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2021-08-04hfs: add lock nesting notation to hfs_find_initDesmond Cheong Zhi Xi
[ Upstream commit b3b2177a2d795e35dc11597b2609eb1e7e57e570 ] Syzbot reports a possible recursive lock in [1]. This happens due to missing lock nesting information. From the logs, we see that a call to hfs_fill_super is made to mount the hfs filesystem. While searching for the root inode, the lock on the catalog btree is grabbed. Then, when the parent of the root isn't found, a call to __hfs_bnode_create is made to create the parent of the root. This eventually leads to a call to hfs_ext_read_extent which grabs a lock on the extents btree. Since the order of locking is catalog btree -> extents btree, this lock hierarchy does not lead to a deadlock. To tell lockdep that this locking is safe, we add nesting notation to distinguish between catalog btrees, extents btrees, and attributes btrees (for HFS+). This has already been done in hfsplus. Link: https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db [1] Link: https://lkml.kernel.org/r/20210701030756.58760-4-desmondcheongzx@gmail.com Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Reported-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com Tested-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-04hfs: fix high memory mapping in hfs_bnode_readDesmond Cheong Zhi Xi
[ Upstream commit 54a5ead6f5e2b47131a7385d0c0af18e7b89cb02 ] Pages that we read in hfs_bnode_read need to be kmapped into kernel address space. However, currently only the 0th page is kmapped. If the given offset + length exceeds this 0th page, then we have an invalid memory access. To fix this, we kmap relevant pages one by one and copy their relevant portions of data. An example of invalid memory access occurring without this fix can be seen in the following crash report: ================================================================== BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline] BUG: KASAN: use-after-free in hfs_bnode_read+0xc4/0xe0 fs/hfs/bnode.c:26 Read of size 2 at addr ffff888125fdcffe by task syz-executor5/4634 CPU: 0 PID: 4634 Comm: syz-executor5 Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x195/0x1f8 lib/dump_stack.c:120 print_address_description.constprop.0+0x1d/0x110 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x7b/0xd4 mm/kasan/report.c:436 check_region_inline mm/kasan/generic.c:180 [inline] kasan_check_range+0x154/0x1b0 mm/kasan/generic.c:186 memcpy+0x24/0x60 mm/kasan/shadow.c:65 memcpy include/linux/fortify-string.h:191 [inline] hfs_bnode_read+0xc4/0xe0 fs/hfs/bnode.c:26 hfs_bnode_read_u16 fs/hfs/bnode.c:34 [inline] hfs_bnode_find+0x880/0xcc0 fs/hfs/bnode.c:365 hfs_brec_find+0x2d8/0x540 fs/hfs/bfind.c:126 hfs_brec_read+0x27/0x120 fs/hfs/bfind.c:165 hfs_cat_find_brec+0x19a/0x3b0 fs/hfs/catalog.c:194 hfs_fill_super+0xc13/0x1460 fs/hfs/super.c:419 mount_bdev+0x331/0x3f0 fs/super.c:1368 hfs_mount+0x35/0x40 fs/hfs/super.c:457 legacy_get_tree+0x10c/0x220 fs/fs_context.c:592 vfs_get_tree+0x93/0x300 fs/super.c:1498 do_new_mount fs/namespace.c:2905 [inline] path_mount+0x13f5/0x20e0 fs/namespace.c:3235 do_mount fs/namespace.c:3248 [inline] __do_sys_mount fs/namespace.c:3456 [inline] __se_sys_mount fs/namespace.c:3433 [inline] __x64_sys_mount+0x2b8/0x340 fs/namespace.c:3433 do_syscall_64+0x37/0xc0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x45e63a Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 88 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9404d410d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000248 RCX: 000000000045e63a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f9404d41120 RBP: 00007f9404d41120 R08: 00000000200002c0 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000003 R14: 00000000004ad5d8 R15: 0000000000000000 The buggy address belongs to the page: page:00000000dadbcf3e refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x125fdc flags: 0x2fffc0000000000(node=0|zone=2|lastcpupid=0x3fff) raw: 02fffc0000000000 ffffea000497f748 ffffea000497f6c8 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888125fdce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888125fdcf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888125fdcf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888125fdd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888125fdd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Link: https://lkml.kernel.org/r/20210701030756.58760-3-desmondcheongzx@gmail.com Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-04hfs: add missing clean-up in hfs_fill_superDesmond Cheong Zhi Xi
