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commit 64d4ce892383b2ad6d782e080d25502f91bf2a38 upstream. Function ext4_empty_dir() doesn't correctly handle directories with holes and crashes on bh->b_data dereference when bh is NULL. Reorganize the loop to use 'offset' variable all the times instead of comparing pointers to current direntry with bh->b_data pointer. Also add more strict checking of '.' and '..' directory entries to avoid entering loop in possibly invalid state on corrupted filesystems. References: CVE-2019-19037 CC: stable@vger.kernel.org Fixes: 4e19d6b65fb4 ("ext4: allow directory holes") Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20191202170213.4761-2-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.