commit 678cce4019d746da6c680c48ba9e6d417803e127 upstream.

The x86_64 implementation of Poly1305 produces the wrong result on some
inputs because poly1305_4block_avx2() incorrectly assumes that when
partially reducing the accumulator, the bits carried from limb 'd4' to
limb 'h0' fit in a 32-bit integer.  This is true for poly1305-generic
which processes only one block at a time.  However, it's not true for
the AVX2 implementation, which processes 4 blocks at a time and
therefore can produce intermediate limbs about 4x larger.

Fix it by making the relevant calculations use 64-bit arithmetic rather
than 32-bit.  Note that most of the carries already used 64-bit
arithmetic, but the d4 -> h0 carry was different for some reason.

To be safe I also made the same change to the corresponding SSE2 code,
though that only operates on 1 or 2 blocks at a time.  I don't think
it's really needed for poly1305_block_sse2(), but it doesn't hurt
because it's already x86_64 code.  It *might* be needed for
poly1305_2block_sse2(), but overflows aren't easy to reproduce there.

This bug was originally detected by my patches that improve testmgr to
fuzz algorithms against their generic implementation.  But also add a
test vector which reproduces it directly (in the AVX2 case).

Fixes: b1ccc8f4 ("crypto: poly1305 - Add a four block AVX2 variant for x86_64")
Fixes: c70f4abe ("crypto: poly1305 - Add a SSE2 SIMD variant for x86_64")
Cc: <stable@vger.kernel.org> # v4.3+
Cc: Martin Willi <martin@strongswan.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NMartin Willi <martin@strongswan.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A lot of asm-optimized routines in arch/x86/crypto/ keep its
constants in .data. This is wrong, they should be on .rodata.

Mnay of these constants are the same in different modules.
For example, 128-bit shuffle mask 0x000102030405060708090A0B0C0D0E0F
exists in at least half a dozen places.

There is a way to let linker merge them and use just one copy.
The rules are as follows: mergeable objects of different sizes
should not share sections. You can't put them all in one .rodata
section, they will lose "mergeability".

GCC puts its mergeable constants in ".rodata.cstSIZE" sections,
or ".rodata.cstSIZE.<object_name>" if -fdata-sections is used.
This patch does the same:

	.section .rodata.cst16.SHUF_MASK, "aM", @progbits, 16

It is important that all data in such section consists of
16-byte elements, not larger ones, and there are no implicit
use of one element from another.

When this is not the case, use non-mergeable section:

	.section .rodata[.VAR_NAME], "a", @progbits

This reduces .data by ~15 kbytes:

    text    data     bss     dec      hex filename
11097415 2705840 2630712 16433967  fac32f vmlinux-prev.o
11112095 2690672 2630712 16433479  fac147 vmlinux.o

Merged objects are visible in System.map:

ffffffff81a28810 r POLY
ffffffff81a28810 r POLY
ffffffff81a28820 r TWOONE
ffffffff81a28820 r TWOONE
ffffffff81a28830 r PSHUFFLE_BYTE_FLIP_MASK <- merged regardless of
ffffffff81a28830 r SHUF_MASK   <------------- the name difference
ffffffff81a28830 r SHUF_MASK
ffffffff81a28830 r SHUF_MASK
..
ffffffff81a28d00 r K512 <- merged three identical 640-byte tables
ffffffff81a28d00 r K512
ffffffff81a28d00 r K512

Use of object names in section name suffixes is not strictly necessary,
but might help if someday link stage will use garbage collection
to eliminate unused sections (ld --gc-sections).
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: Josh Poimboeuf <jpoimboe@redhat.com>
CC: Xiaodong Liu <xiaodong.liu@intel.com>
CC: Megha Dey <megha.dey@intel.com>
CC: linux-crypto@vger.kernel.org
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Extends the x86_64 Poly1305 authenticator by a function processing four
consecutive Poly1305 blocks in parallel using AVX2 instructions.

For large messages, throughput increases by ~15-45% compared to two
block SSE2:

testing speed of poly1305 (poly1305-simd)
test  0 (   96 byte blocks,   16 bytes per update,   6 updates): 3809514 opers/sec,  365713411 bytes/sec
test  1 (   96 byte blocks,   32 bytes per update,   3 updates): 5973423 opers/sec,  573448627 bytes/sec
test  2 (   96 byte blocks,   96 bytes per update,   1 updates): 9446779 opers/sec,  906890803 bytes/sec
test  3 (  288 byte blocks,   16 bytes per update,  18 updates): 1364814 opers/sec,  393066691 bytes/sec
test  4 (  288 byte blocks,   32 bytes per update,   9 updates): 2045780 opers/sec,  589184697 bytes/sec
test  5 (  288 byte blocks,  288 bytes per update,   1 updates): 3711946 opers/sec, 1069040592 bytes/sec
test  6 ( 1056 byte blocks,   32 bytes per update,  33 updates):  573686 opers/sec,  605812732 bytes/sec
test  7 ( 1056 byte blocks, 1056 bytes per update,   1 updates): 1647802 opers/sec, 1740079440 bytes/sec
test  8 ( 2080 byte blocks,   32 bytes per update,  65 updates):  292970 opers/sec,  609378224 bytes/sec
test  9 ( 2080 byte blocks, 2080 bytes per update,   1 updates):  943229 opers/sec, 1961916528 bytes/sec
test 10 ( 4128 byte blocks, 4128 bytes per update,   1 updates):  494623 opers/sec, 2041804569 bytes/sec
test 11 ( 8224 byte blocks, 8224 bytes per update,   1 updates):  254045 opers/sec, 2089271014 bytes/sec

testing speed of poly1305 (poly1305-simd)
test  0 (   96 byte blocks,   16 bytes per update,   6 updates): 3826224 opers/sec,  367317552 bytes/sec
test  1 (   96 byte blocks,   32 bytes per update,   3 updates): 5948638 opers/sec,  571069267 bytes/sec
test  2 (   96 byte blocks,   96 bytes per update,   1 updates): 9439110 opers/sec,  906154627 bytes/sec
test  3 (  288 byte blocks,   16 bytes per update,  18 updates): 1367756 opers/sec,  393913872 bytes/sec
test  4 (  288 byte blocks,   32 bytes per update,   9 updates): 2056881 opers/sec,  592381958 bytes/sec
test  5 (  288 byte blocks,  288 bytes per update,   1 updates): 3711153 opers/sec, 1068812179 bytes/sec
test  6 ( 1056 byte blocks,   32 bytes per update,  33 updates):  574940 opers/sec,  607136745 bytes/sec
test  7 ( 1056 byte blocks, 1056 bytes per update,   1 updates): 1948830 opers/sec, 2057964585 bytes/sec
test  8 ( 2080 byte blocks,   32 bytes per update,  65 updates):  293308 opers/sec,  610082096 bytes/sec
test  9 ( 2080 byte blocks, 2080 bytes per update,   1 updates): 1235224 opers/sec, 2569267792 bytes/sec
test 10 ( 4128 byte blocks, 4128 bytes per update,   1 updates):  684405 opers/sec, 2825226316 bytes/sec
test 11 ( 8224 byte blocks, 8224 bytes per update,   1 updates):  367101 opers/sec, 3019039446 bytes/sec

Benchmark results from a Core i5-4670T.
Signed-off-by: NMartin Willi <martin@strongswan.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>