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Eric Biggers 12d41a023e crypto: dh - Fix double free of ctx->p
When setting the secret with the software Diffie-Hellman implementation,
if allocating 'g' failed (e.g. if it was longer than
MAX_EXTERN_MPI_BITS), then 'p' was freed twice: once immediately, and
once later when the crypto_kpp tfm was destroyed.

Fix it by using dh_free_ctx() (renamed to dh_clear_ctx()) in the error
paths, as that correctly sets the pointers to NULL.

KASAN report:

    MPI: mpi too large (32760 bits)
    ==================================================================
    BUG: KASAN: use-after-free in mpi_free+0x131/0x170
    Read of size 4 at addr ffff88006c7cdf90 by task reproduce_doubl/367

    CPU: 1 PID: 367 Comm: reproduce_doubl Not tainted 4.14.0-rc7-00040-g05298abde6fe #7
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Call Trace:
     dump_stack+0xb3/0x10b
     ? mpi_free+0x131/0x170
     print_address_description+0x79/0x2a0
     ? mpi_free+0x131/0x170
     kasan_report+0x236/0x340
     ? akcipher_register_instance+0x90/0x90
     __asan_report_load4_noabort+0x14/0x20
     mpi_free+0x131/0x170
     ? akcipher_register_instance+0x90/0x90
     dh_exit_tfm+0x3d/0x140
     crypto_kpp_exit_tfm+0x52/0x70
     crypto_destroy_tfm+0xb3/0x250
     __keyctl_dh_compute+0x640/0xe90
     ? kasan_slab_free+0x12f/0x180
     ? dh_data_from_key+0x240/0x240
     ? key_create_or_update+0x1ee/0xb20
     ? key_instantiate_and_link+0x440/0x440
     ? lock_contended+0xee0/0xee0
     ? kfree+0xcf/0x210
     ? SyS_add_key+0x268/0x340
     keyctl_dh_compute+0xb3/0xf1
     ? __keyctl_dh_compute+0xe90/0xe90
     ? SyS_add_key+0x26d/0x340
     ? entry_SYSCALL_64_fastpath+0x5/0xbe
     ? trace_hardirqs_on_caller+0x3f4/0x560
     SyS_keyctl+0x72/0x2c0
     entry_SYSCALL_64_fastpath+0x1f/0xbe
    RIP: 0033:0x43ccf9
    RSP: 002b:00007ffeeec96158 EFLAGS: 00000246 ORIG_RAX: 00000000000000fa
    RAX: ffffffffffffffda RBX: 000000000248b9b9 RCX: 000000000043ccf9
    RDX: 00007ffeeec96170 RSI: 00007ffeeec96160 RDI: 0000000000000017
    RBP: 0000000000000046 R08: 0000000000000000 R09: 0248b9b9143dc936
    R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000000
    R13: 0000000000409670 R14: 0000000000409700 R15: 0000000000000000

    Allocated by task 367:
     save_stack_trace+0x16/0x20
     kasan_kmalloc+0xeb/0x180
     kmem_cache_alloc_trace+0x114/0x300
     mpi_alloc+0x4b/0x230
     mpi_read_raw_data+0xbe/0x360
     dh_set_secret+0x1dc/0x460
     __keyctl_dh_compute+0x623/0xe90
     keyctl_dh_compute+0xb3/0xf1
     SyS_keyctl+0x72/0x2c0
     entry_SYSCALL_64_fastpath+0x1f/0xbe

    Freed by task 367:
     save_stack_trace+0x16/0x20
     kasan_slab_free+0xab/0x180
     kfree+0xb5/0x210
     mpi_free+0xcb/0x170
     dh_set_secret+0x2d7/0x460
     __keyctl_dh_compute+0x623/0xe90
     keyctl_dh_compute+0xb3/0xf1
     SyS_keyctl+0x72/0x2c0
     entry_SYSCALL_64_fastpath+0x1f/0xbe

Fixes: 802c7f1c84 ("crypto: dh - Add DH software implementation")
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-10 19:20:16 +08:00
arch Linux 4.14-rc3 2017-11-03 22:10:18 +08:00
block block: fix a crash caused by wrong API 2017-09-25 08:56:05 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: dh - Fix double free of ctx->p 2017-11-10 19:20:16 +08:00
Documentation dt-bindings: rng: Document BCM7278 RNG200 compatible 2017-11-10 19:20:08 +08:00
drivers hwrng: iproc-rng200 - Add support for BCM7278 2017-11-10 19:20:12 +08:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs cifs: move to generic async completion 2017-11-03 22:11:21 +08:00
include crypto: drbg - move to generic async completion 2017-11-03 22:11:19 +08:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel Linux 4.14-rc3 2017-11-03 22:10:18 +08:00
lib Merge branch 'parisc-4.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2017-09-23 06:14:06 -10:00
mm fs: Fix page cache inconsistency when mixing buffered and AIO DIO 2017-09-25 08:56:05 -06:00
net net: use -ENOSPC for transient busy indication 2017-11-03 22:11:17 +08:00
samples media updates for v4.14-rc1 2017-09-07 12:53:14 -07:00
scripts objtool: Skip unreachable warnings for GCC 4.4 and older 2017-09-28 07:23:02 +02:00
security ima: move to generic async completion 2017-11-03 22:11:21 +08:00
sound vfs: constify path argument to kernel_read_file_from_path 2017-09-14 20:18:45 -07:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:06:31 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig kbuild: migrate all arch to the kconfig mainmenu upgrade 2010-09-19 22:54:11 -04:00
MAINTAINERS MAINTAINERS: update maintainer for qat 2017-11-06 14:45:01 +08:00
Makefile Linux 4.14-rc3 2017-10-01 14:54:54 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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