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2017-07-17VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)David Howells
Firstly by applying the following with coccinelle's spatch: @@ expression SB; @@ -SB->s_flags & MS_RDONLY +sb_rdonly(SB) to effect the conversion to sb_rdonly(sb), then by applying: @@ expression A, SB; @@ ( -(!sb_rdonly(SB)) && A +!sb_rdonly(SB) && A | -A != (sb_rdonly(SB)) +A != sb_rdonly(SB) | -A == (sb_rdonly(SB)) +A == sb_rdonly(SB) | -!(sb_rdonly(SB)) +!sb_rdonly(SB) | -A && (sb_rdonly(SB)) +A && sb_rdonly(SB) | -A || (sb_rdonly(SB)) +A || sb_rdonly(SB) | -(sb_rdonly(SB)) != A +sb_rdonly(SB) != A | -(sb_rdonly(SB)) == A +sb_rdonly(SB) == A | -(sb_rdonly(SB)) && A +sb_rdonly(SB) && A | -(sb_rdonly(SB)) || A +sb_rdonly(SB) || A ) @@ expression A, B, SB; @@ ( -(sb_rdonly(SB)) ? 1 : 0 +sb_rdonly(SB) | -(sb_rdonly(SB)) ? A : B +sb_rdonly(SB) ? A : B ) to remove left over excess bracketage and finally by applying: @@ expression A, SB; @@ ( -(A & MS_RDONLY) != sb_rdonly(SB) +(bool)(A & MS_RDONLY) != sb_rdonly(SB) | -(A & MS_RDONLY) == sb_rdonly(SB) +(bool)(A & MS_RDONLY) == sb_rdonly(SB) ) to make comparisons against the result of sb_rdonly() (which is a bool) work correctly. Signed-off-by: David Howells <dhowells@redhat.com>
2017-07-15Merge branch 'work.mount' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull ->s_options removal from Al Viro: "Preparations for fsmount/fsopen stuff (coming next cycle). Everything gets moved to explicit ->show_options(), killing ->s_options off + some cosmetic bits around fs/namespace.c and friends. Basically, the stuff needed to work with fsmount series with minimum of conflicts with other work. It's not strictly required for this merge window, but it would reduce the PITA during the coming cycle, so it would be nice to have those bits and pieces out of the way" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: isofs: Fix isofs_show_options() VFS: Kill off s_options and helpers orangefs: Implement show_options 9p: Implement show_options isofs: Implement show_options afs: Implement show_options affs: Implement show_options befs: Implement show_options spufs: Implement show_options bpf: Implement show_options ramfs: Implement show_options pstore: Implement show_options omfs: Implement show_options hugetlbfs: Implement show_options VFS: Don't use save/replace_mount_options if not using generic_show_options VFS: Provide empty name qstr VFS: Make get_filesystem() return the affected filesystem VFS: Clean up whitespace in fs/namespace.c and fs/super.c Provide a function to create a NUL-terminated string from unterminated data
2017-07-08Merge branch 'work.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc filesystem updates from Al Viro: "Assorted normal VFS / filesystems stuff..." * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: dentry name snapshots Make statfs properly return read-only state after emergency remount fs/dcache: init in_lookup_hashtable minix: Deinline get_block, save 2691 bytes fs: Reorder inode_owner_or_capable() to avoid needless fs: warn in case userspace lied about modprobe return
2017-07-07dentry name snapshotsAl Viro
take_dentry_name_snapshot() takes a safe snapshot of dentry name; if the name is a short one, it gets copied into caller-supplied structure, otherwise an extra reference to external name is grabbed (those are never modified). In either case the pointer to stable string is stored into the same structure. dentry must be held by the caller of take_dentry_name_snapshot(), but may be freely dropped afterwards - the snapshot will stay until destroyed by release_dentry_name_snapshot(). Intended use: struct name_snapshot s; take_dentry_name_snapshot(&s, dentry); ... access s.name ... release_dentry_name_snapshot(&s); Replaces fsnotify_oldname_...(), gets used in fsnotify to obtain the name to pass down with event. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-07-06VFS: Provide empty name qstrDavid Howells
Provide an empty name (ie. "") qstr for general use. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-29fs: Reorder inode_owner_or_capable() to avoid needlessKees Cook
Checking for capabilities should be the last operation when performing access control tests so that PF_SUPERPRIV is set only when it was required for success (implying that the capability was needed for the operation). Reported-by: Solar Designer <solar@openwall.com> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-05-18Merge remote-tracking branch 'mauro-exp/docbook3' into death-to-docbookJonathan Corbet
Mauro says: This patch series convert the remaining DocBooks to ReST. The first version was originally send as 3 patch series: [PATCH 00/36] Convert DocBook documents to ReST [PATCH 0/5] Convert more books to ReST [PATCH 00/13] Get rid of DocBook The lsm book was added as if it were a text file under Documentation. The plan is to merge it with another file under Documentation/security, after both this series and a security Documentation patch series gets merged. It also adjusts some Sphinx-pedantic errors/warnings on some kernel-doc markups. I also added some patches here to add PDF output for all existing ReST books.
