attr.c 4.2 KB

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  1. /*
  2. * linux/fs/attr.c
  3. *
  4. * Copyright (C) 1991, 1992 Linus Torvalds
  5. * changes by Thomas Schoebel-Theuer
  6. */
  7. #include <linux/module.h>
  8. #include <linux/time.h>
  9. #include <linux/mm.h>
  10. #include <linux/string.h>
  11. #include <linux/smp_lock.h>
  12. #include <linux/capability.h>
  13. #include <linux/fsnotify.h>
  14. #include <linux/fcntl.h>
  15. #include <linux/quotaops.h>
  16. #include <linux/security.h>
  17. /* Taken over from the old code... */
  18. /* POSIX UID/GID verification for setting inode attributes. */
  19. int inode_change_ok(struct inode *inode, struct iattr *attr)
  20. {
  21. int retval = -EPERM;
  22. unsigned int ia_valid = attr->ia_valid;
  23. /* If force is set do it anyway. */
  24. if (ia_valid & ATTR_FORCE)
  25. goto fine;
  26. /* Make sure a caller can chown. */
  27. if ((ia_valid & ATTR_UID) &&
  28. (current->fsuid != inode->i_uid ||
  29. attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
  30. goto error;
  31. /* Make sure caller can chgrp. */
  32. if ((ia_valid & ATTR_GID) &&
  33. (current->fsuid != inode->i_uid ||
  34. (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
  35. !capable(CAP_CHOWN))
  36. goto error;
  37. /* Make sure a caller can chmod. */
  38. if (ia_valid & ATTR_MODE) {
  39. if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  40. goto error;
  41. /* Also check the setgid bit! */
  42. if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
  43. inode->i_gid) && !capable(CAP_FSETID))
  44. attr->ia_mode &= ~S_ISGID;
  45. }
  46. /* Check for setting the inode time. */
  47. if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
  48. if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
  49. goto error;
  50. }
  51. fine:
  52. retval = 0;
  53. error:
  54. return retval;
  55. }
  56. EXPORT_SYMBOL(inode_change_ok);
  57. int inode_setattr(struct inode * inode, struct iattr * attr)
  58. {
  59. unsigned int ia_valid = attr->ia_valid;
  60. if (ia_valid & ATTR_SIZE &&
  61. attr->ia_size != i_size_read(inode)) {
  62. int error = vmtruncate(inode, attr->ia_size);
  63. if (error)
  64. return error;
  65. }
  66. if (ia_valid & ATTR_UID)
  67. inode->i_uid = attr->ia_uid;
  68. if (ia_valid & ATTR_GID)
  69. inode->i_gid = attr->ia_gid;
  70. if (ia_valid & ATTR_ATIME)
  71. inode->i_atime = timespec_trunc(attr->ia_atime,
  72. inode->i_sb->s_time_gran);
  73. if (ia_valid & ATTR_MTIME)
  74. inode->i_mtime = timespec_trunc(attr->ia_mtime,
  75. inode->i_sb->s_time_gran);
  76. if (ia_valid & ATTR_CTIME)
  77. inode->i_ctime = timespec_trunc(attr->ia_ctime,
  78. inode->i_sb->s_time_gran);
  79. if (ia_valid & ATTR_MODE) {
  80. umode_t mode = attr->ia_mode;
  81. if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
  82. mode &= ~S_ISGID;
  83. inode->i_mode = mode;
  84. }
  85. mark_inode_dirty(inode);
  86. return 0;
  87. }
  88. EXPORT_SYMBOL(inode_setattr);
  89. int notify_change(struct dentry * dentry, struct iattr * attr)
  90. {
  91. struct inode *inode = dentry->d_inode;
  92. mode_t mode;
  93. int error;
  94. struct timespec now;
  95. unsigned int ia_valid = attr->ia_valid;
  96. mode = inode->i_mode;
  97. now = current_fs_time(inode->i_sb);
  98. attr->ia_ctime = now;
  99. if (!(ia_valid & ATTR_ATIME_SET))
  100. attr->ia_atime = now;
  101. if (!(ia_valid & ATTR_MTIME_SET))
  102. attr->ia_mtime = now;
  103. if (ia_valid & ATTR_KILL_SUID) {
  104. attr->ia_valid &= ~ATTR_KILL_SUID;
  105. if (mode & S_ISUID) {
  106. if (!(ia_valid & ATTR_MODE)) {
  107. ia_valid = attr->ia_valid |= ATTR_MODE;
  108. attr->ia_mode = inode->i_mode;
  109. }
  110. attr->ia_mode &= ~S_ISUID;
  111. }
  112. }
  113. if (ia_valid & ATTR_KILL_SGID) {
  114. attr->ia_valid &= ~ ATTR_KILL_SGID;
  115. if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
  116. if (!(ia_valid & ATTR_MODE)) {
  117. ia_valid = attr->ia_valid |= ATTR_MODE;
  118. attr->ia_mode = inode->i_mode;
  119. }
  120. attr->ia_mode &= ~S_ISGID;
  121. }
  122. }
  123. if (!attr->ia_valid)
  124. return 0;
  125. if (ia_valid & ATTR_SIZE)
  126. down_write(&dentry->d_inode->i_alloc_sem);
  127. if (inode->i_op && inode->i_op->setattr) {
  128. error = security_inode_setattr(dentry, attr);
  129. if (!error)
  130. error = inode->i_op->setattr(dentry, attr);
  131. } else {
  132. error = inode_change_ok(inode, attr);
  133. if (!error)
  134. error = security_inode_setattr(dentry, attr);
  135. if (!error) {
  136. if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
  137. (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
  138. error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
  139. if (!error)
  140. error = inode_setattr(inode, attr);
  141. }
  142. }
  143. if (ia_valid & ATTR_SIZE)
  144. up_write(&dentry->d_inode->i_alloc_sem);
  145. if (!error)
  146. fsnotify_change(dentry, ia_valid);
  147. return error;
  148. }
  149. EXPORT_SYMBOL(notify_change);