Andrey Ryabinin 2490908309 mpi: Fix NULL ptr dereference in mpi_powm() [ver #3] ... commit f5527fffff3f002b0a6b376163613b82f69de073 upstream. This fixes CVE-2016-8650. If mpi_powm() is given a zero exponent, it wants to immediately return either 1 or 0, depending on the modulus. However, if the result was initalised with zero limb space, no limbs space is allocated and a NULL-pointer exception ensues. Fix this by allocating a minimal amount of limb space for the result when the 0-exponent case when the result is 1 and not touching the limb space when the result is 0. This affects the use of RSA keys and X.509 certificates that carry them. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6 PGD 0 Oops: 0002 [#1] SMP Modules linked in: CPU: 3 PID: 3014 Comm: keyctl Not tainted 4.9.0-rc6-fscache+ #278 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 task: ffff8804011944c0 task.stack: ffff880401294000 RIP: 0010:[<ffffffff8138ce5d>] [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6 RSP: 0018:ffff880401297ad8 EFLAGS: 00010212 RAX: 0000000000000000 RBX: ffff88040868bec0 RCX: ffff88040868bba0 RDX: ffff88040868b260 RSI: ffff88040868bec0 RDI: ffff88040868bee0 RBP: ffff880401297ba8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000047 R11: ffffffff8183b210 R12: 0000000000000000 R13: ffff8804087c7600 R14: 000000000000001f R15: ffff880401297c50 FS: 00007f7a7918c700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000401250000 CR4: 00000000001406e0 Stack: ffff88040868bec0 0000000000000020 ffff880401297b00 ffffffff81376cd4 0000000000000100 ffff880401297b10 ffffffff81376d12 ffff880401297b30 ffffffff81376f37 0000000000000100 0000000000000000 ffff880401297ba8 Call Trace: [<ffffffff81376cd4>] ? __sg_page_iter_next+0x43/0x66 [<ffffffff81376d12>] ? sg_miter_get_next_page+0x1b/0x5d [<ffffffff81376f37>] ? sg_miter_next+0x17/0xbd [<ffffffff8138ba3a>] ? mpi_read_raw_from_sgl+0xf2/0x146 [<ffffffff8132a95c>] rsa_verify+0x9d/0xee [<ffffffff8132acca>] ? pkcs1pad_sg_set_buf+0x2e/0xbb [<ffffffff8132af40>] pkcs1pad_verify+0xc0/0xe1 [<ffffffff8133cb5e>] public_key_verify_signature+0x1b0/0x228 [<ffffffff8133d974>] x509_check_for_self_signed+0xa1/0xc4 [<ffffffff8133cdde>] x509_cert_parse+0x167/0x1a1 [<ffffffff8133d609>] x509_key_preparse+0x21/0x1a1 [<ffffffff8133c3d7>] asymmetric_key_preparse+0x34/0x61 [<ffffffff812fc9f3>] key_create_or_update+0x145/0x399 [<ffffffff812fe227>] SyS_add_key+0x154/0x19e [<ffffffff81001c2b>] do_syscall_64+0x80/0x191 [<ffffffff816825e4>] entry_SYSCALL64_slow_path+0x25/0x25 Code: 56 41 55 41 54 53 48 81 ec a8 00 00 00 44 8b 71 04 8b 42 04 4c 8b 67 18 45 85 f6 89 45 80 0f 84 b4 06 00 00 85 c0 75 2f 41 ff ce <49> c7 04 24 01 00 00 00 b0 01 75 0b 48 8b 41 18 48 83 38 01 0f RIP [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6 RSP <ffff880401297ad8> CR2: 0000000000000000 ---[ end trace d82015255d4a5d8d ]--- Basically, this is a backport of a libgcrypt patch: http://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=patch;h=6e1adb05d290aeeb1c230c763970695f4a538526 Fixes: cdec9cb516 ("crypto: GnuPG based MPI lib - source files (part 1)") Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com> cc: linux-ima-devel@lists.sourceforge.net Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-12-02 09:09:01 +01:00
..