2017-05-16fs: add a blank lines on some kernel-doc commentsMauro Carvalho Chehab
Sphinx gets confused when it finds identation without a good reason for it and without a preceding blank line: ./fs/mpage.c:347: ERROR: Unexpected indentation. ./fs/namei.c:4303: ERROR: Unexpected indentation. ./fs/fs-writeback.c:2060: ERROR: Unexpected indentation. No functional changes. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-05-12Merge branch 'work.sane_pwd' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Making sure that something like a referral point won't end up as pwd or root. The main part is the last commit (fixing mntns_install()); that one fixes a hard-to-hit race. The fchdir() commit is making fchdir(2) a bit more robust - it should be impossible to get opened files (even O_PATH ones) for referral points in the first place, so the existing checks are OK, but checking the same thing as in chdir(2) is just as cheap. The path_init() commit removes a redundant check that shouldn't have been there in the first place" * 'work.sane_pwd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: make sure that mntns_install() doesn't end up with referral for root path_init(): don't bother with checking MAY_EXEC for LOOKUP_ROOT make sure that fchdir() won't accept referral points, etc.
2017-05-08fs: semove set but not checked AOP_FLAG_UNINTERRUPTIBLE flagTetsuo Handa
Commit afddba49d18f ("fs: introduce write_begin, write_end, and perform_write aops") introduced AOP_FLAG_UNINTERRUPTIBLE flag which was checked in pagecache_write_begin(), but that check was removed by 4e02ed4b4a2f ("fs: remove prepare_write/commit_write"). Between these two commits, commit d9414774dc0c ("cifs: Convert cifs to new aops.") added a check in cifs_write_begin(), but that check was soon removed by commit a98ee8c1c707 ("[CIFS] fix regression in cifs_write_begin/cifs_write_end"). Therefore, AOP_FLAG_UNINTERRUPTIBLE flag is checked nowhere. Let's remove this flag. This patch has no functionality changes. Link: http://lkml.kernel.org/r/1489294781-53494-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Nick Piggin <npiggin@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03Merge branch 'next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "Highlights: IMA: - provide ">" and "<" operators for fowner/uid/euid rules KEYS: - add a system blacklist keyring - add KEYCTL_RESTRICT_KEYRING, exposes keyring link restriction functionality to userland via keyctl() LSM: - harden LSM API with __ro_after_init - add prlmit security hook, implement for SELinux - revive security_task_alloc hook TPM: - implement contextual TPM command 'spaces'" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (98 commits) tpm: Fix reference count to main device tpm_tis: convert to using locality callbacks tpm: fix handling of the TPM 2.0 event logs tpm_crb: remove a cruft constant keys: select CONFIG_CRYPTO when selecting DH / KDF apparmor: Make path_max parameter readonly apparmor: fix parameters so that the permission test is bypassed at boot apparmor: fix invalid reference to index variable of iterator line 836 apparmor: use SHASH_DESC_ON_STACK security/apparmor/lsm.c: set debug messages apparmor: fix boolreturn.cocci warnings Smack: Use GFP_KERNEL for smk_netlbl_mls(). smack: fix double free in smack_parse_opts_str() KEYS: add SP800-56A KDF support for DH KEYS: Keyring asymmetric key restrict method with chaining KEYS: Restrict asymmetric key linkage using a specific keychain KEYS: Add a lookup_restriction function for the asymmetric key type KEYS: Add KEYCTL_RESTRICT_KEYRING KEYS: Consistent ordering for __key_link_begin and restrict check KEYS: Add an optional lookup_restriction hook to key_type ...
