swverify(8)
Contents
swverify -- Verify Software
Posix:
swverify [-d|-r] [-F] [-f file] [-t targetfile] \
[-x option=value] [-X options_file] [-W option] \
[software_selections] [@targets]
swverify # Verify standard input
swverify selection [@ target] # Verify Installed Software
swverify -d [@ target]
swverify -d @- # dash means standard input
swverify [--scm|--order-files] -d @. # . means current directory
swverify [--scm|--order-files] -d @:package_directory
Implementation Extension:
swverify [-Wd] -Wemit-digest-file [portable_archive_file]
swverify [-Wd] -Wemit-signed-file [portable_archive_file]
swverify [-Wd] [-Wsha1] -Wemit-digest-file [portable_archive_file]
swverify [-Wd] -Wget-sig-if=sigfilename [portable_archive_file]
The swverify utility checks the accuracy of software in distributions
and installed_software. If no options are given, a serial distribution
on stdin is verified.
Currently, swverify does not read the defaults files. "/" is the
default target for installed software. Stdin is the default target for
distributions. The built-in value of "installed_software_catalog" is
"var/lib/swbis/catalog".
-d
Specify to operate on a distribution rather than installed
software.
-r
Specify that target is an alternate root target. (Not currently
used)
software_selections
See other man pages.
targets
See other man pages. Currently, only one (1) target can be
specified.
-x option=value
Specify the extended option overriding the defaults file value.
This option not yet implemented.
-X FILE
Specify the extended options filename, FILE, overriding the
default filename. This option not yet implemented.
Other POSIX options not implemented.
Not yet implemented.
-W option[,option,...]
Specify the implementation extension option.
Syntax: -W option[=option_argument[,option...]
Options may be separated by a comma.
--checksig | -W checksig
This is the default action and is the same as the POSIX syntax
"-d @target". If target file is not a directory then verify
archive md5 and sha1 and gpg signature directly from the file.
If target file is a directory, attempt to verify the signature
using GNU tar and gpg and if successful execute the distributor
extension script checksig. If checksig does not exist then exit
with failure.
FILE may be "." (current directory) or "-" (standard input). A
serial archive file may be compressed with gzip, bzip2, or Unix
compress.
--order-catalog
Use the order of files in catalog/dfiles/files to recreate the
signed data when verifying the directory (unpacked tarball) form
of the package.
--cvs
Read and process information in the ./catalog (before it is
authenticated) to correct the file sytem meta-data in an attempt
to verify the GPG signature. It only affects verification on
the directory (unpacked tarball), not tarball verification. It
is required when verifying an exported or working SCM (Source
Code Management, such as CVS) directory if the SCM does not
preserve and restore file system meta-data. This option also
emliminates the dependency on the order of files in file system
directories.
--scm
Currently, same as the --cvs option.
--no-checkdigest
When verifying the directory form, do not run the checkdigest
script even if the GPG signed data contains the checkdigest
script.
--signed-file [FILE]
Write the GPG signed portion of the package to stdout without
verifying it. Read archive file FILE or standard input and
write the signed file (i.e. gpg's signed stuff) to stdout. This
is the catalog section of the Posix package. This option is
supported for the tarball file and unpacked tarball directory.
Use of the --scm option may be required for the unpacked tarball
directory form.
--digest-file [FILE]
Write the payload portion of the package to stdout without
verifying its digest matches the digest in the signed data.
This is the storage section of the Posix package. This option
is not supported for the unpacked tarball form.
-W emit-signed-file | -W C
Same as --signed-data. Also the same as -WC
-W emit-digest-file [FILE]
Same as --digest-data. Also the same as -WS
-W show-auth-files | -W d
Writes the relevent security file to stderr. Applies to emit-
digest-file and emit-signed-file modes.
-W sig-number=N
Operates on the Nth signature, 0 is last, 1 is the first.
