Commit Graph
10 Commits
Author SHA1 Message Date
Wei Liu d44cbbe0f3 kdd: fix build again
Restore Tim's patch. The one that was committed was recreated by me
because git didn't accept my saved copy. I made some mistakes while
recreating that patch and here we are.

Fixes: 3471cafbdd ("kdd: stop using [0] arrays to access packet contents")
Reported-by: Michael Young <m.a.young@durham.ac.uk>
Signed-off-by: Wei Liu <wl@xen.org>
Reviewed-by: Tim Deegan <tim@xen.org>
Release-acked-by: Paul Durrant <paul@xen.org>
2020-07-06 08:38:03 +00:00
Tim Deegan 3471cafbdd kdd: stop using [0] arrays to access packet contents
GCC 10 is unhappy about this, and we already use 64k buffers
in the only places where packets are allocated, so move the
64k size into the packet definition.

Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Tim Deegan <tim@xen.org>
Acked-by: Wei Liu <wl@xen.org>
Release-acked-by: Paul Durrant <paul@xen.org>
2020-06-26 10:41:33 +00:00
Julian Tuminaro 0022387cef Fix the KDD_LOG statements to use appropriate format specifier for printing uint64_t
Previous commit in kdd.c had a small issue which lead to warning/error while compiling
on 32-bit systems due to mismatch of type size while doing type cast from uint64_t to
void *

Signed-off-by: Jenish Rakholiya <rjenish@cmu.edu>
Signed-off-by: Julian Tuminaro <jtuminar@andrew.cmu.edu>
Acked-by: Tim Deegan <tim@xen.org>
2019-12-01 22:06:15 +00:00
julian.tuminaro@gmail.com 53e9ecffde kdd.c: Add support for initial handshake in KD protocol for Win 7, 8 and 10 (64 bit)
Current implementation of find_os is based on the hard-coded values for
different Windows version. It uses the value for get the address to
start looking for DOS header in the given specified range. However, this
is not scalable to all version of Windows as it will require us to keep
adding new entries and also due to KASLR, chances of not hitting the PE
header is significant. We implement a way for 64-bit systems to use IDT
entry to get a valid exception/interrupt handler and then move back into
the memory to find the valid DOS header. Since IDT entries are protected
by PatchGuard, we think our assumption that IDT entries will not be
corrupted is valid for our purpose. Once we have the image base, we
search for the DBGKD_GET_VERSION64 structure type in .data section to
get information required for handshake.

Currently, this is a work in progress feature and current patch only
supports the handshake and memory read/write on 64-bit systems.

NOTE: This is the Updated version of the previous patch submitted
NOTE: This has currently been only tested when debugging was not enabled
on the guest Windows.

Signed-off-by: Jenish Rakholiya <rjenish@cmu.edu>
Signed-off-by: Julian Tuminaro <jtuminar@andrew.cmu.edu>
Reviewed-by: Tim Deegan <tim@xen.org>
Reviewed-by: Paul Durrant <paul@xen.org>
2019-11-29 20:49:34 +00:00
Wei Liu 48a70499e6 tools/kdd: work around gcc 8.1 bug
Gcc 8.1 has a bug that causes kdd fail to build. Rewrite the code to
work around that bug.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86827

Signed-off-by: Tim Deegan <tim@xen.org>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
2018-08-20 11:49:46 +01:00
Marek Marczykowski-Górecki 2de2b10b22 tools/kdd: alternative way of muting spurious gcc warning
Older gcc does not support #pragma GCC diagnostics, so use alternative
approach - change variable type to uint32_t (this code handle 32-bit
requests only anyway), which apparently also avoid gcc complaining about
this (otherwise correct) code.

Fixes 437e00fea0 "tools/kdd: mute spurious
gcc warning"

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Acked-by: Tim Deegan <tim@xen.org>
2018-05-29 10:51:02 +01:00
Marek Marczykowski-Górecki 437e00fea0 tools/kdd: mute spurious gcc warning
gcc-8 complains:

    kdd.c:698:13: error: 'memcpy' offset [-204, -717] is out of the bounds [0, 216] of object 'ctrl' with type 'kdd_ctrl' {aka 'union <anonymous>'} [-Werror=array-bounds]
                 memcpy(buf, ((uint8_t *)&ctrl.c32) + offset, len);
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    kdd.c: In function 'kdd_select_callback':
    kdd.c:642:14: note: 'ctrl' declared here
         kdd_ctrl ctrl;
                  ^~~~

But this is impossible - 'offset' is unsigned and correctly validated
few lines before.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-Acked-by: Juergen Gross <jgross@suse.com>
2018-04-06 09:06:19 +01:00
Tim Deegan bfd9a2095f tools/kdd: don't use a pointer to an unaligned field.
The 'val' field in the packet is byte-aligned (because it is part of a
packed struct), but the pointer argument to kdd_rdmsr() has the normal
alignment constraints for a uint64_t *.  Use a local variable to make sure
the passed pointer has the correct alignment.

Reported-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Tim Deegan <tim@xen.org>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Tested-by: Roger Pau Monné <roger.pau@citrix.com>
2017-03-15 10:57:00 +00:00
Andrew Cooper bec4135fdc tools/kdd: Fix uninitialised variable warning
Clang warns:

  kdd.c:1031:9: error: variable 'fd' is used uninitialized whenever '||'
  condition is true [-Werror,-Wsometimes-uninitialized]
      if (argc != 4
          ^~~~~~~~~
  kdd.c:1040:20: note: uninitialized use occurs here
      if (select(fd + 1, &fds, NULL, NULL, NULL) > 0)
                 ^~

This situation can't actually happen, as usage() is a terminal path.  Annotate
it appropriately.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
2016-04-27 20:31:48 +01:00
Tim Deegan 5717f51369 "kdd" Windows debugger stub.
kdd runs in dom0, attaches to a domain and speaks the Windows kd serial
protocol over a TCP connection (which should go to kd or windbg, e.g.
by having another VM with its virtual COM1 set up as a TCP listener).

It doesn't do breakpoints &c yet, and windbg can get quite confused
since the kernel debugger's not actually running, but it's good enough
to extract backtraces from wedged VMs.

Signed-off-by: Tim Deegan <Tim.Deegan@citrix.com>
2010-10-26 11:56:31 +01:00