From 7cd94146cd504016315608e297219f9fb7b1413b Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 26 Nov 2007 18:47:40 -0500 Subject: Security: round mmap hint address above mmap_min_addr If mmap_min_addr is set and a process attempts to mmap (not fixed) with a non-null hint address less than mmap_min_addr the mapping will fail the security checks. Since this is just a hint address this patch will round such a hint address above mmap_min_addr. gcj was found to try to be very frugal with vm usage and give hint addresses in the 8k-32k range. Without this patch all such programs failed and with the patch they happily get a higher address. This patch is wrappad in CONFIG_SECURITY since mmap_min_addr doesn't exist without it and there would be no security check possible no matter what. So we should not bother compiling in this rounding if it is just a waste of time. Signed-off-by: Eric Paris Signed-off-by: James Morris --- include/linux/mm.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 520238cbae5..1b7b95c67ac 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -12,6 +12,7 @@ #include #include #include +#include struct mempolicy; struct anon_vma; @@ -512,6 +513,21 @@ static inline void set_page_links(struct page *page, enum zone_type zone, set_page_section(page, pfn_to_section_nr(pfn)); } +/* + * If a hint addr is less than mmap_min_addr change hint to be as + * low as possible but still greater than mmap_min_addr + */ +static inline unsigned long round_hint_to_min(unsigned long hint) +{ +#ifdef CONFIG_SECURITY + hint &= PAGE_MASK; + if (((void *)hint != NULL) && + (hint < mmap_min_addr)) + return PAGE_ALIGN(mmap_min_addr); +#endif + return hint; +} + /* * Some inline functions in vmstat.h depend on page_zone() */ -- cgit v1.2.3