Generally, access to the kernel debugger is considered to be unsafe from
a security perspective since it presents an unrestricted interface to
inspect or modify the system state, including sensitive data such as
signing keys.
However, having some access to debugger functionality on production
systems may be useful in determining the cause of a panic or hang.
Therefore, it is desirable to have an optional policy which allows
limited use of ddb(4) while disabling the functionality which could
reveal system secrets.
This loadable MAC module allows for the use of some ddb(4) commands
while preventing the execution of others. The commands have been broadly
grouped into three categories:
- Those which are 'safe' and will not emit sensitive data (e.g. trace).
Generally, these commands are deterministic and don't accept
arguments.
- Those which are definitively unsafe (e.g. examine <addr>, search
<addr> <value>)
- Commands which may be safe to execute depending on the arguments
provided (e.g. show thread <addr>).
Safe commands have been flagged as such with the DB_CMD_MEMSAFE flag.
Commands requiring extra validation can provide a function to do so.
For example, 'show thread <addr>' can be used as long as addr can be
checked against the system's list of process structures.
The policy also prevents debugger backends other than ddb(4) from
executing, for example gdb(4).
Reviewed by: markj, pauamma_gundo.com (manpages)
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D35371
The change is for the example in textdump.4 and the default ddb.conf.
First of all, doadump now requires an argument and it won't do a
textdump if the argument is not 'true'.
And 'textdump dump' is more idiomatic anyway.
For what it's worth, ddb 'dump' command seems to always request a vmcore
dump even if a textdump was requested earlier, e.g., by 'textdump set'.
Finally, ddb 'call' command is not documented.
MFC after: 2 weeks
This helps pkgbase as this config file will now be tagged as a config file.
Approved by: allanjude (mentor)
Differential Revision: https://reviews.freebsd.org/D16675
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
No functional change intended.
Unfortunately filemon/meta mode tracks all indirect dependencies here
since ld(1) is reading libelf when linking in libkvm. Churn would be
reduced if this was able to be limited to direct dependencies.
Sponsored by: EMC / Isilon Storage Division
Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.
Still need to add real targets under targets/ to build packages.
Differential Revision: D2796
Reviewed by: brooks imp
portion of the capture buffer (db_capture_bufoff vs db_capture_bufsize).
This could result in outputting garbage (e.g. lots of 'p' characters if
DIAGNOSTIC is enabled) after the end of the capture buffer. While here,
fix a spelling nit.
Reported by: Mikolaj Golub to my trociny of gmail
MFC after: 3 days
alowing the DDB output capture buffer to be easily extracted from
user space. Both of these commands include -M/-N arguments, allowing
them to be used with kernel crash dumps (or /dev/mem).
This makes it easier to use DDB scripting and output capture with
minidumps or full dumps rather than with text dumps, allowing DDB
output (scripted or otherwise) to be easily extracted from a crash
dump.
MFC after: 1 week
Discussed with: brooks, jhb
managed from userspace. It is largely a wrapper for sysctl()
calls, but because the sysctls for adding and removing scripts
are awkward to use directly, this provides an easier-to-use
interface.
MFC after: 3 months
