* [PATCH] block/ssh: add support for sha256 host key fingerprints
@ 2021-06-22 11:51 Daniel P. Berrangé
2021-06-22 12:04 ` Richard W.M. Jones
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Daniel P. Berrangé @ 2021-06-22 11:51 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, Daniel P. Berrangé,
qemu-block, Richard W.M. Jones, Markus Armbruster, Max Reitz,
Eric Blake
Currently the SSH block driver supports MD5 and SHA1 for host key
fingerprints. This is a cryptographically sensitive operation and
so these hash algorithms are inadequate by modern standards. This
adds support for SHA256 which has been supported in libssh since
the 0.8.1 release.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
Note I can't actually get iotest '207' to fully pass. It always
complains that it can't validate the "known_hosts" file
qemu-img: Could not open 'TEST_IMG': no host key was found in known_hosts
it seems to rely on some specific developer host setup that my
laptop doesn't satisfy. It would be useful if any pre-requisite
could be documented in the iotest.
At least the sha256 verification step I added to 207 does pass
though.
block/ssh.c | 3 +++
qapi/block-core.json | 3 ++-
tests/qemu-iotests/207 | 54 ++++++++++++++++++++++++++++++++++++++
tests/qemu-iotests/207.out | 25 ++++++++++++++++++
4 files changed, 84 insertions(+), 1 deletion(-)
diff --git a/block/ssh.c b/block/ssh.c
index b51a031620..d008caf059 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -442,6 +442,9 @@ static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
} else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
return check_host_key_hash(s, hkc->u.hash.hash,
SSH_PUBLICKEY_HASH_SHA1, errp);
+ } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA256) {
+ return check_host_key_hash(s, hkc->u.hash.hash,
+ SSH_PUBLICKEY_HASH_SHA256, errp);
}
g_assert_not_reached();
break;
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 2ea294129e..4247dc46a5 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -3186,11 +3186,12 @@
#
# @md5: The given hash is an md5 hash
# @sha1: The given hash is an sha1 hash
+# @sha256: The given hash is an sha256 hash
#
# Since: 2.12
##
{ 'enum': 'SshHostKeyCheckHashType',
- 'data': [ 'md5', 'sha1' ] }
+ 'data': [ 'md5', 'sha1', 'sha256' ] }
##
# @SshHostKeyHash:
diff --git a/tests/qemu-iotests/207 b/tests/qemu-iotests/207
index f9f3fd7131..0f5c4bc8a0 100755
--- a/tests/qemu-iotests/207
+++ b/tests/qemu-iotests/207
@@ -73,6 +73,9 @@ with iotests.FilePath('t.img') as disk_path, \
iotests.log("=== Test host-key-check options ===")
iotests.log("")
+ iotests.log("--- no host key checking --")
+ iotests.log("")
+
vm.launch()
blockdev_create(vm, { 'driver': 'ssh',
'location': {
@@ -90,6 +93,9 @@ with iotests.FilePath('t.img') as disk_path, \
iotests.img_info_log(remote_path)
+ iotests.log("--- known_hosts key checking --")
+ iotests.log("")
+
vm.launch()
blockdev_create(vm, { 'driver': 'ssh',
'location': {
@@ -115,6 +121,7 @@ with iotests.FilePath('t.img') as disk_path, \
# Mappings of base64 representations to digests
md5_keys = {}
sha1_keys = {}
+ sha256_keys = {}
for key in keys:
md5_keys[key] = subprocess.check_output(
@@ -125,6 +132,10 @@ with iotests.FilePath('t.img') as disk_path, \
'echo %s | base64 -d | sha1sum -b | cut -d" " -f1' % key,
shell=True).rstrip().decode('ascii')
+ sha256_keys[key] = subprocess.check_output(
+ 'echo %s | base64 -d | sha256sum -b | cut -d" " -f1' % key,
+ shell=True).rstrip().decode('ascii')
+
vm.launch()
# Find correct key first
@@ -150,6 +161,9 @@ with iotests.FilePath('t.img') as disk_path, \
vm.shutdown()
iotests.notrun('Did not find a key that fits 127.0.0.1')
+ iotests.log("--- explicit md5 key checking --")
