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b3b7e1d0b4
On 64K pages the size of the extent_buffer::pages array is 1 and compilation with -Warray-bounds warns due to kaddr = page_address(eb->pages[idx + 1]); when reading byte range crossing page boundary. This does never actually overflow the array because on 64K because all the data fit in one page and bounds are checked by check_setget_bounds. To fix the reported overflows and warnings add a compile-time condition that will allow compiler to eliminate the dead code that reads from the idx + 1 page. Link: https://lore.kernel.org/lkml/20210623083901.1d49d19d@canb.auug.org.au/ CC: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
172 lines
6.2 KiB
C
172 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*/
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#include <asm/unaligned.h>
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#include "ctree.h"
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static bool check_setget_bounds(const struct extent_buffer *eb,
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const void *ptr, unsigned off, int size)
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{
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const unsigned long member_offset = (unsigned long)ptr + off;
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if (member_offset > eb->len) {
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btrfs_warn(eb->fs_info,
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"bad eb member start: ptr 0x%lx start %llu member offset %lu size %d",
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(unsigned long)ptr, eb->start, member_offset, size);
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return false;
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}
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if (member_offset + size > eb->len) {
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btrfs_warn(eb->fs_info,
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"bad eb member end: ptr 0x%lx start %llu member offset %lu size %d",
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(unsigned long)ptr, eb->start, member_offset, size);
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return false;
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}
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return true;
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}
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/*
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* Macro templates that define helpers to read/write extent buffer data of a
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* given size, that are also used via ctree.h for access to item members by
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* specialized helpers.
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*
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* Generic helpers:
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* - btrfs_set_8 (for 8/16/32/64)
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* - btrfs_get_8 (for 8/16/32/64)
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*
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* Generic helpers with a token (cached address of the most recently accessed
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* page):
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* - btrfs_set_token_8 (for 8/16/32/64)
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* - btrfs_get_token_8 (for 8/16/32/64)
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*
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* The set/get functions handle data spanning two pages transparently, in case
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* metadata block size is larger than page. Every pointer to metadata items is
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* an offset into the extent buffer page array, cast to a specific type. This
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* gives us all the type checking.
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*
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* The extent buffer pages stored in the array pages do not form a contiguous
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* phyusical range, but the API functions assume the linear offset to the range
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* from 0 to metadata node size.
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*/
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#define DEFINE_BTRFS_SETGET_BITS(bits) \
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u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \
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const void *ptr, unsigned long off) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const unsigned long idx = get_eb_page_index(member_offset); \
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const unsigned long oip = get_eb_offset_in_page(token->eb, \
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member_offset); \
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const int size = sizeof(u##bits); \
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u8 lebytes[sizeof(u##bits)]; \
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const int part = PAGE_SIZE - oip; \
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\
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ASSERT(token); \
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ASSERT(token->kaddr); \
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ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
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if (token->offset <= member_offset && \
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member_offset + size <= token->offset + PAGE_SIZE) { \
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return get_unaligned_le##bits(token->kaddr + oip); \
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} \
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token->kaddr = page_address(token->eb->pages[idx]); \
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token->offset = idx << PAGE_SHIFT; \
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if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE ) \
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return get_unaligned_le##bits(token->kaddr + oip); \
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\
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memcpy(lebytes, token->kaddr + oip, part); \
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token->kaddr = page_address(token->eb->pages[idx + 1]); \
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token->offset = (idx + 1) << PAGE_SHIFT; \
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memcpy(lebytes + part, token->kaddr, size - part); \
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return get_unaligned_le##bits(lebytes); \
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} \
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u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
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const void *ptr, unsigned long off) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
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const unsigned long idx = get_eb_page_index(member_offset); \
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char *kaddr = page_address(eb->pages[idx]); \
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const int size = sizeof(u##bits); \
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const int part = PAGE_SIZE - oip; \
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u8 lebytes[sizeof(u##bits)]; \
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\
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ASSERT(check_setget_bounds(eb, ptr, off, size)); \
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if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) \
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return get_unaligned_le##bits(kaddr + oip); \
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\
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memcpy(lebytes, kaddr + oip, part); \
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kaddr = page_address(eb->pages[idx + 1]); \
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memcpy(lebytes + part, kaddr, size - part); \
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return get_unaligned_le##bits(lebytes); \
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} \
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void btrfs_set_token_##bits(struct btrfs_map_token *token, \
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const void *ptr, unsigned long off, \
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u##bits val) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const unsigned long idx = get_eb_page_index(member_offset); \
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const unsigned long oip = get_eb_offset_in_page(token->eb, \
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member_offset); \
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const int size = sizeof(u##bits); \
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u8 lebytes[sizeof(u##bits)]; \
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const int part = PAGE_SIZE - oip; \
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\
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ASSERT(token); \
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ASSERT(token->kaddr); \
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ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
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if (token->offset <= member_offset && \
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member_offset + size <= token->offset + PAGE_SIZE) { \
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put_unaligned_le##bits(val, token->kaddr + oip); \
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return; \
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} \
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token->kaddr = page_address(token->eb->pages[idx]); \
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token->offset = idx << PAGE_SHIFT; \
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if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \
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put_unaligned_le##bits(val, token->kaddr + oip); \
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return; \
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} \
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put_unaligned_le##bits(val, lebytes); \
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memcpy(token->kaddr + oip, lebytes, part); \
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token->kaddr = page_address(token->eb->pages[idx + 1]); \
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token->offset = (idx + 1) << PAGE_SHIFT; \
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memcpy(token->kaddr, lebytes + part, size - part); \
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} \
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void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \
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unsigned long off, u##bits val) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
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const unsigned long idx = get_eb_page_index(member_offset); \
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char *kaddr = page_address(eb->pages[idx]); \
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const int size = sizeof(u##bits); \
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const int part = PAGE_SIZE - oip; \
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u8 lebytes[sizeof(u##bits)]; \
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\
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ASSERT(check_setget_bounds(eb, ptr, off, size)); \
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if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \
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put_unaligned_le##bits(val, kaddr + oip); \
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return; \
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} \
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\
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put_unaligned_le##bits(val, lebytes); \
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memcpy(kaddr + oip, lebytes, part); \
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kaddr = page_address(eb->pages[idx + 1]); \
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memcpy(kaddr, lebytes + part, size - part); \
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}
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DEFINE_BTRFS_SETGET_BITS(8)
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DEFINE_BTRFS_SETGET_BITS(16)
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DEFINE_BTRFS_SETGET_BITS(32)
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DEFINE_BTRFS_SETGET_BITS(64)
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void btrfs_node_key(const struct extent_buffer *eb,
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struct btrfs_disk_key *disk_key, int nr)
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{
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unsigned long ptr = btrfs_node_key_ptr_offset(nr);
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read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
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struct btrfs_key_ptr, key, disk_key);
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}
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