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Commit 9886e836 authored by David Howells's avatar David Howells Committed by Linus Torvalds
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AFS: Stop readlink() on AFS crashing due to NULL 'file' ptr 



kAFS crashes when asked to read a symbolic link because page_getlink()
passes a NULL file pointer to read_mapping_page(), but afs_readpage()
expects a file pointer from which to extract a key.

Modify afs_readpage() to request the appropriate key from the calling
process's keyrings if a file struct is not supplied with one attached.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1e23502c

fs/afs/file.c

+15 −3
Original line number Diff line number Diff line
@@ -134,9 +134,16 @@ static int afs_readpage(struct file *file, struct page *page) 


	inode = page->mapping->host;



	ASSERT(file != NULL);

	if (file) {

		key = file->private_data;

		ASSERT(key != NULL);

	} else {

		key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);

		if (IS_ERR(key)) {

			ret = PTR_ERR(key);

			goto error_nokey;

		}

	}



	_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
@@ -207,12 +214,17 @@ static int afs_readpage(struct file *file, struct page *page) 
		unlock_page(page);

	}



	if (!file)

		key_put(key);

	_leave(" = 0");

	return 0;



error:

	SetPageError(page);

	unlock_page(page);

	if (!file)

		key_put(key);

error_nokey:

	_leave(" = %d", ret);

	return ret;

}