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[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 <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:
parent
4a3fd211cc
commit
2af482a7ed
1 changed files with 30 additions and 9 deletions
39
fs/open.c
39
fs/open.c
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@ -567,12 +567,12 @@ asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
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audit_inode(NULL, dentry);
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err = -EROFS;
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if (IS_RDONLY(inode))
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err = mnt_want_write(file->f_path.mnt);
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if (err)
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goto out_putf;
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err = -EPERM;
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if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
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goto out_putf;
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goto out_drop_write;
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mutex_lock(&inode->i_mutex);
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if (mode == (mode_t) -1)
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mode = inode->i_mode;
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@ -581,6 +581,8 @@ asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
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err = notify_change(dentry, &newattrs);
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mutex_unlock(&inode->i_mutex);
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out_drop_write:
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mnt_drop_write(file->f_path.mnt);
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out_putf:
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fput(file);
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out:
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@ -600,13 +602,13 @@ asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
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goto out;
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inode = nd.path.dentry->d_inode;
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error = -EROFS;
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if (IS_RDONLY(inode))
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error = mnt_want_write(nd.path.mnt);
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if (error)
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goto dput_and_out;
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error = -EPERM;
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if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
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goto dput_and_out;
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goto out_drop_write;
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mutex_lock(&inode->i_mutex);
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if (mode == (mode_t) -1)
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@ -616,6 +618,8 @@ asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
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error = notify_change(nd.path.dentry, &newattrs);
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mutex_unlock(&inode->i_mutex);
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out_drop_write:
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mnt_drop_write(nd.path.mnt);
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dput_and_out:
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path_put(&nd.path);
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out:
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@ -638,9 +642,6 @@ static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
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printk(KERN_ERR "chown_common: NULL inode\n");
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goto out;
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}
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error = -EROFS;
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if (IS_RDONLY(inode))
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goto out;
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error = -EPERM;
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if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
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goto out;
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@ -671,7 +672,12 @@ asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
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error = user_path_walk(filename, &nd);
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if (error)
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goto out;
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error = mnt_want_write(nd.path.mnt);
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if (error)
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goto out_release;
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error = chown_common(nd.path.dentry, user, group);
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mnt_drop_write(nd.path.mnt);
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out_release:
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path_put(&nd.path);
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out:
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return error;
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@ -691,7 +697,12 @@ asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
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error = __user_walk_fd(dfd, filename, follow, &nd);
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if (error)
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goto out;
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error = mnt_want_write(nd.path.mnt);
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if (error)
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goto out_release;
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error = chown_common(nd.path.dentry, user, group);
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mnt_drop_write(nd.path.mnt);
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out_release:
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path_put(&nd.path);
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out:
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return error;
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@ -705,7 +716,12 @@ asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group
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error = user_path_walk_link(filename, &nd);
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if (error)
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goto out;
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error = mnt_want_write(nd.path.mnt);
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if (error)
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goto out_release;
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error = chown_common(nd.path.dentry, user, group);
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mnt_drop_write(nd.path.mnt);
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out_release:
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path_put(&nd.path);
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out:
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return error;
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@ -722,9 +738,14 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
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if (!file)
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goto out;
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error = mnt_want_write(file->f_path.mnt);
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if (error)
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goto out_fput;
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dentry = file->f_path.dentry;
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audit_inode(NULL, dentry);
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error = chown_common(dentry, user, group);
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mnt_drop_write(file->f_path.mnt);
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out_fput:
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fput(file);
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out:
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return error;
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