commit 175b8d89fe292796811fdee87fa39799a5b6b87a upstream. syzbot spotted a potential out-of-bounds shift in the PCM OSS layer where it calculates the buffer size with the arbitrary shift value given via an ioctl. Add a range check for avoiding the undefined behavior. As the value can be treated by a signed integer, the max shift should be 30. Reported-by: syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20201209084552.17109-2-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.
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