[openssh-commits] [openssh] 01/04: upstream: repair PubkeyAcceptedKeyTypes (and friends) after RSA
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djm pushed a commit to branch master
in repository openssh.
commit 312d2f2861a2598ed08587cb6c45c0e98a85408f
Author: djm at openbsd.org <djm at openbsd.org>
Date: Wed Jul 4 13:49:31 2018 +0000
upstream: repair PubkeyAcceptedKeyTypes (and friends) after RSA
signature work - returns ability to add/remove/specify algorithms by
wildcard.
Algorithm lists are now fully expanded when the server/client configs
are finalised, so errors are reported early and the config dumps
(e.g. "ssh -G ...") now list the actual algorithms selected.
Clarify that, while wildcards are accepted in algorithm lists, they
aren't full pattern-lists that support negation.
(lots of) feedback, ok markus@
OpenBSD-Commit-ID: a8894c5c81f399a002f02ff4fe6b4fa46b1f3207
---
compat.c | 18 +++++------
kex.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++-----------
kex.h | 4 +--
match.c | 36 ++++++++++++++++++----
match.h | 5 ++--
readconf.c | 38 +++++++++++++++++-------
servconf.c | 32 ++++++++++++++------
ssh_config.5 | 8 ++---
sshconnect2.c | 10 ++++---
sshd_config.5 | 8 ++---
10 files changed, 187 insertions(+), 67 deletions(-)
diff --git a/compat.c b/compat.c
index 8335f2a9..d8fd6eaf 100644
--- a/compat.c
+++ b/compat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.c,v 1.109 2018/07/03 11:42:12 djm Exp $ */
+/* $OpenBSD: compat.c,v 1.110 2018/07/04 13:49:31 djm Exp $ */
/*
* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
*
@@ -190,8 +190,8 @@ compat_cipher_proposal(char *cipher_prop)
if (!(datafellows & SSH_BUG_BIGENDIANAES))
return cipher_prop;
debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
- if ((cipher_prop = match_filter_list(cipher_prop, "aes*")) == NULL)
- fatal("match_filter_list failed");
+ if ((cipher_prop = match_filter_blacklist(cipher_prop, "aes*")) == NULL)
+ fatal("match_filter_blacklist failed");
debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
if (*cipher_prop == '\0')
fatal("No supported ciphers found");
@@ -204,8 +204,8 @@ compat_pkalg_proposal(char *pkalg_prop)
if (!(datafellows & SSH_BUG_RSASIGMD5))
return pkalg_prop;
debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
- if ((pkalg_prop = match_filter_list(pkalg_prop, "ssh-rsa")) == NULL)
- fatal("match_filter_list failed");
+ if ((pkalg_prop = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL)
+ fatal("match_filter_blacklist failed");
debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
if (*pkalg_prop == '\0')
fatal("No supported PK algorithms found");
@@ -219,14 +219,14 @@ compat_kex_proposal(char *p)
return p;
debug2("%s: original KEX proposal: %s", __func__, p);
if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
- if ((p = match_filter_list(p,
+ if ((p = match_filter_blacklist(p,
"curve25519-sha256 at libssh.org")) == NULL)
- fatal("match_filter_list failed");
+ fatal("match_filter_blacklist failed");
if ((datafellows & SSH_OLD_DHGEX) != 0) {
- if ((p = match_filter_list(p,
+ if ((p = match_filter_blacklist(p,
"diffie-hellman-group-exchange-sha256,"
"diffie-hellman-group-exchange-sha1")) == NULL)
- fatal("match_filter_list failed");
+ fatal("match_filter_blacklist failed");
}
debug2("%s: compat KEX proposal: %s", __func__, p);
if (*p == '\0')
diff --git a/kex.c b/kex.c
index d0a5f1b6..2fd052e9 100644
--- a/kex.c
+++ b/kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.c,v 1.137 2018/07/03 11:39:54 djm Exp $ */
+/* $OpenBSD: kex.c,v 1.138 2018/07/04 13:49:31 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
*
@@ -174,7 +174,7 @@ kex_names_cat(const char *a, const char *b)
size_t len;
if (a == NULL || *a == '\0')
- return NULL;
+ return strdup(b);
if (b == NULL || *b == '\0')
return strdup(a);
if (strlen(b) > 1024*1024)
@@ -209,27 +209,88 @@ kex_names_cat(const char *a, const char *b)
* specified names should be removed.
