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2019-01-16cuse: fix ioctlMiklos Szeredi1-1/+1
cuse_process_init_reply() doesn't initialize fc->max_pages and thus all cuse bases ioctls fail with ENOMEM. Reported-by: Andreas Steinmetz <ast@domdv.de> Fixes: 5da784cce430 ("fuse: add max_pages to init_out") Cc: <stable@vger.kernel.org> # v4.20 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-12-28mm: convert totalram_pages and totalhigh_pages variables to atomicArun KS1-1/+1
totalram_pages and totalhigh_pages are made static inline function. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-10fuse: Fix memory leak in fuse_dev_free()Takeshi Misawa1-0/+1
When ntfs is unmounted, the following leak is reported by kmemleak. kmemleak report: unreferenced object 0xffff880052bf4400 (size 4096): comm "mount.ntfs", pid 16530, jiffies 4294861127 (age 3215.836s) hex dump (first 32 bytes): 00 44 bf 52 00 88 ff ff 00 44 bf 52 00 88 ff ff .D.R.....D.R.... 10 44 bf 52 00 88 ff ff 10 44 bf 52 00 88 ff ff .D.R.....D.R.... backtrace: [<00000000bf4a2f8d>] fuse_fill_super+0xb22/0x1da0 [fuse] [<000000004dde0f0c>] mount_bdev+0x263/0x320 [<0000000025aebc66>] mount_fs+0x82/0x2bf [<0000000042c5a6be>] vfs_kern_mount.part.33+0xbf/0x480 [<00000000ed10cd5b>] do_mount+0x3de/0x2ad0 [<00000000d59ff068>] ksys_mount+0xba/0xd0 [<000000001bda1bcc>] __x64_sys_mount+0xba/0x150 [<00000000ebe26304>] do_syscall_64+0x151/0x490 [<00000000d25f2b42>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [<000000002e0abd2c>] 0xffffffffffffffff fuse_dev_alloc() allocate fud->pq.processing. But this hash table is not freed. Fix this by freeing fud->pq.processing. Signed-off-by: Takeshi Misawa <jeliantsurux@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: be2ff42c5d6e ("fuse: Use hash table to link processing request")
2018-11-22fuse: Add bad inode check in fuse_destroy_inode()Myungho Jung1-1/+1
make_bad_inode() sets inode->i_mode to S_IFREG if I/O error is detected in fuse_do_getattr()/fuse_do_setattr(). If the inode is not a regular file, write_files and queued_writes in fuse_inode are not initialized and have NULL or invalid pointers written by other members in a union. So, list_empty() returns false in fuse_destroy_inode(). Add is_bad_inode() to check if make_bad_inode() was called. Reported-by: syzbot+b9c89b84423073226299@syzkaller.appspotmail.com Fixes: ab2257e9941b ("fuse: reduce size of struct fuse_inode") Signed-off-by: Myungho Jung <mhjungk@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-15fuse: enable caching of symlinksDan Schatzberg1-1/+3
FUSE file reads are cached in the page cache, but symlink reads are not. This patch enables FUSE READLINK operations to be cached which can improve performance of some FUSE workloads. In particular, I'm working on a FUSE filesystem for access to source code and discovered that about a 10% improvement to build times is achieved with this patch (there are a lot of symlinks in the source tree). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-15fuse: allow fine grained attr cache invaldationMiklos Szeredi1-0/+2
This patch adds the infrastructure for more fine grained attribute invalidation. Currently only 'atime' is invalidated separately. The use of this infrastructure is extended to the statx(2) interface, which for now means that if only 'atime' is invalid and STATX_ATIME is not specified in the mask argument, then no GETATTR request will be generated. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: add max_pages to init_outConstantine Shulyupin1-1/+7
Replace FUSE_MAX_PAGES_PER_REQ with the configurable parameter max_pages to improve performance. Old RFC with detailed description of the problem and many fixes by Mitsuo Hayasaka (mitsuo.hayasaka.hu@hitachi.com): - https://lkml.org/lkml/2012/7/5/136 We've encountered performance degradation and fixed it on a big and complex virtual environment. Environment to reproduce degradation and improvement: 1. Add lag to user mode FUSE Add nanosleep(&(struct timespec){ 0, 1000 }, NULL); to xmp_write_buf in passthrough_fh.c 2. patch UM fuse with configurable max_pages parameter. The patch will be provided latter. 3. run test script and perform test on tmpfs fuse_test() { cd /tmp mkdir -p fusemnt passthrough_fh -o max_pages=$1 /tmp/fusemnt grep fuse /proc/self/mounts dd conv=fdatasync oflag=dsync if=/dev/zero of=fusemnt/tmp/tmp \ count=1K bs=1M 2>&1 | grep -v records rm fusemnt/tmp/tmp killall passthrough_fh } Test results: passthrough_fh /tmp/fusemnt fuse.passthrough_fh \ rw,nosuid,nodev,relatime,user_id=0,group_id=0 0 0 1073741824 bytes (1.1 GB) copied, 1.73867 s, 618 MB/s passthrough_fh /tmp/fusemnt fuse.passthrough_fh \ rw,nosuid,nodev,relatime,user_id=0,group_id=0,max_pages=256 0 0 1073741824 bytes (1.1 GB) copied, 1.15643 s, 928 MB/s Obviously with bigger lag the difference between 'before' and 'after' will be more significant. Mitsuo Hayasaka, in 2012 (https://lkml.org/lkml/2012/7/5/136), observed improvement from 400-550 to 520-740. Signed-off-by: Constantine Shulyupin <const@MakeLinux.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: reduce size of struct fuse_inodeMiklos Szeredi1-12/+4