-W get-sig-if=outputfile
Verifies the archive digests by comparing to the digests in the
catalog and if they match write the sigfile to outputfile and
the signed data to stdout.
Not yet implemented.
checkdigest <path>/catalog/<dfiles>/checkdigest
This script was named 'checksig'. As of 2006-03-28, the name of this
script should be 'checkdigest'. The name 'checksig' should be
considered deprecated for new packages.
A software distributor may choose to provide a checkdigest script. The
checkdigest script is part of the distribution object. It is used to
verify the directory form of a distribution (as distinguished from
installed_software). The verified attributes are the same as those
verified from the archive file form with the addition of the
distribution file list. In addition the script may chose to verify the
adjunct_md5sum and file.md5 digests and symbolic links. Due to the
constraints of reproducing the archive message digests from the
directory, which include tar utility dependence and file owner/group
specification, this script may not be useful to all distributors.
Execution Environment
The script may require the SW_CONTROL_TAG environment variable be set
to "checkdigest" or "checkfile" and if not exit with failure. swverify
will set this variable to "checkfile" if the --scm or --cvs option is
used, and otherwise to "checkdigest". The script may take different
action based on the value. Currently, the checkdigest script used by
the swbis source package will omit the archive digests checks if set to
SW_CONTROL_TAG="checkfile" since reproducing the archive digest is not
possible when the package is exported from CVS due to file system meta-
data non-preservation. In this case the file list is checked and the
md5 and sha1 digests are verified for each regular file.
The design separates the payload and catalog, therefore, verification
requires verifying the storage section md5 and sha1 message digests and
then verifying the signature of the catalog. Naturally, it is required
that the signed data include the storage section message digests and
that they match the storage sections. The storage section digests are
stored as separate attribute files in the dfiles catalog directory.
The checksig (i.e. swverify -d @-) mode verifies a tarballs embedded
signature. This mode checks all the security files in the package and
is the preferred way to authenticate a package. The emit-signed-file,
emit-digest-file modes are useful for testing, sanity checks and custom
applications. The get-sig-if is the function used when verifying a
tarball.
Verifying a POSIX Distribution Archive Manually
The design of the authentication attributes supports manual
verification of the archive file (e.g. tarball) form of the
distribution, that is verification take place on the uncompressed
archive using 'gpg', GNU 'tar' and the swbis utility 'swverify' (or the
library utility 'arf2arf').
The authentication requires the following steps:
1) Obtain the signature from the package.
2) Recreate the signed data and present this byte stream and
the signature to GNU privacy guard (gpg) for authentication.
3) Obtain the message digest (md5, sha1,) contained in the
control file in the authenticated archive byte stream.
4) Recreate the digest byte stream and present to the appropriate
hash generation program to generate the message digest.
5) Compare the digest message generated in step 4 to the
authenicated digest obtained in step 3.
1) Obtain the signature from the package.
#!/bin/sh
tar zxf - -O \*/catalog/dfiles/signature < swbis-0.460.tar.gz
2) Recreate the signed data
#!/bin/sh
swverify -WC < swbis-0.460.tar.gz | gpg --verify /dev/tty -
# Cut and paste the signature file obtained in step 1
3) Obtain the message digest
#!/bin/sh
swverify -WC < swbis-0.460.tar.gz | \
tar xf - -O \*/catalog/dfiles/md5sum
4) Create the digested byte stream
#!/bin/sh
swverify -WS < swbis-0.460.tar.gz | md5sum
Verifying a POSIX Distribution Directory Manually
Verifying the unpacked tarball package form.
The design of the authentication attributes supports manual
verification of the directory (unpacked) form of the distribution, that
is verification takes place on the leading package directory and its
contents. It should be noted that it is left to the user to verify that
the archive installed no files outside of this directory as this would
likely indicate a trojan'ed package.
If authenticating on a GNU/Linux system using GNU tar it is possible to
validate the archive message digests and signature if the following are
true:
1) The package file is a tar archive.