*/
int
-kex_assemble_names(const char *def, char **list)
+kex_assemble_names(char **listp, const char *def, const char *all)
{
- char *ret;
+ char *cp, *tmp, *patterns;
+ char *list = NULL, *ret = NULL, *matching = NULL, *opatterns = NULL;
+ int r = SSH_ERR_INTERNAL_ERROR;
- if (list == NULL || *list == NULL || **list == '\0') {
- *list = strdup(def);
+ if (listp == NULL || *listp == NULL || **listp == '\0') {
+ if ((*listp = strdup(def)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
return 0;
}
- if (**list == '+') {
- if ((ret = kex_names_cat(def, *list + 1)) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- free(*list);
- *list = ret;
- } else if (**list == '-') {
- if ((ret = match_filter_list(def, *list + 1)) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- free(*list);
- *list = ret;
+
+ list = *listp;
+ *listp = NULL;
+ if (*list == '+') {
+ /* Append names to default list */
+ if ((tmp = kex_names_cat(def, list + 1)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(list);
+ list = tmp;
+ } else if (*list == '-') {
+ /* Remove names from default list */
+ if ((*listp = match_filter_blacklist(def, list + 1)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(list);
+ /* filtering has already been done */
+ return 0;
+ } else {
+ /* Explicit list, overrides default - just use "list" as is */
}
- return 0;
+ /*
+ * The supplied names may be a pattern-list. For the -list case,
+ * the patterns are applied above. For the +list and explicit list
+ * cases we need to do it now.
+ */
+ ret = NULL;
+ if ((patterns = opatterns = strdup(list)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ /* Apply positive (i.e. non-negated) patterns from the list */
+ while ((cp = strsep(&patterns, ",")) != NULL) {
+ if (*cp == '!') {
+ /* negated matches are not supported here */
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto fail;
+ }
+ free(matching);
+ if ((matching = match_filter_whitelist(all, cp)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ if ((tmp = kex_names_cat(ret, matching)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(ret);
+ ret = tmp;
+ }
+ if (ret == NULL || *ret == '\0') {
+ /* An empty name-list is an error */
+ /* XXX better error code? */
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto fail;
+ }
+
+ /* success */
+ *listp = ret;
+ ret = NULL;
+ r = 0;
+
+ fail:
+ free(matching);
+ free(opatterns);
+ free(list);
+ free(ret);
+ return r;
}
/* put algorithm proposal into buffer */
diff --git a/kex.h b/kex.h
index 6210630d..3ffae2df 100644
--- a/kex.h
+++ b/kex.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.h,v 1.84 2018/07/03 11:39:54 djm Exp $ */
+/* $OpenBSD: kex.h,v 1.85 2018/07/04 13:49:31 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
@@ -169,7 +169,7 @@ struct kex {
int kex_names_valid(const char *);
char *kex_alg_list(char);
char *kex_names_cat(const char *, const char *);
-int kex_assemble_names(const char *, char **);
+int kex_assemble_names(char **, const char *, const char *);
int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **);
int kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
diff --git a/match.c b/match.c
index 3cf40306..bb3e95f6 100644
--- a/match.c
+++ b/match.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: match.c,v 1.37 2017/03/10 04:24:55 djm Exp $ */
+/* $OpenBSD: match.c,v 1.38 2018/07/04 13:49:31 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo at cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo at cs.hut.fi>, Espoo, Finland
@@ -294,16 +294,20 @@ match_list(const char *client, const char *server, u_int *next)
}
/*
- * Filters a comma-separated list of strings, excluding any entry matching
- * the 'filter' pattern list. Caller must free returned string.
+ * Filter proposal using pattern-list filter.
+ * "blacklist" determines sense of filter:
+ * non-zero indicates that items matching filter should be excluded.
+ * zero indicates that only items matching filter should be included.
+ * returns NULL on allocation error, otherwise caller must free result.
*/
-char *
-match_filter_list(const char *proposal, const char *filter)
+static char *
+filter_list(const char *proposal, const char *filter, int blacklist)
{
size_t len = strlen(proposal) + 1;
char *fix_prop = malloc(len);
char *orig_prop = strdup(proposal);
char *cp, *tmp;
+ int r;
if (fix_prop == NULL || orig_prop == NULL) {
free(orig_prop);
@@ -314,7 +318,8 @@ match_filter_list(const char *proposal, const char *filter)
tmp = orig_prop;
*fix_prop = '\0';
while ((cp = strsep(&tmp, ",")) != NULL) {
- if (match_pattern_list(cp, filter, 0) != 1) {
+ r = match_pattern_list(cp, filter, 0);
+ if ((blacklist && r != 1) || (!blacklist && r == 1)) {
if (*fix_prop != '\0')
strlcat(fix_prop, ",", len);
strlcat(fix_prop, cp, len);
@@ -324,3 +329,22 @@ match_filter_list(const char *proposal, const char *filter)
return fix_prop;
}
+/*
+ * Filters a comma-separated list of strings, excluding any entry matching
+ * the 'filter' pattern list. Caller must free returned string.
