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da9592edeb
Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
192 lines
4.8 KiB
C
192 lines
4.8 KiB
C
/*
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* linux/fs/attr.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* changes by Thomas Schoebel-Theuer
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*/
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#include <linux/module.h>
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#include <linux/time.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/capability.h>
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#include <linux/fsnotify.h>
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#include <linux/fcntl.h>
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#include <linux/quotaops.h>
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#include <linux/security.h>
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/* Taken over from the old code... */
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/* POSIX UID/GID verification for setting inode attributes. */
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int inode_change_ok(struct inode *inode, struct iattr *attr)
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{
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int retval = -EPERM;
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unsigned int ia_valid = attr->ia_valid;
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/* If force is set do it anyway. */
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if (ia_valid & ATTR_FORCE)
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goto fine;
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/* Make sure a caller can chown. */
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if ((ia_valid & ATTR_UID) &&
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(current_fsuid() != inode->i_uid ||
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attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
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goto error;
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/* Make sure caller can chgrp. */
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if ((ia_valid & ATTR_GID) &&
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(current_fsuid() != inode->i_uid ||
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(!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
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!capable(CAP_CHOWN))
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goto error;
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/* Make sure a caller can chmod. */
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if (ia_valid & ATTR_MODE) {
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if (!is_owner_or_cap(inode))
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goto error;
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/* Also check the setgid bit! */
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if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
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inode->i_gid) && !capable(CAP_FSETID))
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attr->ia_mode &= ~S_ISGID;
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}
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/* Check for setting the inode time. */
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if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
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if (!is_owner_or_cap(inode))
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goto error;
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}
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fine:
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retval = 0;
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error:
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return retval;
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}
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EXPORT_SYMBOL(inode_change_ok);
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int inode_setattr(struct inode * inode, struct iattr * attr)
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{
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unsigned int ia_valid = attr->ia_valid;
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if (ia_valid & ATTR_SIZE &&
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attr->ia_size != i_size_read(inode)) {
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int error = vmtruncate(inode, attr->ia_size);
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if (error)
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return error;
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}
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if (ia_valid & ATTR_UID)
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inode->i_uid = attr->ia_uid;
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if (ia_valid & ATTR_GID)
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inode->i_gid = attr->ia_gid;
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if (ia_valid & ATTR_ATIME)
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inode->i_atime = timespec_trunc(attr->ia_atime,
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inode->i_sb->s_time_gran);
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if (ia_valid & ATTR_MTIME)
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inode->i_mtime = timespec_trunc(attr->ia_mtime,
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inode->i_sb->s_time_gran);
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if (ia_valid & ATTR_CTIME)
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inode->i_ctime = timespec_trunc(attr->ia_ctime,
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inode->i_sb->s_time_gran);
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if (ia_valid & ATTR_MODE) {
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umode_t mode = attr->ia_mode;
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if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
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mode &= ~S_ISGID;
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inode->i_mode = mode;
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}
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mark_inode_dirty(inode);
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return 0;
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}
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EXPORT_SYMBOL(inode_setattr);
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int notify_change(struct dentry * dentry, struct iattr * attr)
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{
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struct inode *inode = dentry->d_inode;
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mode_t mode = inode->i_mode;
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int error;
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struct timespec now;
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unsigned int ia_valid = attr->ia_valid;
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if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
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if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
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return -EPERM;
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}
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now = current_fs_time(inode->i_sb);
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attr->ia_ctime = now;
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if (!(ia_valid & ATTR_ATIME_SET))
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attr->ia_atime = now;
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if (!(ia_valid & ATTR_MTIME_SET))
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attr->ia_mtime = now;
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if (ia_valid & ATTR_KILL_PRIV) {
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attr->ia_valid &= ~ATTR_KILL_PRIV;
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ia_valid &= ~ATTR_KILL_PRIV;
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error = security_inode_need_killpriv(dentry);
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if (error > 0)
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error = security_inode_killpriv(dentry);
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if (error)
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return error;
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}
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/*
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* We now pass ATTR_KILL_S*ID to the lower level setattr function so
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* that the function has the ability to reinterpret a mode change
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* that's due to these bits. This adds an implicit restriction that
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* no function will ever call notify_change with both ATTR_MODE and
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* ATTR_KILL_S*ID set.
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*/
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if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
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(ia_valid & ATTR_MODE))
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BUG();
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if (ia_valid & ATTR_KILL_SUID) {
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if (mode & S_ISUID) {
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ia_valid = attr->ia_valid |= ATTR_MODE;
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attr->ia_mode = (inode->i_mode & ~S_ISUID);
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}
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}
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if (ia_valid & ATTR_KILL_SGID) {
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if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
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if (!(ia_valid & ATTR_MODE)) {
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ia_valid = attr->ia_valid |= ATTR_MODE;
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attr->ia_mode = inode->i_mode;
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}
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attr->ia_mode &= ~S_ISGID;
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}
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}
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if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
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return 0;
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error = security_inode_setattr(dentry, attr);
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if (error)
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return error;
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if (ia_valid & ATTR_SIZE)
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down_write(&dentry->d_inode->i_alloc_sem);
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if (inode->i_op && inode->i_op->setattr) {
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error = inode->i_op->setattr(dentry, attr);
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} else {
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error = inode_change_ok(inode, attr);
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if (!error) {
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if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
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(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
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error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
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if (!error)
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error = inode_setattr(inode, attr);
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}
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}
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if (ia_valid & ATTR_SIZE)
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up_write(&dentry->d_inode->i_alloc_sem);
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if (!error)
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fsnotify_change(dentry, ia_valid);
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return error;
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}
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EXPORT_SYMBOL(notify_change);
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