27 Commits
v0.3 ... v0.6

Author SHA1 Message Date
78ccd56afe License changed from LGPL to GPL as in COPYING
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-09-04 16:51:44 +03:00
f1ba3e7b45 Version 0.6 release
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-08-28 16:37:52 +03:00
d7d74e5648 Fix cleanup in the case of errors
Proper memory cleanup is not really necessary for command line
utility because all memory is cleaned up when it quits. But as
code does it most of the cases, fix other places.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-08-28 15:20:16 +03:00
15dab873b5 fix the crash when key file is not found
Error in error handling caused crash when key file is not found.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-08-27 15:44:18 +03:00
971b286169 make --imahash or --imasig optional for EVM signing
One might not want to change/set IMA xattr value when performing
EVM signing.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-08-13 16:55:14 +03:00
2406322914 perform uuid format checking and error handling
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-08-13 16:55:14 +03:00
b3a5fcbca2 make argument for '-u' option as optional
-u required to provide uuid or '-', which was confusing.
Now -u does not require '-' argument to read uuid automatically.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-08-13 16:55:10 +03:00
59ef0a0b99 Save full security.ima attribute to a file
Right now if -f option is passed in, we only save the actual signature to
a file and not the full security.ima attribute.

I think it makes more sense to save full security.ima attribute so that
it can act as detached signatures and one can install signature later.
That is signing can take place on build server and detached signatures
can be generated and these signatures can be installed later on target.

One can use following steps.

evmctl ima_sign -f -x -a sha256 /tmp/data.txt

hexdump -v -e '1/1 "%02x"' /tmp/data.txt.sig > /tmp/data.txt.sig.hex
printf "# file: /tmp/data.txt\nsecurity.ima=0x" | cat - /tmp/data.txt.sig.hex | setfattr --restore -

evmctl ima_verify /tmp/data.txt

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-08-09 15:57:26 +03:00
ab18c60ec1 Get signature version from the header
Currently we assume signature version is v1 until and unless -x is
specified on kernel command line. Given the fact that signature version
information is available in signature itself, it is much better to get
it from there and not require user to pass -x during verification phase.

If user passed -x on command line, then honor it.

Now one can do following.

	evmctl ima_sign -x /tmp/data.txt
	evmctl ima_verify /tmp/data.txt

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-08-09 15:57:26 +03:00
d9678295b9 Move key file selection to later phase
Following patch reads signature version from header and based
on that key file needs to be selected.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-08-09 15:57:18 +03:00
0df73005a3 Use enums for signature versions
Using enums for fixed values looks cleaner. Also I am planning to use
version field in more places in next patch. So use enums intead of
numbers like 1 and 2.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-08-09 15:55:53 +03:00
b49e2251a0 Let user specified hash algo take precedence
After applying previous patch, we will always get hash algo info from
signature and if user specified one on command line, that will be overridden.

This is like breaking old behavior. So keep track whether user specified
hash algo on command line or not. If user did not specify one then get
hash algo info from signature otherwise use the one user provided.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-08-09 15:55:49 +03:00
fa3c365cce Get hash algorithm info from the signature
If one signs a file using hash algo -sha256 then one needs to specify
signature during verification also. Otherwise evmctl using default sha1
for calculating hash and signature verification fails. One needs to
specify -a sha256 on command line even during signature verification
phase to make sure file is signed right.

I think that's completely unnecessary. A user is not always supposed
to know what algorithm was used to generate signature. User is only
concered with whether this signature is valid or not.