2017-04-21make sure that mntns_install() doesn't end up with referral for rootAl Viro
new flag: LOOKUP_DOWN. If the starting point is overmounted, cross into whatever's mounted on top, triggering referrals et.al. Use that instead of follow_down_one() loop in mntns_install(), handle errors properly. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-21path_init(): don't bother with checking MAY_EXEC for LOOKUP_ROOTAl Viro
we'll hit that check in link_path_walk() anyway. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-15vfs: don't do RCU lookup of empty pathnamesLinus Torvalds
Normal pathname lookup doesn't allow empty pathnames, but using AT_EMPTY_PATH (with name_to_handle_at() or fstatat(), for example) you can trigger an empty pathname lookup. And not only is the RCU lookup in that case entirely unnecessary (because we'll obviously immediately finalize the end result), it is actively wrong. Why? An empth path is a special case that will return the original 'dirfd' dentry - and that dentry may not actually be RCU-free'd, resulting in a potential use-after-free if we were to initialize the path lazily under the RCU read lock and depend on complete_walk() finalizing the dentry. Found by syzkaller and KASAN. Reported-by: Dmitry Vyukov <dvyukov@google.com> Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-29fs: switch order of CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH checksStephen Smalley
generic_permission() presently checks CAP_DAC_OVERRIDE prior to CAP_DAC_READ_SEARCH. This can cause misleading audit messages when using a LSM such as SELinux or AppArmor, since CAP_DAC_OVERRIDE may not be required for the operation. Flip the order of the tests so that CAP_DAC_OVERRIDE is only checked when required for the operation. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: John Johansen <john.johansen@canonical.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-02Merge remote-tracking branch 'ovl/for-viro' into for-linusAl Viro
Overlayfs-related series from Miklos and Amir
2017-03-02Merge branch 'work.namei' into for-linusAl Viro
2017-02-07vfs: create vfs helper vfs_tmpfile()Amir Goldstein
Factor out some common vfs bits from do_tmpfile() to be used by overlayfs for concurrent copy up. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-02fs: Better permission checking for submountsEric W. Biederman
To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem. The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks. Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks. Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate. vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action. sget and sget_userns are modified to not perform any permission checks on submounts. follow_automount is modified to stop using override_creds as that has proven problemantic. do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it. autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking. cifs is modified to pass the mountpoint all of the way down to vfs_submount. debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function. Cc: stable@vger.kernel.org Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-02-01vfs: open() with O_CREAT should not create inodes with unknown idsSeth Forshee
may_create() rejects creation of inodes with ids which lack a mapping into s_user_ns. However for O_CREAT may_o_create() is is used instead. Add a similar check there. Fixes: 036d523641c6 ("vfs: Don't create inodes with a uid or gid unknown to the vfs") Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-01-09namei.c: split unlazy_walk()Al Viro
In all but one case, the last two arguments are NULL and 0 resp.; almost everyone just wants to switch nameidata to non-RCU mode. The only exception is lookup_fast(), where we have a child dentry we want to legitimize as well. Split these two cases. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-09namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-09lookup_fast(): clean up the logics around the fallback to non-rcu modeAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-08namei: fold unlazy_link() into its sole callerAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-17Merge uncontroversial parts of branch 'readlink' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull partial readlink cleanups from Miklos Szeredi. This is the uncontroversial part of the readlink cleanup patch-set that simplifies the default readlink handling. Miklos and Al are still discussing the rest of the series. * git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: vfs: make generic_readlink() static vfs: remove ".readlink = generic_readlink" assignments vfs: default to generic_readlink() vfs: replace calling i_op->readlink with vfs_readlink() proc/self: use generic_readlink ecryptfs: use vfs_get_link() bad_inode: add missing i_op initializers