Do this by grouping fields used for cached writes and putting them into a union with fileds used for cached readdir (with obviously no overlap, since we don't have hybrid objects). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: add readdir cache versionMiklos Szeredi1-0/+1
Allow the cache to be invalidated when page(s) have gone missing. In this case increment the version of the cache and reset to an empty state. Add a version number to the directory stream in struct fuse_file as well, indicating the version of the cache it's supposed to be reading. If the cache version doesn't match the stream's version, then reset the stream to the beginning of the cache. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: allow caching readdirMiklos Szeredi1-0/+4
This patch just adds the cache filling functions, which are invoked if FOPEN_CACHE_DIR flag is set in the OPENDIR reply. Cache reading and cache invalidation are added by subsequent patches. The directory cache uses the page cache. Directory entries are packed into a page in the same format as in the READDIR reply. A page only contains whole entries, the space at the end of the page is cleared. The page is locked while being modified. Multiple parallel readdirs on the same directory can fill the cache; the only constraint is that continuity must be maintained (d_off of last entry points to position of current entry). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: Use hash table to link processing requestKirill Tkhai1-8/+19
We noticed the performance bottleneck in FUSE running our Virtuozzo storage over rdma. On some types of workload we observe 20% of times spent in request_find() in profiler. This function is iterating over long requests list, and it scales bad. The patch introduces hash table to reduce the number of iterations, we do in this function. Hash generating algorithm is taken from hash_add() function, while 256 lines table is used to store pending requests. This fixes problem and improves the performance. Reported-by: Alexey Kuznetsov <kuznet@virtuozzo.com> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: introduce fc->bg_lockKirill Tkhai1-0/+3
To reduce contention of fc->lock, this patch introduces bg_lock for protection of fields related to background queue. These are: max_background, congestion_threshold, num_background, active_background, bg_queue and blocked. This allows next patch to make async reads not requiring fc->lock, so async reads and writes will have better performance executed in parallel. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-26fuse: convert last timespec use to timespec64Arnd Bergmann1-4/+4
All of fuse uses 64-bit timestamps with the exception of the fuse_change_attributes(), so let's convert this one as well. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-26fuse: fix initial parallel diropsMiklos Szeredi1-4/+10
If parallel dirops are enabled in FUSE_INIT reply, then first operation may leave fi->mutex held. Reported-by: syzbot <syzbot+3f7b29af1baa9d0a55be@syzkaller.appspotmail.com> Fixes: 5c672ab3f0ee ("fuse: serialize dirops by default") Cc: <stable@vger.kernel.org> # v4.7 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-26fuse: Fix oops at process_init_reply()Miklos Szeredi1-14/+11
syzbot is hitting NULL pointer dereference at process_init_reply(). This is because deactivate_locked_super() is called before response for initial request is processed. Fix this by aborting and waiting for all requests (including FUSE_INIT) before resetting fc->sb. Original patch by Tetsuo Handa <penguin-kernel@I-love.SKAURA.ne.jp>. Reported-by: syzbot <syzbot+b62f08f4d5857755e3bc@syzkaller.appspotmail.com> Fixes: e27c9d3877a0 ("fuse: fuse: add time_gran to INIT_OUT") Cc: <stable@vger.kernel.org> # v3.19 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-26fuse: umount should wait for all requestsMiklos Szeredi1-0/+2
fuse_abort_conn() does not guarantee that all async requests have actually finished aborting (i.e. their ->end() function is called). This could actually result in still used inodes after umount. Add a helper to wait until all requests are fully done. This is done by looking at the "num_waiting" counter. When this counter drops to zero, we can be sure that no more requests are outstanding. Fixes: 0d8e84b0432b ("fuse: simplify request abort") Cc: <stable@vger.kernel.org> # v4.2 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-06-15Merge tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playgroundLinus Torvalds1-1/+1
