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mm/highmem: Add VM_BUG_ON() to mem*_page() calls 

Add VM_BUG_ON bounds checks to ensure the newly lifted and created page
memory operations do not result in corrupted data in neighbor pages.[1][2]

[1] https://lore.kernel.org/lkml/20201210053502.GS1563847@iweiny-DESK2.sc.intel.com/
[2] https://lore.kernel.org/lkml/20210209110931.00f00e47d9a0529fcee2ff01@linux-foundation.org/

Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Ira Weiny 2021-02-10 09:49:28 -08:00 committed by David Sterba
parent 6a0996db68
commit ca18f6ea01
1 changed files with 5 additions and 0 deletions
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5
include/linux/highmem.h
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@ -283,6 +283,7 @@ static inline void memcpy_page(struct page *dst_page, size_t dst_off,
char *dst = kmap_local_page(dst_page);
char *src = kmap_local_page(src_page);
VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
memcpy(dst + dst_off, src + src_off, len);
kunmap_local(src);
kunmap_local(dst);
@ -295,6 +296,7 @@ static inline void memmove_page(struct page *dst_page, size_t dst_off,
char *dst = kmap_local_page(dst_page);
char *src = kmap_local_page(src_page);
VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
memmove(dst + dst_off, src + src_off, len);
kunmap_local(src);
kunmap_local(dst);
@ -305,6 +307,7 @@ static inline void memset_page(struct page *page, size_t offset, int val,
{
char *addr = kmap_local_page(page);
VM_BUG_ON(offset + len > PAGE_SIZE);
memset(addr + offset, val, len);
kunmap_local(addr);
}
@ -314,6 +317,7 @@ static inline void memcpy_from_page(char *to, struct page *page,
{
char *from = kmap_local_page(page);
VM_BUG_ON(offset + len > PAGE_SIZE);
memcpy(to, from + offset, len);
kunmap_local(from);
}
@ -323,6 +327,7 @@ static inline void memcpy_to_page(struct page *page, size_t offset,
{
char *to = kmap_local_page(page);
VM_BUG_ON(offset + len > PAGE_SIZE);
memcpy(to + offset, from, len);
kunmap_local(to);
}