Bug fix to ensure that proper bounds are enforced when importing digest
cache files from previous fwknopd executions. This bug
was discovered through fuzzing with American Fuzzy Lop (AFL) as driven
by the test/afl/fuzzing-wrappers/server-digest-cache.sh wrapper.
Previous to this fix, fwknopd could be made to crash through a malicious
digest cache file (normally in /var/run/fwknop/digest.cache) upon
initial import.
Bug fix to ensure that a User-Agent string can be specified when the
fwknop client uses wget via SSL to resolve the external IP address. This
closes issue #134 on github reported by Barry Allard. The fwknop now
uses the wget '-U' option to specify the User-Agent string with a
default of "Fwknop/<version>". In addition, a new command line argument
"--use-wget-user-agent" to allow the default wget User-Agent string to
apply instead.
External IP resolution via '-R' (or '--resolve-ip-http') is now done via SSL by
default. The IP resolution URL is now 'https://www.cipherdyne.org/cgi-gin/myip',
and a warning is generated in '-R' mode whenever a non-HTTPS URL is specified
(it is safer just to use the default). The fwknop client leverages 'wget' for
this operation since that is cleaner than having fwknop link against an SSL
library.
With this commit PF rules are added correctly regardless of whether ALTQ support
is available or not. Thanks to Barry Allard for discovering and reporting this
issue. Closes issue #121 on github.
Bug fix discovered with the libfiu fault injection tag
"fko_get_username_init" combined with valgrind analysis. This bug
is only triggered after a valid authenticated and decrypted SPA
packet is sniffed by fwknopd:
==11181== Conditional jump or move depends on uninitialised value(s)
==11181== at 0x113B6D: incoming_spa (incoming_spa.c:707)
==11181== by 0x11559F: process_packet (process_packet.c:211)
==11181== by 0x5270857: ??? (in /usr/lib/x86_64-linux-gnu/libpcap.so.1.4.0)
==11181== by 0x114BCC: pcap_capture (pcap_capture.c:270)
==11181== by 0x10F32C: main (fwknopd.c:195)
==11181== Uninitialised value was created by a stack allocation
==11181== at 0x113476: incoming_spa (incoming_spa.c:294)
When validating access.conf stanzas make sure that one of
GPG_REMOTE_ID or GPG_FINGERPRINT_ID is specified whenever GnuPG
signatures are to be verified for incoming SPA packets. Signature
verification is the default, and can only be disabled with
GPG_DISABLE_SIG but this is NOT recommended.
Add a new GPG_FINGERPRINT_ID variable to the access.conf file
so that full GnuPG fingerprints can be required for incoming SPA packets
in addition to the appreviated GnuPG signatures listed in GPG_REMOTE_ID.
From the test suite, an example fingerprint is
GPG_FINGERPRINT_ID 00CC95F05BC146B6AC4038C9E36F443C6A3FAD56
Bug fix to correct a memory leak in GnuPG SPA packet handling within
the gpg_decrypt() function. Here is the specific valgrind leak record
that enabled the bug to be found (note that the new valgrind
suppressions usage was critical for finding this bug among all other
libgpgme memory leaks):
==23983== 1,044 bytes in 1 blocks are definitely lost in loss record 7 of 8
==23983== at 0x4C2C494: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==23983== by 0x4E41D3A: gpg_decrypt (fko_encryption.c:422)
==23983== by 0x4E42520: fko_decrypt_spa_data (fko_encryption.c:626)
==23983== by 0x1155B0: incoming_spa (incoming_spa.c:519)
==23983== by 0x1180A7: process_packet (process_packet.c:211)
==23983== by 0x506D857: ??? (in /usr/lib/x86_64-linux-gnu/libpcap.so.1.4.0)
==23983== by 0x117865: pcap_capture (pcap_capture.c:270)
==23983== by 0x10F937: main (fwknopd.c:353)
- [server] When GnuPG is used, the default now is to require that
incoming SPA packets are signed by a key listed in GPG_REMOTE_ID for each
access.conf stanza. In other words, the usage of GPG_REQUIRE_SIG
is no longer necessary in order to authenticate SPA packets via the
GnuPG signature. Verification of GnuPG signatures can be disabled with a
new access.conf variable GPG_DISABLE_SIG, but this is NOT a
recommended configuration.
- [client+server] Add --gpg-exe command line argument and GPG_EXE
config variable to ~/.fwknoprc and the access.conf file so that the path
to GnuPG can be changed from the default /usr/bin/gpg path.
Michael Rash