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 --- include/asm-x86_64/a.out.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/asm-x86_64/a.out.h') diff --git a/include/asm-x86_64/a.out.h b/include/asm-x86_64/a.out.h index 5952914f412..7255cde0653 100644 --- a/include/asm-x86_64/a.out.h +++ b/include/asm-x86_64/a.out.h @@ -21,7 +21,7 @@ struct exec #ifdef __KERNEL__ #include -#define STACK_TOP (test_thread_flag(TIF_IA32) ? IA32_PAGE_OFFSET : TASK_SIZE) +#define STACK_TOP TASK_SIZE #endif #endif /* __A_OUT_GNU_H__ */ -- cgit v1.2.3