+ iotests.log("")
+
blockdev_create(vm, { 'driver': 'ssh',
'location': {
'path': disk_path,
@@ -164,6 +178,7 @@ with iotests.FilePath('t.img') as disk_path, \
}
},
'size': 2097152 })
+
blockdev_create(vm, { 'driver': 'ssh',
'location': {
'path': disk_path,
@@ -182,6 +197,9 @@ with iotests.FilePath('t.img') as disk_path, \
iotests.img_info_log(remote_path)
+ iotests.log("--- explicit sha1 key checking --")
+ iotests.log("")
+
vm.launch()
blockdev_create(vm, { 'driver': 'ssh',
'location': {
@@ -215,6 +233,42 @@ with iotests.FilePath('t.img') as disk_path, \
iotests.img_info_log(remote_path)
+ iotests.log("--- explicit sha256 key checking --")
+ iotests.log("")
+
+ vm.launch()
+ blockdev_create(vm, { 'driver': 'ssh',
+ 'location': {
+ 'path': disk_path,
+ 'server': {
+ 'host': '127.0.0.1',
+ 'port': '22'
+ },
+ 'host-key-check': {
+ 'mode': 'hash',
+ 'type': 'sha256',
+ 'hash': 'wrong',
+ }
+ },
+ 'size': 2097152 })
+ blockdev_create(vm, { 'driver': 'ssh',
+ 'location': {
+ 'path': disk_path,
+ 'server': {
+ 'host': '127.0.0.1',
+ 'port': '22'
+ },
+ 'host-key-check': {
+ 'mode': 'hash',
+ 'type': 'sha256',
+ 'hash': sha256_keys[matching_key],
+ }
+ },
+ 'size': 4194304 })
+ vm.shutdown()
+
+ iotests.img_info_log(remote_path)
+
#
# Invalid path and user
#
diff --git a/tests/qemu-iotests/207.out b/tests/qemu-iotests/207.out
index 1239d9d648..aeb8569d77 100644
--- a/tests/qemu-iotests/207.out
+++ b/tests/qemu-iotests/207.out
@@ -16,6 +16,8 @@ virtual size: 4 MiB (4194304 bytes)
=== Test host-key-check options ===
+--- no host key checking --
+
{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "none"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 8388608}}}
{"return": {}}
{"execute": "job-dismiss", "arguments": {"id": "job0"}}
@@ -25,6 +27,8 @@ image: TEST_IMG
file format: IMGFMT
virtual size: 8 MiB (8388608 bytes)
+--- known_hosts key checking --
+
{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "known_hosts"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
{"return": {}}
{"execute": "job-dismiss", "arguments": {"id": "job0"}}
@@ -34,6 +38,8 @@ image: TEST_IMG
file format: IMGFMT
virtual size: 4 MiB (4194304 bytes)
+--- explicit md5 key checking --
+
{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "md5"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
{"return": {}}
Job failed: remote host key does not match host_key_check 'wrong'
@@ -49,6 +55,8 @@ image: TEST_IMG
file format: IMGFMT
virtual size: 8 MiB (8388608 bytes)
+--- explicit sha1 key checking --
+
{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "sha1"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
{"return": {}}
Job failed: remote host key does not match host_key_check 'wrong'
@@ -64,6 +72,23 @@ image: TEST_IMG
file format: IMGFMT
virtual size: 4 MiB (4194304 bytes)
+--- explicit sha256 key checking --
+
+{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "sha256"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
+{"return": {}}
+Job failed: remote host key does not match host_key_check 'wrong'
+{"execute": "job-dismiss", "arguments": {"id": "job0"}}
+{"return": {}}
+
+{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "HASH", "mode": "hash", "type": "sha256"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
+{"return": {}}
+{"execute": "job-dismiss", "arguments": {"id": "job0"}}
+{"return": {}}
+
+image: TEST_IMG
+file format: IMGFMT
+virtual size: 4 MiB (4194304 bytes)
+
=== Invalid path and user ===
{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "none"}, "path": "/this/is/not/an/existing/path", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
--