2) The installed version of GNU tar produces archives with
bit-for-bit sameness relative to the swpackage(8) utility
that generated the signature and message digests. For packages
made with swbis versions >= 0.474 and with format option "ustar"
you will need GNU tar 1.14 or 1.15.*
3) The package has a single leading package directory, like a source
package.
4) The package catalog contains the 'checkdigest' script.
5) The package catalog contains the distribution file list.
6) The ownership names are present and have the same uid's and gid's.
7) The package was unpacked with a version of tar that
preserves all file times. Use for example "tar xpf".
In this example, the package has a single path name prefix called,
namedir and the file owner/group are root. These restrictions are
suited to source packages.
Verify the signature:
#!/bin/sh
tar cf - -b1 --owner=root --group=root \
--exclude=namedir/catalog/dfiles/signature \
namedir/catalog | gpg --verify namedir/catalog/dfiles/signature -
If this fails try using GNU tar option --posix. If this fails then,
try experimenting with the owner, group, and numeric-id options. If
you are unable to verify a tar byte stream using gpg(1) that contains
the storage section message digests, then the package cannot be
authenticated.
Assuming you successfully verified the catalog as shown above, now
generate the message digest and compare it to the md5sum file attribute
from the same byte stream that gpg(1) claims is authenticate.
#!/bin/sh
grep -v namedir/catalog namedir/catalog/dfiles/files | \
tar cf - -b1 --owner=root --group=root \
--files-from=- --no-recursion | md5sum
tar cf - -b1 --owner=root --group=root \
--exclude=namedir/catalog/dfiles/signature \
namedir/catalog | tar xf - -O namedir/catalog/dfiles/md5sum
Likewise for the sha1 digest.
If the package has symbolic links, Verify the adjunct_md5sum:
#!/bin/sh
grep -v namedir/catalog namedir/catalog/dfiles/files | \
( while read file; do if [ ! -h $file ]; then echo $file; fi done; )|\
tar cf - -b1 --owner=root --group=root \
--files-from=- --no-recursion | md5sum
cat namedir/catalog/dfiles/adjunct_md5sum
The symbolic link files must be verified manually by comparing to the
INFO file information.
Verifying a POSIX distribution in tar format
Below is output from successful authentication. The authentication
requires checking the archive md5 message digest (and sha1 if present).
All present message digests must succeed and if this is true then the
signed file is written and gpg proceeds to check the signature. If the
sig_header file is present then the requirement that its data be
identical to the ustar header of every signature file is enforced. If
any one of these checks fails, authentication fails.
#!/bin/sh
swverify --checksig mypackage-00.1.tar.gz
# - or -
swverify -d @- < mypackage-00.1.tar.gz
gpg: /home/userx/.gnupg/options:82: deprecated option "honor-http-proxy"
gpg: please use "keyserver-options honor-http-proxy" instead
gpg: WARNING: using insecure memory!
gpg: please see http://www.gnupg.org/faq.html for more information
swbis: Archive digest: md5 OK (Good)
swbis: Archive digest: sha1 OK (Good)
gpg: Signature made Sun Mar 16 20:28:23 2003 EST using DSA key ID 82B0DBE4
gpg: Good signature from "Test User (pass=Iforgot) localhost>"
Primary key fingerprint: 77BB A98E B3A2 ED4C 217E 8A25 2BF4 28AB 82D0 DDE4
Verifying the Directory Form of a Distribution
Authenticating using 'swverify' is subject to the same constraints as
verifying manually using GNU tools because swverify implements this
using GNU tools.
'swverify' when verifying the directory form of a distribution attempts
to authenticate the exported catalog signature. If it is successful it
executes the 'checkdigest' script found in the 'catalog/dfiles'
directory of the exported catalog. If the 'checkdigest' script does
not exist, authentication fails. 'swverify' will only attempt to run
the 'checkdigest' script if it is found in the dfiles directory of an
authenticated catalog.
