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Sriharsha Allenki 563cdec835 usb: xhci: Fix NULL pointer dereference when enqueuing trbs from urb sg list
commit 3c6f8cb92c upstream.

On platforms with IOMMU enabled, multiple SGs can be coalesced into one
by the IOMMU driver. In that case the SG list processing as part of the
completion of a urb on a bulk endpoint can result into a NULL pointer
dereference with the below stack dump.

<6> Unable to handle kernel NULL pointer dereference at virtual address 0000000c
<6> pgd = c0004000
<6> [0000000c] *pgd=00000000
<6> Internal error: Oops: 5 [#1] PREEMPT SMP ARM
<2> PC is at xhci_queue_bulk_tx+0x454/0x80c
<2> LR is at xhci_queue_bulk_tx+0x44c/0x80c
<2> pc : [<c08907c4>]    lr : [<c08907bc>]    psr: 000000d3
<2> sp : ca337c80  ip : 00000000  fp : ffffffff
<2> r10: 00000000  r9 : 50037000  r8 : 00004000
<2> r7 : 00000000  r6 : 00004000  r5 : 00000000  r4 : 00000000
<2> r3 : 00000000  r2 : 00000082  r1 : c2c1a200  r0 : 00000000
<2> Flags: nzcv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment none
<2> Control: 10c0383d  Table: b412c06a  DAC: 00000051
<6> Process usb-storage (pid: 5961, stack limit = 0xca336210)
<snip>
<2> [<c08907c4>] (xhci_queue_bulk_tx)
<2> [<c0881b3c>] (xhci_urb_enqueue)
<2> [<c0831068>] (usb_hcd_submit_urb)
<2> [<c08350b4>] (usb_sg_wait)
<2> [<c089f384>] (usb_stor_bulk_transfer_sglist)
<2> [<c089f2c0>] (usb_stor_bulk_srb)
<2> [<c089fe38>] (usb_stor_Bulk_transport)
<2> [<c089f468>] (usb_stor_invoke_transport)
<2> [<c08a11b4>] (usb_stor_control_thread)
<2> [<c014a534>] (kthread)

The above NULL pointer dereference is the result of block_len and the
sent_len set to zero after the first SG of the list when IOMMU driver
is enabled. Because of this the loop of processing the SGs has run
more than num_sgs which resulted in a sg_next on the last SG of the
list which has SG_END set.

Fix this by check for the sg before any attributes of the sg are
accessed.

[modified reason for null pointer dereference in commit message subject -Mathias]
Fixes: f9c589e142 ("xhci: TD-fragment, align the unsplittable case with a bounce buffer")
Cc: stable@vger.kernel.org
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200514110432.25564-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-20 08:18:48 +02:00
arch arm64: fix the flush_icache_range arguments in machine_kexec 2020-05-20 08:18:43 +02:00
block block, bfq: fix use-after-free in bfq_idle_slice_timer_body 2020-04-17 10:48:42 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto gcc-10: avoid shadowing standard library 'free()' in crypto 2020-05-20 08:18:46 +02:00
Documentation arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419 2020-04-29 16:31:08 +02:00
drivers usb: xhci: Fix NULL pointer dereference when enqueuing trbs from urb sg list 2020-05-20 08:18:48 +02:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs NFSv4: Fix fscache cookie aux_data to ensure change_attr is included 2020-05-20 08:18:43 +02:00
include ALSA: rawmidi: Fix racy buffer resize under concurrent accesses 2020-05-20 08:18:47 +02:00
init Stop the ad-hoc games with -Wno-maybe-initialized 2020-05-20 08:18:45 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:18:40 +02:00
kernel Stop the ad-hoc games with -Wno-maybe-initialized 2020-05-20 08:18:45 +02:00
lib lib: devres: add a helper function for ioremap_uc 2020-05-10 10:30:11 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm shmem: fix possible deadlocks on shmlock_user_lock 2020-05-20 08:18:32 +02:00
net netfilter: nft_set_rbtree: Introduce and use nft_rbtree_interval_start() 2020-05-20 08:18:44 +02:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-29 16:31:27 +02:00
scripts scripts/decodecode: fix trapping instruction formatting 2020-05-14 07:57:23 +02:00
security selinux: properly handle multiple messages in selinux_netlink_send() 2020-05-06 08:13:32 +02:00
sound ALSA: usb-audio: Add control message quirk delay for Kingston HyperX headset 2020-05-20 08:18:47 +02:00
tools objtool: Fix stack offset tracking for indirect CFAs 2020-05-14 07:57:23 +02:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt KVM: arm64: Fix 32bit PC wrap-around 2020-05-14 07:57:20 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 16:38:49 +01:00
Makefile gcc-10: disable 'restrict' warning for now 2020-05-20 08:18:46 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.