* changes by Thomas Schoebel-Theuer
*/
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/string.h>
-#include <linux/smp_lock.h>
-#include <linux/dnotify.h>
+#include <linux/capability.h>
+#include <linux/fsnotify.h>
#include <linux/fcntl.h>
-#include <linux/quotaops.h>
#include <linux/security.h>
-#include <linux/time.h>
-
-/* Taken over from the old code... */
+#include <linux/evm.h>
-/* POSIX UID/GID verification for setting inode attributes. */
-int inode_change_ok(struct inode *inode, struct iattr *attr)
+/**
+ * inode_change_ok - check if attribute changes to an inode are allowed
+ * @inode: inode to check
+ * @attr: attributes to change
+ *
+ * Check if we are allowed to change the attributes contained in @attr
+ * in the given inode. This includes the normal unix access permission
+ * checks, as well as checks for rlimits and others.
+ *
+ * Should be called as the first thing in ->setattr implementations,
+ * possibly after taking additional locks.
+ */
+int inode_change_ok(const struct inode *inode, struct iattr *attr)
{
- int retval = -EPERM;
unsigned int ia_valid = attr->ia_valid;
+ /*
+ * First check size constraints. These can't be overriden using
+ * ATTR_FORCE.
+ */
+ if (ia_valid & ATTR_SIZE) {
+ int error = inode_newsize_ok(inode, attr->ia_size);
+ if (error)
+ return error;
+ }
+
/* If force is set do it anyway. */
if (ia_valid & ATTR_FORCE)
- goto fine;
+ return 0;
/* Make sure a caller can chown. */
if ((ia_valid & ATTR_UID) &&
- (current->fsuid != inode->i_uid ||
+ (current_fsuid() != inode->i_uid ||
attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
- goto error;
+ return -EPERM;
/* Make sure caller can chgrp. */
if ((ia_valid & ATTR_GID) &&
- (current->fsuid != inode->i_uid ||
+ (current_fsuid() != inode->i_uid ||
(!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
!capable(CAP_CHOWN))
- goto error;
+ return -EPERM;
/* Make sure a caller can chmod. */
if (ia_valid & ATTR_MODE) {
- if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
- goto error;
+ if (!inode_owner_or_capable(inode))
+ return -EPERM;
/* Also check the setgid bit! */
if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
inode->i_gid) && !capable(CAP_FSETID))
}
/* Check for setting the inode time. */
- if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
- if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
- goto error;
+ if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
+ if (!inode_owner_or_capable(inode))
+ return -EPERM;
}
-fine:
- retval = 0;
-error:
- return retval;
-}
+ return 0;
+}
EXPORT_SYMBOL(inode_change_ok);
-int inode_setattr(struct inode * inode, struct iattr * attr)
+/**
+ * inode_newsize_ok - may this inode be truncated to a given size
+ * @inode: the inode to be truncated
+ * @offset: the new size to assign to the inode
+ * @Returns: 0 on success, -ve errno on failure
+ *
+ * inode_newsize_ok must be called with i_mutex held.
+ *
+ * inode_newsize_ok will check filesystem limits and ulimits to check that the
+ * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
+ * when necessary. Caller must not proceed with inode size change if failure is
+ * returned. @inode must be a file (not directory), with appropriate
+ * permissions to allow truncate (inode_newsize_ok does NOT check these
+ * conditions).
+ */
+int inode_newsize_ok(const struct inode *inode, loff_t offset)
{
- unsigned int ia_valid = attr->ia_valid;
- int error = 0;
-
- if (ia_valid & ATTR_SIZE) {
- if (attr->ia_size != i_size_read(inode)) {
- error = vmtruncate(inode, attr->ia_size);
- if (error || (ia_valid == ATTR_SIZE))
- goto out;
- } else {
- /*
- * We skipped the truncate but must still update
- * timestamps
- */
- ia_valid |= ATTR_MTIME|ATTR_CTIME;
- }
+ if (inode->i_size < offset) {
+ unsigned long limit;
+
+ limit = rlimit(RLIMIT_FSIZE);
+ if (limit != RLIM_INFINITY && offset > limit)
+ goto out_sig;
+ if (offset > inode->i_sb->s_maxbytes)
+ goto out_big;
+ } else {
+ /*
+ * truncation of in-use swapfiles is disallowed - it would
+ * cause subsequent swapout to scribble on the now-freed
+ * blocks.
+ */
+ if (IS_SWAPFILE(inode))
+ return -ETXTBSY;
}
+ return 0;
+out_sig:
+ send_sig(SIGXFSZ, current, 0);
+out_big:
+ return -EFBIG;
+}
+EXPORT_SYMBOL(inode_newsize_ok);
+
+/**
+ * setattr_copy - copy simple metadata updates into the generic inode
+ * @inode: the inode to be updated
+ * @attr: the new attributes
+ *
+ * setattr_copy must be called with i_mutex held.
+ *
+ * setattr_copy updates the inode's metadata with that specified
+ * in attr. Noticeably missing is inode size update, which is more complex
+ * as it requires pagecache updates.
+ *
+ * The inode is not marked as dirty after this operation. The rationale is
+ * that for "simple" filesystems, the struct inode is the inode storage.