2.31.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] block/ssh: add support for sha256 host key fingerprints
2021-06-22 11:51 [PATCH] block/ssh: add support for sha256 host key fingerprints Daniel P. Berrangé
@ 2021-06-22 12:04 ` Richard W.M. Jones
2021-06-22 12:27 ` Philippe Mathieu-Daudé
2021-06-30 10:52 ` Kevin Wolf
2 siblings, 0 replies; 4+ messages in thread
From: Richard W.M. Jones @ 2021-06-22 12:04 UTC (permalink / raw)
To: Daniel P. Berrangé
Cc: Kevin Wolf, qemu-block, Markus Armbruster, qemu-devel, Max Reitz,
Eric Blake
On Tue, Jun 22, 2021 at 12:51:56PM +0100, Daniel P. Berrangé wrote:
> Currently the SSH block driver supports MD5 and SHA1 for host key
> fingerprints. This is a cryptographically sensitive operation and
> so these hash algorithms are inadequate by modern standards. This
> adds support for SHA256 which has been supported in libssh since
> the 0.8.1 release.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Patch looks sensible:
Acked-by: Richard W.M. Jones <rjones@redhat.com>
Would you mind taking a look at nbdkit-ssh-plugin? This is arguably
more important (for Red Hat) since we no longer use the SSH driver in
qemu for V2V and switched to using nbdkit some time ago. The
nbdkit-ssh-plugin appears to only support SHA1 from a cursory look.
Rich.
>
> Note I can't actually get iotest '207' to fully pass. It always
> complains that it can't validate the "known_hosts" file
>
> qemu-img: Could not open 'TEST_IMG': no host key was found in known_hosts
>
> it seems to rely on some specific developer host setup that my
> laptop doesn't satisfy. It would be useful if any pre-requisite
> could be documented in the iotest.
>
> At least the sha256 verification step I added to 207 does pass
> though.
>
> block/ssh.c | 3 +++
> qapi/block-core.json | 3 ++-
> tests/qemu-iotests/207 | 54 ++++++++++++++++++++++++++++++++++++++
> tests/qemu-iotests/207.out | 25 ++++++++++++++++++
> 4 files changed, 84 insertions(+), 1 deletion(-)
>
> diff --git a/block/ssh.c b/block/ssh.c
> index b51a031620..d008caf059 100644
> --- a/block/ssh.c
> +++ b/block/ssh.c
> @@ -442,6 +442,9 @@ static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
> } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
> return check_host_key_hash(s, hkc->u.hash.hash,
> SSH_PUBLICKEY_HASH_SHA1, errp);
> + } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA256) {
> + return check_host_key_hash(s, hkc->u.hash.hash,
> + SSH_PUBLICKEY_HASH_SHA256, errp);
> }
> g_assert_not_reached();
> break;
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 2ea294129e..4247dc46a5 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -3186,11 +3186,12 @@
> #
> # @md5: The given hash is an md5 hash
> # @sha1: The given hash is an sha1 hash
> +# @sha256: The given hash is an sha256 hash
> #
> # Since: 2.12
> ##
> { 'enum': 'SshHostKeyCheckHashType',
> - 'data': [ 'md5', 'sha1' ] }
> + 'data': [ 'md5', 'sha1', 'sha256' ] }
>
> ##
> # @SshHostKeyHash:
> diff --git a/tests/qemu-iotests/207 b/tests/qemu-iotests/207
> index f9f3fd7131..0f5c4bc8a0 100755
> --- a/tests/qemu-iotests/207
> +++ b/tests/qemu-iotests/207
> @@ -73,6 +73,9 @@ with iotests.FilePath('t.img') as disk_path, \
> iotests.log("=== Test host-key-check options ===")
> iotests.log("")
>
> + iotests.log("--- no host key checking --")
> + iotests.log("")
> +
> vm.launch()
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> @@ -90,6 +93,9 @@ with iotests.FilePath('t.img') as disk_path, \
>
> iotests.img_info_log(remote_path)
>
> + iotests.log("--- known_hosts key checking --")
> + iotests.log("")
> +
> vm.launch()
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> @@ -115,6 +121,7 @@ with iotests.FilePath('t.img') as disk_path, \
> # Mappings of base64 representations to digests