Pull inode timestamps conversion to timespec64 from Arnd Bergmann: "This is a late set of changes from Deepa Dinamani doing an automated treewide conversion of the inode and iattr structures from 'timespec' to 'timespec64', to push the conversion from the VFS layer into the individual file systems. As Deepa writes: 'The series aims to switch vfs timestamps to use struct timespec64. Currently vfs uses struct timespec, which is not y2038 safe. The series involves the following: 1. Add vfs helper functions for supporting struct timepec64 timestamps. 2. Cast prints of vfs timestamps to avoid warnings after the switch. 3. Simplify code using vfs timestamps so that the actual replacement becomes easy. 4. Convert vfs timestamps to use struct timespec64 using a script. This is a flag day patch. Next steps: 1. Convert APIs that can handle timespec64, instead of converting timestamps at the boundaries. 2. Update internal data structures to avoid timestamp conversions' Thomas Gleixner adds: 'I think there is no point to drag that out for the next merge window. The whole thing needs to be done in one go for the core changes which means that you're going to play that catchup game forever. Let's get over with it towards the end of the merge window'" * tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground: pstore: Remove bogus format string definition vfs: change inode times to use struct timespec64 pstore: Convert internal records to timespec64 udf: Simplify calls to udf_disk_stamp_to_time fs: nfs: get rid of memcpys for inode times ceph: make inode time prints to be long long lustre: Use long long type to print inode time fs: add timespec64_truncate()
2018-06-07Merge tag 'fuse-update-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuseLinus Torvalds1-16/+34
Pull fuse updates from Miklos Szeredi: "The most interesting part of this update is user namespace support, mostly done by Eric Biederman. This enables safe unprivileged fuse mounts within a user namespace. There are also a couple of fixes for bugs found by syzbot and miscellaneous fixes and cleanups" * tag 'fuse-update-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: don't keep dead fuse_conn at fuse_fill_super(). fuse: fix control dir setup and teardown fuse: fix congested state leak on aborted connections fuse: Allow fully unprivileged mounts fuse: Ensure posix acls are translated outside of init_user_ns fuse: add writeback documentation fuse: honor AT_STATX_FORCE_SYNC fuse: honor AT_STATX_DONT_SYNC fuse: Restrict allow_other to the superblock's namespace or a descendant fuse: Support fuse filesystems outside of init_user_ns fuse: Fail all requests with invalid uids or gids fuse: Remove the buggy retranslation of pids in fuse_dev_do_read fuse: return -ECONNABORTED on /dev/fuse read after abort fuse: atomic_o_trunc should truncate pagecache
2018-06-05vfs: change inode times to use struct timespec64Deepa Dinamani1-1/+1
struct timespec is not y2038 safe. Transition vfs to use y2038 safe struct timespec64 instead. The change was made with the help of the following cocinelle script. This catches about 80% of the changes. All the header file and logic changes are included in the first 5 rules. The rest are trivial substitutions. I avoid changing any of the function signatures or any other filesystem specific data structures to keep the patch simple for review. The script can be a little shorter by combining different cases. But, this version was sufficient for my usecase. virtual patch @ depends on patch @ identifier now; @@ - struct timespec + struct timespec64 current_time ( ... ) { - struct timespec now = current_kernel_time(); + struct timespec64 now = current_kernel_time64(); ... - return timespec_trunc( + return timespec64_trunc( ... ); } @ depends on patch @ identifier xtime; @@ struct \( iattr \| inode \| kstat \) { ... - struct timespec xtime; + struct timespec64 xtime; ... } @ depends on patch @ identifier t; @@ struct inode_operations { ... int (*update_time) (..., - struct timespec t, + struct timespec64 t, ...); ... } @ depends on patch @ identifier t; identifier fn_update_time =~ "update_time$"; @@ fn_update_time (..., - struct timespec *t, + struct timespec64 *t, ...) { ... } @ depends on patch @ identifier t; @@ lease_get_mtime( ... , - struct timespec *t + struct timespec64 *t ) { ... } @te depends on patch forall@ identifier ts; local idexpression struct inode *inode_node; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn_update_time =~ "update_time$"; identifier fn; expression e, E3; local idexpression struct inode *node1; local idexpression struct inode *node2; local idexpression struct iattr *attr1; local idexpression struct iattr *attr2; local idexpression struct iattr attr; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; @@ ( ( - struct timespec ts; + struct timespec64 ts; | - struct timespec ts = current_time(inode_node); + struct timespec64 ts = current_time(inode_node); ) <+... when != ts ( - timespec_equal(&inode_node->i_xtime, &ts) + timespec64_equal(&inode_node->i_xtime, &ts) | - timespec_equal(&ts, &inode_node->i_xtime) + timespec64_equal(&ts, &inode_node->i_xtime) | - timespec_compare(&inode_node->i_xtime, &ts) + timespec64_compare(&inode_node->i_xtime, &ts) | - timespec_compare(&ts, &inode_node->i_xtime) + timespec64_compare(&ts, &inode_node->i_xtime) | ts = current_time(e) | fn_update_time(..., &ts,...) | inode_node->i_xtime = ts | node1->i_xtime = ts | ts = inode_node->i_xtime | <+... attr1->ia_xtime ...