So retrieve hash algorithm info from signature and use that.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-07-15 18:02:02 +03:00
00caa1d5ba Put right hash algo info in digital signature version 1 header
hdr->hash for signature version 1 contains the info about what hash
algorithm has been used for signing the file. Currently we always set
hdr->hash to DIGEST_ALGO_SHA1. But one can sign file using SHA256 using
option "-a sha256". In that case we should put right hash algo info
in signature header. Fix it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-07-15 18:01:05 +03:00
b48f4f9c7e Fix hash array size in verify_ima()
Now evmctl supports different hash algorithms and sha512 will produce
64 byte digest. verify_ima() still allocates only 20bytes to store hash.
This does not work with larger hashes.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-07-15 18:00:32 +03:00
16d40dbdf6 evmctl: Fix signature verification code for V2 digital signature
For V2 of digital signature we store signature at hdr->sig and not at
hdr->sig + 2. That's the property of V1 of signature.

Fix the verification code otherwise it fails with following message.

RSA_public_decrypt() failed: -1
error:0407006A:rsa routines:RSA_padding_check_PKCS1_type_1:block type is not 01
error:04067072:rsa routines:RSA_EAY_PUBLIC_DECRYPT:padding check failed

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
2013-07-10 16:45:38 +01:00
3f0c0a3c84 Fix verification using signature file
Signature file does not contain xattr prefix.
Add signature xattr prefix manually.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-07-10 16:00:53 +01:00
076fd302bb support for asymmetric crypto keys and new signature format
Asymmetric keys were introduced in linux-3.7 to verify the signature on
signed kernel modules. The asymmetric keys infrastructure abstracts the
signature verification from the crypto details. Asymmetric crypto keys
support allows to import X509 public key certificate in a DER format
into the kernel keyring. Asymmetric keys require a new signature format.
'evmctl -x' or 'evmctl --x509' option can be used to utilize new
signature format.

Using of key filename after the file name for signing and verification commands
is a bit odd. This patch add '--key' parameter to specify non-default key file.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2013-02-11 16:12:08 +02:00
1d24a94bb5 added uuid support for EVM
Latest version of EVM uses file system UUID as part of an HMAC
calculation to prevent pasting of inode metadata from other file
systems. This patch adds support for adding file system UUID
to HMAC calculation. It is necessary to specify '-u -' or '--uuid -'
on evmctl command line.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2013-02-11 16:07:30 +02:00
5be54eaca4 Update README
README updated.
Module signing info has been removed. Module signing is done now in kernel
source tree and uses appended signatures. No need to create sig files or
set extended attributes. Information about test scripts has been removed.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-10 15:37:40 +03:00
a58cd9f4af Remove test scripts
Test scripts are not used at all.
All needed information is in README.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-10 15:17:42 +03:00
c8b4f34fd4 remove directory entry list sorting
Directory entries list sorting is not needed.
Entries are read always in the same order.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-06 14:08:54 +03:00
c171931236 added ima signature verification support
For debugging puporse it is usefull to have signature verification
functionality. It supports use of xattrs and .sig files.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-06 14:08:54 +03:00
ba07c9d4b1 do not output type prefix for sig files
sig files do not need type prefix as they are contain only signatures.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-06 14:08:54 +03:00
203f058903 added support for kernel module signature
Kernel module signature is appended to the kernel module.
Kernel signature also contains signature length and magic.
Added --modsig parameter to generate kernel module signature.

Signature can be added to the module like: cat module.sig >> module.ko

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-06 14:08:54 +03:00
72ad26c3be disable printing signature when using sigfiles
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-06 14:08:54 +03:00
f41d43026b Remove tag creation
Better to create tag manually when release is done.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-09-06 14:08:54 +03:00
16 changed files with 801 additions and 384 deletions

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@ -1,2 +1,5 @@
Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Dmitry Kasatkin <d.kasatkin@samsung.com>
CONTRIBUTORS:
Vivek Goyal <vgoyal@redhat.com>

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@ -1,3 +1,13 @@
2013-08-28 Dmitry Kasatkin <d.kasatkin@samsung.com>
version 0.6
* support for asymmetric crypto keys and new signature format (v2)
* fixes to set correct hash algo for digital signature v1
* uuid support for EVM
* signature verification support
* test scripts removed
* README updates
2012-05-18 Dmitry Kasatkin <dmitry.kasatkin@intel.com>
version 0.3