[ Upstream commit 16ee572eaf0d09daa4c8a755fdb71e40dbf8562d ] Patch series "hfs: fix various errors", v2. This series ultimately aims to address a lockdep warning in hfs_find_init reported by Syzbot [1]. The work done for this led to the discovery of another bug, and the Syzkaller repro test also reveals an invalid memory access error after clearing the lockdep warning. Hence, this series is broken up into three patches: 1. Add a missing call to hfs_find_exit for an error path in hfs_fill_super 2. Fix memory mapping in hfs_bnode_read by fixing calls to kmap 3. Add lock nesting notation to tell lockdep that the observed locking hierarchy is safe This patch (of 3): Before exiting hfs_fill_super, the struct hfs_find_data used in hfs_find_init should be passed to hfs_find_exit to be cleaned up, and to release the lock held on the btree. The call to hfs_find_exit is missing from an error path. We add it back in by consolidating calls to hfs_find_exit for error paths. Link: https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db [1] Link: https://lkml.kernel.org/r/20210701030756.58760-1-desmondcheongzx@gmail.com Link: https://lkml.kernel.org/r/20210701030756.58760-2-desmondcheongzx@gmail.com Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-28fs/hfs/extent.c: fix array out of bounds read of array extentColin Ian King
[ Upstream commit 6c9a3f843a29d6894dfc40df338b91dbd78f0ae3 ] Currently extent and index i are both being incremented causing an array out of bounds read on extent[i]. Fix this by removing the extraneous increment of extent. Ernesto said: : This is only triggered when deleting a file with a resource fork. I : may be wrong because the documentation isn't clear, but I don't think : you can create those under linux. So I guess nobody was testing them. : : > A disk space leak, perhaps? : : That's what it looks like in general. hfs_free_extents() won't do : anything if the block count doesn't add up, and the error will be : ignored. Now, if the block count randomly does add up, we could see : some corruption. Detected by CoverityScan, CID#711541 ("Out of bounds read") Link: http://lkml.kernel.org/r/20180831140538.31566-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Ernesto A. Fernndez <ernesto.mnd.fernandez@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-28hfs: fix return value of hfs_get_block()Ernesto A. Fernández
[ Upstream commit 1267a07be5ebbff2d2739290f3d043ae137c15b4 ] Direct writes to empty inodes fail with EIO. The generic direct-io code is in part to blame (a patch has been submitted as "direct-io: allow direct writes to empty inodes"), but hfs is worse affected than the other filesystems because the fallback to buffered I/O doesn't happen. The problem is the return value of hfs_get_block() when called with !create. Change it to be more consistent with the other modules. Link: http://lkml.kernel.org/r/4538ab8c35ea37338490525f0f24cbc37227528c.1539195310.git.ernesto.mnd.fernandez@gmail.com Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-28hfs: prevent btree data loss on ENOSPCErnesto A. Fernández
[ Upstream commit 54640c7502e5ed41fbf4eedd499e85f9acc9698f ] Inserting a new record in a btree may require splitting several of its nodes. If we hit ENOSPC halfway through, the new nodes will be left orphaned and their records will be lost. This could mean lost inodes or extents. Henceforth, check the available disk space before making any changes. This still leaves the potential problem of corruption on ENOMEM. There is no need to reserve space before deleting a catalog record, as we do for hfsplus. This difference is because hfs index nodes have fixed length keys. Link: http://lkml.kernel.org/r/ab5fc8a7d5ffccfd5f27b1cf2cb4ceb6c110da74.1536269131.git.ernesto.mnd.fernandez@gmail.com Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-28hfs: fix BUG on bnode parent updateErnesto A. Fernández
[ Upstream commit ef75bcc5763d130451a99825f247d301088b790b ] hfs_brec_update_parent() may hit BUG_ON() if the first record of both a leaf node and its parent are changed, and if this forces the parent to be split. It is not possible for this to happen on a valid hfs filesystem because the index nodes have fixed length keys. For reasons I ignore, the hfs module does have support for a number of hfsplus features. A corrupt btree header may report variable length keys and trigger this BUG, so it's better to fix it. Link: http://lkml.kernel.org/r/cf9b02d57f806217a2b1bf5db8c3e39730d8f603.1535682463.git.ernesto.mnd.fernandez@gmail.com Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Viacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-12-17hfs: do not free node before usingPan Bian
