From 2af482a7edfb8810539cacc2fdd8242611ca43bb Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:50 -0800 Subject: [PATCH] r/o bind mounts: elevate write count for chmod/chown callers chown/chmod,etc... don't call permission in the same way that the normal "open for write" calls do. They still write to the filesystem, so bump the write count during these operations. Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/open.c | 39 ++++++++++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 9 deletions(-) (limited to 'fs') diff --git a/fs/open.c b/fs/open.c index e12f17010324..e2df8fd1eb0b 100644 --- a/fs/open.c +++ b/fs/open.c @@ -567,12 +567,12 @@ asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) audit_inode(NULL, dentry); - err = -EROFS; - if (IS_RDONLY(inode)) + err = mnt_want_write(file->f_path.mnt); + if (err) goto out_putf; err = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto out_putf; + goto out_drop_write; mutex_lock(&inode->i_mutex); if (mode == (mode_t) -1) mode = inode->i_mode; @@ -581,6 +581,8 @@ asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) err = notify_change(dentry, &newattrs); mutex_unlock(&inode->i_mutex); +out_drop_write: + mnt_drop_write(file->f_path.mnt); out_putf: fput(file); out: @@ -600,13 +602,13 @@ asmlinkage long sys_fchmodat(int dfd, const char __user *filename, goto out; inode = nd.path.dentry->d_inode; - error = -EROFS; - if (IS_RDONLY(inode)) + error = mnt_want_write(nd.path.mnt); + if (error) goto dput_and_out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto dput_and_out; + goto out_drop_write; mutex_lock(&inode->i_mutex); if (mode == (mode_t) -1) @@ -616,6 +618,8 @@ asmlinkage long sys_fchmodat(int dfd, const char __user *filename, error = notify_change(nd.path.dentry, &newattrs); mutex_unlock(&inode->i_mutex); +out_drop_write: + mnt_drop_write(nd.path.mnt); dput_and_out: path_put(&nd.path); out: @@ -638,9 +642,6 @@ static int chown_common(struct dentry * dentry, uid_t user, gid_t group) printk(KERN_ERR "chown_common: NULL inode\n"); goto out; } - error = -EROFS; - if (IS_RDONLY(inode)) - goto out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto out; @@ -671,7 +672,12 @@ asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) error = user_path_walk(filename, &nd); if (error) goto out; + error = mnt_want_write(nd.path.mnt); + if (error) + goto out_release; error = chown_common(nd.path.dentry, user, group); + mnt_drop_write(nd.path.mnt); +out_release: path_put(&nd.path); out: return error; @@ -691,7 +697,12 @@ asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user, error = __user_walk_fd(dfd, filename, follow, &nd); if (error) goto out; + error = mnt_want_write(nd.path.mnt); + if (error) + goto out_release; error = chown_common(nd.path.dentry, user, group); + mnt_drop_write(nd.path.mnt); +out_release: path_put(&nd.path); out: return error; @@ -705,7 +716,12 @@ asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group error = user_path_walk_link(filename, &nd); if (error) goto out; + error = mnt_want_write(nd.path.mnt); + if (error) + goto out_release; error = chown_common(nd.path.dentry, user, group); + mnt_drop_write(nd.path.mnt); +out_release: path_put(&nd.path); out: return error; @@ -722,9 +738,14 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) if (!file) goto out; + error = mnt_want_write(file->f_path.mnt); + if (error) + goto out_fput; dentry = file->f_path.dentry; audit_inode(NULL, dentry); error = chown_common(dentry, user, group); + mnt_drop_write(file->f_path.mnt); +out_fput: fput(file); out: return error; -- cgit v1.2.3