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2016-05-19Merge branch 'next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "Highlights: - A new LSM, "LoadPin", from Kees Cook is added, which allows forcing of modules and firmware to be loaded from a specific device (this is from ChromeOS, where the device as a whole is verified cryptographically via dm-verity). This is disabled by default but can be configured to be enabled by default (don't do this if you don't know what you're doing). - Keys: allow authentication data to be stored in an asymmetric key. Lots of general fixes and updates. - SELinux: add restrictions for loading of kernel modules via finit_module(). Distinguish non-init user namespace capability checks. Apply execstack check on thread stacks" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (48 commits) LSM: LoadPin: provide enablement CONFIG Yama: use atomic allocations when reporting seccomp: Fix comment typo ima: add support for creating files using the mknodat syscall ima: fix ima_inode_post_setattr vfs: forbid write access when reading a file into memory fs: fix over-zealous use of "const" selinux: apply execstack check on thread stacks selinux: distinguish non-init user namespace capability checks LSM: LoadPin for kernel file loading restrictions fs: define a string representation of the kernel_read_file_id enumeration Yama: consolidate error reporting string_helpers: add kstrdup_quotable_file string_helpers: add kstrdup_quotable_cmdline string_helpers: add kstrdup_quotable selinux: check ss_initialized before revalidating an inode label selinux: delay inode label lookup as long as possible selinux: don't revalidate an inode's label when explicitly setting it selinux: Change bool variable name to index. KEYS: Add KEYCTL_DH_COMPUTE command ...
2016-05-17Merge branch 'work.const-path' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull 'struct path' constification update from Al Viro: "'struct path' is passed by reference to a bunch of Linux security methods; in theory, there's nothing to stop them from modifying the damn thing and LSM community being what it is, sooner or later some enterprising soul is going to decide that it's a good idea. Let's remove the temptation and constify all of those..." * 'work.const-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: constify ima_d_path() constify security_sb_pivotroot() constify security_path_chroot() constify security_path_{link,rename} apparmor: remove useless checks for NULL ->mnt constify security_path_{mkdir,mknod,symlink} constify security_path_{unlink,rmdir} apparmor: constify common_perm_...() apparmor: constify aa_path_link() apparmor: new helper - common_path_perm() constify chmod_common/security_path_chmod constify security_sb_mount() constify chown_common/security_path_chown tomoyo: constify assorted struct path * apparmor_path_truncate(): path->mnt is never NULL constify vfs_truncate() constify security_path_truncate() [apparmor] constify struct path * in a bunch of helpers
2016-05-17Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull parallel filesystem directory handling update from Al Viro. This is the main parallel directory work by Al that makes the vfs layer able to do lookup and readdir in parallel within a single directory. That's a big change, since this used to be all protected by the directory inode mutex. The inode mutex is replaced by an rwsem, and serialization of lookups of a single name is done by a "in-progress" dentry marker. The series begins with xattr cleanups, and then ends with switching filesystems over to actually doing the readdir in parallel (switching to the "iterate_shared()" that only takes the read lock). A more detailed explanation of the process from Al Viro: "The xattr work starts with some acl fixes, then switches ->getxattr to passing inode and dentry separately. This is the point where the things start to get tricky - that got merged into the very beginning of the -rc3-based #work.lookups, to allow untangling the security_d_instantiate() mess. The xattr work itself proceeds to switch a lot of filesystems to generic_...xattr(); no complications there. After that initial xattr work, the series then does the following: - untangle security_d_instantiate() - convert a bunch of open-coded