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path: root/fs/utimes.c
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2008-07-26[PATCH] sanitize __user_walk_fd() et.al.Al Viro
* do not pass nameidata; struct path is all the callers want. * switch to new helpers: user_path_at(dfd, pathname, flags, &path) user_path(pathname, &path) user_lpath(pathname, &path) user_path_dir(pathname, &path) (fail if not a directory) The last 3 are trivial macro wrappers for the first one. * remove nameidata in callers. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26[PATCH] kill nameidata passing to permission(), rename to inode_permission()Al Viro
Incidentally, the name that gives hundreds of false positives on grep is not a good idea... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26[patch 4/4] vfs: immutable inode checking cleanupMiklos Szeredi
Move the immutable and append-only checks from chmod, chown and utimes into notify_change(). Checks for immutable and append-only files are always performed by the VFS and not by the filesystem (see permission() and may_...() in namei.c), so these belong in notify_change(), and not in inode_change_ok(). This should be completely equivalent. CC: Ulrich Drepper <drepper@redhat.com> CC: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26[patch 2/4] vfs: utimes cleanupMiklos Szeredi
Untange the mess that is do_utimes(). Add kerneldoc comment to do_utimes(). CC: Ulrich Drepper <drepper@redhat.com> CC: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26[patch 1/4] vfs: utimes: move owner check into inode_change_ok()Miklos Szeredi
Add a new ia_valid flag: ATTR_TIMES_SET, to handle the UTIMES_OMIT/UTIMES_NOW and UTIMES_NOW/UTIMES_OMIT cases. In these cases neither ATTR_MTIME_SET nor ATTR_ATIME_SET is in the flags, yet the POSIX draft specifies that permission checking is performed the same way as if one or both of the times was explicitly set to a timestamp. See the path "vfs: utimensat(): fix error checking for {UTIME_NOW,UTIME_OMIT} case" by Michael Kerrisk for the patch introducing this behavior. This is a cleanup, as well as allowing filesystems (NFS/fuse/...) to perform their own permission checking instead of the default. CC: Ulrich Drepper <drepper@redhat.com> CC: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-06-23[patch for 2.6.26 4/4] vfs: utimensat(): fix write access check for futimens()Michael Kerrisk
The POSIX.1 draft spec for futimens()/utimensat() says: Only a process with the effective user ID equal to the user ID of the file, *or with write access to the file*, or with appropriate privileges may use futimens() or utimensat() with a null pointer as the times argument or with both tv_nsec fields set to the special value UTIME_NOW. The important piece here is "with write access to the file", and this matters for futimens(), which deals with an argument that is a file descriptor referring to the file whose timestamps are being updated, The standard is saying that the "writability" check is based on the file permissions, not the access mode with which the file is opened. (This behavior is consistent with the semantics of FreeBSD's futimes().) However, Linux is currently doing the latter -- futimens(fd, times) is a library function implemented as utimensat(fd, NULL, times, 0) and within the utimensat() implementation we have the code: f = fget(dfd); // dfd is 'fd' ... if (f) { if (!(f->f_mode & FMODE_WRITE)) goto mnt_drop_write_and_out; The check should instead be based on the file permissions. Thanks to Miklos for pointing out how to do this check. Miklos also pointed out a simplification that could be made to my first version of this patch, since the checks for the pathname and file descriptor cases can now be conflated. Acked-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-06-23[patch for 2.6.26 3/4] vfs: utimensat(): fix error checking for ↵Michael Kerrisk
{UTIME_NOW,UTIME_OMIT} case The POSIX.1 draft spec for utimensat() says: Only a process with the effective user ID equal to the user ID of the file or with appropriate privileges may use futimens() or utimensat() with a non-null times argument that does not have both tv_nsec fields set to UTIME_NOW and does not have both tv_nsec fields set to UTIME_OMIT. If this condition is violated, then the error EPERM should result. However, the current implementation does not generate EPERM if one tv_nsec field is UTIME_NOW while the other is UTIME_OMIT. It should give this error for that case. This patch: a) Repairs that problem. b) Removes the now unneeded nsec_special() helper function. c) Adds some comments to explain the checks that are being performed. Thanks to Miklos, who provided comments on the previous iteration of this patch. As a result, this version is a little simpler and and its logic is better structured. Miklos suggested an alternative idea, migrating the is_owner_or_cap() checks into fs/attr.c:inode_change_ok() via the use of an ATTR_OWNER_CHECK flag. Maybe we could do that later, but for now I've gone with this version, which is IMO simpler, and can be more easily read as being correct. Acked-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-06-23[patch for 2.6.26 1/4] vfs: utimensat(): ignore tv_sec if tv_nsec == ↵Michael Kerrisk
