if the admin has set the maximums to allow flexibility in creating a queue (aka, both a large size and large queue are allowed, but combined they create a queue too large for the RLIMIT_MSGQUEUE of the user), then attempts to create a queue without an attr struct will fail. Switch back to using acceptable defaults regardless of what the maximums are. Note: so far, we only know of a few applications that rely on this behavior (specifically, set the maximums in /proc, then run the application which calls mq_open() without passing in an attr struct, and the application expects the newly created message queue to have the maximum sizes that were set in /proc used on the mq_open() call, and all of those applications that we know of are actually part of regression test suites that were coded to do something like this: for size in 4096 65536 $((1024 * 1024)) $((16 * 1024 * 1024)); do echo $size > /proc/sys/fs/mqueue/msgsize_max mq_open || echo "Error opening mq with size $size" done These test suites that depend on any behavior like this are broken. The concept that programs should rely upon the system wide maximum in order to get their desired results instead of simply using a attr struct to specify what they want is fundamentally unfriendly programming practice for any multi-tasking OS. Fixing this will break those few apps that we know of (and those app authors recognize the brokenness of their code and the need to fix it). However, the following patch "mqueue: separate mqueue default value" allows a workaround in the form of new knobs for the default msg queue creation parameters for any software out there that we don't already know about that might rely on this behavior at the moment. Signed-off-by: Doug Ledford <dledford@redhat.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Joe Korty <joe.korty@ccur.com> Cc: Jiri Slaby <jslaby@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31ipc/mqueue: cleanup definition names and locationsDoug Ledford1-23/+8
Since commit b231cca4381e ("message queues: increase range limits") on Oct 18, 2008, calls to mq_open() that did not pass in an attribute struct and expected to get default values for the size of the queue and the max message size now get the system wide maximums instead of hardwired defaults like they used to get. This was uncovered when one of the earlier patches in this patch set increased the default system wide maximums at the same time it increased the hard ceiling on the system wide maximums (a customer specifically needed the hard ceiling brought back up, the new ceiling that commit b231cca4381e introduced was too low for their production systems). By increasing the default maximums and not realising they were tied to any attempt to create a message queue without an attribute struct, I had inadvertently made it such that all message queue creation attempts without an attribute struct were failing because the new default maximums would create a queue that exceeded the default rlimit for message queue bytes. As a result, the system wide defaults were brought back down to their previous levels, and the system wide ceilings on the maximums were raised to meet the customer's needs. However, the fact that the no attribute struct behavior of mq_open() could be broken by changing the system wide maximums for message queues was seen as fundamentally broken itself. So we hardwired the no attribute case back like it used to be. But, then we realized that on the very off chance that some piece of software in the wild depended on that behavior, we could work around that issue by adding two new knobs to /proc that allowed setting the defaults for message queues created without an attr struct separately from the system wide maximums. What is not an option IMO is to leave the current behavior in place. No piece of software should ever rely on setting the system wide maximums in order to get a desired message queue. Such a reliance would be so fundamentally multitasking OS unfriendly as to not really be tolerable. Fortunately, we don't know of any software in the wild that uses this except for a regression test program that caught the issue in the first place. If there is though, we have made accommodations with the two new /proc knobs (and that's all the accommodations such fundamentally broken software can be allowed).. This patch: The various defines for minimums and maximums of the sysctl controllable mqueue values are scattered amongst different files and named inconsistently. Move them all into ipc_namespace.h and make them have consistent names. Additionally, make the number of queues per namespace also have a minimum and maximum and use the same sysctl function as the other two settable variables. Signed-off-by: Doug Ledford <dledford@redhat.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Joe Korty <joe.korty@ccur.com> Cc: Jiri Slaby <jslaby@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-06vfs: Rename end_writeback() to clear_inode()Jan Kara1-1/+1
After we moved inode_sync_wait() from end_writeback() it doesn't make sense to call the function end_writeback() anymore. Rename it to clear_inode() which well says what the function really does - set I_CLEAR flag. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