[ Upstream commit ce96a407adef126870b3f4a1b73529dd8aa80f49 ] hfs_bmap_free() frees the node via hfs_bnode_put(node). However, it then reads node->this when dumping error message on an error path, which may result in a use-after-free bug. This patch frees the node only when it is never again used. Link: http://lkml.kernel.org/r/1542963889-128825-1-git-send-email-bianpan2016@163.com Fixes: a1185ffa2fc ("HFS rewrite") Signed-off-by: Pan Bian <bianpan2016@163.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Joe Perches <joe@perches.com> Cc: Ernesto A. Fernandez <ernesto.mnd.fernandez@gmail.com> Cc: Viacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-11-27hfs: prevent btree data loss on root splitErnesto A. Fernández
[ Upstream commit d057c036672f33d43a5f7344acbb08cf3a8a0c09 ] This bug is triggered whenever hfs_brec_update_parent() needs to split the root node. The height of the btree is not increased, which leaves the new node orphaned and its records lost. It is not possible for this to happen on a valid hfs filesystem because the index nodes have fixed length keys. For reasons I ignore, the hfs module does have support for a number of hfsplus features. A corrupt btree header may report variable length keys and trigger this bug, so it's better to fix it. Link: http://lkml.kernel.org/r/9750b1415685c4adca10766895f6d5ef12babdb0.1535682463.git.ernesto.mnd.fernandez@gmail.com Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-09-15hfs: prevent crash on exit from failed searchErnesto A. Fernández
[ Upstream commit dc2572791d3a41bab94400af2b6bca9d71ccd303 ] hfs_find_exit() expects fd->bnode to be NULL after a search has failed. hfs_brec_insert() may instead set it to an error-valued pointer. Fix this to prevent a crash. Link: http://lkml.kernel.org/r/53d9749a029c41b4016c495fc5838c9dba3afc52.1530294815.git.ernesto.mnd.fernandez@gmail.com Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Cc: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Cc: Viacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-09-10hfs: fix B-tree corruption after insertion at position 0Hin-Tak Leung
Fix B-tree corruption when a new record is inserted at position 0 in the node in hfs_brec_insert(). This is an identical change to the corresponding hfs b-tree code to Sergei Antonov's "hfsplus: fix B-tree corruption after insertion at position 0", to keep similar code paths in the hfs and hfsplus drivers in sync, where appropriate. Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Sergei Antonov <saproj@gmail.com> Cc: Joe Perches <joe@perches.com> Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Anton Altaparmakov <anton@tuxera.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10hfs,hfsplus: cache pages correctly between bnode_create and bnode_freeHin-Tak Leung
Pages looked up by __hfs_bnode_create() (called by hfs_bnode_create() and hfs_bnode_find() for finding or creating pages corresponding to an inode) are immediately kmap()'ed and used (both read and write) and kunmap()'ed, and should not be page_cache_release()'ed until hfs_bnode_free(). This patch fixes a problem I first saw in July 2012: merely running "du" on a large hfsplus-mounted directory a few times on a reasonably loaded system would get the hfsplus driver all confused and complaining about B-tree inconsistencies, and generates a "BUG: Bad page state". Most recently, I can generate this problem on up-to-date Fedora 22 with shipped kernel 4.0.5, by running "du /" (="/" + "/home" + "/mnt" + other smaller mounts) and "du /mnt" simultaneously on two windows, where /mnt is a lightly-used QEMU VM image of the full Mac OS X 10.9: $ df -i / /home /mnt Filesystem Inodes IUsed IFree IUse% Mounted on /dev/mapper/fedora-root 3276800 551665 2725135 17% / /dev/mapper/fedora-home 52879360 716221 52163139 2% /home /dev/nbd0p2 4294967295 1387818 4293579477 1% /mnt After applying the patch, I was able to run "du /" (60+ times) and "du /mnt" (150+ times) continuously and simultaneously for 6+ hours. There are many reports of the hfsplus driver getting confused under load and generating "BUG: Bad page state" or other similar issues over the years. [1] The unpatched code [2] has always been wrong since it entered the kernel tree. The only reason why it gets away with it is that the kmap/memcpy/kunmap follow very quickly after the page_cache_release() so the kernel has not had a chance to reuse the memory for something else, most of the time. The current RW driver appears to have followed the design and development of the earlier read-only hfsplus driver [3], where-by version 0.1 (Dec 2001) had a B-tree node-centric approach to