lookup_one_len_unlocked() to calls of that thing; one such place (in overlayfs) actually yields a trivial conflict with overlayfs fixes later in the cycle - overlayfs ended up switching to a variant of lookup_one_len_unlocked() sans the permission checks. I would've dropped that commit (it gets overridden on merge from #ovl-fixes in #for-next; proper resolution is to use the variant in mainline fs/overlayfs/super.c), but I didn't want to rebase the damn thing - it was fairly late in the cycle... - some filesystems had managed to depend on lookup/lookup exclusion for *fs-internal* data structures in a way that would break if we relaxed the VFS exclusion. Fixing hadn't been hard, fortunately. - core of that series - parallel lookup machinery, replacing ->i_mutex with rwsem, making lookup_slow() take it only shared. At that point lookups happen in parallel; lookups on the same name wait for the in-progress one to be done with that dentry. Surprisingly little code, at that - almost all of it is in fs/dcache.c, with fs/namei.c changes limited to lookup_slow() - making it use the new primitive and actually switching to locking shared. - parallel readdir stuff - first of all, we provide the exclusion on per-struct file basis, same as we do for read() vs lseek() for regular files. That takes care of most of the needed exclusion in readdir/readdir; however, these guys are trickier than lookups, so I went for switching them one-by-one. To do that, a new method '->iterate_shared()' is added and filesystems are switched to it as they are either confirmed to be OK with shared lock on directory or fixed to be OK with that. I hope to kill the original method come next cycle (almost all in-tree filesystems are switched already), but it's still not quite finished. - several filesystems get switched to parallel readdir. The interesting part here is dealing with dcache preseeding by readdir; that needs minor adjustment to be safe with directory locked only shared. Most of the filesystems doing that got switched to in those commits. Important exception: NFS. Turns out that NFS folks, with their, er, insistence on VFS getting the fuck out of the way of the Smart Filesystem Code That Knows How And What To Lock(tm) have grown the locking of their own. They had their own homegrown rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink is the reader there). Of course, with VFS getting the fuck out of the way, as requested, the actual smarts of the smart filesystem code etc. had become exposed... - do_last/lookup_open/atomic_open cleanups. As the result, open() without O_CREAT locks the directory only shared. Including the ->atomic_open() case. Backmerge from #for-linus in the middle of that - atomic_open() fix got brought in. - then comes NFS switch to saner (VFS-based ;-) locking, killing the homegrown "lookup and readdir are writers" kinda-sorta rwsem. All exclusion for sillyunlink/lookup is done by the parallel lookups mechanism. Exclusion between sillyunlink and rmdir is a real rwsem now - rmdir being the writer. Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel now. - the rest of the series consists of switching a lot of filesystems to parallel readdir; in a lot of cases ->llseek() gets simplified as well. One backmerge in there (again, #for-linus - rockridge fix)" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits) ext4: switch to ->iterate_shared() hfs: switch to ->iterate_shared() hfsplus: switch to ->iterate_shared() hostfs: switch to ->iterate_shared() hpfs: switch to ->iterate_shared() hpfs: handle allocation failures in hpfs_add_pos() gfs2: switch to ->iterate_shared() f2fs: switch to ->iterate_shared() afs: switch to ->iterate_shared() befs: switch to ->iterate_shared() befs: constify stuff a bit isofs: switch to ->iterate_shared() get_acorn_filename(): deobfuscate a bit btrfs: switch to ->iterate_shared() logfs: no need to lock directory in lseek switch ecryptfs to ->iterate_shared 9p: switch to ->iterate_shared() fat: switch to ->iterate_shared() romfs, squashfs: switch to ->iterate_shared() more trivial ->iterate_shared conversions ...
2016-05-17Merge branch 'ovl-fixes' into for-linusAl Viro
Backmerge to resolve a conflict in ovl_lookup_real(); "ovl_lookup_real(): use lookup_one_len_unlocked()" instead, but it was too late in the cycle to rebase.
