From 4c3b3b1decb96e0d6c54b33bfd9f4c15da3b90b1 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 16 Nov 2017 20:04:01 +0000 Subject: [PATCH] dvb_frontend: don't use-after-free the frontend struct (CVE-2017-16648) Plus another fix it seems to depend on. --- debian/changelog | 2 + ...-t-use-after-free-the-frontend-struc.patch | 183 ++++++++++++++++++ ...lways-call-invoke_release-in-fe_free.patch | 47 +++++ debian/patches/series | 2 + 4 files changed, 234 insertions(+) create mode 100644 debian/patches/bugfix/all/dvb_frontend-don-t-use-after-free-the-frontend-struc.patch create mode 100644 debian/patches/bugfix/all/media-dvb-core-always-call-invoke_release-in-fe_free.patch diff --git a/debian/changelog b/debian/changelog index db9414163..03493e67e 100644 --- a/debian/changelog +++ b/debian/changelog @@ -6,6 +6,8 @@ linux (4.14-1~exp1) UNRELEASED; urgency=medium * debian/control: Set Rules-Requires-Root to no * [armhf] drm: Enable DRM_SUN4I, DRM_SUN4I_HDMI, DRM_SUN4I_BACKEND, DRM_SUN8I_MIXER as modules; and DRM_SUN4I_HDMI_CEC (Closes: #881570) + * media: dvb-core: always call invoke_release() in fe_free() + * dvb_frontend: don't use-after-free the frontend struct (CVE-2017-16648) [ Bastian Blank ] * Enable CRYPTO_SHA3. diff --git a/debian/patches/bugfix/all/dvb_frontend-don-t-use-after-free-the-frontend-struc.patch b/debian/patches/bugfix/all/dvb_frontend-don-t-use-after-free-the-frontend-struc.patch new file mode 100644 index 000000000..1db3a0348 --- /dev/null +++ b/debian/patches/bugfix/all/dvb_frontend-don-t-use-after-free-the-frontend-struc.patch @@ -0,0 +1,183 @@ +From: Mauro Carvalho Chehab +Date: Tue, 7 Nov 2017 08:39:39 -0500 +Subject: dvb_frontend: don't use-after-free the frontend struct +Origin: https://git.kernel.org/linus/b1cb7372fa822af6c06c8045963571d13ad6348b +Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-16648 + +dvb_frontend_invoke_release() may free the frontend struct. +So, the free logic can't update it anymore after calling it. + +That's OK, as __dvb_frontend_free() is called only when the +krefs are zeroed, so nobody is using it anymore. + +That should fix the following KASAN error: + +The KASAN report looks like this (running on kernel 3e0cc09a3a2c40ec1ffb6b4e12da86e98feccb11 (4.14-rc5+)): +================================================================== +BUG: KASAN: use-after-free in __dvb_frontend_free+0x113/0x120 +Write of size 8 at addr ffff880067d45a00 by task kworker/0:1/24 + +CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc5-43687-g06ab8a23e0e6 #545 +Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 +Workqueue: usb_hub_wq hub_event +Call Trace: + __dump_stack lib/dump_stack.c:16 + dump_stack+0x292/0x395 lib/dump_stack.c:52 + print_address_description+0x78/0x280 mm/kasan/report.c:252 + kasan_report_error mm/kasan/report.c:351 + kasan_report+0x23d/0x350 mm/kasan/report.c:409 + __asan_report_store8_noabort+0x1c/0x20 mm/kasan/report.c:435 + __dvb_frontend_free+0x113/0x120 drivers/media/dvb-core/dvb_frontend.c:156 + dvb_frontend_put+0x59/0x70 drivers/media/dvb-core/dvb_frontend.c:176 + dvb_frontend_detach+0x120/0x150 drivers/media/dvb-core/dvb_frontend.c:2803 + dvb_usb_adapter_frontend_exit+0xd6/0x160 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:340 + dvb_usb_adapter_exit drivers/media/usb/dvb-usb/dvb-usb-init.c:116 + dvb_usb_exit+0x9b/0x200 drivers/media/usb/dvb-usb/dvb-usb-init.c:132 + dvb_usb_device_exit+0xa5/0xf0 drivers/media/usb/dvb-usb/dvb-usb-init.c:295 + usb_unbind_interface+0x21c/0xa90 drivers/usb/core/driver.c:423 + __device_release_driver drivers/base/dd.c:861 + device_release_driver_internal+0x4f1/0x5c0 drivers/base/dd.c:893 + device_release_driver+0x1e/0x30 drivers/base/dd.c:918 + bus_remove_device+0x2f4/0x4b0 drivers/base/bus.c:565 + device_del+0x5c4/0xab0 drivers/base/core.c:1985 + usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170 + usb_disconnect+0x260/0x7a0 drivers/usb/core/hub.c:2124 + hub_port_connect drivers/usb/core/hub.c:4754 + hub_port_connect_change drivers/usb/core/hub.c:5009 + port_event drivers/usb/core/hub.c:5115 + hub_event+0x1318/0x3740 drivers/usb/core/hub.c:5195 + process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119 + worker_thread+0x221/0x1850 kernel/workqueue.c:2253 + kthread+0x363/0x440 kernel/kthread.c:231 + ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 + +Allocated by task 24: + save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59 + save_stack+0x43/0xd0 