read_cache_page()/page_cache_release() per bnode_get()/bnode_put(), migrating towards version 0.2 (June 2002) of caching and releasing pages per inode extents. When the current RW code first entered the kernel [2] in 2005, there was an REF_PAGES conditional (and "//" commented out code) to switch between B-node centric paging to inode-centric paging. There was a mistake with the direction of one of the REF_PAGES conditionals in __hfs_bnode_create(). In a subsequent "remove debug code" commit [4], the read_cache_page()/page_cache_release() per bnode_get()/bnode_put() were removed, but a page_cache_release() was mistakenly left in (propagating the "REF_PAGES <-> !REF_PAGE" mistake), and the commented-out page_cache_release() in bnode_release() (which should be spanned by !REF_PAGES) was never enabled. References: [1]: Michael Fox, Apr 2013 http://www.spinics.net/lists/linux-fsdevel/msg63807.html ("hfsplus volume suddenly inaccessable after 'hfs: recoff %d too large'") Sasha Levin, Feb 2015 http://lkml.org/lkml/2015/2/20/85 ("use after free") https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740814 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1027887 https://bugzilla.kernel.org/show_bug.cgi?id=42342 https://bugzilla.kernel.org/show_bug.cgi?id=63841 https://bugzilla.kernel.org/show_bug.cgi?id=78761 [2]: http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfs/bnode.c?id=d1081202f1d0ee35ab0beb490da4b65d4bc763db commit d1081202f1d0ee35ab0beb490da4b65d4bc763db Author: Andrew Morton <akpm@osdl.org> Date: Wed Feb 25 16:17:36 2004 -0800 [PATCH] HFS rewrite http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfsplus/bnode.c?id=91556682e0bf004d98a529bf829d339abb98bbbd commit 91556682e0bf004d98a529bf829d339abb98bbbd Author: Andrew Morton <akpm@osdl.org> Date: Wed Feb 25 16:17:48 2004 -0800 [PATCH] HFS+ support [3]: http://sourceforge.net/projects/linux-hfsplus/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.1/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.2/ http://linux-hfsplus.cvs.sourceforge.net/viewvc/linux-hfsplus/linux/\ fs/hfsplus/bnode.c?r1=1.4&r2=1.5 Date: Thu Jun 6 09:45:14 2002 +0000 Use buffer cache instead of page cache in bnode.c. Cache inode extents. [4]: http://git.kernel.org/cgit/linux/kernel/git/\ stable/linux-stable.git/commit/?id=a5e3985fa014029eb6795664c704953720cc7f7d commit a5e3985fa014029eb6795664c704953720cc7f7d Author: Roman Zippel <zippel@linux-m68k.org> Date: Tue Sep 6 15:18:47 2005 -0700 [PATCH] hfs: remove debug code Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net> Signed-off-by: Sergei Antonov <saproj@gmail.com> Reviewed-by: Anton Altaparmakov <anton@tuxera.com> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Sougata Santra <sougata@tuxera.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-04fs: create and use seq_show_option for escapingKees Cook
Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Jan Kara <jack@suse.com> Acked-by: Paul Moore <paul@paul-moore.com> Cc: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-06-23fs: cleanup slight list_entry abuseRasmus Villemoes
list_entry is just a wrapper for container_of, but it is arguably wrong (and slightly confusing) to use it when the pointed-to struct member is not a struct list_head. Use container_of directly instead. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-06-02writeback: separate out include/linux/backing-dev-defs.hTejun Heo
With the planned cgroup writeback support, backing-dev related declarations will be more widely used across block and cgroup; unfortunately, including backing-dev.h from include/linux/blkdev.h makes cyclic include dependency quite likely. This patch separates out backing-dev-defs.h which only has the essential definitions and updates blkdev.h to include it. c files which need access to more backing-dev details now include backing-dev.h directly. This takes backing-dev.h off the common include dependency chain making it a lot easier to use it across block and cgroup. v2: fs/fat build failure fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-04-26Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull fourth vfs update from Al Viro: "d_inode() annotations from David Howells (sat in for-next since before the beginning of merge window) + four assorted fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: RCU pathwalk breakage when running into a symlink overmounting something fix I_DIO_WAKEUP definition direct-io: only inc/dec inode->i_dio_count for file systems fs/9p: fix readdir() VFS: assorted d_backing_inode() annotations VFS: fs/inode.c helpers: d_inode() annotations VFS: fs/cachefiles: d_backing_inode() annotations VFS: fs library helpers: d_inode() annotations VFS: assorted weird filesystems: d_inode() annotations VFS: normal filesystems (and lustre): d_inode() annotations VFS: security/: d_inode() annotations VFS: security/: d_backing_inode() annotations VFS: net/: d_inode() annotations VFS: net/unix: d_backing_inode() annotations VFS: kernel/: d_inode() annotations VFS: audit: d_backing_inode() annotations VFS: Fix up some ->d_inode accesses in the chelsio driver VFS: Cachefiles should perform fs modifications on the top layer only VFS: AF_UNIX sockets should call mknod on the top layer only
