5aad21e5d4
category: bugfix bugzilla: https://gitee.com/src-openeuler/leveldb/issues/I6YTZP?from=project-issue commit 2964b803b857932ff7499d7bebb61dc5514dab7c CVE: NA Signed-off-by: Guangzhong Yao <yaoguangzhong@xfusion.com>
41 lines
1.4 KiB
Diff
41 lines
1.4 KiB
Diff
From 2964b803b857932ff7499d7bebb61dc5514dab7c Mon Sep 17 00:00:00 2001
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From: costan <costan@google.com>
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Date: Wed, 23 Aug 2017 20:59:46 -0700
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Subject: [PATCH] leveldb: Fix alignment code in SSE4.2-optimized CRC32C.
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When faced with a pointer that is misaligned by K bytes (pointer % 8 ==
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K), the code previously moved forward by K bytes. In order to end up
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with an aligned pointer, the code must move by 8 - K bytes.
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This lands https://github.com/google/leveldb/pull/488
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-------------
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Created by MOE: https://github.com/google/moe
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MOE_MIGRATED_REVID=166295921
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---
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port/port_posix_sse.cc | 8 ++++++--
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1 file changed, 6 insertions(+), 2 deletions(-)
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diff --git a/port/port_posix_sse.cc b/port/port_posix_sse.cc
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index 1e519ba..08d9aee 100644
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--- a/port/port_posix_sse.cc
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+++ b/port/port_posix_sse.cc
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@@ -92,8 +92,12 @@ uint32_t AcceleratedCRC32C(uint32_t crc, const char* buf, size_t size) {
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} while (0)
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if (size > 16) {
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- // Process unaligned bytes
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- for (unsigned int i = reinterpret_cast<uintptr_t>(p) % 8; i; --i) {
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+ // Point x at first 8-byte aligned byte in string. This must be inside the
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+ // string, due to the size check above.
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+ const uintptr_t pval = reinterpret_cast<uintptr_t>(p);
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+ const uint8_t* x = reinterpret_cast<const uint8_t*>(((pval + 7) >> 3) << 3);
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+ // Process bytes until p is 8-byte aligned.
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+ while (p != x) {
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STEP1;
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}
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--
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2.40.0.windows.1
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