diff options
| author | Eric Paris <eparis@redhat.com> | 2007-11-27 00:47:40 +0100 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2007-12-05 14:25:10 +0100 |
| commit | 7cd94146cd504016315608e297219f9fb7b1413b (patch) | |
| tree | 1d118d6af0a6d3efb9be66f7305827aee2ceffea /include | |
| parent | security: protect from stack expantion into low vm addresses (diff) | |
| download | linux-7cd94146cd504016315608e297219f9fb7b1413b.tar.xz linux-7cd94146cd504016315608e297219f9fb7b1413b.zip | |
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 <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 520238cbae5d..1b7b95c67aca 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -12,6 +12,7 @@ #include <linux/prio_tree.h> #include <linux/debug_locks.h> #include <linux/mm_types.h> +#include <linux/security.h> struct mempolicy; struct anon_vma; @@ -513,6 +514,21 @@ static inline void set_page_links(struct page *page, enum zone_type zone, } /* + * 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() */ #include <linux/vmstat.h> |