> md5_keys = {}
> sha1_keys = {}
> + sha256_keys = {}
>
> for key in keys:
> md5_keys[key] = subprocess.check_output(
> @@ -125,6 +132,10 @@ with iotests.FilePath('t.img') as disk_path, \
> 'echo %s | base64 -d | sha1sum -b | cut -d" " -f1' % key,
> shell=True).rstrip().decode('ascii')
>
> + sha256_keys[key] = subprocess.check_output(
> + 'echo %s | base64 -d | sha256sum -b | cut -d" " -f1' % key,
> + shell=True).rstrip().decode('ascii')
> +
> vm.launch()
>
> # Find correct key first
> @@ -150,6 +161,9 @@ with iotests.FilePath('t.img') as disk_path, \
> vm.shutdown()
> iotests.notrun('Did not find a key that fits 127.0.0.1')
>
> + iotests.log("--- explicit md5 key checking --")
> + iotests.log("")
> +
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> 'path': disk_path,
> @@ -164,6 +178,7 @@ with iotests.FilePath('t.img') as disk_path, \
> }
> },
> 'size': 2097152 })
> +
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> 'path': disk_path,
> @@ -182,6 +197,9 @@ with iotests.FilePath('t.img') as disk_path, \
>
> iotests.img_info_log(remote_path)
>
> + iotests.log("--- explicit sha1 key checking --")
> + iotests.log("")
> +
> vm.launch()
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> @@ -215,6 +233,42 @@ with iotests.FilePath('t.img') as disk_path, \
>
> iotests.img_info_log(remote_path)
>
> + iotests.log("--- explicit sha256 key checking --")
> + iotests.log("")
> +
> + vm.launch()
> + blockdev_create(vm, { 'driver': 'ssh',
> + 'location': {
> + 'path': disk_path,
> + 'server': {
> + 'host': '127.0.0.1',
> + 'port': '22'
> + },
> + 'host-key-check': {
> + 'mode': 'hash',
> + 'type': 'sha256',
> + 'hash': 'wrong',
> + }
> + },
> + 'size': 2097152 })
> + blockdev_create(vm, { 'driver': 'ssh',
> + 'location': {
> + 'path': disk_path,
> + 'server': {
> + 'host': '127.0.0.1',
> + 'port': '22'
> + },
> + 'host-key-check': {
> + 'mode': 'hash',
> + 'type': 'sha256',
> + 'hash': sha256_keys[matching_key],
> + }
> + },
> + 'size': 4194304 })
> + vm.shutdown()
> +
> + iotests.img_info_log(remote_path)
> +
> #
> # Invalid path and user
> #
> diff --git a/tests/qemu-iotests/207.out b/tests/qemu-iotests/207.out
> index 1239d9d648..aeb8569d77 100644
> --- a/tests/qemu-iotests/207.out
> +++ b/tests/qemu-iotests/207.out
> @@ -16,6 +16,8 @@ virtual size: 4 MiB (4194304 bytes)
>
> === Test host-key-check options ===
>
> +--- no host key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "none"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 8388608}}}
> {"return": {}}
> {"execute": "job-dismiss", "arguments": {"id": "job0"}}
> @@ -25,6 +27,8 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 8 MiB (8388608 bytes)
>
> +--- known_hosts key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "known_hosts"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
> {"return": {}}
> {"execute": "job-dismiss", "arguments": {"id": "job0"}}
> @@ -34,6 +38,8 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 4 MiB (4194304 bytes)
>
> +--- explicit md5 key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "md5"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
> {"return": {}}
> Job failed: remote host key does not match host_key_check 'wrong'
> @@ -49,6 +55,8 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 8 MiB (8388608 bytes)
>
> +--- explicit sha1 key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "sha1"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
> {"return": {}}
> Job failed: remote host key does not match host_key_check 'wrong'
> @@ -64,6 +72,23 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 4 MiB (4194304 bytes)
>
> +--- explicit sha256 key checking --
> +
