This is a note to let you know that I've just added the patch titled
parisc: Fix csum_ipv6_magic on 64-bit systems
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
parisc-fix-csum_ipv6_magic-on-64-bit-systems.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 21b1d28f2d4e3119f463044872a0df48afb80c73
Author: Guenter Roeck <linux@xxxxxxxxxxxx>
Date: Tue Feb 13 15:46:31 2024 -0800
parisc: Fix csum_ipv6_magic on 64-bit systems
[ 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@xxxxxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Reviewed-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h
index e619e67440db9..c949aa20fa162 100644
--- a/arch/parisc/include/asm/checksum.h
+++ b/arch/parisc/include/asm/checksum.h
@@ -137,8 +137,8 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
" add,dc %3, %0, %0\n" /* fold in proto+len | carry bit */
" extrd,u %0, 31, 32, %4\n"/* copy upper half down */
" depdi 0, 31, 32, %0\n"/* clear upper half */
-" add %4, %0, %0\n" /* fold into 32-bits */
-" addc 0, %0, %0\n" /* add carry */
+" add,dc %4, %0, %0\n" /* fold into 32-bits, plus carry */
+" addc 0, %0, %0\n" /* add final carry */
#else