mm/kasan/kasan.c:447 + set_track mm/kasan/kasan.c:459 + kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 + kmem_cache_alloc_trace+0x11e/0x2d0 mm/slub.c:2772 + kmalloc ./include/linux/slab.h:493 + kzalloc ./include/linux/slab.h:666 + dtt200u_fe_attach+0x4c/0x110 drivers/media/usb/dvb-usb/dtt200u-fe.c:212 + dtt200u_frontend_attach+0x35/0x80 drivers/media/usb/dvb-usb/dtt200u.c:136 + dvb_usb_adapter_frontend_init+0x32b/0x660 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:286 + dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:86 + dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:162 + dvb_usb_device_init+0xf73/0x17f0 drivers/media/usb/dvb-usb/dvb-usb-init.c:277 + dtt200u_usb_probe+0xa1/0xe0 drivers/media/usb/dvb-usb/dtt200u.c:155 + usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 + really_probe drivers/base/dd.c:413 + driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 + __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 + bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 + __device_attach+0x26b/0x3c0 drivers/base/dd.c:710 + device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 + bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 + device_add+0xd0b/0x1660 drivers/base/core.c:1835 + usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932 + generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174 + usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266 + really_probe drivers/base/dd.c:413 + driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 + __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 + bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 + __device_attach+0x26b/0x3c0 drivers/base/dd.c:710 + device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 + bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 + device_add+0xd0b/0x1660 drivers/base/core.c:1835 + usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457 + hub_port_connect drivers/usb/core/hub.c:4903 + hub_port_connect_change drivers/usb/core/hub.c:5009 + port_event drivers/usb/core/hub.c:5115 + hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195 + process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119 + worker_thread+0x221/0x1850 kernel/workqueue.c:2253 + kthread+0x363/0x440 kernel/kthread.c:231 + ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 + +Freed by task 24: + save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59 + save_stack+0x43/0xd0 mm/kasan/kasan.c:447 + set_track mm/kasan/kasan.c:459 + kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:524 + slab_free_hook mm/slub.c:1390 + slab_free_freelist_hook mm/slub.c:1412 + slab_free mm/slub.c:2988 + kfree+0xf6/0x2f0 mm/slub.c:3919 + dtt200u_fe_release+0x3c/0x50 drivers/media/usb/dvb-usb/dtt200u-fe.c:202 + dvb_frontend_invoke_release.part.13+0x1c/0x30 drivers/media/dvb-core/dvb_frontend.c:2790 + dvb_frontend_invoke_release drivers/media/dvb-core/dvb_frontend.c:2789 + __dvb_frontend_free+0xad/0x120 drivers/media/dvb-core/dvb_frontend.c:153 + dvb_frontend_put+0x59/0x70 drivers/media/dvb-core/dvb_frontend.c:176 + dvb_frontend_detach+0x120/0x150 drivers/media/dvb-core/dvb_frontend.c:2803 + dvb_usb_adapter_frontend_exit+0xd6/0x160 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:340 + dvb_usb_adapter_exit drivers/media/usb/dvb-usb/dvb-usb-init.c:116 + dvb_usb_exit+0x9b/0x200 drivers/media/usb/dvb-usb/dvb-usb-init.c:132 + dvb_usb_device_exit+0xa5/0xf0 drivers/media/usb/dvb-usb/dvb-usb-init.c:295 + usb_unbind_interface+0x21c/0xa90 drivers/usb/core/driver.c:423 + __device_release_driver drivers/base/dd.c:861 + device_release_driver_internal+0x4f1/0x5c0 drivers/base/dd.c:893 + device_release_driver+0x1e/0x30 drivers/base/dd.c:918 + bus_remove_device+0x2f4/0x4b0 drivers/base/bus.c:565 + device_del+0x5c4/0xab0 drivers/base/core.c:1985 + usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170 + usb_disconnect+0x260/0x7a0 drivers/usb/core/hub.c:2124 + hub_port_connect drivers/usb/core/hub.c:4754 + hub_port_connect_change drivers/usb/core/hub.c:5009 + port_event drivers/usb/core/hub.c:5115 + hub_event+0x1318/0x3740 drivers/usb/core/hub.c:5195 + process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119 + worker_thread+0x221/0x1850 kernel/workqueue.c:2253 + kthread+0x363/0x440 kernel/kthread.c:231 + ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 + +The buggy address belongs to the object at ffff880067d45500 + which belongs to the cache