+> = ts | ts = attr1->ia_xtime | ts.tv_sec | ts.tv_nsec | btrfs_set_stack_timespec_sec(..., ts.tv_sec) | btrfs_set_stack_timespec_nsec(..., ts.tv_nsec) | - ts = timespec64_to_timespec( + ts = ... -) | - ts = ktime_to_timespec( + ts = ktime_to_timespec64( ...) | - ts = E3 + ts = timespec_to_timespec64(E3) | - ktime_get_real_ts(&ts) + ktime_get_real_ts64(&ts) | fn(..., - ts + timespec64_to_timespec(ts) ,...) ) ...+> ( <... when != ts - return ts; + return timespec64_to_timespec(ts); ...> ) | - timespec_equal(&node1->i_xtime1, &node2->i_xtime2) + timespec64_equal(&node1->i_xtime2, &node2->i_xtime2) | - timespec_equal(&node1->i_xtime1, &attr2->ia_xtime2) + timespec64_equal(&node1->i_xtime2, &attr2->ia_xtime2) | - timespec_compare(&node1->i_xtime1, &node2->i_xtime2) + timespec64_compare(&node1->i_xtime1, &node2->i_xtime2) | node1->i_xtime1 = - timespec_trunc(attr1->ia_xtime1, + timespec64_trunc(attr1->ia_xtime1, ...) | - attr1->ia_xtime1 = timespec_trunc(attr2->ia_xtime2, + attr1->ia_xtime1 = timespec64_trunc(attr2->ia_xtime2, ...) | - ktime_get_real_ts(&attr1->ia_xtime1) + ktime_get_real_ts64(&attr1->ia_xtime1) | - ktime_get_real_ts(&attr.ia_xtime1) + ktime_get_real_ts64(&attr.ia_xtime1) ) @ depends on patch @ struct inode *node; struct iattr *attr; identifier fn; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; expression e; @@ ( - fn(node->i_xtime); + fn(timespec64_to_timespec(node->i_xtime)); | fn(..., - node->i_xtime); + timespec64_to_timespec(node->i_xtime)); | - e = fn(attr->ia_xtime); + e = fn(timespec64_to_timespec(attr->ia_xtime)); ) @ depends on patch forall @ struct inode *node; struct iattr *attr; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); fn (..., - &attr->ia_xtime, + &ts, ...); ) ...+> } @ depends on patch forall @ struct inode *node; struct iattr *attr; struct kstat *stat; identifier ia_xtime =~ "^ia_[acm]time$"; identifier i_xtime =~ "^i_[acm]time$"; identifier xtime =~ "^[acm]time$"; identifier fn, ret; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime); + &ts); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime); + &ts); | + ts = timespec64_to_timespec(stat->xtime); ret = fn (..., - &stat->xtime); + &ts); ) ...+> } @ depends on patch @ struct inode *node; struct inode *node2; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier i_xtime3 =~ "^i_[acm]time$"; struct iattr *attrp; struct iattr *attrp2; struct iattr attr ; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; struct kstat *stat; struct kstat stat1; struct timespec64 ts; identifier xtime =~ "^[acmb]time$"; expression e; @@ ( ( node->i_xtime2 \| attrp->ia_xtime2 \| attr.ia_xtime2 \) = node->i_xtime1 ; | node->i_xtime2 = \( node2->i_xtime1 \| timespec64_trunc(...) \); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \); | node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \); | stat->xtime = node2->i_xtime1; | stat1.xtime = node2->i_xtime1; | ( node->i_xtime2 \| attrp->ia_xtime2 \) = attrp->ia_xtime1 ; | ( attrp->ia_xtime1 \| attr.ia_xtime1 \) = attrp2->ia_xtime2; | - e = node->i_xtime1; + e = timespec64_to_timespec( node->i_xtime1 ); | - e = attrp->ia_xtime1; + e = timespec64_to_timespec( attrp->ia_xtime1 ); | node->i_xtime1 = current_time(...); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | - node->i_xtime1 = e; + node->i_xtime1 = timespec_to_timespec64(e); ) Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Cc: <anton@tuxera.com> Cc: <balbi@kernel.org> Cc: <bfields@fieldses.org> Cc: <darrick.wong@oracle.com> Cc: <dhowells@redhat.com> Cc: <dsterba@suse.com> Cc: <dwmw2@infradead.org> Cc: <hch@lst.de> Cc: <hirofumi@mail.parknet.co.jp> Cc: <hubcap@omnibond.com> Cc: <jack@suse.com> Cc: <jaegeuk@kernel.org> Cc: <jaharkes@cs.cmu.edu> Cc: <jslaby@suse.com> Cc: <keescook@chromium.org> Cc: <mark@fasheh.com> Cc: <miklos@szeredi.hu> Cc: <nico@linaro.org> Cc: <reiserfs-devel@vger.kernel.org> Cc: <richard@nod.at> Cc: <sage@redhat.com> Cc: <sfrench@samba.org> Cc: <swhiteho@redhat.com> Cc: <tj@kernel.org> Cc: <trond.myklebust@primarydata.com> Cc: <tytso@mit.edu> Cc: <viro@zeniv.linux.org.uk>
2018-05-31fuse: don't keep dead fuse_conn at fuse_fill_super().Tetsuo Handa1-0/+1
syzbot is reporting use-after-free at fuse_kill_sb_blk() [1]. Since sb->s_fs_info field is not cleared after fc was released by fuse_conn_put() when initialization failed, fuse_kill_sb_blk() finds already released fc and tries to hold the lock. Fix this by clearing sb->s_fs_info field after calling fuse_conn_put(). [1] https://syzkaller.appspot.com/bug?id=a07a680ed0a9290585ca424546860464dd9658db Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+ec3986119086fe4eec97@syzkaller.appspotmail.com> Fixes: 3b463ae0c626 ("fuse: invalidation reverse calls") Cc: John Muir <john@jmuir.com> Cc: Csaba Henk <csaba@gluster.com> Cc: Anand Avati <avati@redhat.com> Cc: <stable@vger.kernel.org> # v2.6.31 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-05-31fuse: Allow fully unprivileged mountsEric W. Biederman1-1/+1
