From 84929801e14d968caeb84795bfbb88f04283fbd9 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Tue, 21 Jun 2005 17:14:32 -0700 Subject: [PATCH] x86_64: TASK_SIZE fixes for compatibility mode processes Appended patch will setup compatibility mode TASK_SIZE properly. This will fix atleast three known bugs that can be encountered while running compatibility mode apps. a) A malicious 32bit app can have an elf section at 0xffffe000. During exec of this app, we will have a memory leak as insert_vm_struct() is not checking for return value in syscall32_setup_pages() and thus not freeing the vma allocated for the vsyscall page. And instead of exec failing (as it has addresses > TASK_SIZE), we were allowing it to succeed previously. b) With a 32bit app, hugetlb_get_unmapped_area/arch_get_unmapped_area may return addresses beyond 32bits, ultimately causing corruption because of wrap-around and resulting in SEGFAULT, instead of returning ENOMEM. c) 32bit app doing this below mmap will now fail. mmap((void *)(0xFFFFE000UL), 0x10000UL, PROT_READ|PROT_WRITE, MAP_FIXED|MAP_PRIVATE|MAP_ANON, 0, 0); Signed-off-by: Zou Nan hai Signed-off-by: Suresh Siddha Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86_64/mm/fault.c') diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c index 5d6b211..57d3ab1 100644 --- a/arch/x86_64/mm/fault.c +++ b/arch/x86_64/mm/fault.c @@ -350,7 +350,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code) * (error_code & 4) == 0, and that the fault was not a * protection error (error_code & 1) == 0. */ - if (unlikely(address >= TASK_SIZE)) { + if (unlikely(address >= TASK_SIZE64)) { if (!(error_code & 5) && ((address >= VMALLOC_START && address < VMALLOC_END) || (address >= MODULES_VADDR && address < MODULES_END))) { -- cgit v1.1