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@ -1,6 +1,6 @@
SUBDIRS = src tests
SUBDIRS = src
#EXTRA_DIST = LEGAL acinclude.m4 include
EXTRA_DIST = autogen.sh
ACLOCAL_AMFLAGS = -I m4
@ -11,7 +11,6 @@ pkgname = $(PACKAGE_NAME)-$(PACKAGE_VERSION)
tarname = $(pkgname).tar.gz
$(tarname):
git tag v$(PACKAGE_VERSION)
git archive --format=tar --prefix=$(pkgname)/ v$(PACKAGE_VERSION) $(FILES) | gzip >$@
tar: $(tarname)

154
README
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@ -1,52 +1,146 @@
ima-evm-utils - IMA/EVM signing utility
=========================================
1. Generate private key
Contents:
# plain key
openssl genrsa -out privkey_evm.pem 1024
1. Key and signature formats
2. Key generation
3. Initialization
4. Signing
# encrypted key
openssl genrsa -des3 -out privkey_evm.pem 1024
# set password for the key
openssl rsa -in /etc/keys/privkey_evm.pem -out privkey_evm_enc.pem -des3
Key and signature formats
-------------------------
EVM support (v2) in latest version of the kernel adds the file system UUID to
the HMAC calculation. It is controlled by the CONFIG_EVM_HMAC_VERSION and
version 2 is enabled by default. To include the UUID to the signature calculation,
it is necessary to provide '--uuid' or '-u' parameter to the 'sign' command.
UUID can be provided on command line in form of '-uUUID' or '--uuid=UUID'.
Latest kernel got IMA/EVM support for using X509 certificates and asymmetric key
support for verifying digital signatures. The new command line parameter
'-x' or '--x509' was added to the evmctl to enable using of X509 certificates
and new signature format.
Key generation
--------------
Generate private key in plain text format
$ openssl genrsa -out privkey_evm.pem 1024
Generate encrypted private key
$ openssl genrsa -des3 -out privkey_evm.pem 1024
Make encrypted private key from unencrypted
$ openssl rsa -in /etc/keys/privkey_evm.pem -out privkey_evm_enc.pem -des3
Generate self-signed X509 certificate and private key for using kernel asymmetric
keys support
$ openssl req -new -nodes -utf8 -sha1 -days 36500 -batch \
-x509 -config x509_evm.genkey \
-outform DER -out x509_evm.der -keyout privkey_evm.pem
Configuration file x509_evm.genkey:
# Begining of the file
[ req ]
default_bits = 1024
distinguished_name = req_distinguished_name
prompt = no
string_mask = utf8only
x509_extensions = myexts
[ req_distinguished_name ]
O = Magrathea
CN = Glacier signing key
emailAddress = slartibartfast@magrathea.h2g2
[ myexts ]
basicConstraints=critical,CA:FALSE
keyUsage=digitalSignature
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid
# EOF
Get public key
$ openssl rsa -pubout -in privkey_evm.pem -out pubkey_evm.pem
Copy keys to /etc/keys
$ cp pubkey_evm.pem /etc/keys
$ scp pubkey_evm.pem target:/etc/keys
or
openssl pkcs8 -topk8 -in /etc/keys/privkey_evm.pem -out privkey_evm_enc.pem
$ cp x509_evm.pem /etc/keys
$ scp x509_evm.pem target:/etc/keys
2. Generate public key
openssl rsa -pubout -in privkey_evm.pem -out pubkey_evm.pem
Initialization
--------------
3. Copy public (+private if to sign on device) key to the device/qemu /etc/keys
IMA/EVM initialization should be normally done from initial RAM file system
before mounting root filesystem.
scp pubkey_evm.pem mad:/etc/keys
Here is an example script /etc/initramfs-tools/scripts/local-top/ima.sh
4. Load keys and enable EVM
# import EVM HMAC key
keyctl clear @u
keyctl add user kmk "testing123" @u
keyctl add encrypted evm-key "load `cat /etc/keys/evm-key`" @u
evm_enable.sh
# import IMA public key
ima_id=`keyctl newring _ima @u`
evmctl import /etc/keys/pubkey_evm.pem $ima_id
This should be done at early phase, before mounting root filesystem.
# import EVM public key
evm_id=`keyctl newring _evm @u`
evmctl import /etc/keys/pubkey_evm.pem $evm_id
5. Sign EVM and use hash value for IMA - common case
# enable EVM
echo "1" > /sys/kernel/security/evm
evmctl sign --imahash test.txt
6. Sign IMA and EVM - for immutable files and modules
Import X509 certificate into the kernel keyring (since kernel 3.9?)
evmctl sign --imasig test.txt
$ evmctl -x import /etc/keys/x509_evm.der `keyctl search @u keyring _ima`
$ evmctl -x import /etc/keys/x509_evm.der `keyctl search @u keyring _evm`
7. Sign whole filesystem
evm_sign_all.sh
or
find / \( -fstype rootfs -o -fstype ext3 -o -fstype ext4 \) ! -path "/lib/modules/*" -type f -uid 0 -exec evmctl sign --imahash '{}' \;
find /lib/modules ! -name "*.ko" -type f -uid 0 -exec evmctl sign --imahash '{}' \;
# security.ima needs to have signature for modules
find /lib/modules -name "*.ko" -type f -uid 0 -exec evmctl sign --imasig '{}' \;
Signing
-------
# generate signatures in .sig files
find /lib/modules -name "*.ko" -type f -uid 0 -exec evmctl -n --sigfile ima_sign '{}' \;
Default public key: /etc/keys/pubkey_evm.pem
Default private key: /etc/keys/privkey_evm.pem
Default X509 certificate: /etc/keys/x509_evm.der
8. Label filesystem in fix mode...
Signing for using X509 certificates is done using '-x' or '--x509' parameter.
Signing for using new the EVM HMAC format is done using '-u' or '--uuid' parameter.
ima_fix_dir.sh <dir>
Sign file with EVM signature and use hash value for IMA - common case
$ evmctl sign [-u] [-x] --imahash test.txt
Sign file with both IMA and EVM signatures - for immutable files
$ evmctl sign [-u] [-x] --imasig test.txt
Sign file with IMA signature - for immutable files
$ evmctl ima_sign [-x] test.txt
Label whole filesystem with EVM signatures
$ find / \( -fstype rootfs -o -fstype ext4 \) -exec evmctl sign [-u] [-x] --imahash '{}' \;
Label filesystem in fix mode - kernel sets correct values to IMA and EVM xattrs
$ find / \( -fstype rootfs -o -fstype ext4 \) -exec sh -c "< '{}'" \;

