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When initializing a no-key name, fscrypt_fname_disk_to_usr() sets the
minor_hash to 0 if the (major) hash is 0.
This doesn't make sense because 0 is a valid hash code, so we shouldn't
ignore the filesystem-provided minor_hash in that case. Fix this by
removing the special case for 'hash == 0'.
This is an old bug that appears to have originated when the encryption
code in ext4 and f2fs was moved into fs/crypto/. The original ext4 and
f2fs code passed the hash by pointer instead of by value. So
'if (hash)' actually made sense then, as it was checking whether a
pointer was NULL. But now the hashes are passed by value, and
filesystems just pass 0 for any hashes they don't have. There is no
need to handle this any differently from the hashes actually being 0.
It is difficult to reproduce this bug, as it only made a difference in
the case where a filename's 32-bit major hash happened to be 0.
However, it probably had the largest chance of causing problems on
ubifs, since ubifs uses minor_hash to do lookups of no-key names, in
addition to using it as a readdir cookie. ext4 only uses minor_hash as
a readdir cookie, and f2fs doesn't use minor_hash at all.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.