2015-04-17Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge third patchbomb from Andrew Morton: - various misc things - a couple of lib/ optimisations - provide DIV_ROUND_CLOSEST_ULL() - checkpatch updates - rtc tree - befs, nilfs2, hfs, hfsplus, fatfs, adfs, affs, bfs - ptrace fixes - fork() fixes - seccomp cleanups - more mmap_sem hold time reductions from Davidlohr * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (138 commits) proc: show locks in /proc/pid/fdinfo/X docs: add missing and new /proc/PID/status file entries, fix typos drivers/rtc/rtc-at91rm9200.c: make IO endian agnostic Documentation/spi/spidev_test.c: fix warning drivers/rtc/rtc-s5m.c: allow usage on device type different than main MFD type .gitignore: ignore *.tar MAINTAINERS: add Mediatek SoC mailing list tomoyo: reduce mmap_sem hold for mm->exe_file powerpc/oprofile: reduce mmap_sem hold for exe_file oprofile: reduce mmap_sem hold for mm->exe_file mips: ip32: add platform data hooks to use DS1685 driver lib/Kconfig: fix up HAVE_ARCH_BITREVERSE help text x86: switch to using asm-generic for seccomp.h sparc: switch to using asm-generic for seccomp.h powerpc: switch to using asm-generic for seccomp.h parisc: switch to using asm-generic for seccomp.h mips: switch to using asm-generic for seccomp.h microblaze: use asm-generic for seccomp.h arm: use asm-generic for seccomp.h seccomp: allow COMPAT sigreturn overrides ...
2015-04-17hfs: incorrect return valuesChengyu Song
In case of memory allocation error, the return should be -ENOMEM, instead of -ENOSPC. Signed-off-by: Chengyu Song <csong84@gatech.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15VFS: normal filesystems (and lustre): d_inode() annotationsDavid Howells
that's the bulk of filesystem drivers dealing with inodes of their own Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11direct_IO: remove rw from a_ops->direct_IO()Omar Sandoval
Now that no one is using rw, remove it completely. Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11direct_IO: use iov_iter_rw() instead of rw everywhereOmar Sandoval
The rw parameter to direct_IO is redundant with iov_iter->type, and treated slightly differently just about everywhere it's used: some users do rw & WRITE, and others do rw == WRITE where they should be doing a bitwise check. Simplify this with the new iov_iter_rw() helper, which always returns either READ or WRITE. Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11Remove rw from {,__,do_}blockdev_direct_IO()Omar Sandoval
Most filesystems call through to these at some point, so we'll start here. Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11make new_sync_{read,write}() staticAl Viro
All places outside of core VFS that checked ->read and ->write for being NULL or called the methods directly are gone now, so NULL {read,write} with non-NULL {read,write}_iter will do the right thing in all cases. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-03-25fs: move struct kiocb to fs.hChristoph Hellwig
struct kiocb now is a generic I/O container, so move it to fs.h. Also do a #include diet for aio.h while we're at it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-10fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmpRasmus Villemoes
Relying on the sign (after casting to int) of the difference of two quantities for comparison is usually wrong. For example, should a-b turn out to be 2^31, the return value of cmp(a,b) is -2^31; but that would also be the return value from cmp(b, a). So a compares less than b and b compares less than a. One can also easily find three values a,b,c such that a compares less than b, b compares less than c, but a does not compare less than c. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14fs/hfs/hfs_fs.h: remove redundant sys_tz declarationFabian Frederick
sys_tz is already declared in include/linux/time.h Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-05-06write_iter variants of {__,}generic_file_aio_write()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06switch simple generic_file_aio_read() users to ->read_iter()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06switch {__,}blockdev_direct_IO() to iov_iterAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06get rid of pointless iov_length() in ->direct_IO()Al Viro