2016-05-16namei: Improve hash mixing if CONFIG_DCACHE_WORD_ACCESSGeorge Spelvin
The hash mixing between adding the next 64 bits of name was just a bit weak. Replaced with a still very fast but slightly more effective mixing function. Signed-off-by: George Spelvin <linux@horizon.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-11Merge branch 'ovl-fixes' into for-linusAl Viro
2016-05-10vfs: add lookup_hash() helperMiklos Szeredi
Overlayfs needs lookup without inode_permission() and already has the name hash (in form of dentry->d_name on overlayfs dentry). It also doesn't support filesystems with d_op->d_hash() so basically it only needs the actual hashed lookup from lookup_one_len_unlocked() So add a new helper that does unlocked lookup of a hashed name. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-05-10vfs: rename: check backing inode being equalMiklos Szeredi
If a file is renamed to a hardlink of itself POSIX specifies that rename(2) should do nothing and return success. This condition is checked in vfs_rename(). However it won't detect hard links on overlayfs where these are given separate inodes on the overlayfs layer. Overlayfs itself detects this condition and returns success without doing anything, but then vfs_rename() will proceed as if this was a successful rename (detach_mounts(), d_move()). The correct thing to do is to detect this condition before even calling into overlayfs. This patch does this by calling vfs_select_inode() to get the underlying inodes. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> # v4.2+
2016-05-02lookup_open(): lock the parent shared unless O_CREAT is givenAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02lookup_open(): put the dentry fed to ->lookup() or ->atomic_open() into ↵Al Viro
in-lookup hash Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02lookup_open(): expand the call of real_lookup()Al Viro
... and lose the duplicate IS_DEADDIR() - we'd already checked that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02atomic_open(): reorder and clean up a bitAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02lookup_open(): lift the "fallback to !O_CREAT" logics from atomic_open()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02atomic_open(): be paranoid about may_open() return valueAl Viro
It should never return positives; however, with Linux S&M crowd involved, no bogosity is impossible. Results would be unpleasant... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02atomic_open(): delay open_to_namei_flags() until the method callAl Viro
nobody else needs that transformation. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02do_last(): take fput() on error after opening to out:Al Viro
make it conditional on *opened & FILE_OPENED; in addition to getting rid of exit_fput: thing, it simplifies atomic_open() cleanup on may_open() failure. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02do_last(): get rid of duplicate ELOOP checkAl Viro
may_open() will catch it Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02atomic_open(): massage the create_error logics a bitAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02atomic_open(): consolidate "overridden ENOENT" in open-yourself casesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02atomic_open(): don't bother with EEXIST check - it's done in do_last()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02Merge branch 'for-linus' into work.lookupsAl Viro
2016-05-02lookup_open(): expand the call of vfs_create()Al Viro
Lift IS_DEADDIR handling up into the part common with atomic_open(), remove it from the latter. Collapse permission checks into the call of may_o_create(), getting it closer to atomic_open() case. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02path_openat(): take O_PATH handling out of do_last()Al Viro
do_last() and lookup_open() simpler that way and so does O_PATH itself. As it bloody well should: we find what the pathname resolves to, same way as in stat() et.al. and associate it with FMODE_PATH struct file. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02parallel lookups: actual switch to rwsemAl Viro
ta-da! The main issue is the lack of down_write_killable(), so the places like readdir.c switched to plain inode_lock(); once killable variants of rwsem primitives appear, that'll be dealt with. lockdep side also might need more work Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02parallel lookups machinery, part 4 (and last)Al Viro