2012-05-03userns: Replace user_ns_map_uid and user_ns_map_gid with from_kuid and from_kgidEric W. Biederman1-2/+1
These function are no longer needed replace them with their more useful equivalents. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-04-07mqueue: Explicitly capture the user namespace to send the notification to.Eric W. Biederman1-1/+8
Stop relying on user->user_ns which is going away and instead capture the user_namespace of the process we are supposed to notify. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-04-07userns: Use cred->user_ns instead of cred->user->user_nsEric W. Biederman1-1/+1
Optimize performance and prepare for the removal of the user_ns reference from user_struct. Remove the slow long walk through cred->user->user_ns and instead go straight to cred->user_ns. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-03-21hugetlbfs: fix alignment of huge page requestsSteven Truelove1-1/+1
When calling shmget() with SHM_HUGETLB, shmget aligns the request size to PAGE_SIZE, but this is not sufficient. Modify hugetlb_file_setup() to align requests to the huge page size, and to accept an address argument so that all alignment checks can be performed in hugetlb_file_setup(), rather than in its callers. Change newseg() and mmap_pgoff() to match the new prototype and eliminate a now redundant alignment check. [akpm@linux-foundation.org: fix build] Signed-off-by: Steven Truelove <steven.truelove@utoronto.ca> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-20switch open-coded instances of d_make_root() to new helperAl Viro1-17/+7
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-15[PATCH v3] ipc: provide generic compat versions of IPC syscallsChris Metcalf1-6/+64
When using the "compat" APIs, architectures will generally want to be able to make direct syscalls to msgsnd(), shmctl(), etc., and in the kernel we would want them to be handled directly by compat_sys_xxx() functions, as is true for other compat syscalls. However, for historical reasons, several of the existing compat IPC syscalls do not do this. semctl() expects a pointer to the fourth argument, instead of the fourth argument itself. msgsnd(), msgrcv() and shmat() expect arguments in different order. This change adds an ARCH_WANT_OLD_COMPAT_IPC config option that can be set to preserve this behavior for ports that use it (x86, sparc, powerpc, s390, and mips). No actual semantics are changed for those architectures, and there is only a minimal amount of code refactoring in ipc/compat.c. Newer architectures like tile (and perhaps future architectures such as arm64 and unicore64) should not select this option, and thus can avoid having any IPC-specific code at all in their architecture-specific compat layer. In the same vein, if this option is not selected, IPC_64 mode is assumed, since that's what the <asm-generic> headers expect. The workaround code in "tile" for msgsnd() and msgrcv() is removed with this change; it also fixes the bug that shmat() and semctl() were not being properly handled. Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-02-14security: trim security.hAl Viro1-0/+2
Trim security.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
2012-01-23SHM_UNLOCK: fix Unevictable pages stranded after swapHugh Dickins1-1/+1
Commit cc39c6a9bbde ("mm: account skipped entries to avoid looping in find_get_pages") correctly fixed an infinite loop; but left a problem that find_get_pages() on shmem would return 0 (appearing to callers to mean end of tree) when it meets a run of nr_pages swap entries. The only uses of find_get_pages() on shmem are via pagevec_lookup(), called from invalidate_mapping_pages(), and from shmctl SHM_UNLOCK's scan_mapping_unevictable_pages(). The first is already commented, and not worth worrying about; but the second can leave pages on the Unevictable list after an unusual sequence of swapping and locking. Fix that by using shmem_find_get_pages_and_swap() (then ignoring the swap) instead of pagevec_lookup(). But I don't want to contaminate vmscan.c with shmem internals, nor shmem.c with LRU locking. So move scan_mapping_unevictable_pages() into shmem.c, renaming it shmem_unlock_mapping(); and rename check_move_unevictable_page() to check_move_unevictable_pages(), looping down an array of pages, oftentimes under the same lock. Leave out the "rotate unevictable list" block: that's a leftover from when this was used for /proc/sys/vm/scan_unevictable_pages, whose flawed handling involved looking at pages at tail of LRU. Was there significance to the sequence first ClearPageUnevictable, then test page_evictable, then SetPageUnevictable here? I think not, we're under LRU lock, and have no barriers between those. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michel Lespinasse <walken@google.com> Cc: <stable@vger.kernel.org> [back to 3.1 but will need respins] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23SHM_UNLOCK: fix long unpreemptible sectionHugh Dickins1-15/+22
