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-rw-r--r--fs/attr.c50
1 files changed, 38 insertions, 12 deletions
diff --git a/fs/attr.c b/fs/attr.c
index 42bb42bb3c72..a19a64d41e7e 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -17,19 +17,22 @@
#include <linux/ima.h>
/**
- * inode_change_ok - check if attribute changes to an inode are allowed
- * @inode: inode to check
+ * setattr_prepare - check if attribute changes to a dentry are allowed
+ * @dentry: dentry 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.
+ * in the given dentry. This includes the normal unix access permission
+ * checks, as well as checks for rlimits and others. The function also clears
+ * SGID bit from mode if user is not allowed to set it. Also file capabilities
+ * and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
*
* 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 setattr_prepare(struct dentry *dentry, struct iattr *attr)
{
+ struct inode *inode = d_inode(dentry);
unsigned int ia_valid = attr->ia_valid;
/*
@@ -44,7 +47,7 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr)
/* If force is set do it anyway. */
if (ia_valid & ATTR_FORCE)
- return 0;
+ goto kill_priv;
/* Make sure a caller can chown. */
if ((ia_valid & ATTR_UID) &&
@@ -77,9 +80,19 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr)
return -EPERM;
}
+kill_priv:
+ /* User has permission for the change */
+ if (ia_valid & ATTR_KILL_PRIV) {
+ int error;
+
+ error = security_inode_killpriv(dentry);
+ if (error)
+ return error;
+ }
+
return 0;
}
-EXPORT_SYMBOL(inode_change_ok);
+EXPORT_SYMBOL(setattr_prepare);
/**
* inode_newsize_ok - may this inode be truncated to a given size
@@ -202,6 +215,21 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de
return -EPERM;
}
+ /*
+ * If utimes(2) and friends are called with times == NULL (or both
+ * times are UTIME_NOW), then we need to check for write permission
+ */
+ if (ia_valid & ATTR_TOUCH) {
+ if (IS_IMMUTABLE(inode))
+ return -EPERM;
+
+ if (!inode_owner_or_capable(inode)) {
+ error = inode_permission(inode, MAY_WRITE);
+ if (error)
+ return error;
+ }
+ }
+
if ((ia_valid & ATTR_MODE)) {
umode_t amode = attr->ia_mode;
/* Flag setting protected by i_mutex */
@@ -217,13 +245,11 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de
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)
+ if (error < 0)
return error;
+ if (error == 0)
+ ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
}
/*