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[PATCH] r/o bind mounts: elevate write count for chmod/chown callers

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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 <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dave Hansen 2008-02-15 14:37:50 -08:00 committed by Al Viro
parent 4a3fd211cc
commit 2af482a7ed
1 changed files with 30 additions and 9 deletions
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39
fs/open.c
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@ -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;