2016-12-17Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "In this pile: - autofs-namespace series - dedupe stuff - more struct path constification" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits) ocfs2: implement the VFS clone_range, copy_range, and dedupe_range features ocfs2: charge quota for reflinked blocks ocfs2: fix bad pointer cast ocfs2: always unlock when completing dio writes ocfs2: don't eat io errors during _dio_end_io_write ocfs2: budget for extent tree splits when adding refcount flag ocfs2: prohibit refcounted swapfiles ocfs2: add newlines to some error messages ocfs2: convert inode refcount test to a helper simple_write_end(): don't zero in short copy into uptodate exofs: don't mess with simple_write_{begin,end} 9p: saner ->write_end() on failing copy into non-uptodate page fix gfs2_stuffed_write_end() on short copies fix ceph_write_end() nfs_write_end(): fix handling of short copies vfs: refactor clone/dedupe_file_range common functions fs: try to clone files first in vfs_copy_file_range vfs: misc struct path constification namespace.c: constify struct path passed to a bunch of primitives quota: constify struct path in quota_on ...
2016-12-16Merge branch 'work.autofs' into for-linusAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-16Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This update contains: - try to clone on copy-up - allow renaming a directory - split source into managable chunks - misc cleanups and fixes It does not contain the read-only fd data inconsistency fix, which Al didn't like. I'll leave that to the next year..." * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (36 commits) ovl: fix reStructuredText syntax errors in documentation ovl: fix return value of ovl_fill_super ovl: clean up kstat usage ovl: fold ovl_copy_up_truncate() into ovl_copy_up() ovl: create directories inside merged parent opaque ovl: opaque cleanup ovl: show redirect_dir mount option ovl: allow setting max size of redirect ovl: allow redirect_dir to default to "on" ovl: check for emptiness of redirect dir ovl: redirect on rename-dir ovl: lookup redirects ovl: consolidate lookup for underlying layers ovl: fix nested overlayfs mount ovl: check namelen ovl: split super.c ovl: use d_is_dir() ovl: simplify lookup ovl: check lower existence of rename target ovl: rename: simplify handling of lower/merged directory ...
2016-12-16Revert "vfs: rename: check backing inode being equal"Miklos Szeredi
This reverts commit 9409e22acdfc9153f88d9b1ed2bd2a5b34d2d3ca. Since commit 51f7e52dc943 ("ovl: share inode for hard link") there's no need to call d_real_inode() to check two overlay inodes for equality. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09vfs: make generic_readlink() staticMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09vfs: remove ".readlink = generic_readlink" assignmentsMiklos Szeredi
If .readlink == NULL implies generic_readlink(). Generated by: to_del="\.readlink.*=.*generic_readlink" for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09vfs: default to generic_readlink()Miklos Szeredi
If i_op->readlink is NULL, but i_op->get_link is set then vfs_readlink() defaults to calling generic_readlink(). The IOP_DEFAULT_READLINK flag indicates that the above conditions are met and the default action can be taken. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09vfs: replace calling i_op->readlink with vfs_readlink()Miklos Szeredi
Also check d_is_symlink() in callers instead of inode->i_op->readlink because following patches will allow NULL ->readlink for symlinks. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-05namei: fold should_follow_link() with the step into not-followed linkAl Viro
All callers are followed by the same boilerplate - "if it has returned 0, update nd->path/inode/seq - we are not following a symlink here". Pull it into the function itself, renaming it into step_into(). Rename WALK_GET to WALK_FOLLOW, while we are at it - more descriptive name. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05namei: pass both WALK_GET and WALK_MORE to should_follow_link()Al Viro
... and pull put_link() logics into it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05namei: invert WALK_PUT logicsAl Viro
... turning the condition for put_link() in walk_component() into "WALK_MORE not passed and depth is non-zero". Again, makes for simpler arguments. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()Al Viro
Simplifies the arguments both for it and for walk_component() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05namei: saner calling conventions for mountpoint_last()Al Viro