> +{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "sha256"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
> +{"return": {}}
> +Job failed: remote host key does not match host_key_check 'wrong'
> +{"execute": "job-dismiss", "arguments": {"id": "job0"}}
> +{"return": {}}
> +
> +{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "HASH", "mode": "hash", "type": "sha256"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
> +{"return": {}}
> +{"execute": "job-dismiss", "arguments": {"id": "job0"}}
> +{"return": {}}
> +
> +image: TEST_IMG
> +file format: IMGFMT
> +virtual size: 4 MiB (4194304 bytes)
> +
> === Invalid path and user ===
>
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "none"}, "path": "/this/is/not/an/existing/path", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
> --
> 2.31.1
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines. Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] block/ssh: add support for sha256 host key fingerprints
2021-06-22 11:51 [PATCH] block/ssh: add support for sha256 host key fingerprints Daniel P. Berrangé
2021-06-22 12:04 ` Richard W.M. Jones
@ 2021-06-22 12:27 ` Philippe Mathieu-Daudé
2021-06-30 10:52 ` Kevin Wolf
2 siblings, 0 replies; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2021-06-22 12:27 UTC (permalink / raw)
To: Daniel P. Berrangé, qemu-devel, Pino Toscano
Cc: Kevin Wolf, qemu-block, Markus Armbruster, Richard W.M. Jones,
Max Reitz, Eric Blake
On 6/22/21 1:51 PM, Daniel P. Berrangé wrote:
> Currently the SSH block driver supports MD5 and SHA1 for host key
> fingerprints. This is a cryptographically sensitive operation and
> so these hash algorithms are inadequate by modern standards. This
> adds support for SHA256 which has been supported in libssh since
> the 0.8.1 release.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>
> Note I can't actually get iotest '207' to fully pass. It always
> complains that it can't validate the "known_hosts" file
>
> qemu-img: Could not open 'TEST_IMG': no host key was found in known_hosts
>
> it seems to rely on some specific developer host setup that my
> laptop doesn't satisfy. It would be useful if any pre-requisite
> could be documented in the iotest.
>
> At least the sha256 verification step I added to 207 does pass
> though.
+Pino
> block/ssh.c | 3 +++
> qapi/block-core.json | 3 ++-
> tests/qemu-iotests/207 | 54 ++++++++++++++++++++++++++++++++++++++
> tests/qemu-iotests/207.out | 25 ++++++++++++++++++
> 4 files changed, 84 insertions(+), 1 deletion(-)
>
> diff --git a/block/ssh.c b/block/ssh.c
> index b51a031620..d008caf059 100644
> --- a/block/ssh.c
> +++ b/block/ssh.c
> @@ -442,6 +442,9 @@ static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
> } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
> return check_host_key_hash(s, hkc->u.hash.hash,
> SSH_PUBLICKEY_HASH_SHA1, errp);
> + } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA256) {
> + return check_host_key_hash(s, hkc->u.hash.hash,
> + SSH_PUBLICKEY_HASH_SHA256, errp);
Easier to read as a switch() :)
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> }
> g_assert_not_reached();
> break;
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 2ea294129e..4247dc46a5 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -3186,11 +3186,12 @@
> #
> # @md5: The given hash is an md5 hash
> # @sha1: The given hash is an sha1 hash
> +# @sha256: The given hash is an sha256 hash
> #
> # Since: 2.12
> ##
> { 'enum': 'SshHostKeyCheckHashType',
> - 'data': [ 'md5', 'sha1' ] }
> + 'data': [ 'md5', 'sha1', 'sha256' ] }
>
> ##
> # @SshHostKeyHash:
> diff --git a/tests/qemu-iotests/207 b/tests/qemu-iotests/207
> index f9f3fd7131..0f5c4bc8a0 100755
