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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | /* * linux/fs/attr.c * * Copyright (C) 1991, 1992 Linus Torvalds * changes by Thomas Schoebel-Theuer */ #include <linux/sched.h> #include <linux/mm.h> #include <linux/string.h> #include <linux/smp_lock.h> #include <linux/dnotify.h> #include <linux/fcntl.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) && (!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; } void inode_setattr(struct inode * inode, 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) inode->i_gid = attr->ia_gid; if (ia_valid & ATTR_SIZE) vmtruncate(inode, attr->ia_size); if (ia_valid & ATTR_ATIME) inode->i_atime = attr->ia_atime; if (ia_valid & ATTR_MTIME) inode->i_mtime = attr->ia_mtime; if (ia_valid & ATTR_CTIME) inode->i_ctime = attr->ia_ctime; if (ia_valid & ATTR_MODE) { inode->i_mode = attr->ia_mode; if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) inode->i_mode &= ~S_ISGID; } mark_inode_dirty(inode); } static 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; int error; time_t now = CURRENT_TIME; unsigned int ia_valid = attr->ia_valid; if (!inode) BUG(); attr->ia_ctime = now; if (!(ia_valid & ATTR_ATIME_SET)) attr->ia_atime = now; if (!(ia_valid & ATTR_MTIME_SET)) attr->ia_mtime = now; lock_kernel(); if (inode->i_op && inode->i_op->setattr) error = inode->i_op->setattr(dentry, attr); else { error = inode_change_ok(inode, attr); if (!error) inode_setattr(inode, attr); } unlock_kernel(); if (!error) { unsigned long dn_mask = setattr_mask(ia_valid); if (dn_mask) inode_dir_notify(dentry->d_parent->d_inode, dn_mask); } return error; } |