UTIME_OMIT or UTIME_NOW The POSIX.1 draft spec for utimensat() says that if a times[n].tv_nsec field is UTIME_OMIT or UTIME_NOW, then the value in the corresponding tv_sec field is ignored. See the last sentence of this para, from the spec: If the tv_nsec field of a timespec structure has the special value UTIME_NOW, the file's relevant timestamp shall be set to the greatest value supported by the file system that is not greater than the current time. If the tv_nsec field has the special value UTIME_OMIT, the file's relevant timestamp shall not be changed. In either case, the tv_sec field shall be ignored. However the current Linux implementation requires the tv_sec value to be zero (or the EINVAL error results). This requirement should be removed. Acked-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-06-23[patch for 2.6.26 2/4] vfs: utimensat(): be consistent with utime() for ↵Michael Kerrisk
immutable and append-only files This patch fixes utimensat() to make its behavior consistent with that of utime()/utimes() when dealing with files marked immutable and append-only. The current utimensat() implementation also returns EPERM if 'times' is non-NULL and the tv_nsec fields are both UTIME_NOW. For consistency, the (times != NULL && times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) case should be treated like the traditional utimes() case where 'times' is NULL. That is, the call should succeed for a file marked append-only and should give the error EACCES if the file is marked as immutable. The simple way to do this is to set 'times' to NULL if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW). This is also the natural approach, since POSIX.1 semantics consider the times == {{x, UTIME_NOW}, {y, UTIME_NOW}} to be exactly equivalent to the case for times == NULL. (Thanks to Miklos for pointing this out.) Patch 3 in this series relies on the simplification provided by this patch. Acked-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01vfs: fix permission checking in sys_utimensatMiklos Szeredi
If utimensat() is called with both times set to UTIME_NOW or one of them to UTIME_NOW and the other to UTIME_OMIT, then it will update the file time without any permission checking. I don't think this can be used for anything other than a local DoS, but could be quite bewildering at that (e.g. "Why was that large source tree rebuilt when I didn't modify anything???") This affects all kernels from 2.6.22, when the utimensat() syscall was introduced. Fix by doing the same permission checking as for the "times == NULL" case. Thanks to Michael Kerrisk, whose utimensat-non-conformances-and-fixes.patch in -mm also fixes this (and breaks other stuff), only he didn't realize the security implications of this bug. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-19[PATCH] r/o bind mounts: elevate write count for do_utimes()Dave Hansen
Now includes fix for oops seen by akpm. "never let a libc developer write your kernel code" - hch "nor, apparently, a kernel developer" - akpm Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-02-14Introduce path_put()Jan Blunck
* Add path_put() functions for releasing a reference to the dentry and vfsmount of a struct path in the right order * Switch from path_release(nd) to path_put(&nd->path) * Rename dput_path() to path_put_conditional() [akpm@linux-foundation.org: fix cifs] Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Cc: <linux-fsdevel@vger.kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Steven French <sfrench@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14Embed a struct path into struct nameidata instead of nd->{dentry,mnt}Jan Blunck
This is the central patch of a cleanup series. In most cases there is no good reason why someone would want to use a dentry for itself. This series reflects that fact and embeds a struct path into nameidata. Together with the other patches of this series - it enforced the correct order of getting/releasing the reference count on <dentry,vfsmount> pairs - it prepares the VFS for stacking support since it is essential to have a struct path in every place where the stack can be traversed - it reduces the overall code size: without patch series: text data bss dec hex filename 5321639 858418 715768 6895825 6938d1 vmlinux with patch series: text data bss dec hex filename 5320026 858418 715768 6894212 693284 vmlinux This patch: Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix cifs] [akpm@linux-foundation.org: fix smack] Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06fs/utimes.c should #include <linux/syscalls.h>Adrian Bunk
Every file should include the headers containing the prototypes for its global functions. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17VFS: check nanoseconds in utimensatMiklos Szeredi
utimensat() (and possibly other callers of do_utimes()) didn't check if the nanosecond value was within the allowed range. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid checkSatyam Sharma
Introduce is_owner_or_cap() macro in fs.h, and convert over relevant users to it. This is done because we want to avoid bugs in the future where we check for only effective fsuid of the current task against a file's owning uid, without simultaneously checking for CAP_FOWNER as well, thus violating its semantics. [ XFS uses special macros and structures, and in general looked ... untouchable, so we leave it alone -- but it has been looked over. ] The (current->fsuid != inode->i_uid) check in generic_permission() and exec_permission_lite() is left alone, because those operations are covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone. Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in> Cc: Al Viro <viro@ftp.linux.org.uk> Acked-by: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16utime(s): Honour CAP_FOWNER when times==NULLSatyam Sharma
