10e031fbe5
[ Upstream commit 4b75b12d70506e31fc02356bbca60f8d5ca012d0 ]
hppa 64-bit systems calculates the IPv6 checksum using 64-bit add
operations. The last add folds protocol and length fields into the 64-bit
result. While unlikely, this operation can overflow. The overflow can be
triggered with a code sequence such as the following.
/* try to trigger massive overflows */
memset(tmp_buf, 0xff, sizeof(struct in6_addr));
csum_result = csum_ipv6_magic((struct in6_addr *)tmp_buf,
(struct in6_addr *)tmp_buf,
0xffff, 0xff, 0xffffffff);
Fix the problem by adding any overflows from the final add operation into
the calculated checksum. Fortunately, we can do this without additional
cost by replacing the add operation used to fold the checksum into 32 bit
with "add,dc" to add in the missing carry.
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.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.