Now that the fuse and the vfs work is complete. Allow the fuse filesystem to be mounted by the root user in a user namespace. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-05-31fuse: Ensure posix acls are translated outside of init_user_nsEric W. Biederman1-0/+7
Ensure the translation happens by failing to read or write posix acls when the filesystem has not indicated it supports posix acls. This ensures that modern cached posix acl support is available and used when dealing with posix acls. This is important because only that path has the code to convernt the uids and gids in posix acls into the user namespace of a fuse filesystem. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-23fuse: define the filesystem as untrustedMimi Zohar1-0/+3
Files on FUSE can change at any point in time without IMA being able to detect it. The file data read for the file signature verification could be totally different from what is subsequently read, making the signature verification useless. FUSE can be mounted by unprivileged users either today with fusermount installed with setuid, or soon with the upcoming patches to allow FUSE mounts in a non-init user namespace. This patch sets the SB_I_IMA_UNVERIFIABLE_SIGNATURE flag and when appropriate sets the SB_I_UNTRUSTED_MOUNTER flag. Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Seth Forshee <seth.forshee@canonical.com> Cc: Dongsu Park <dongsu@kinvolk.io> Cc: Alban Crequy <alban@kinvolk.io> Acked-by: Serge Hallyn <serge@hallyn.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-20fuse: Support fuse filesystems outside of init_user_nsEric W. Biederman1-12/+19
In order to support mounts from namespaces other than init_user_ns, fuse must translate uids and gids to/from the userns of the process servicing requests on /dev/fuse. This patch does that, with a couple of restrictions on the namespace: - The userns for the fuse connection is fixed to the namespace from which /dev/fuse is opened. - The namespace must be the same as s_user_ns. These restrictions simplify the implementation by avoiding the need to pass around userns references and by allowing fuse to rely on the checks in setattr_prepare for ownership changes. Either restriction could be relaxed in the future if needed. For cuse the userns used is the opener of /dev/cuse. Semantically the cuse support does not appear safe for unprivileged users. Practically the permissions on /dev/cuse only make it accessible to the global root user. If something slips through the cracks in a user namespace the only users who will be able to use the cuse device are those users mapped into the user namespace. Translation in the posix acl is updated to use the uuser namespace of the filesystem. Avoiding cases which might bypass this translation is handled in a following change. This change is stronlgy based on a similar change from Seth Forshee and Dongsu Park. Cc: Seth Forshee <seth.forshee@canonical.com> Cc: Dongsu Park <dongsu@kinvolk.io> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-20fuse: return -ECONNABORTED on /dev/fuse read after abortSzymon Lukasz1-3/+6
Currently the userspace has no way of knowing whether the fuse connection ended because of umount or abort via sysfs. It makes it hard for filesystems to free the mountpoint after abort without worrying about removing some new mount. The patch fixes it by returning different errors when userspace reads from /dev/fuse (-ENODEV for umount and -ECONNABORTED for abort). Add a new capability flag FUSE_ABORT_ERROR. If set and the connection is gone because of sysfs abort, reading from the device will return -ECONNABORTED. Signed-off-by: Szymon Lukasz <noh4hss@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-27Rename superblock flags (MS_xyz -> SB_xyz)Linus Torvalds1-6/+6
This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-3/+3
Merge updates from Andrew Morton: - a few misc bits - ocfs2 updates - almost all of MM * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (131 commits) memory hotplug: fix comments when adding section mm: make alloc_node_mem_map a void call if we don't have CONFIG_FLAT_NODE_MEM_MAP mm: simplify nodemask printing mm,oom_reaper: remove pointless kthread_run() error check mm/page_ext.c: check if page_ext is not prepared writeback: remove unused function parameter mm: do not rely on preempt_count in print_vma_addr mm, sparse: do not swamp log with huge vmemmap allocation failures mm/hmm: remove redundant variable align_end mm/list_lru.c: mark expected switch fall-through mm/shmem.c: mark expected switch fall-through mm/page_alloc.c: broken deferred calculation mm: don't warn about allocations which stall for too long fs: fuse: account fuse_inode slab memory as reclaimable mm, page_alloc: fix potential false positive in __zone_watermark_ok mm: mlock: remove lru_add_drain_all() mm, sysctl: make NUMA stats configurable shmem: convert shmem_init_inodecache() to void Unify migrate_pages and move_pages access checks mm, pagevec: rename pagevec drained field ...