+ * The caller is free to mark the inode dirty afterwards if needed.
+ */
+void setattr_copy(struct inode *inode, const struct iattr *attr)
+{
+ unsigned int ia_valid = attr->ia_valid;
+
if (ia_valid & ATTR_UID)
inode->i_uid = attr->ia_uid;
if (ia_valid & ATTR_GID)
mode &= ~S_ISGID;
inode->i_mode = mode;
}
- mark_inode_dirty(inode);
-out:
- return error;
-}
-
-EXPORT_SYMBOL(inode_setattr);
-
-int setattr_mask(unsigned int ia_valid)
-{
- unsigned long dn_mask = 0;
-
- if (ia_valid & ATTR_UID)
- dn_mask |= DN_ATTRIB;
- if (ia_valid & ATTR_GID)
- dn_mask |= DN_ATTRIB;
- if (ia_valid & ATTR_SIZE)
- dn_mask |= DN_MODIFY;
- /* both times implies a utime(s) call */
- if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
- dn_mask |= DN_ATTRIB;
- else if (ia_valid & ATTR_ATIME)
- dn_mask |= DN_ACCESS;
- else if (ia_valid & ATTR_MTIME)
- dn_mask |= DN_MODIFY;
- if (ia_valid & ATTR_MODE)
- dn_mask |= DN_ATTRIB;
- return dn_mask;
}
+EXPORT_SYMBOL(setattr_copy);
int notify_change(struct dentry * dentry, struct iattr * attr)
{
struct inode *inode = dentry->d_inode;
- mode_t mode;
+ umode_t mode = inode->i_mode;
int error;
struct timespec now;
unsigned int ia_valid = attr->ia_valid;
- if (!inode)
- BUG();
+ if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
+ if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
+ return -EPERM;
+ }
+
+ if ((ia_valid & ATTR_MODE)) {
+ umode_t amode = attr->ia_mode;
+ /* Flag setting protected by i_mutex */
+ if (is_sxid(amode))
+ inode->i_flags &= ~S_NOSEC;
+ }
- mode = inode->i_mode;
now = current_fs_time(inode->i_sb);
attr->ia_ctime = now;
attr->ia_atime = now;
if (!(ia_valid & ATTR_MTIME_SET))
attr->ia_mtime = now;
+ if (ia_valid & ATTR_KILL_PRIV) {
+ attr->ia_valid &= ~ATTR_KILL_PRIV;
+ ia_valid &= ~ATTR_KILL_PRIV;
+ error = security_inode_need_killpriv(dentry);
+ if (error > 0)
+ error = security_inode_killpriv(dentry);
+ if (error)
+ return error;
+ }
+
+ /*
+ * We now pass ATTR_KILL_S*ID to the lower level setattr function so
+ * that the function has the ability to reinterpret a mode change
+ * that's due to these bits. This adds an implicit restriction that
+ * no function will ever call notify_change with both ATTR_MODE and
+ * ATTR_KILL_S*ID set.
+ */
+ if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
+ (ia_valid & ATTR_MODE))
+ BUG();
+
if (ia_valid & ATTR_KILL_SUID) {
- attr->ia_valid &= ~ATTR_KILL_SUID;
if (mode & S_ISUID) {
- if (!(ia_valid & ATTR_MODE)) {
- ia_valid = attr->ia_valid |= ATTR_MODE;
- attr->ia_mode = inode->i_mode;
- }
- attr->ia_mode &= ~S_ISUID;
+ ia_valid = attr->ia_valid |= ATTR_MODE;
+ attr->ia_mode = (inode->i_mode & ~S_ISUID);
}
}
if (ia_valid & ATTR_KILL_SGID) {
- attr->ia_valid &= ~ ATTR_KILL_SGID;
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
if (!(ia_valid & ATTR_MODE)) {
ia_valid = attr->ia_valid |= ATTR_MODE;
attr->ia_mode &= ~S_ISGID;
}
}
- if (!attr->ia_valid)
+ if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
return 0;
- if (ia_valid & ATTR_SIZE)
- down_write(&dentry->d_inode->i_alloc_sem);
-
- if (inode->i_op && inode->i_op->setattr) {
- error = security_inode_setattr(dentry, attr);
- if (!error)
- error = inode->i_op->setattr(dentry, attr);
- } else {
- error = inode_change_ok(inode, attr);
- if (!error)
- error = security_inode_setattr(dentry, attr);
- if (!error) {
- if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
- (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
- error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
- if (!error)
- error = inode_setattr(inode, attr);
- }
- }
+ error = security_inode_setattr(dentry, attr);
+ if (error)
+ return error;
- if (ia_valid & ATTR_SIZE)
- up_write(&dentry->d_inode->i_alloc_sem);
+ if (inode->i_op->setattr)
+ error = inode->i_op->setattr(dentry, attr);
+ else
+ error = simple_setattr(dentry, attr);
if (!error) {
- unsigned long dn_mask = setattr_mask(ia_valid);
- if (dn_mask)
- dnotify_parent(dentry, dn_mask);
+ fsnotify_change(dentry, ia_valid);
+ evm_inode_post_setattr(dentry, ia_valid);
}
+
return error;
}
projects / linux-flexiantxendom0-3.2.10.git / blobdiff