From 134a24cd895c5d138d639a0741ad27e389cd4562 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 3 Aug 2016 17:55:00 +0200 Subject: [PATCH] s390/crc32-vx: Fix checksum calculation for small sizes The current prealign logic will fail for sizes < alignment, as the new datalen passed to the vector function is smaller than zero. Being a size_t this gets wrapped to a huge number causing memory overruns and wrong data. Let's add an early exit if the size is smaller than the minimal size with alignment. This will also avoid calling the software fallback twice for all sizes smaller than the minimum size (prealign + remaining) Signed-off-by: Christian Borntraeger Fixes: f848dbd3bc1a ("s390/crc32-vx: add crypto API module for optimized CRC-32 algorithms") Reviewed-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky --- arch/s390/crypto/crc32-vx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/s390/crypto/crc32-vx.c b/arch/s390/crypto/crc32-vx.c index 577ae1d4ae89..2bad9d837029 100644 --- a/arch/s390/crypto/crc32-vx.c +++ b/arch/s390/crypto/crc32-vx.c @@ -51,6 +51,9 @@ u32 crc32c_le_vgfm_16(u32 crc, unsigned char const *buf, size_t size); struct kernel_fpu vxstate; \ unsigned long prealign, aligned, remaining; \ \ + if (datalen < VX_MIN_LEN + VX_ALIGN_MASK) \ + return ___crc32_sw(crc, data, datalen); \ + \ if ((unsigned long)data & VX_ALIGN_MASK) { \ prealign = VX_ALIGNMENT - \ ((unsigned long)data & VX_ALIGN_MASK); \ @@ -59,9 +62,6 @@ u32 crc32c_le_vgfm_16(u32 crc, unsigned char const *buf, size_t size); data = (void *)((unsigned long)data + prealign); \ } \ \ - if (datalen < VX_MIN_LEN) \ - return ___crc32_sw(crc, data, datalen); \ - \ aligned = datalen & ~VX_ALIGN_MASK; \ remaining = datalen & VX_ALIGN_MASK; \ \ -- 2.39.5