If we *do* run into an in-lookup match, we need to wait for it to cease being in-lookup. Fortunately, we do have unused space in in-lookup dentries - d_lru is never looked at until it stops being in-lookup. So we can stash a pointer to wait_queue_head from stack frame of the caller of ->lookup(). Some precautions are needed while waiting, but it's not that hard - we do hold a reference to dentry we are waiting for, so it can't go away. If it's found to be in-lookup the wait_queue_head is still alive and will remain so at least while ->d_lock is held. Moreover, the condition we are waiting for becomes true at the same point where everything on that wq gets woken up, so we can just add ourselves to the queue once. d_alloc_parallel() gets a pointer to wait_queue_head_t from its caller; lookup_slow() adjusted, d_add_ci() taught to use d_alloc_parallel() if the dentry passed to it happens to be in-lookup one (i.e. if it's been called from the parallel lookup). That's pretty much it - all that remains is to switch ->i_mutex to rwsem and have lookup_slow() take it shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02parallel lookups machinery, part 3Al Viro
We will need to be able to check if there is an in-lookup dentry with matching parent/name. Right now it's impossible, but as soon as start locking directories shared such beasts will appear. Add a secondary hash for locating those. Hash chains go through the same space where d_alias will be once it's not in-lookup anymore. Search is done under the same bitlock we use for modifications - with the primary hash we can rely on d_rehash() into the wrong chain being the worst that could happen, but here the pointers are buggered once it's removed from the chain. On the other hand, the chains are not going to be long and normally we'll end up adding to the chain anyway. That allows us to avoid bothering with ->d_lock when doing the comparisons - everything is stable until removed from chain. New helper: d_alloc_parallel(). Right now it allocates, verifies that no hashed and in-lookup matches exist and adds to in-lookup hash. Returns ERR_PTR() for error, hashed match (in the unlikely case it's been found) or new dentry. In-lookup matches trigger BUG() for now; that will change in the next commit when we introduce waiting for ongoing lookup to finish. Note that in-lookup matches won't be possible until we actually go for shared locking. lookup_slow() switched to use of d_alloc_parallel(). Again, these commits are separated only for making it easier to review. All this machinery will start doing something useful only when we go for shared locking; it's just that the combination is too large for my taste. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02beginning of transition to parallel lookups - marking in-lookup dentriesAl Viro
marked as such when (would be) parallel lookup is about to pass them to actual ->lookup(); unmarked when * __d_add() is about to make it hashed, positive or not. * __d_move() (from d_splice_alias(), directly or via __d_unalias()) puts a preexisting dentry in its place * in caller of ->lookup() if it has escaped all of the above. Bug (WARN_ON, actually) if it reaches the final dput() or d_instantiate() while still marked such. As the result, we are guaranteed that for as long as the flag is set, dentry will * remain negative unhashed with positive refcount * never have its ->d_alias looked at * never have its ->d_lru looked at * never have its ->d_parent and ->d_name changed Right now we have at most one such for any given parent directory. With parallel lookups that restriction will weaken to * only exist when parent is locked shared * at most one with given (parent,name) pair (comparison of names is according to ->d_compare()) * only exist when there's no hashed dentry with the same (parent,name) Transition will take the next several commits; unfortunately, we'll only be able to switch to rwsem at the end of this series. The reason for not making it a single patch is to simplify review. New primitives: d_in_lookup() (a predicate checking if dentry is in the in-lookup state) and d_lookup_done() (tells the system that we are done with lookup and if it's still marked as in-lookup, it should cease to be such). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02lookup_slow(): bugger off on IS_DEADDIR() from the very beginningAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02Merge getxattr prototype change into work.lookupsAl Viro
The rest of work.xattr stuff isn't needed for this branch
2016-05-01ima: add support for creating files using the mknodat syscallMimi Zohar
Commit 3034a14 "ima: pass 'opened' flag to identify newly created files" stopped identifying empty files as new files. However new empty files can be created using the mknodat syscall. On systems with IMA-appraisal enabled, these empty files are not labeled with security.ima extended attributes properly, preventing them from subsequently being opened in order to write the file data contents. This patch defines a new hook named ima_post_path_mknod() to mark these empty files, created using mknodat, as new in order to allow the file data contents to be written. In addition, files with security.ima xattrs containing a file signature are considered "immutable" and can not be modified. The file contents need to be written, before signing the file. This patch relaxes this requirement for new files, allowing the file signature to be written before the file contents. Changelog: - defer identifying files with signatures stored as security.ima (based on Dmitry Rozhkov's comments) - removing tests (eg. dentry, dentry->d_inode, inode->i_size == 0) (based on Al's review) Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Al Viro <<viro@zeniv.linux.org.uk> Tested-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
