From: Kirill Korotaev Date: Tue, 17 May 2005 04:53:50 +0000 (-0700) Subject: [PATCH] do_swap_page() can map random data if swap read fails X-Git-Tag: v2.6.12-rc5~124 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b81074800b98ac50b64d4c8d34e8abf0fda5e3d1;p=linux-2.6 [PATCH] do_swap_page() can map random data if swap read fails There is a bug in do_swap_page(): when swap page happens to be unreadable, page filled with random data is mapped into user address space. The fix is to check for PageUptodate and send SIGBUS in case of error. Signed-Off-By: Kirill Korotaev Signed-Off-By: Alexey Kuznetsov Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/memory.c b/mm/memory.c index 6bad4c4064..d209f745db 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1701,12 +1701,13 @@ static int do_swap_page(struct mm_struct * mm, spin_lock(&mm->page_table_lock); page_table = pte_offset_map(pmd, address); if (unlikely(!pte_same(*page_table, orig_pte))) { - pte_unmap(page_table); - spin_unlock(&mm->page_table_lock); - unlock_page(page); - page_cache_release(page); ret = VM_FAULT_MINOR; - goto out; + goto out_nomap; + } + + if (unlikely(!PageUptodate(page))) { + ret = VM_FAULT_SIGBUS; + goto out_nomap; } /* The page isn't present yet, go ahead with the fault. */ @@ -1741,6 +1742,12 @@ static int do_swap_page(struct mm_struct * mm, spin_unlock(&mm->page_table_lock); out: return ret; +out_nomap: + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + unlock_page(page); + page_cache_release(page); + goto out; } /*