do_utimes() does not honour CAP_FOWNER when times==NULL. Trivial and obvious one-line fix. Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-08Fix permission checking for the new utimensat() system callLinus Torvalds
Commit 1c710c896eb461895d3c399e15bb5f20b39c9073 added the utimensat() system call, but didn't handle the case of checking for the writability of the target right, when the target was a file descriptor, not a filename. We cannot use vfs_permission(MAY_WRITE) for that case, and need to simply check whether the file descriptor is writable. The oops from using the wrong function was noticed and narrowed down by Markus Trippelsdorf. Cc: Ulrich Drepper <drepper@redhat.com> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Al Viro <viro@ftp.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08utimensat implementationUlrich Drepper
Implement utimensat(2) which is an extension to futimesat(2) in that it a) supports nano-second resolution for the timestamps b) allows to selectively ignore the atime/mtime value c) allows to selectively use the current time for either atime or mtime d) supports changing the atime/mtime of a symlink itself along the lines of the BSD lutimes(3) functions For this change the internally used do_utimes() functions was changed to accept a timespec time value and an additional flags parameter. Additionally the sys_utime function was changed to match compat_sys_utime which already use do_utimes instead of duplicating the work. Also, the completely missing futimensat() functionality is added. We have such a function in glibc but we have to resort to using /proc/self/fd/* which not everybody likes (chroot etc). Test application (the syscall number will need per-arch editing): #include <errno.h> #include <fcntl.h> #include <time.h> #include <sys/time.h> #include <stddef.h> #include <syscall.h> #define __NR_utimensat 280 #define UTIME_NOW ((1l << 30) - 1l) #define UTIME_OMIT ((1l << 30) - 2l) int main(void) { int status = 0; int fd = open("ttt", O_RDWR|O_CREAT|O_EXCL, 0666); if (fd == -1) error (1, errno, "failed to create test file \"ttt\""); struct stat64 st1; if (fstat64 (fd, &st1) != 0) error (1, errno, "fstat failed"); struct timespec t[2]; t[0].tv_sec = 0; t[0].tv_nsec = 0; t[1].tv_sec = 0; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); struct stat64 st2; if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0) { puts ("atim not reset to zero"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("mtim not reset to zero"); status = 1; } if (status != 0) goto out; t[0] = st1.st_atim; t[1].tv_sec = 0; t[1].tv_nsec = UTIME_OMIT; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != st1.st_atim.tv_sec || st2.st_atim.tv_nsec != st1.st_atim.tv_nsec) { puts ("atim not set"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("mtim changed from zero"); status = 1; } if (status != 0) goto out; t[0].tv_sec = 0; t[0].tv_nsec = UTIME_OMIT; t[1] = st1.st_mtim; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != st1.st_atim.tv_sec || st2.st_atim.tv_nsec != st1.st_atim.tv_nsec) { puts ("mtim changed from original time"); status = 1; } if (st2.st_mtim.tv_sec != st1.st_mtim.tv_sec || st2.st_mtim.tv_nsec != st1.st_mtim.tv_nsec) { puts ("mtim not set"); status = 1; } if (status != 0) goto out; sleep (2); t[0].tv_sec = 0; t[0].tv_nsec = UTIME_NOW; t[1].tv_sec = 0; t[1].tv_nsec = UTIME_NOW; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); struct timeval tv; gettimeofday(&tv,NULL); if (st2.st_atim.tv_sec <= st1.st_atim.tv_sec || st2.st_atim.tv_sec > tv.tv_sec) { puts ("atim not set to NOW"); status = 1; } if (st2.st_mtim.tv_sec <= st1.st_mtim.tv_sec || st2.st_mtim.tv_sec > tv.tv_sec) { puts ("mtim not set to NOW"); status = 1; } if (symlink ("ttt", "tttsym") != 0) error (1, errno, "cannot create symlink"); t[0].tv_sec = 0; t[0].tv_nsec = 0; t[1].tv_sec = 0; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, AT_FDCWD, "tttsym", t, AT_SYMLINK_NOFOLLOW) != 0) error (1, errno, "utimensat failed"); if (lstat64 ("tttsym", &st2) != 0) error (1, errno, "lstat failed"); if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0) { puts ("symlink atim not reset to zero"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("symlink mtim not reset to zero"); status = 1; } if (status != 0) goto out; t[0].tv_sec = 1; t[0].tv_nsec = 0; t[1].tv_sec = 1; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, fd, NULL, t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != 1 || st2.st_atim.tv_nsec != 0) { puts ("atim not reset to one"); status = 1; } if (st2.st_mtim.tv_sec != 1 || st2.st_mtim.tv_nsec != 0) { puts ("mtim not reset to one"); status = 1; } if (status == 0) puts ("all OK"); out: close (fd); unlink ("ttt"); unlink ("tttsym"); return status; } [akpm@linux-foundation.org: add missing i386 syscall table entry] Signed-off-by: Ulrich Drepper <drepper@redhat.com> Cc: Alexey Dobriyan <adobriyan@openvz.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-04[PATCH] severing fs.h, radix-tree.h -> sched.hAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-10-01[PATCH] Create fs/utimes.cAlexey Dobriyan
* fs/open.c is getting bit crowdy * preparation to lutimes(2) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>