842
fonts
lz4	lib: lz4: fixed zram with lz4 on big endian machines	2016-05-04 14:48:41 -07:00
lzo
mpi	mpi: Fix NULL ptr dereference in mpi_powm() [ver #3]	2016-12-02 09:09:01 +01:00
raid6
reed_solomon
xz
zlib_deflate
zlib_inflate
.gitignore
argv_split.c
asn1_decoder.c	KEYS: Fix ASN.1 indefinite length object parsing	2016-09-15 08:27:50 +02:00
assoc_array.c	assoc_array: don't call compare_object() on a node	2016-05-04 14:48:40 -07:00
atomic64_test.c
atomic64.c
audit.c
bcd.c
bch.c
bitmap.c
bitrev.c
bsearch.c
btree.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
bug.c
build_OID_registry
bust_spinlocks.c
check_signature.c
checksum.c
clz_ctz.c
clz_tab.c
cmdline.c
compat_audit.c
cordic.c
cpu_rmap.c
cpu-notifier-error-inject.c
cpumask.c
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
crc7.c
crc8.c
crc16.c
crc32.c
crc32defs.h
ctype.c
debug_info.c
debug_locks.c
debugobjects.c
dec_and_lock.c
decompress_bunzip2.c
decompress_inflate.c
decompress_unlz4.c
decompress_unlzma.c
decompress_unlzo.c
decompress_unxz.c
decompress.c
devres.c
digsig.c
div64.c	remove abs64()	2015-11-09 15:11:24 -08:00
dma-debug.c	dma-debug: avoid spinlock recursion when disabling dma-debug	2016-06-07 18:14:37 -07:00
dump_stack.c	dump_stack: avoid potential deadlocks	2016-02-25 12:01:23 -08:00
dynamic_debug.c	lib/dynamic_debug.c: use kstrdup_const	2015-11-06 17:50:42 -08:00
dynamic_queue_limits.c
earlycpio.c
extable.c
fault-inject.c
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_bit.c
flex_array.c
flex_proportions.c
gcd.c
gen_crc32table.c
genalloc.c	lib/genalloc.c: start search from start of chunk	2016-11-18 10:48:36 +01:00
glob.c
halfmd4.c	lib/halfmd4.c: use rol32 inline function in the ROUND macro	2015-11-06 17:50:42 -08:00
hexdump.c	lib/hexdump.c: truncate output in case of overflow	2015-11-06 17:50:42 -08:00
hweight.c
idr.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
inflate.c
int_sqrt.c
interval_tree_test.c
interval_tree.c
iomap_copy.c
iomap.c
iommu-common.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc	2015-11-05 16:34:48 -08:00
iommu-helper.c
ioremap.c
iov_iter.c	fix iov_iter_fault_in_readable()	2016-09-24 10:07:43 +02:00
irq_regs.c
is_single_threaded.c	lib/is_single_threaded.c: change current_is_single_threaded() to use for_each_thread()	2015-11-06 17:50:42 -08:00
jedec_ddr_data.c
kasprintf.c	lib/kasprintf.c: introduce kvasprintf_const	2015-11-06 17:50:42 -08:00
Kconfig	lib: sw842: select crc32	2016-03-03 15:07:24 -08:00
Kconfig.debug	Nothing exciting, minor tweaks and cleanups.	2015-11-09 15:53:39 -08:00
Kconfig.kasan	mm, slub, kasan: enable user tracking by default with KASAN=y	2015-11-05 19:34:48 -08:00
Kconfig.kgdb
Kconfig.kmemcheck
kfifo.c
klist.c	klist: fix starting point removed bug in klist iterators	2016-02-25 12:01:16 -08:00
kobject_uevent.c
kobject.c	lib/kobject.c: use kvasprintf_const for formatting ->name	2015-11-06 17:50:42 -08:00
kstrtox.c	lib: add "on"/"off" support to kstrtobool	2016-10-28 03:01:31 -04:00
kstrtox.h
lcm.c
libcrc32c.c	crypto: crc32c - Fix crc32c soft dependency	2016-02-17 12:31:04 -08:00
list_debug.c
list_sort.c
llist.c	lib/llist.c: fix data race in llist_del_first	2015-11-06 17:50:42 -08:00
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c
lockref.c
lru_cache.c
Makefile	test_printf: test printf family at runtime	2015-11-06 17:50:42 -08:00
md5.c
memory-notifier-error-inject.c
memweight.c
net_utils.c
nlattr.c
nmi_backtrace.c
notifier-error-inject.c
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c
once.c
parser.c
pci_iomap.c
percpu_counter.c
percpu_ida.c	mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM	2015-11-06 17:50:42 -08:00
percpu_test.c
percpu-refcount.c
plist.c
pm-notifier-error-inject.c
proportions.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
radix-tree.c	radix-tree: fix race in gang lookup	2016-02-25 12:01:23 -08:00
random32.c
ratelimit.c
rational.c
rbtree_test.c
rbtree.c
reciprocal_div.c
rhashtable.c	rhashtable: Kill harmless RCU warning in rhashtable_walk_init	2015-12-18 23:44:18 -05:00
scatterlist.c
seq_buf.c
sg_split.c
sha1.c
show_mem.c
smp_processor_id.c
sort.c
stmp_device.c
string_helpers.c	string_helpers: fix precision loss for some inputs	2016-02-25 12:01:21 -08:00
string.c	lib: move strtobool() to kstrtobool()	2016-10-28 03:01:30 -04:00
strncpy_from_user.c
strnlen_user.c
swiotlb.c
syscall.c
test_bpf.c	bpf: add mod default A and X test cases	2015-11-05 00:05:50 -05:00
test_firmware.c
test_kasan.c	lib: test_kasan: add some testcases	2015-11-05 19:34:48 -08:00
test_module.c
test_printf.c	test_printf: test printf family at runtime	2015-11-06 17:50:42 -08:00
test_rhashtable.c
test_static_key_base.c
test_static_keys.c
test_user_copy.c
test-hexdump.c
test-kstrtox.c
test-string_helpers.c	lib/test-string_helpers.c: fix and improve string_get_size() tests	2016-05-11 11:21:26 +02:00
textsearch.c
timerqueue.c
ts_bm.c
ts_fsm.c
ts_kmp.c
ucs2_string.c	lib/ucs2_string: Correct ucs2 -> utf8 conversion	2016-03-03 15:07:09 -08:00
usercopy.c
uuid.c
vsprintf.c	lib/vsprintf.c: update documentation	2015-11-06 17:50:42 -08:00