> --- a/tests/qemu-iotests/207
> +++ b/tests/qemu-iotests/207
> @@ -73,6 +73,9 @@ with iotests.FilePath('t.img') as disk_path, \
> iotests.log("=== Test host-key-check options ===")
> iotests.log("")
>
> + iotests.log("--- no host key checking --")
> + iotests.log("")
> +
> vm.launch()
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> @@ -90,6 +93,9 @@ with iotests.FilePath('t.img') as disk_path, \
>
> iotests.img_info_log(remote_path)
>
> + iotests.log("--- known_hosts key checking --")
> + iotests.log("")
> +
> vm.launch()
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> @@ -115,6 +121,7 @@ with iotests.FilePath('t.img') as disk_path, \
> # Mappings of base64 representations to digests
> md5_keys = {}
> sha1_keys = {}
> + sha256_keys = {}
>
> for key in keys:
> md5_keys[key] = subprocess.check_output(
> @@ -125,6 +132,10 @@ with iotests.FilePath('t.img') as disk_path, \
> 'echo %s | base64 -d | sha1sum -b | cut -d" " -f1' % key,
> shell=True).rstrip().decode('ascii')
>
> + sha256_keys[key] = subprocess.check_output(
> + 'echo %s | base64 -d | sha256sum -b | cut -d" " -f1' % key,
> + shell=True).rstrip().decode('ascii')
> +
> vm.launch()
>
> # Find correct key first
> @@ -150,6 +161,9 @@ with iotests.FilePath('t.img') as disk_path, \
> vm.shutdown()
> iotests.notrun('Did not find a key that fits 127.0.0.1')
>
> + iotests.log("--- explicit md5 key checking --")
> + iotests.log("")
> +
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> 'path': disk_path,
> @@ -164,6 +178,7 @@ with iotests.FilePath('t.img') as disk_path, \
> }
> },
> 'size': 2097152 })
> +
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> 'path': disk_path,
> @@ -182,6 +197,9 @@ with iotests.FilePath('t.img') as disk_path, \
>
> iotests.img_info_log(remote_path)
>
> + iotests.log("--- explicit sha1 key checking --")
> + iotests.log("")
> +
> vm.launch()
> blockdev_create(vm, { 'driver': 'ssh',
> 'location': {
> @@ -215,6 +233,42 @@ with iotests.FilePath('t.img') as disk_path, \
>
> iotests.img_info_log(remote_path)
>
> + iotests.log("--- explicit sha256 key checking --")
> + iotests.log("")
> +
> + vm.launch()
> + blockdev_create(vm, { 'driver': 'ssh',
> + 'location': {
> + 'path': disk_path,
> + 'server': {
> + 'host': '127.0.0.1',
> + 'port': '22'
> + },
> + 'host-key-check': {
> + 'mode': 'hash',
> + 'type': 'sha256',
> + 'hash': 'wrong',
> + }
> + },
> + 'size': 2097152 })
> + blockdev_create(vm, { 'driver': 'ssh',
> + 'location': {
> + 'path': disk_path,
> + 'server': {
> + 'host': '127.0.0.1',
> + 'port': '22'
> + },
> + 'host-key-check': {
> + 'mode': 'hash',
> + 'type': 'sha256',
> + 'hash': sha256_keys[matching_key],
> + }
> + },
> + 'size': 4194304 })
> + vm.shutdown()
> +
> + iotests.img_info_log(remote_path)
> +
> #
> # Invalid path and user
> #
> diff --git a/tests/qemu-iotests/207.out b/tests/qemu-iotests/207.out
> index 1239d9d648..aeb8569d77 100644
> --- a/tests/qemu-iotests/207.out
> +++ b/tests/qemu-iotests/207.out
> @@ -16,6 +16,8 @@ virtual size: 4 MiB (4194304 bytes)
>
> === Test host-key-check options ===
>
> +--- no host key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "none"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 8388608}}}
> {"return": {}}
> {"execute": "job-dismiss", "arguments": {"id": "job0"}}
> @@ -25,6 +27,8 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 8 MiB (8388608 bytes)
>
> +--- known_hosts key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "known_hosts"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
> {"return": {}}
> {"execute": "job-dismiss", "arguments": {"id": "job0"}}
> @@ -34,6 +38,8 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 4 MiB (4194304 bytes)
>