2017-11-15fs: fuse: account fuse_inode slab memory as reclaimableJohannes Weiner1-3/+3
Fuse inodes are currently included in the unreclaimable slab counts - SUnreclaim in /proc/meminfo, slab_unreclaimable in /proc/vmstat and the per-cgroup memory.stat. But they are reclaimable just like other filesystems' inodes, and /proc/sys/vm/drop_caches frees them easily. Mark the slab cache reclaimable. Link: http://lkml.kernel.org/r/20171102202727.12539-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15Merge tag 'modules-for-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linuxLinus Torvalds1-2/+2
Pull module updates from Jessica Yu: "Summary of modules changes for the 4.15 merge window: - treewide module_param_call() cleanup, fix up set/get function prototype mismatches, from Kees Cook - minor code cleanups" * tag 'modules-for-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: Do not paper over type mismatches in module_param_call() treewide: Fix function prototypes for module_param_call() module: Prepare to convert all module_param_call() prototypes kernel/module: Delete an error message for a failed memory allocation in add_module_usage()
2017-10-31treewide: Fix function prototypes for module_param_call()Kees Cook1-2/+2
Several function prototypes for the set/get functions defined by module_param_call() have a slightly wrong argument types. This fixes those in an effort to clean up the calls when running under type-enforced compiler instrumentation for CFI. This is the result of running the following semantic patch: @match_module_param_call_function@ declarer name module_param_call; identifier _name, _set_func, _get_func; expression _arg, _mode; @@ module_param_call(_name, _set_func, _get_func, _arg, _mode); @fix_set_prototype depends on match_module_param_call_function@ identifier match_module_param_call_function._set_func; identifier _val, _param; type _val_type, _param_type; @@ int _set_func( -_val_type _val +const char * _val , -_param_type _param +const struct kernel_param * _param ) { ... } @fix_get_prototype depends on match_module_param_call_function@ identifier match_module_param_call_function._get_func; identifier _val, _param; type _val_type, _param_type; @@ int _get_func( -_val_type _val +char * _val , -_param_type _param +const struct kernel_param * _param ) { ... } Two additional by-hand changes are included for places where the above Coccinelle script didn't notice them: drivers/platform/x86/thinkpad_acpi.c fs/lockd/svc.c Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2017-10-18Convert fs/*/* to SB_I_VERSIONMatthew Garrett1-1/+1
[AV: in addition to the fix in previous commit] Signed-off-by: Matthew Garrett <mjg59@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-05-20Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+8
Pull block fixes from Jens Axboe: "A small collection of fixes that should go into this cycle. - a pull request from Christoph for NVMe, which ended up being manually applied to avoid pulling in newer bits in master. Mostly fibre channel fixes from James, but also a few fixes from Jon and Vijay - a pull request from Konrad, with just a single fix for xen-blkback from Gustavo. - a fuseblk bdi fix from Jan, fixing a regression in this series with the dynamic backing devices. - a blktrace fix from Shaohua, replacing sscanf() with kstrtoull(). - a request leak fix for drbd from Lars, fixing a regression in the last series with the kref changes. This will go to stable as well" * 'for-linus' of git://git.kernel.dk/linux-block: nvmet: release the sq ref on rdma read errors nvmet-fc: remove target cpu scheduling flag nvme-fc: stop queues on error detection nvme-fc: require target or discovery role for fc-nvme targets nvme-fc: correct port role bits nvme: unmap CMB and remove sysfs file in reset path blktrace: fix integer parse fuseblk: Fix warning in super_setup_bdi_name() block: xen-blkback: add null check to avoid null pointer dereference drbd: fix request leak introduced by locking/atomic, kref: Kill kref_sub()
2017-05-17fuseblk: Fix warning in super_setup_bdi_name()Jan Kara1-1/+8
Commit 5f7f7543f52e "fuse: Convert to separately allocated bdi" didn't properly handle fuseblk filesystem. When fuse_bdi_init() is called for that filesystem type, sb->s_bdi is already initialized (by set_bdev_super()) to point to block device's bdi and consequently super_setup_bdi_name() complains about this fact when reseting bdi to the private one. Fix the problem by properly dropping bdi reference in fuse_bdi_init() before creating a private bdi in super_setup_bdi_name(). Fixes: 5f7f7543f52e ("fuse: Convert to separately allocated bdi") Reported-by: Rakesh Pandit <rakesh@tuxera.com> Tested-by: Rakesh Pandit <rakesh@tuxera.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-05-10Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuseLinus Torvalds1-3/+6
Pull fuse updates from Miklos Szeredi: "Support for pid namespaces from Seth and refcount_t work from Elena" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: Add support for pid namespaces fuse: convert fuse_conn.count from atomic_t to refcount_t fuse: convert fuse_req.count from atomic_t to refcount_t fuse: convert fuse_file.count from atomic_t to refcount_t
