diff options
Diffstat (limited to 'fs/attr.c')
| -rw-r--r-- | fs/attr.c | 50 |
1 files changed, 38 insertions, 12 deletions
diff --git a/fs/attr.c b/fs/attr.c index 236d11300216..c902b3d53508 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; } /* |