leave the result in nd->path, have caller do follow_mount() and copy it to the final destination. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05namei.c: get rid of user_path_parent()Al Viro
direct use of filename_parentat() is just as readable Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05vfs: misc struct path constificationAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-02vfs: change d_manage() to take a struct pathIan Kent
For the autofs module to be able to reliably check if a dentry is a mountpoint in a multiple namespace environment the ->d_manage() dentry operation will need to take a path argument instead of a dentry. Link: http://lkml.kernel.org/r/20161011053352.27645.83962.stgit@pluto.themaw.net Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Omar Sandoval <osandov@osandov.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-10-14Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This update contains fixes to the "use mounter's permission to access underlying layers" area, and miscellaneous other fixes and cleanups. No new features this time" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: use vfs_get_link() vfs: add vfs_get_link() helper ovl: use generic_readlink ovl: explain error values when removing acl from workdir ovl: Fix info leak in ovl_lookup_temp() ovl: during copy up, switch to mounter's creds early ovl: lookup: do getxattr with mounter's permission ovl: copy_up_xattr(): use strnlen
2016-10-14vfs: add vfs_get_link() helperMiklos Szeredi
This helper is for filesystems that want to read the symlink and are better off with the get_link() interface (returning a char *) rather than the readlink() interface (copy into a userspace buffer). Also call the LSM hook for readlink (not get_link) since this is for symlink reading not following. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: ">rename2() work from Miklos + current_time() from Deepa" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: Replace current_fs_time() with current_time() fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps fs: Replace CURRENT_TIME with current_time() for inode timestamps fs: proc: Delete inode time initializations in proc_alloc_inode() vfs: Add current_time() api vfs: add note about i_op->rename changes to porting fs: rename "rename2" i_op to "rename" vfs: remove unused i_op->rename fs: make remaining filesystems use .rename2 libfs: support RENAME_NOREPLACE in simple_rename() fs: support RENAME_NOREPLACE for local filesystems ncpfs: fix unused variable warning
2016-09-27fs: rename "rename2" i_op to "rename"Miklos Szeredi
Generated patch: sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2` sed -i "s/\brename2\b/rename/g" `git grep -wl rename2` Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-27vfs: remove unused i_op->renameMiklos Szeredi
No in-tree uses remain. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-16vfs: update ovl inode before relatime checkMiklos Szeredi
On overlayfs relatime_need_update() needs inode times to be correct on overlay inode. But i_mtime and i_ctime are updated by filesystem code on underlying inode only, so they will be out-of-date on the overlay inode. This patch copies the times from the underlying inode if needed. This can't be done if called from RCU lookup (link following) but link m/ctime are not updated by fs, so this is all right. This patch doesn't change functionality for anything but overlayfs. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-08-07fs: return EPERM on immutable inodeEryu Guan
In most cases, EPERM is returned on immutable inode, and there're only a few places returning EACCES. I noticed this when running LTP on overlayfs, setxattr03 failed due to unexpected EACCES on immutable inode. So converting all EACCES to EPERM on immutable inode. Acked-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull userns vfs updates from Eric Biederman: "This tree contains some very long awaited work on generalizing the user namespace support for mounting filesystems to include filesystems with a backing store. The real world target is fuse but the goal is to update the vfs to allow any filesystem to be supported. This patchset is based on a lot of code review and testing to approach that goal. While looking at what is needed to support the fuse filesystem it became clear that there were things like xattrs for security modules that needed special treatment. That the resolution of those concerns would not be fuse specific. That sorting out these general issues made most sense at the generic level, where the right people could be drawn into the conversation, and the issues could be solved for everyone. At a high level what this patchset