2017-04-20fuse: Get rid of bdi_initializedJan Kara1-2/+0
It is not needed anymore since bdi is initialized whenever superblock exists. CC: Miklos Szeredi <miklos@szeredi.hu> CC: linux-fsdevel@vger.kernel.org Suggested-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-20fuse: Convert to separately allocated bdiJan Kara1-29/+13
Allocate struct backing_dev_info separately instead of embedding it inside the superblock. This unifies handling of bdi among users. CC: Miklos Szeredi <miklos@szeredi.hu> CC: linux-fsdevel@vger.kernel.org Acked-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-18fuse: Add support for pid namespacesSeth Forshee1-0/+3
When the userspace process servicing fuse requests is running in a pid namespace then pids passed via the fuse fd are not being translated into that process' namespace. Translation is necessary for the pid to be useful to that process. Since no use case currently exists for changing namespaces all translations can be done relative to the pid namespace in use when fuse_conn_init() is called. For fuse this translates to mount time, and for cuse this is when /dev/cuse is opened. IO for this connection from another namespace will return errors. Requests from processes whose pid cannot be translated into the target namespace will have a value of 0 for in.h.pid. File locking changes based on previous work done by Eric Biederman. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-04-18fuse: convert fuse_conn.count from atomic_t to refcount_tElena Reshetova1-3/+3
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-18fuse: fix root dentry initializationMiklos Szeredi1-1/+2
Add missing dentry initialization to root dentry. Fixes: f75fdf22b0a8 ("fuse: don't use ->d_time") Reported-by: Andreas Reis <andreas.reis@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-01fuse: get rid of fc->flagsMiklos Szeredi1-8/+10
Only two flags: "default_permissions" and "allow_other". All other flags are handled via bitfields. So convert these two as well. They don't change during the lifetime of the filesystem, so this is quite safe. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-01fuse: Add posix ACL supportSeth Forshee1-1/+8
Add a new INIT flag, FUSE_POSIX_ACL, for negotiating ACL support with userspace. When it is set in the INIT response, ACL support will be enabled. ACL support also implies "default_permissions". When ACL support is enabled, the kernel will cache and have responsibility for enforcing ACLs. ACL xattrs will be passed to userspace, which is responsible for updating the ACLs in the filesystem, keeping the file mode in sync, and inheritance of default ACLs when new filesystem nodes are created. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-01fuse: handle killpriv in userspace fsMiklos Szeredi1-1/+3
Only userspace filesystem can do the killing of suid/sgid without races. So introduce an INIT flag and negotiate support for this. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-01fuse: Use generic xattr opsSeth Forshee1-0/+1
In preparation for posix acl support, rework fuse to use xattr handlers and the generic setxattr/getxattr/listxattr callbacks. Split the xattr code out into it's own file, and promote symbols to module-global scope as needed. Functionally these changes have no impact, as fuse still uses a single handler for all xattrs which uses the old callbacks. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-08-06Merge branch 'work.const-qstr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-6/+2
Pull qstr constification updates from Al Viro: "Fairly self-contained bunch - surprising lot of places passes struct qstr * as an argument when const struct qstr * would suffice; it complicates analysis for no good reason. I'd prefer to feed that separately from the assorted fixes (those are in #for-linus and with somewhat trickier topology)" * 'work.const-qstr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: qstr: constify instances in adfs qstr: constify instances in lustre qstr: constify instances in f2fs qstr: constify instances in ext2 qstr: constify instances in vfat qstr: constify instances in procfs qstr: constify instances in fuse qstr constify instances in fs/dcache.c qstr: constify instances in nfs qstr: constify instances in ocfs2 qstr: constify instances in autofs4 qstr: constify instances in hfs qstr: constify instances in hfsplus qstr: constify instances in logfs qstr: constify dentry_init_security
2016-07-30qstr: constify instances in fuseAl Viro1-6/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-07-29fuse: fix wrong assignment of ->flags in fuse_send_init()Wei Fang1-1/+1
FUSE_HAS_IOCTL_DIR should be assigned to ->flags, it may be a typo. Signed-off-by: Wei Fang <fangwei1@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 69fe05c90ed5 ("fuse: add missing INIT flags") Cc: <stable@vger.kernel.org>
2016-06-30fuse: serialize dirops by defaultMiklos Szeredi1-1/+18
Negotiate with userspace filesystems whether they support parallel readdir and lookup. Disable parallelism by default for fear of breaking fuse filesystems. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 9902af79c01a ("parallel lookups: actual switch to rwsem") Fixes: d9b3dbdcfd62 ("fuse: switch to ->iterate_shared()")
