From 2c27c65ed0696f0b5df2dad2cf6462d72164d547 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 4 Jun 2010 11:30:04 +0200 Subject: check ATTR_SIZE contraints in inode_change_ok Make sure we check the truncate constraints early on in ->setattr by adding those checks to inode_change_ok. Also clean up and document inode_change_ok to make this obvious. As a fallout we don't have to call inode_newsize_ok from simple_setsize and simplify it down to a truncate_setsize which doesn't return an error. This simplifies a lot of setattr implementations and means we use truncate_setsize almost everywhere. Get rid of fat_setsize now that it's trivial and mark ext2_setsize static to make the calling convention obvious. Keep the inode_newsize_ok in vmtruncate for now as all callers need an audit for its removal anyway. Note: setattr code in ecryptfs doesn't call inode_change_ok at all and needs a deeper audit, but that is left for later. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/attr.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index ed44d8ae8bf1..7ca41811afa1 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -14,35 +14,53 @@ #include #include -/* Taken over from the old code... */ - -/* POSIX UID/GID verification for setting inode attributes. */ +/** + * inode_change_ok - check if attribute changes to an inode are allowed + * @inode: inode 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. + * + * 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 retval = -EPERM; unsigned int ia_valid = attr->ia_valid; + /* + * First check size constraints. These can't be overriden using + * ATTR_FORCE. + */ + if (ia_valid & ATTR_SIZE) { + int error = inode_newsize_ok(inode, attr->ia_size); + if (error) + return error; + } + /* If force is set do it anyway. */ if (ia_valid & ATTR_FORCE) - goto fine; + return 0; /* 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; + return -EPERM; /* 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; + return -EPERM; /* Make sure a caller can chmod. */ if (ia_valid & ATTR_MODE) { if (!is_owner_or_cap(inode)) - goto error; + return -EPERM; /* Also check the setgid bit! */ if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : inode->i_gid) && !capable(CAP_FSETID)) @@ -52,12 +70,10 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr) /* Check for setting the inode time. */ if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) { if (!is_owner_or_cap(inode)) - goto error; + return -EPERM; } -fine: - retval = 0; -error: - return retval; + + return 0; } EXPORT_SYMBOL(inode_change_ok); @@ -113,7 +129,7 @@ EXPORT_SYMBOL(inode_newsize_ok); * * setattr_copy updates the inode's metadata with that specified * in attr. Noticably missing is inode size update, which is more complex - * as it requires pagecache updates. See simple_setsize. + * as it requires pagecache updates. * * The inode is not marked as dirty after this operation. The rationale is * that for "simple" filesystems, the struct inode is the inode storage. -- cgit v1.2.3-55-g7522