Tavis Ormandy 462e635e5b install_special_mapping skips security_file_mmap check. ... The install_special_mapping routine (used, for example, to setup the vdso) skips the security check before insert_vm_struct, allowing a local attacker to bypass the mmap_min_addr security restriction by limiting the available pages for special mappings. bprm_mm_init() also skips the check, and although I don't think this can be used to bypass any restrictions, I don't see any reason not to have the security check. $ uname -m x86_64 $ cat /proc/sys/vm/mmap_min_addr 65536 $ cat install_special_mapping.s section .bss resb BSS_SIZE section .text global _start _start: mov eax, __NR_pause int 0x80 $ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s $ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o $ ./install_special_mapping & [1] 14303 $ cat /proc/14303/maps 0000f000-00010000 r-xp 00000000 00:00 0 [vdso] 00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping 00011000-ffffe000 rwxp 00000000 00:00 0 [stack] It's worth noting that Red Hat are shipping with mmap_min_addr set to 4096. Signed-off-by: Tavis Ormandy <taviso@google.com> Acked-by: Kees Cook <kees@ubuntu.com> Acked-by: Robert Swiecki <swiecki@google.com> [ Changed to not drop the error code - akpm ] Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2010-12-15 12:30:36 -08:00
..
Kconfig	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2010-10-22 17:31:36 -07:00
Kconfig.debug	…
Makefile	percpu: use percpu allocator on UP too	2010-10-02 10:26:05 +03:00
backing-dev.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6	2010-10-26 17:58:44 -07:00
bootmem.c	x86, memblock: Replace e820_/_early string with memblock_	2010-08-27 11:13:47 -07:00
bounce.c	bounce: call flush_dcache_page() after bounce_copy_vec()	2010-09-09 18:57:25 -07:00
compaction.c	mm: compaction: handle active and inactive fairly in too_many_isolated	2010-09-09 18:57:24 -07:00
debug-pagealloc.c	…
dmapool.c	mm: add a might_sleep_if() to dma_pool_alloc()	2010-10-26 16:52:08 -07:00
fadvise.c	readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM	2010-03-06 11:26:25 -08:00
failslab.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
filemap.c	Call the filesystem back whenever a page is removed from the page cache	2010-12-02 09:55:21 -05:00
filemap_xip.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
fremap.c	Avoid pgoff overflow in remap_file_pages	2010-09-25 09:34:58 -07:00
highmem.c	mm,x86: fix kmap_atomic_push vs ioremap_32.c	2010-10-27 18:03:05 -07:00
hugetlb.c	mm/hugetlb.c: avoid double unlock_page() in hugetlb_fault()	2010-12-02 14:51:14 -08:00
hwpoison-inject.c	HWPOISON, hugetlb: support hwpoison injection for hugepage	2010-08-11 09:23:11 +02:00
init-mm.c	mm: provide init_mm mm_context initializer	2010-08-09 20:44:54 -07:00
internal.h	mm: fix is_mem_section_removable() page_order BUG_ON check	2010-10-26 16:52:11 -07:00
kmemcheck.c	kmemcheck: Fix build errors due to missing slab.h	2010-03-30 22:02:32 +09:00
kmemleak-test.c	…
kmemleak.c	kmemleak: Fix typo in the comment	2010-08-08 21:57:23 +01:00
ksm.c	ksm: annotate ksm_thread_mutex is no deadlock source	2010-12-02 14:51:15 -08:00
maccess.c	MN10300: Save frame pointer in thread_info struct rather than global var	2010-10-27 17:29:01 +01:00
madvise.c	HWPOISON: Add a madvise() injector for soft page offlining	2009-12-16 12:20:00 +01:00
memblock.c	memblock: Annotate memblock functions with __init_memblock	2010-10-11 16:00:52 -07:00
memcontrol.c	cgroups: make swap accounting default behavior configurable	2010-11-25 06:50:45 +09:00
