Minimal supplement to upstream Kernel Self Protection Project changes. Features already provided by SELinux + Yama and archs other than multiarch arm64 / x86_64 aren't in scope. Only tags have stable history. Shared IRC channel with KSPP: irc.libera.chat #linux-hardening
9c6e7853c5
New ea_inode feature allows putting large xattr values into external inodes. struct ext4_xattr_entry and the attribute name however have to remain in the inode extra space or external attribute block. Once that space is exhausted, no further entries can be added. Some of that space could also be used by values that fit in there at the time of addition. So, a single xattr entry whose value barely fits in the external block could prevent further entries being added. To mitigate the problem, this patch introduces a notion of reserved space in the external attribute block that cannot be used by value data. This reserve is enforced when ea_inode feature is enabled. The amount of reserve is arbitrarily chosen to be min(block_size/8, 1024). The table below shows how much space is reserved for each block size and the guaranteed mininum number of entries that can be placed in the external attribute block. block size reserved bytes entries (name length = 16) 1k 128 3 2k 256 7 4k 512 15 8k 1024 31 16k 1024 31 32k 1024 31 64k 1024 31 Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
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| README | ||
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.