does a couple of simple things: - Add a user namespace owner (s_user_ns) to struct super_block. - Teach the vfs to handle filesystem uids and gids not mapping into to kuids and kgids and being reported as INVALID_UID and INVALID_GID in vfs data structures. By assigning a user namespace owner filesystems that are mounted with only user namespace privilege can be detected. This allows security modules and the like to know which mounts may not be trusted. This also allows the set of uids and gids that are communicated to the filesystem to be capped at the set of kuids and kgids that are in the owning user namespace of the filesystem. One of the crazier corner casees this handles is the case of inodes whose i_uid or i_gid are not mapped into the vfs. Most of the code simply doesn't care but it is easy to confuse the inode writeback path so no operation that could cause an inode write-back is permitted for such inodes (aka only reads are allowed). This set of changes starts out by cleaning up the code paths involved in user namespace permirted mounts. Then when things are clean enough adds code that cleanly sets s_user_ns. Then additional restrictions are added that are possible now that the filesystem superblock contains owner information. These changes should not affect anyone in practice, but there are some parts of these restrictions that are changes in behavior. - Andy's restriction on suid executables that does not honor the suid bit when the path is from another mount namespace (think /proc/[pid]/fd/) or when the filesystem was mounted by a less privileged user. - The replacement of the user namespace implicit setting of MNT_NODEV with implicitly setting SB_I_NODEV on the filesystem superblock instead. Using SB_I_NODEV is a stronger form that happens to make this state user invisible. The user visibility can be managed but it caused problems when it was introduced from applications reasonably expecting mount flags to be what they were set to. There is a little bit of work remaining before it is safe to support mounting filesystems with backing store in user namespaces, beyond what is in this set of changes. - Verifying the mounter has permission to read/write the block device during mount. - Teaching the integrity modules IMA and EVM to handle filesystems mounted with only user namespace root and to reduce trust in their security xattrs accordingly. - Capturing the mounters credentials and using that for permission checks in d_automount and the like. (Given that overlayfs already does this, and we need the work in d_automount it make sense to generalize this case). Furthermore there are a few changes that are on the wishlist: - Get all filesystems supporting posix acls using the generic posix acls so that posix_acl_fix_xattr_from_user and posix_acl_fix_xattr_to_user may be removed. [Maintainability] - Reducing the permission checks in places such as remount to allow the superblock owner to perform them. - Allowing the superblock owner to chown files with unmapped uids and gids to something that is mapped so the files may be treated normally. I am not considering even obvious relaxations of permission checks until it is clear there are no more corner cases that need to be locked down and handled generically. Many thanks to Seth Forshee who kept this code alive, and putting up with me rewriting substantial portions of what he did to handle more corner cases, and for his diligent testing and reviewing of my changes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits) fs: Call d_automount with the filesystems creds fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns evm: Translate user/group ids relative to s_user_ns when computing HMAC dquot: For now explicitly don't support filesystems outside of init_user_ns quota: Handle quota data stored in s_user_ns in quota_setxquota quota: Ensure qids map to the filesystem vfs: Don't create inodes with a uid or gid unknown to the vfs vfs: Don't modify inodes with a uid or gid unknown to the vfs cred: Reject inodes with invalid ids in set_create_file_as() fs: Check for invalid i_uid in may_follow_link() vfs: Verify acls are valid within superblock's s_user_ns. userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS fs: Refuse uid/gid changes which don't map into s_user_ns selinux: Add support for unprivileged mounts from user namespaces Smack: Handle labels consistently in untrusted mounts Smack: Add support for unprivileged mounts from user namespaces fs: Treat foreign mounts as nosuid fs: Limit file caps to the user namespace of the super block userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag userns: Remove implicit MNT_NODEV fragility. ...
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