all callers have iov_length(iter->iov, iter->nr_segs) == iov_iter_count(iter) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06pass iov_iter to ->direct_IO()Al Viro
unmodified, for now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-04Merge tag 'ext4_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Major changes for 3.14 include support for the newly added ZERO_RANGE and COLLAPSE_RANGE fallocate operations, and scalability improvements in the jbd2 layer and in xattr handling when the extended attributes spill over into an external block. Other than that, the usual clean ups and minor bug fixes" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (42 commits) ext4: fix premature freeing of partial clusters split across leaf blocks ext4: remove unneeded test of ret variable ext4: fix comment typo ext4: make ext4_block_zero_page_range static ext4: atomically set inode->i_flags in ext4_set_inode_flags() ext4: optimize Hurd tests when reading/writing inodes ext4: kill i_version support for Hurd-castrated file systems ext4: each filesystem creates and uses its own mb_cache fs/mbcache.c: doucple the locking of local from global data fs/mbcache.c: change block and index hash chain to hlist_bl_node ext4: Introduce FALLOC_FL_ZERO_RANGE flag for fallocate ext4: refactor ext4_fallocate code ext4: Update inode i_size after the preallocation ext4: fix partial cluster handling for bigalloc file systems ext4: delete path dealloc code in ext4_ext_handle_uninitialized_extents ext4: only call sync_filesystm() when remounting read-only fs: push sync_filesystem() down to the file system's remount_fs() jbd2: improve error messages for inconsistent journal heads jbd2: minimize region locked by j_list_lock in jbd2_journal_forget() jbd2: minimize region locked by j_list_lock in journal_get_create_access() ...
2014-04-03mm + fs: store shadow entries in page cacheJohannes Weiner
Reclaim will be leaving shadow entries in the page cache radix tree upon evicting the real page. As those pages are found from the LRU, an iput() can lead to the inode being freed concurrently. At this point, reclaim must no longer install shadow pages because the inode freeing code needs to ensure the page tree is really empty. Add an address_space flag, AS_EXITING, that the inode freeing code sets under the tree lock before doing the final truncate. Reclaim will check for this flag before installing shadow pages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-13fs: push sync_filesystem() down to the file system's remount_fs()Theodore Ts'o
Previously, the no-op "mount -o mount /dev/xxx" operation when the file system is already mounted read-write causes an implied, unconditional syncfs(). This seems pretty stupid, and it's certainly documented or guaraunteed to do this, nor is it particularly useful, except in the case where the file system was mounted rw and is getting remounted read-only. However, it's possible that there might be some file systems that are actually depending on this behavior. In most file systems, it's probably fine to only call sync_filesystem() when transitioning from read-write to read-only, and there are some file systems where this is not needed at all (for example, for a pseudo-filesystem or something like romfs). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Evgeniy Dushistov <dushistov@mail.ru> Cc: Jan Kara <jack@suse.cz> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Anders Larsen <al@alarsen.net> Cc: Phillip Lougher <phillip@squashfs.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: xfs@oss.sgi.com Cc: linux-btrfs@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Cc: codalist@coda.cs.cmu.edu Cc: linux-ext4@vger.kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net Cc: fuse-devel@lists.sourceforge.net Cc: cluster-devel@redhat.com Cc: linux-mtd@lists.infradead.org Cc: jfs-discussion@lists.sourceforge.net Cc: linux-nfs@vger.kernel.org Cc: linux-nilfs@vger.kernel.org Cc: linux-ntfs-dev@lists.sourceforge.net Cc: ocfs2-devel@oss.oracle.com Cc: reiserfs-devel@vger.kernel.org
2013-11-13fs/hfs/btree.h: remove duplicate definesMichael Opdenacker
This patch removes duplicate defines from fs/hfs/btree.h [akpm@linux-foundation.org: retain the comments] Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com> Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12truncate: drop 'oldsize' truncate_pagecache() parameterKirill A. Shutemov