kmalloc-2048 of size 2048 +The buggy address is located 1280 bytes inside of + 2048-byte region [ffff880067d45500, ffff880067d45d00) +The buggy address belongs to the page: +page:ffffea00019f5000 count:1 mapcount:0 mapping: (null) +index:0x0 compound_mapcount: 0 +flags: 0x100000000008100(slab|head) +raw: 0100000000008100 0000000000000000 0000000000000000 00000001000f000f +raw: dead000000000100 dead000000000200 ffff88006c002d80 0000000000000000 +page dumped because: kasan: bad access detected + +Memory state around the buggy address: + ffff880067d45900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb + ffff880067d45980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb + ffff880067d45a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb + ^ + ffff880067d45a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb + ffff880067d45b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb +================================================================== + +Fixes: ead666000a5f ("media: dvb_frontend: only use kref after initialized") + +Reported-by: Andrey Konovalov +Suggested-by: Matthias Schwarzott +Tested-by: Andrey Konovalov +Signed-off-by: Mauro Carvalho Chehab +--- + drivers/media/dvb-core/dvb_frontend.c | 7 ++----- + 1 file changed, 2 insertions(+), 5 deletions(-) + +diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c +index d485d5f6cc88..3ad83359098b 100644 +--- a/drivers/media/dvb-core/dvb_frontend.c ++++ b/drivers/media/dvb-core/dvb_frontend.c +@@ -150,11 +150,8 @@ static void __dvb_frontend_free(struct dvb_frontend *fe) + + dvb_frontend_invoke_release(fe, fe->ops.release); + +- if (!fepriv) +- return; +- +- kfree(fepriv); +- fe->frontend_priv = NULL; ++ if (fepriv) ++ kfree(fepriv); + } + + static void dvb_frontend_free(struct kref *ref) diff --git a/debian/patches/bugfix/all/media-dvb-core-always-call-invoke_release-in-fe_free.patch b/debian/patches/bugfix/all/media-dvb-core-always-call-invoke_release-in-fe_free.patch new file mode 100644 index 000000000..bcf2cca5a --- /dev/null +++ b/debian/patches/bugfix/all/media-dvb-core-always-call-invoke_release-in-fe_free.patch @@ -0,0 +1,47 @@ +From: Daniel Scheller +Date: Sun, 29 Oct 2017 11:43:22 -0400 +Subject: media: dvb-core: always call invoke_release() in fe_free() +Origin: https://git.kernel.org/linus/62229de19ff2b7f3e0ebf4d48ad99061127d0281 + +Follow-up to: ead666000a5f ("media: dvb_frontend: only use kref after initialized") + +The aforementioned commit fixed refcount OOPSes when demod driver attaching +succeeded but tuner driver didn't. However, the use count of the attached +demod drivers don't go back to zero and thus couldn't be cleanly unloaded. +Improve on this by calling dvb_frontend_invoke_release() in +__dvb_frontend_free() regardless of fepriv being NULL, instead of returning +when fepriv is NULL. This is safe to do since _invoke_release() will check +for passed pointers being valid before calling the .release() function. + +[mchehab@s-opensource.com: changed the logic a little bit to reduce + conflicts with another bug fix patch under review] +Fixes: ead666000a5f ("media: dvb_frontend: only use kref after initialized") +Signed-off-by: Daniel Scheller +Signed-off-by: Mauro Carvalho Chehab +--- + drivers/media/dvb-core/dvb_frontend.c | 9 +++++---- + 1 file changed, 5 insertions(+), 4 deletions(-) + +diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c +index daaf969719e4..d485d5f6cc88 100644 +--- a/drivers/media/dvb-core/dvb_frontend.c ++++ b/drivers/media/dvb-core/dvb_frontend.c +@@ -145,13 +145,14 @@ static void __dvb_frontend_free(struct dvb_frontend *fe) + { + struct dvb_frontend_private *fepriv = fe->frontend_priv; + +- if (!fepriv) +- return; +- +- dvb_free_device(fepriv->dvbdev); ++ if (fepriv) ++ dvb_free_device(fepriv->dvbdev); + + dvb_frontend_invoke_release(fe, fe->ops.release); + ++ if (!fepriv) ++ return; ++ + kfree(fepriv); + fe->frontend_priv = NULL; + } diff --git a/debian/patches/series b/debian/patches/series index 9929ad6b4..92ab41846 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -112,6 +112,8 @@ features/all/lockdown/arm64-add-kernel-config-option-to-lock-down-when.patch # Security fixes debian/i386-686-pae-pci-set-pci-nobios-by-default.patch +bugfix/all/media-dvb-core-always-call-invoke_release-in-fe_free.patch +bugfix/all/dvb_frontend-don-t-use-after-free-the-frontend-struc.patch # Fix exported symbol versions bugfix/all/module-disable-matching-missing-version-crc.patch