'swverify' currently has no provision to verify the archive section
(i.e. the file storage structure) of a directory (unpacked) form of a
POSIX distribution. It is the role of the checkdigest script to do
this.
For example, if filemypackage-00.1 is a directory unpacked with a tar
reading utility that preserved file times then try,
#!/bin/sh
swverify --checksig mypackage-00.1
or change directory into mypackage-00.1 and use the POSIX syntax:
swverify -d @.
swverify -d @`pwd`/mypackage-00.1
Below is example output of a package with a 'checksig' script.
swverify: Attempting to verify using --posix tar option.
gpg: /home/userx/.gnupg/options:82: deprecated option "honor-http-proxy"
gpg: please use "keyserver-options honor-http-proxy" instead
gpg: WARNING: using insecure memory!
gpg: please see http://www.gnupg.org/faq.html for more information
gpg: Signature made Sun Mar 16 21:00:54 2003 EST using DSA key ID 82B0DBE4
gpg: BAD signature from "Test User (pass=Iforgot) localhost>"
swverify: First attempt failed.
swverify: Attempting to verify without using --posix tar option.
gpg: /home/jhl/.gnupg/options:82: deprecated option "honor-http-proxy"
gpg: please use "keyserver-options honor-http-proxy" instead
gpg: WARNING: using insecure memory!
gpg: please see http://www.gnupg.org/faq.html for more information
gpg: Signature made Sun Mar 16 21:00:54 2003 EST using DSA key ID 82B0DBE4
gpg: Good signature from "Test User (pass=Iforgot) localhost>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 77BB A98E B3A2 ED4C 217E 8A25 2BF4 28AB 82D0 DDE4
swverify: GPG signature verified.
swverify: Got it!
swverify: The vendor extension script checksig can now be executed.
checksig: Checking files OK (Good)
checksig: Checking Archive md5 OK (Good)
checksig: Checking Archive sha1 OK (Good)
gpg: /home/userx/.gnupg/options:82: deprecated option "honor-http-proxy"
gpg: please use "keyserver-options honor-http-proxy" instead
gpg: WARNING: using insecure memory!
gpg: please see http://www.gnupg.org/faq.html for more information
gpg: Signature made Sun Mar 16 21:00:54 2003 EST using DSA key ID 82B0DBE4
gpg: Good signature from "Test User (pass=Iforgot) localhost>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 77BB A98E B3A2 ED4C 217E 8A25 2BF4 28AB 82D0 DDE4
checksig: Signature proper OK (Good)
checksig: /usr/bin/gpg exit status : 0
Verifying Installed Software
(This capability is only partially implemented.) Verifying Installed
Software involves comparing the package meta-data to the live file
system. The validity of a successful comparison depends on the
validity of the installed software catalog. swverify makes no attempt
to check the validity of the entire catalog, however, it can use the
distribution GPG signature, which is stored in the catalog, to
authenticate the meta-data of the selected package.
Below is an example. Note, the package is selected on the basis of its
product or bundle tag.
$ swverify -r your_product_tag @ /
swverify: verifying installed software at:
swverify: //var/lib/swbis/catalog/swbis/your_product_tag/0.000/0
gpg: WARNING: --honor-http-proxy is a deprecated option.
gpg: please use "--keyserver-options honor-http-proxy" instead
gpg: Signature made Fri Feb 20 00:21:00 2004 EST using DSA key ID 82B0DBE4
gpg: Good signature from "Test User (pass=Iforgot) localhost>"
Fingerprint: 77BB B98D A3A2 ED4C 217E 9A25 8BF4 05AB 82B0 DBE4
swverify: Warning: file checks not implemented
swverify: signature verification return status=0
Create the digest byte stream -Wemit-digest-file mode:
Here are some examples that verify the archive digests.