scan_mapping_unevictable_pages() is used to make SysV SHM_LOCKed pages evictable again once the shared memory is unlocked. It does this with pagevec_lookup()s across the whole object (which might occupy most of memory), and takes 300ms to unlock 7GB here. A cond_resched() every PAGEVEC_SIZE pages would be good. However, KOSAKI-san points out that this is called under shmem.c's info->lock, and it's also under shm.c's shm_lock(), both spinlocks. There is no strong reason for that: we need to take these pages off the unevictable list soonish, but those locks are not required for it. So move the call to scan_mapping_unevictable_pages() from shmem.c's unlock handling up to shm.c's unlock handling. Remove the recently added barrier, not needed now we have spin_unlock() before the scan. Use get_file(), with subsequent fput(), to make sure we have a reference to mapping throughout scan_mapping_unevictable_pages(): that's something that was previously guaranteed by the shm_lock(). Remove shmctl's lru_add_drain_all(): we don't fault in pages at SHM_LOCK time, and we lazily discover them to be Unevictable later, so it serves no purpose for SHM_LOCK; and serves no purpose for SHM_UNLOCK, since pages still on pagevec are not marked Unevictable. The original code avoided redundant rescans by checking VM_LOCKED flag at its level: now avoid them by checking shp's SHM_LOCKED. The original code called scan_mapping_unevictable_pages() on a locked area at shm_destroy() time: perhaps we once had accounting cross-checks which required that, but not now, so skip the overhead and just let inode eviction deal with them. Put check_move_unevictable_page() and scan_mapping_unevictable_pages() under CONFIG_SHMEM (with stub for the TINY case when ramfs is used), more as comment than to save space; comment them used for SHM_UNLOCK. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23ipc/mqueue: simplify reading msgqueue limitDavidlohr Bueso1-2/+1
Because the current task is being used to get the limit, we can simply use rlimit() instead of task_rlimit(). Signed-off-by: Davidlohr Bueso <dave@gnu.org> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10user namespace: make signal.c respect user namespacesSerge E. Hallyn1-1/+6
ipc/mqueue.c: for __SI_MESQ, convert the uid being sent to recipient's user namespace. (new, thanks Oleg) __send_signal: convert current's uid to the recipient's user namespace for any siginfo which is not SI_FROMKERNEL (patch from Oleg, thanks again :) do_notify_parent and do_notify_parent_cldstop: map task's uid to parent's user namespace ptrace_signal maps parent's uid into current's user namespace before including in signal to current. IIUC Oleg has argued that this shouldn't matter as the debugger will play with it, but it seems like not converting the value currently being set is misleading. Changelog: Sep 20: Inspired by Oleg's suggestion, define map_cred_ns() helper to simplify callers and help make clear what we are translating (which uid into which namespace). Passing the target task would make callers even easier to read, but we pass in user_ns because current_user_ns() != task_cred_xxx(current, user_ns). Sep 20: As recommended by Oleg, also put task_pid_vnr() under rcu_read_lock in ptrace_signal(). Sep 23: In send_signal(), detect when (user) signal is coming from an ancestor or unrelated user namespace. Pass that on to __send_signal, which sets si_uid to 0 or overflowuid if needed. Oct 12: Base on Oleg's fixup_uid() patch. On top of that, handle all SI_FROMKERNEL cases at callers, because we can't assume sender is current in those cases. Nov 10: (mhelsley) rename fixup_uid to more meaningful usern_fixup_signal_uid Nov 10: (akpm) make the !CONFIG_USER_NS case clearer Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> From: Serge Hallyn <serge.hallyn@canonical.com> Subject: __send_signal: pass q->info, not info, to userns_fixup_signal_uid (v2) Eric Biederman pointed out that passing info is a bug and could lead to a NULL pointer deref to boot. A collection of signal, securebits, filecaps, cap_bounds, and a few other ltp tests passed with this kernel. Changelog: Nov 18: previous patch missed a leading '&' Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> From: Dan Carpenter <dan.carpenter@oracle.com> Subject: ipc/mqueue: lock() => unlock() typo There was a double lock typo introduced in b085f4bd6b21 "user namespace: make signal.c respect user namespaces" Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-03switch mq_open() to umode_tAl Viro1-1/+1
2012-01-03mqueue: propagate umode_tAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03switch ->create() to umode_tAl Viro1-2/+2
vfs_create() ignores everything outside of 16bit subset of its mode argument; switching it to umode_t is obviously equivalent and it's the only caller of the method Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03vfs: fix the stupidity with i_dentry in inode destructorsAl Viro1-1/+0
Seeing that just about every destructor got that INIT_LIST_HEAD() copied into it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once(); the cost of taking it into inode_init_always() will be negligible for pipes and sockets and negative for everything else. Not to mention the removal of boilerplate code from ->destroy_inode() instances... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-12-09... and the same kind of leak for mqueueAl Viro2-10/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>