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Sriharsha Allenki 3c6f8cb92c usb: xhci: Fix NULL pointer dereference when enqueuing trbs from urb sg list
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>
2020-05-14 13:44:37 +02:00
arch A set of fixes for x86: 2020-05-10 11:59:53 -07:00
block bdi: use bdi_dev_name() to get device name 2020-05-09 16:07:39 -06:00
certs
crypto gcc-10: avoid shadowing standard library 'free()' in crypto 2020-05-09 15:58:04 -07:00
Documentation Bugfixes, mostly for ARM and AMD, and more documentation. 2020-05-07 09:50:59 -07:00
drivers usb: xhci: Fix NULL pointer dereference when enqueuing trbs from urb sg list 2020-05-14 13:44:37 +02:00
fs block-5.7-2020-05-09 2020-05-10 11:16:07 -07:00
include block-5.7-2020-05-09 2020-05-10 11:16:07 -07:00
init gcc-10: mark more functions __init to avoid section mismatch warnings 2020-05-09 17:50:03 -07:00
ipc ipc/mqueue.c: change __do_notify() to bypass check_kill_permission() 2020-05-07 19:27:20 -07:00
kernel Stop the ad-hoc games with -Wno-maybe-initialized 2020-05-09 13:57:10 -07:00
lib ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST 2020-05-07 19:27:21 -07:00
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mm block-5.7-2020-05-09 2020-05-10 11:16:07 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 20:53:22 -07:00
samples tracing: Fix doc mistakes in trace sample 2020-05-07 13:32:57 -04:00
scripts scripts/gdb: repair rb_first() and rb_last() 2020-05-07 19:27:20 -07:00
security selinux/stable-5.7 PR 20200430 2020-04-30 16:35:45 -07:00
sound sound fixes for 5.7-rc4 2020-05-01 11:05:28 -07:00
tools A set of fixes for x86: 2020-05-10 11:59:53 -07:00
usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt KVM: arm64: Fix 32bit PC wrap-around 2020-05-01 09:51:08 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2020-04-18 13:49:33 +02:00
.cocciconfig
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MAINTAINERS Fixes for an endianness handling bug that prevented mounts on 2020-05-08 10:27:00 -07:00
Makefile Linux 5.7-rc5 2020-05-10 15:16:58 -07:00
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