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Alexander Shishkin
6293890419
commitec5b5ad6e2upstream. The 'nr_pages' attribute of the 'msc' subdevices parses a comma-separated list of window sizes, passed from userspace. However, there is a bug in the string parsing logic wherein it doesn't exclude the comma character from the range of characters as it consumes them. This leads to an out-of-bounds access given a sufficiently long list. For example: > # echo 8,8,8,8 > /sys/bus/intel_th/devices/0-msc0/nr_pages > ================================================================== > BUG: KASAN: slab-out-of-bounds in memchr+0x1e/0x40 > Read of size 1 at addr ffff8803ffcebcd1 by task sh/825 > > CPU: 3 PID: 825 Comm: npktest.sh Tainted: G W 4.20.0-rc1+ > Call Trace: > dump_stack+0x7c/0xc0 > print_address_description+0x6c/0x23c > ? memchr+0x1e/0x40 > kasan_report.cold.5+0x241/0x308 > memchr+0x1e/0x40 > nr_pages_store+0x203/0xd00 [intel_th_msu] Fix this by accounting for the comma character. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Fixes:ba82664c13("intel_th: Add Memory Storage Unit driver") Cc: stable@vger.kernel.org # v4.4+ 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.