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c0eb027e5a
Normal pathname lookup doesn't allow empty pathnames, but using AT_EMPTY_PATH (with name_to_handle_at() or fstatat(), for example) you can trigger an empty pathname lookup. And not only is the RCU lookup in that case entirely unnecessary (because we'll obviously immediately finalize the end result), it is actively wrong. Why? An empth path is a special case that will return the original 'dirfd' dentry - and that dentry may not actually be RCU-free'd, resulting in a potential use-after-free if we were to initialize the path lazily under the RCU read lock and depend on complete_walk() finalizing the dentry. Found by syzkaller and KASAN. Reported-by: Dmitry Vyukov <dvyukov@google.com> Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| firmware | ||
| fs | ||
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| kernel | ||
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| .cocciconfig | ||
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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.