diff options
Diffstat (limited to 'fs/attr.c')
| -rw-r--r-- | fs/attr.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/fs/attr.c b/fs/attr.c new file mode 100644 index 000000000000..c3c76fe78346 --- /dev/null +++ b/fs/attr.c @@ -0,0 +1,208 @@ +/* + * linux/fs/attr.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * changes by Thomas Schoebel-Theuer + */ + +#include <linux/module.h> +#include <linux/time.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/smp_lock.h> +#include <linux/dnotify.h> +#include <linux/fcntl.h> +#include <linux/quotaops.h> +#include <linux/security.h> +#include <linux/time.h> + +/* Taken over from the old code... */ + +/* POSIX UID/GID verification for setting inode attributes. */ +int inode_change_ok(struct inode *inode, struct iattr *attr) +{ + int retval = -EPERM; + unsigned int ia_valid = attr->ia_valid; + + /* If force is set do it anyway. */ + if (ia_valid & ATTR_FORCE) + goto fine; + + /* Make sure a caller can chown. */ + if ((ia_valid & ATTR_UID) && + (current->fsuid != inode->i_uid || + attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN)) + goto error; + + /* Make sure caller can chgrp. */ + if ((ia_valid & ATTR_GID) && + (current->fsuid != inode->i_uid || + (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) && + !capable(CAP_CHOWN)) + goto error; + + /* Make sure a caller can chmod. */ + if (ia_valid & ATTR_MODE) { + if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) + goto error; + /* Also check the setgid bit! */ + if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : + inode->i_gid) && !capable(CAP_FSETID)) + attr->ia_mode &= ~S_ISGID; + } + + /* 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; + } +fine: + retval = 0; +error: + return retval; +} + +EXPORT_SYMBOL(inode_change_ok); + +int inode_setattr(struct inode * inode, struct iattr * attr) +{ + 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 (ia_valid & ATTR_UID) + inode->i_uid = attr->ia_uid; + if (ia_valid & ATTR_GID) + inode->i_gid = attr->ia_gid; + if (ia_valid & ATTR_ATIME) + inode->i_atime = timespec_trunc(attr->ia_atime, + inode->i_sb->s_time_gran); + if (ia_valid & ATTR_MTIME) + inode->i_mtime = timespec_trunc(attr->ia_mtime, + inode->i_sb->s_time_gran); + if (ia_valid & ATTR_CTIME) + inode->i_ctime = timespec_trunc(attr->ia_ctime, + inode->i_sb->s_time_gran); + if (ia_valid & ATTR_MODE) { + umode_t mode = attr->ia_mode; + + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) + 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; +} + +int notify_change(struct dentry * dentry, struct iattr * attr) +{ + struct inode *inode = dentry->d_inode; + mode_t mode; + int error; + struct timespec now; + unsigned int ia_valid = attr->ia_valid; + + if (!inode) + BUG(); + + mode = inode->i_mode; + now = current_fs_time(inode->i_sb); + + attr->ia_ctime = now; + if (!(ia_valid & ATTR_ATIME_SET)) + attr->ia_atime = now; + if (!(ia_valid & ATTR_MTIME_SET)) + attr->ia_mtime = now; + 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; + } + } + 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 = inode->i_mode; + } + attr->ia_mode &= ~S_ISGID; + } + } + if (!attr->ia_valid) + 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); + } + } + + if (ia_valid & ATTR_SIZE) + up_write(&dentry->d_inode->i_alloc_sem); + + if (!error) { + unsigned long dn_mask = setattr_mask(ia_valid); + if (dn_mask) + dnotify_parent(dentry, dn_mask); + } + return error; +} + +EXPORT_SYMBOL(notify_change); |