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@ -1,7 +1,7 @@
# autoconf script
AC_PREREQ([2.65])
AC_INIT(ima-evm-utils, 0.3, dmitry.kasatkin@intel.com)
AC_INIT(ima-evm-utils, 0.6, d.kasatkin@samsung.com)
AM_INIT_AUTOMAKE(AC_PACKAGE_NAME, AC_PACKAGE_VERSION)
AC_CONFIG_HEADERS([config.h])
AC_CONFIG_MACRO_DIR([m4])
@ -30,6 +30,9 @@ AC_SUBST(OPENSSL_LIBS)
AC_CHECK_HEADER(unistd.h)
AC_CHECK_HEADERS(openssl/conf.h)
AC_CHECK_HEADERS(attr/xattr.h, , [AC_MSG_ERROR([attr/xattr.h header not found. You need the libattr development package.])])
AC_CHECK_HEADERS(keyutils.h, , [AC_MSG_ERROR([keyutils.h header not found. You need the libkeyutils development package.])])
#debug support - yes for a while
PKG_ARG_ENABLE(debug, "yes", DEBUG, [Enable Debug support])
if test $pkg_cv_enable_debug = yes; then
@ -46,7 +49,6 @@ fi
AC_CONFIG_FILES([Makefile
src/Makefile
tests/Makefile
ima-evm-utils.spec
])
AC_OUTPUT