truncate_pagecache() doesn't care about old size since commit cedabed49b39 ("vfs: Fix vmtruncate() regression"). Let's drop it. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-29Don't pass inode to ->d_hash() and ->d_compare()Linus Torvalds
Instances either don't look at it at all (the majority of cases) or only want it to find the superblock (which can be had as dentry->d_sb). A few cases that want more are actually safe with dentry->d_inode - the only precaution needed is the check that it hadn't been replaced with NULL by rmdir() or by overwriting rename(), which case should be simply treated as cache miss. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-06-29[readdir] convert hfsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-05-24hfs: avoid crash in hfs_bnode_createJeff Mahoney
Commit 634725a92938 ("hfs: cleanup HFS+ prints") removed the BUG_ON in hfs_bnode_create in hfsplus. This patch removes it from the hfs version and avoids an fsfuzzer crash. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Acked-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-07Merge branch 'akpm' (incoming from Andrew)Linus Torvalds
Merge more incoming from Andrew Morton: - Various fixes which were stalled or which I picked up recently - A large rotorooting of the AIO code. Allegedly to improve performance but I don't really have good performance numbers (I might have lost the email) and I can't raise Kent today. I held this out of 3.9 and we could give it another cycle if it's all too late/scary. I ended up taking only the first two thirds of the AIO rotorooting. I left the percpu parts and the batch completion for later. - Linus * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (33 commits) aio: don't include aio.h in sched.h aio: kill ki_retry aio: kill ki_key aio: give shared kioctx fields their own cachelines aio: kill struct aio_ring_info aio: kill batch allocation aio: change reqs_active to include unreaped completions aio: use cancellation list lazily aio: use flush_dcache_page() aio: make aio_read_evt() more efficient, convert to hrtimers wait: add wait_event_hrtimeout() aio: refcounting cleanup aio: make aio_put_req() lockless aio: do fget() after aio_get_req() aio: dprintk() -> pr_debug() aio: move private stuff out of aio.h aio: add kiocb_cancel() aio: kill return value of aio_complete() char: add aio_{read,write} to /dev/{null,zero} aio: remove retry-based AIO ...
2013-05-07aio: don't include aio.h in sched.hKent Overstreet
Faster kernel compiles by way of fewer unnecessary includes. [akpm@linux-foundation.org: fix fallout] [akpm@linux-foundation.org: fix build] Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-05hfs: SMP race on directory close()Al Viro
->open_dir_list needs protection... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-04-30hfs/hfsplus: convert printks to pr_<level>Joe Perches
Use a more current logging style. Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt hfsplus now uses "hfsplus: " for all messages. Coalesce formats. Prefix debugging messages too. Signed-off-by: Joe Perches <joe@perches.com> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30hfs/hfsplus: convert dprint to hfs_dbgJoe Perches
Use a more current logging style. Rename macro and uses. Add do {} while (0) to macro. Add DBG_ to macro. Add and use hfs_dbg_cont variant where appropriate. Signed-off-by: Joe Perches <joe@perches.com> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30hfs: add error checking for hfs_find_init()Alexey Khoroshilov
hfs_find_init() may fail with ENOMEM, but there are places, where the returned value is not checked. The consequences can be very unpleasant, e.g. kfree uninitialized pointer and inappropriate mutex unlocking. The patch adds checks for errors in hfs_find_init(). Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru> Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-03fs: Limit sys_mount to only request filesystem modules.Eric W. Biederman
Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Reported-by: Kees Cook <keescook@google.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-02-26Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...
2013-02-22new helper: file_inode(file)Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-01-21fs/hfs: remove depends on CONFIG_EXPERIMENTALKees Cook
The CONFIG_EXPERIMENTAL config item has not carried much meaning for a while now and is almost always enabled by default. As agreed during the Linux kernel summit, remove it from any "depends on" lines in Kconfigs. Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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