#!/bin/sh
cat your-tarball | swverify -Wd -WS | md5sum
Your should see a pair of identical digests. Use the -Wsha1 option to
check the sha1 digest in a similar manner.
** IMPORTANT **
This does not mean that the data is authenticate in the sense of being
attributable to a person, merely that the md5sum attribute and the
payload byte stream match.
To inspect the digested data, try:
#!/bin/sh
cat your-tarball | swverify -WS | tar tvf -
Create the signed byte stream -Wemit-signed-file mode:
Here is an example which allows inspection of the signed file.
cat your-tarball | swverify -WC | tar tvf -
-Wget-sig-if mode:
This is the mode that is used internally when verifying a tarball.
Below is an example of using this mode manually.
#!/bin/sh
cat your-tarball | swverify -Wget-sig-if=/dev/tty | \
gpg --verify /dev/tty -
Now try to copy and paste the sigfile and gpg should attempt to verify
the signature.
Note: This verifies the md5 or sha1 digests before writing the
signed data to stdout. If the sha1 or md5 match fails then an
empty file is written to stdout.
Examples of verifying distributions and installed software.
Distribution Verification
* Verify a tar archive
swverify -d < foo-1.1.tar.gz
or
swverify -d @`pwd`/foo-1.1.tar.gz
or
swverify -d @:foo-1.1.tar.gz
or
cat foo-1.1.tar.gz | swverify -d @-
Note: --checksig and '-d' perform the same operations.
* Verify a unpacked distribution
swverify -d @`pwd`/foo-1.1
or
cd foo-1.1; swverify -d @.
or
swverify -d @:foo-1.1
Note: --checksig and '-d' perform the same operations.
* Verify an exported SCM Directory
# This is the same as directory verification except the '--cvs' option is needed.
Installed Software Verification
* Verify installed software
swverify foo.foo @/tmp/test
or
swverify foo.foo # at default target
Exit status of the checksig script or gpg utility for --checksig
directory operation. 0 if successful on all targets, 1 if failed on
all targets, 2 if failed on some targets.
/var/lib/swbis/catalog # Location of installed catalog
/usr/lib/swbis/swdefaults
/usr/lib/swbis/swbisdefaults
$HOME/.swbis/swdefaults
$HOME/.swbis/swbisdefaults
IEEE Std 1387.2-1995 (ISO/IEC 15068-2:1999), Open Group CAE C701.
info swbis
sw(5), swbis(1), swign(1), swpackage(8), gpg(1), libexec/swbis/arf2arf
swverify: The verification utility of the swbis project.
Author: Jim Lowe Email: jhlowe at acm.org
Version: 1.13
Last Updated: 2010-02-04
Copying: GNU Free Documentation License
The signature file's archive header (or data) is not part of the signed
data therefore it may be subject to undetectable tampering, however,
swverify does perform sanity checks on the pathname, permissions and
filetype if the sig_header file (See sw(5) manual page.) is not present
[due to being signed by a old swpackage version], and if sig_header is
present, swverify requires that it match the sig file header. The
ability to verify the unpacked directory form of the package depends on
many factors not immediately obvious, among them are the tar header
uname and gname, and whether they are preserved by the reading utility,
and whether these names are in the system database files /etc/passwd
and /etc/group, and if so, whether they assign the same uid/gid as the
package.
Verification of the directory form of a distribution (i.e. the
installed tarball path name prefix) such as running 'swverify -d @.'
after running 'swign @.' will fail if the order of directory entries is
not compatible with traditional Unix file system directory entry
ordering, which is the order of file creation. This ordering is almost
always apparent on Ext2 file system for small directories (but not
always for big directories). Ext3, reiserFS, and DarwinOS et.al file
systems do not have this ordering, use of the '--order-catalog' option
is therefore required. Use of the '--cvs' or '--order-catalog' options
is theoretically problematic because it causes the use and
interpretation of data in the verification of that same data therefore
opening possible attack vectors.
swverify(8)