2016-04-30atomic_open(): fix the handling of create_errorAl Viro
* if we have a hashed negative dentry and either CREAT|EXCL on r/o filesystem, or CREAT|TRUNC on r/o filesystem, or CREAT|EXCL with failing may_o_create(), we should fail with EROFS or the error may_o_create() has returned, but not ENOENT. Which is what the current code ends up returning. * if we have CREAT|TRUNC hitting a regular file on a read-only filesystem, we can't fail with EROFS here. At the very least, not until we'd done follow_managed() - we might have a writable file (or a device, for that matter) bound on top of that one. Moreover, the code downstream will see that O_TRUNC and attempt to grab the write access (*after* following possible mount), so if we really should fail with EROFS, it will happen. No need to do that inside atomic_open(). The real logics is much simpler than what the current code is trying to do - if we decided to go for simple lookup, ended up with a negative dentry *and* had create_error set, fail with create_error. No matter whether we'd got that negative dentry from lookup_real() or had found it in dcache. Cc: stable@vger.kernel.org # v3.6+ Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-10don't bother with ->d_inode->i_sb - it's always equal to ->d_sbAl Viro
... and neither can ever be NULL Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-31posix_acl: Inode acl caching fixesAndreas Gruenbacher
When get_acl() is called for an inode whose ACL is not cached yet, the get_acl inode operation is called to fetch the ACL from the filesystem. The inode operation is responsible for updating the cached acl with set_cached_acl(). This is done without locking at the VFS level, so another task can call set_cached_acl() or forget_cached_acl() before the get_acl inode operation gets to calling set_cached_acl(), and then get_acl's call to set_cached_acl() results in caching an outdate ACL. Prevent this from happening by setting the cached ACL pointer to a task-specific sentinel value before calling the get_acl inode operation. Move the responsibility for updating the cached ACL from the get_acl inode operations to get_acl(). There, only set the cached ACL if the sentinel value hasn't changed. The sentinel values are chosen to have odd values. Likewise, the value of ACL_NOT_CACHED is odd. In contrast, ACL object pointers always have an even value (ACLs are aligned in memory). This allows to distinguish uncached ACLs values from ACL objects. In addition, switch from guarding inode->i_acl and inode->i_default_acl upates by the inode->i_lock spinlock to using xchg() and cmpxchg(). Filesystems that do not want ACLs returned from their get_acl inode operations to be cached must call forget_cached_acl() to prevent the VFS from doing so. (Patch written by Al Viro and Andreas Gruenbacher.) Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-31fix the braino in "namei: massage lookup_slow() to be usable by ↵Al Viro
lookup_one_len_unlocked()" We should try to trigger automount *before* bailing out on negative dentry. Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Reported-by: Arend van Spriel <arend@broadcom.com> Tested-by: Arend van Spriel <arend@broadcom.com> Tested-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-28constify security_path_{mkdir,mknod,symlink}Al Viro
... as well as unix_mknod() and may_o_create() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14kill dentry_unhash()Al Viro
the last user is gone Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14namei: teach lookup_slow() to skip revalidateAl Viro
... and make mountpoint_last() use it. That makes all candidates for lookup with parent locked shared go through lookup_slow(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14namei: massage lookup_slow() to be usable by lookup_one_len_unlocked()Al Viro
Return dentry and don't pass nameidata or path; lift crossing mountpoints into the caller. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14lookup_one_len_unlocked(): use lookup_dcache()Al Viro
No need to lock parent just because of ->d_revalidate() on child; contrary to the stale comment, lookup_dcache() *can* be used without locking the parent. Result can be moved as soon as we return, of course, but the same is true for lookup_one_len_unlocked() itself. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14namei: simplify invalidation logics in lookup_dcache()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14namei: change calling conventions for lookup_{fast,slow} and follow_managed()Al Viro