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-8/+8
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14kmemcg: account certain kmem allocations to memcgVladimir Davydov1-2/+2
Mark those kmem allocations that are known to be easily triggered from userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to memcg. For the list, see below: - threadinfo - task_struct - task_delay_info - pid - cred - mm_struct - vm_area_struct and vm_region (nommu) - anon_vma and anon_vma_chain - signal_struct - sighand_struct - fs_struct - files_struct - fdtable and fdtable->full_fds_bits - dentry and external_name - inode for all filesystems. This is the most tedious part, because most filesystems overwrite the alloc_inode method. The list is far from complete, so feel free to add more objects. Nevertheless, it should be close to "account everything" approach and keep most workloads within bounds. Malevolent users will be able to breach the limit, but this was possible even with the former "account everything" approach (simply because it did not account everything in fact). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-03Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespaceLinus Torvalds1-6/+3
Pull user namespace updates from Eric Biederman: "Long ago and far away when user namespaces where young it was realized that allowing fresh mounts of proc and sysfs with only user namespace permissions could violate the basic rule that only root gets to decide if proc or sysfs should be mounted at all. Some hacks were put in place to reduce the worst of the damage could be done, and the common sense rule was adopted that fresh mounts of proc and sysfs should allow no more than bind mounts of proc and sysfs. Unfortunately that rule has not been fully enforced. There are two kinds of gaps in that enforcement. Only filesystems mounted on empty directories of proc and sysfs should be ignored but the test for empty directories was insufficient. So in my tree directories on proc, sysctl and sysfs that will always be empty are created specially. Every other technique is imperfect as an ordinary directory can have entries added even after a readdir returns and shows that the directory is empty. Special creation of directories for mount points makes the code in the kernel a smidge clearer about it's purpose. I asked container developers from the various container projects to help test this and no holes were found in the set of mount points on proc and sysfs that are created specially. This set of changes also starts enforcing the mount flags of fresh mounts of proc and sysfs are consistent with the existing mount of proc and sysfs. I expected this to be the boring part of the work but unfortunately unprivileged userspace winds up mounting fresh copies of proc and sysfs with noexec and nosuid clear when root set those flags on the previous mount of proc and sysfs. So for now only the atime, read-only and nodev attributes which userspace happens to keep consistent are enforced. Dealing with the noexec and nosuid attributes remains for another time. This set of changes also addresses an issue with how open file descriptors from /proc/<pid>/ns/* are displayed. Recently readlink of /proc/<pid>/fd has been triggering a WARN_ON that has not been meaningful since it was added (as all of the code in the kernel was converted) and is not now actively wrong. There is also a short list of issues that have not been fixed yet that I will mention briefly. It is possible to rename a directory from below to above a bind mount. At which point any directory pointers below the renamed directory can be walked up to the root directory of the filesystem. With user namespaces enabled a bind mount of the bind mount can be created allowing the user to pick a directory whose children they can rename to outside of the bind mount. This is challenging to fix and doubly so because all obvious solutions must touch code that is in the performance part of pathname resolution. As mentioned above there is also a question of how to ensure that developers by accident or with purpose do not introduce exectuable files on sysfs and proc and in doing so introduce security regressions in the current userspace that will not be immediately obvious and as such are likely to require breaking userspace in painful ways once they are recognized" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: vfs: Remove incorrect debugging WARN in prepend_path mnt: Update fs_fully_visible to test for permanently empty directories sysfs: Create mountpoints with sysfs_create_mount_point sysfs: Add support for permanently empty directories to serve as mount points. kernfs: Add support for always empty directories. proc: Allow creating permanently empty directories that serve as mount points sysctl: Allow creating permanently empty directories that serve as mountpoints. fs: Add helper functions for permanently empty directories. vfs: Ignore unlocked mounts in fs_fully_visible mnt: Modify fs_fully_visible to deal with locked ro nodev and atime mnt: Refactor the logic for mounting sysfs and proc in a user namespace
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