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@ -3,7 +3,7 @@ Version: @PACKAGE_VERSION@
Release: 1%{?dist}
Summary: @PACKAGE_NAME@ - IMA/EVM control utility
Group: System/Libraries
License: LGPLv2
License: GPLv2
#URL:
Source0: %{name}-%{version}.tar.gz
BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root

File diff suppressed because it is too large Load Diff

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@ -1,7 +0,0 @@
pkglibexec_PROGRAMS = openclose
openclose_SOURCES = openclose.c
dist_pkglibexec_SCRIPTS = evm_enable.sh evm_genkey.sh evm_sign_all.sh evm_sign_modules.sh \
ima_fix_dir.sh evm_hmac_all.sh evm_hmac_modules.sh

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@ -1,25 +0,0 @@
#!/bin/sh
# import EVM HMAC key
keyctl clear @u
keyctl add user kmk "testing123" @u
keyctl add encrypted evm-key "load `cat /etc/keys/evm-key`" @u
# import Moule public key
mod_id=`keyctl newring _module @u`
evmctl import /etc/keys/pubkey_evm.pem $mod_id
# import IMA public key
ima_id=`keyctl newring _ima @u`
evmctl import /etc/keys/pubkey_evm.pem $ima_id
# import EVM public key
evm_id=`keyctl newring _evm @u`
evmctl import /etc/keys/pubkey_evm.pem $evm_id
# enable EVM
echo "1" > /sys/kernel/security/evm
# enable module checking
echo "1" > /sys/kernel/security/ima/module_check

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@ -1,8 +0,0 @@
#!/bin/sh
keyctl add user kmk "testing123" @u
key=`keyctl add encrypted evm-key "new user:kmk 32" @u`
keyctl print $key >/etc/keys/evm-key
keyctl list @u

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@ -1,14 +0,0 @@
#!/bin/sh
verbose=""
if [ "$1" = "-v" ] ; then
verbose="-v"
shift 1
fi
dir=${1:-/}
echo "Label: $dir"
find $dir \( -fstype rootfs -o -fstype ext3 -o -fstype ext4 \) \( -type f -o -type d \) -exec evmctl hmac --imahash $verbose '{}' \;

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@ -1,14 +0,0 @@
#!/bin/sh
verbose=""
if [ "$1" = "-v" ] ; then
verbose="-v"
shift 1
fi
dir=${1:-/lib/modules}
echo "HMAC modules: $dir"
find $dir -name "*.ko" -type f -exec evmctl hmac --imasig $verbose '{}' \;

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@ -1,14 +0,0 @@
#!/bin/sh
verbose=""
if [ "$1" = "-v" ] ; then
verbose="-v"
shift 1
fi
dir=${1:-/}
echo "Label: $dir"
find $dir \( -fstype rootfs -o -fstype ext3 -o -fstype ext4 \) -type f -exec evmctl sign --imahash $verbose '{}' \;

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@ -1,14 +0,0 @@
#!/bin/sh
verbose=""
if [ "$1" = "-v" ] ; then
verbose="-v"
shift 1
fi
dir=${1:-/lib/modules}
echo "Signing modules: $dir"
find $dir -name "*.ko" -type f -exec evmctl sign --imasig $verbose '{}' \;

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@ -1,8 +0,0 @@
#!/bin/sh
dir=${1:-/}
echo "Fixing dir: $dir"
find $dir \( -fstype rootfs -o -fstype ext3 -o -fstype ext4 \) -type f -exec openclose '{}' \;

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@ -1,20 +0,0 @@
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
int fd;
fd = open(argv[1], O_RDONLY);
if (fd < 0) {
perror("open()");
exit(1);
}
close(fd);
return 0;
}