memory-failure.c	mem-hotplug: introduce {un}lock_memory_hotplug()	2010-12-02 14:51:15 -08:00
memory.c	use clear_page()/copy_page() in favor of memset()/memcpy() on whole pages	2010-10-26 16:52:13 -07:00
memory_hotplug.c	mem-hotplug: introduce {un}lock_memory_hotplug()	2010-12-02 14:51:15 -08:00
mempolicy.c	mm/mempolicy.c: add rcu read lock to protect pid structure	2010-12-02 14:51:14 -08:00
mempool.c	…
migrate.c	mm: fix error reporting in move_pages() syscall	2010-10-26 16:52:11 -07:00
mincore.c	mincore: do nested page table walks	2010-05-25 08:06:58 -07:00
mlock.c	mm: Move vma_stack_continue into mm.h	2010-09-09 09:05:06 -07:00
mm_init.c	…
mmap.c	install_special_mapping skips security_file_mmap check.	2010-12-15 12:30:36 -08:00
mmu_context.c	exit: fix oops in sync_mm_rss	2010-03-24 16:31:21 -07:00
mmu_notifier.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
mmzone.c	mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake	2010-09-09 18:57:25 -07:00
mprotect.c	perf_events: Fix perf_counter_mmap() hook in mprotect()	2010-11-09 10:19:38 -08:00
mremap.c	mm: remove pte_*map_nested()	2010-10-26 16:52:08 -07:00
msync.c	sanitize vfs_fsync calling conventions	2010-05-21 18:31:21 -04:00
nommu.c	nommu: yield CPU while disposing VM	2010-11-25 06:50:38 +09:00
oom_kill.c	oom: kill all threads sharing oom killed task's mm	2010-10-26 16:52:05 -07:00
page-writeback.c	writeback: remove the internal 5% low bound on dirty_ratio	2010-10-26 16:52:08 -07:00
page_alloc.c	PM / Hibernate: Fix memory corruption related to swap	2010-12-06 23:52:08 +01:00
page_cgroup.c	kmemleak: Annotate false positive in init_section_page_cgroup()	2010-07-19 11:54:14 +01:00
page_io.c	block: unify flags for struct bio and struct request	2010-08-07 18:20:39 +02:00
page_isolation.c	mm: page_isolation: codeclean fix comment and rm unneeded val init	2010-10-26 16:52:11 -07:00
pagewalk.c	mm: remove call to find_vma in pagewalk for non-hugetlbfs	2010-11-25 06:50:46 +09:00
percpu-km.c	percpu: clear memory allocated with the km allocator	2010-10-02 10:28:42 +03:00
percpu-vm.c	percpu: move vmalloc based chunk management into percpu-vm.c	2010-05-01 08:30:50 +02:00
percpu.c	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2010-10-24 13:41:39 -07:00
prio_tree.c	…
quicklist.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
readahead.c	readahead.c: fix comment	2010-05-25 08:07:00 -07:00
rmap.c	rmap: make anon_vma_chain_free() static	2010-10-26 16:52:10 -07:00
shmem.c	convert get_sb_nodev() users	2010-10-29 04:16:31 -04:00
slab.c	replace nested max/min macros with {max,min}3 macro	2010-10-26 16:52:12 -07:00
slob.c	slob: fix gfp flags for order-0 page allocations	2010-10-02 10:24:28 +03:00
slub.c	slub: Fix a crash during slabinfo -v	2010-12-04 09:53:49 +02:00
sparse-vmemmap.c	x86: Use memblock to replace early_res	2010-08-27 11:12:29 -07:00
sparse.c	sparsemem: on no vmemmap path put mem_map on node high too	2010-05-25 08:06:56 -07:00
swap.c	fuse: use release_pages()	2010-10-27 18:03:17 -07:00
swap_state.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
swapfile.c	/proc/swaps: support polling	2010-10-26 16:52:11 -07:00
thrash.c	…
truncate.c	Call the filesystem back whenever a page is removed from the page cache	2010-12-02 09:55:21 -05:00
util.c	export __get_user_pages_fast() function	2010-10-24 10:51:24 +02:00
vmalloc.c	vmalloc: eagerly clear ptes on vunmap	2010-12-02 14:51:15 -08:00
vmscan.c	Call the filesystem back whenever a page is removed from the page cache	2010-12-02 09:55:21 -05:00
vmstat.c	vmstat: fix dirty threshold ordering	2010-12-02 14:51:14 -08:00