> +--- explicit md5 key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "md5"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
> {"return": {}}
> Job failed: remote host key does not match host_key_check 'wrong'
> @@ -49,6 +55,8 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 8 MiB (8388608 bytes)
>
> +--- explicit sha1 key checking --
> +
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "sha1"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
> {"return": {}}
> Job failed: remote host key does not match host_key_check 'wrong'
> @@ -64,6 +72,23 @@ image: TEST_IMG
> file format: IMGFMT
> virtual size: 4 MiB (4194304 bytes)
>
> +--- explicit sha256 key checking --
> +
> +{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "wrong", "mode": "hash", "type": "sha256"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 2097152}}}
> +{"return": {}}
> +Job failed: remote host key does not match host_key_check 'wrong'
> +{"execute": "job-dismiss", "arguments": {"id": "job0"}}
> +{"return": {}}
> +
> +{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"hash": "HASH", "mode": "hash", "type": "sha256"}, "path": "TEST_DIR/PID-t.img", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
> +{"return": {}}
> +{"execute": "job-dismiss", "arguments": {"id": "job0"}}
> +{"return": {}}
> +
> +image: TEST_IMG
> +file format: IMGFMT
> +virtual size: 4 MiB (4194304 bytes)
> +
> === Invalid path and user ===
>
> {"execute": "blockdev-create", "arguments": {"job-id": "job0", "options": {"driver": "ssh", "location": {"host-key-check": {"mode": "none"}, "path": "/this/is/not/an/existing/path", "server": {"host": "127.0.0.1", "port": "22"}}, "size": 4194304}}}
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] block/ssh: add support for sha256 host key fingerprints
2021-06-22 11:51 [PATCH] block/ssh: add support for sha256 host key fingerprints Daniel P. Berrangé
2021-06-22 12:04 ` Richard W.M. Jones
2021-06-22 12:27 ` Philippe Mathieu-Daudé
@ 2021-06-30 10:52 ` Kevin Wolf
2 siblings, 0 replies; 4+ messages in thread
From: Kevin Wolf @ 2021-06-30 10:52 UTC (permalink / raw)
To: Daniel P. Berrangé
Cc: qemu-block, qemu-devel, Markus Armbruster, Richard W.M. Jones,
Max Reitz, Eric Blake
Am 22.06.2021 um 13:51 hat Daniel P. Berrangé geschrieben:
> Currently the SSH block driver supports MD5 and SHA1 for host key
> fingerprints. This is a cryptographically sensitive operation and
> so these hash algorithms are inadequate by modern standards. This
> adds support for SHA256 which has been supported in libssh since
> the 0.8.1 release.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Thanks, applied to the block branch.
> Note I can't actually get iotest '207' to fully pass. It always
> complains that it can't validate the "known_hosts" file
>
> qemu-img: Could not open 'TEST_IMG': no host key was found in known_hosts
>
> it seems to rely on some specific developer host setup that my
> laptop doesn't satisfy. It would be useful if any pre-requisite
> could be documented in the iotest.
>
> At least the sha256 verification step I added to 207 does pass
> though.
It passes for me when I make sure to add 127.0.0.1 to known_hosts first.
My ~/.ssh/config also has these lines, probably from a previous run,
which may or may not be necessary:
Host 127.0.0.1
HostKeyAlgorithms ssh-rsa
Kevin
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-06-30 10:53 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-22 11:51 [PATCH] block/ssh: add support for sha256 host key fingerprints Daniel P. Berrangé
2021-06-22 12:04 ` Richard W.M. Jones
2021-06-22 12:27 ` Philippe Mathieu-Daudé
2021-06-30 10:52 ` Kevin Wolf
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