Have lookup_fast() return 1 on success and 0 on "need to fall back"; lookup_slow() and follow_managed() return positive (1) on success. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-14namei: untanlge lookup_fast()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-05lookup_dcache(): lift d_alloc() into callersAl Viro
... and kill need_lookup thing Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-05do_last(): reorder and simplify a bitAl Viro
bugger off on negatives a bit earlier, simplify the tests Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-02-27do_last(): ELOOP failure exit should be done after leaving RCU modeAl Viro
... or we risk seeing a bogus value of d_is_symlink() there. Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-02-27should_follow_link(): validate ->d_seq after having decided to followAl Viro
... otherwise d_is_symlink() above might have nothing to do with the inode value we've got. Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-02-27namei: ->d_inode of a pinned dentry is stable only for positivesAl Viro
both do_last() and walk_component() risk picking a NULL inode out of dentry about to become positive, *then* checking its flags and seeing that it's not negative anymore and using (already stale by then) value they'd fetched earlier. Usually ends up oopsing soon after that... Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-02-27do_last(): don't let a bogus return value from ->open() et.al. to confuse usAl Viro
... into returning a positive to path_openat(), which would interpret that as "symlink had been encountered" and proceed to corrupt memory, etc. It can only happen due to a bug in some ->open() instance or in some LSM hook, etc., so we report any such event *and* make sure it doesn't trick us into further unpleasantness. Cc: stable@vger.kernel.org # v3.6+, at least Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-22wrappers for ->i_mutex accessAl Viro
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-12Merge branch 'work.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "All kinds of stuff. That probably should've been 5 or 6 separate branches, but by the time I'd realized how large and mixed that bag had become it had been too close to -final to play with rebasing. Some fs/namei.c cleanups there, memdup_user_nul() introduction and switching open-coded instances, burying long-dead code, whack-a-mole of various kinds, several new helpers for ->llseek(), assorted cleanups and fixes from various people, etc. One piece probably deserves special mention - Neil's lookup_one_len_unlocked(). Similar to lookup_one_len(), but gets called without ->i_mutex and tries to avoid ever taking it. That, of course, means that it's not useful for any directory modifications, but things like getting inode attributes in nfds readdirplus are fine with that. I really should've asked for moratorium on lookup-related changes this cycle, but since I hadn't done that early enough... I *am* asking for that for the coming cycle, though - I'm going to try and get conversion of i_mutex to rwsem with ->lookup() done under lock taken shared. There will be a patch closer to the end of the window, along the lines of the one Linus had posted last May - mechanical conversion of ->i_mutex accesses to inode_lock()/inode_unlock()/inode_trylock()/ inode_is_locked()/inode_lock_nested(). To quote Linus back then: ----- | This is an automated patch using | | sed 's/mutex_lock(&\(.*\)->i_mutex)/inode_lock(\1)/' | sed 's/mutex_unlock(&\(.*\)->i_mutex)/inode_unlock(\1)/' | sed 's/mutex_lock_nested(&\(.*\)->i_mutex,[ ]*I_MUTEX_\([A-Z0-9_]*\))/inode_lock_nested(\1, I_MUTEX_\2)/' | sed 's/mutex_is_locked(&\(.*\)->i_mutex)/inode_is_locked(\1)/' | sed 's/mutex_trylock(&\(.*\)->i_mutex)/inode_trylock(\1)/' | | with a very few manual fixups ----- I'm going to send that once the ->i_mutex-affecting stuff in -next gets mostly merged (or when Linus says he's about to stop taking merges)" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) nfsd: don't hold i_mutex over userspace upcalls fs:affs:Replace time_t with time64_t fs/9p: use fscache mutex rather than spinlock proc: add a reschedule point in proc_readfd_common() logfs: constify logfs_block_ops structures fcntl: allow to set O_DIRECT flag on pipe fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE fs: xattr: Use kvfree() [s390] page_to_phys() always returns a multiple of PAGE_SIZE nbd: use ->compat_ioctl() fs: use block_device name vsprintf helper lib/vsprintf: add %*pg format specifier fs: use gendisk->disk_name where possible poll: plug an unused argument to do_poll amdkfd: don't open-code memdup_user() cdrom: don't open-code memdup_user() rsxx: don't open-code memdup_user() mtip32xx: don't open-code memdup_user() [um] mconsole: don't open-code memdup_user_nul() [um] hostaudio: don't open-code memdup_user() ...