+ */
+char *
+match_filter_blacklist(const char *proposal, const char *filter)
+{
+ return filter_list(proposal, filter, 1);
+}
+
+/*
+ * Filters a comma-separated list of strings, including only entries matching
+ * the 'filter' pattern list. Caller must free returned string.
+ */
+char *
+match_filter_whitelist(const char *proposal, const char *filter)
+{
+ return filter_list(proposal, filter, 0);
+}
diff --git a/match.h b/match.h
index 937ba041..852b1a5c 100644
--- a/match.h
+++ b/match.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: match.h,v 1.17 2017/02/03 23:01:19 djm Exp $ */
+/* $OpenBSD: match.h,v 1.18 2018/07/04 13:49:31 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo at cs.hut.fi>
@@ -20,7 +20,8 @@ int match_hostname(const char *, const char *);
int match_host_and_ip(const char *, const char *, const char *);
int match_user(const char *, const char *, const char *, const char *);
char *match_list(const char *, const char *, u_int *);
-char *match_filter_list(const char *, const char *);
+char *match_filter_blacklist(const char *, const char *);
+char *match_filter_whitelist(const char *, const char *);
/* addrmatch.c */
int addr_match_list(const char *, const char *);
diff --git a/readconf.c b/readconf.c
index 8d202954..2bc27075 100644
--- a/readconf.c
+++ b/readconf.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: readconf.c,v 1.291 2018/06/10 23:45:41 djm Exp $ */
+/* $OpenBSD: readconf.c,v 1.292 2018/07/04 13:49:31 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo at cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo at cs.hut.fi>, Espoo, Finland
@@ -1936,6 +1936,8 @@ fill_default_options_for_canonicalization(Options *options)
void
fill_default_options(Options * options)
{
+ char *all_cipher, *all_mac, *all_kex, *all_key;
+
if (options->forward_agent == -1)
options->forward_agent = 0;
if (options->forward_x11 == -1)
@@ -2082,14 +2084,27 @@ fill_default_options(Options * options)
options->fingerprint_hash = SSH_FP_HASH_DEFAULT;
if (options->update_hostkeys == -1)
options->update_hostkeys = 0;
- if (kex_assemble_names(KEX_CLIENT_ENCRYPT, &options->ciphers) != 0 ||
- kex_assemble_names(KEX_CLIENT_MAC, &options->macs) != 0 ||
- kex_assemble_names(KEX_CLIENT_KEX, &options->kex_algorithms) != 0 ||
- kex_assemble_names(KEX_DEFAULT_PK_ALG,
- &options->hostbased_key_types) != 0 ||
- kex_assemble_names(KEX_DEFAULT_PK_ALG,
- &options->pubkey_key_types) != 0)
+
+ /* Expand KEX name lists */
+ all_cipher = cipher_alg_list(',', 0);
+ all_mac = mac_alg_list(',');
+ all_kex = kex_alg_list(',');
+ all_key = sshkey_alg_list(0, 0, 1, ',');
+ if (kex_assemble_names(&options->ciphers,
+ KEX_CLIENT_ENCRYPT, all_cipher) != 0 ||
+ kex_assemble_names(&options->macs,
+ KEX_CLIENT_MAC, all_mac) != 0 ||
+ kex_assemble_names(&options->kex_algorithms,
+ KEX_CLIENT_KEX, all_kex) != 0 ||
+ kex_assemble_names(&options->hostbased_key_types,
+ KEX_DEFAULT_PK_ALG, all_key) != 0 ||
+ kex_assemble_names(&options->pubkey_key_types,
+ KEX_DEFAULT_PK_ALG, all_key) != 0)
fatal("%s: kex_assemble_names failed", __func__);
+ free(all_cipher);
+ free(all_mac);
+ free(all_kex);
+ free(all_key);
#define CLEAR_ON_NONE(v) \
do { \
@@ -2537,11 +2552,14 @@ void
dump_client_config(Options *o, const char *host)
{
int i;
- char buf[8];
+ char buf[8], *all_key;
/* This is normally prepared in ssh_kex2 */
- if (kex_assemble_names(KEX_DEFAULT_PK_ALG, &o->hostkeyalgorithms) != 0)
+ all_key = sshkey_alg_list(0, 0, 1, ',');
+ if (kex_assemble_names( &o->hostkeyalgorithms,
+ KEX_DEFAULT_PK_ALG, all_key) != 0)
fatal("%s: kex_assemble_names failed", __func__);
+ free(all_key);
/* Most interesting options first: user, host, port */
dump_cfg_string(oUser, o->user);
diff --git a/servconf.c b/servconf.c
index a41fdc26..a54219f0 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
-/* $OpenBSD: servconf.c,v 1.334 2018/07/03 10:59:35 djm Exp $ */
+/* $OpenBSD: servconf.c,v 1.335 2018/07/04 13:49:31 djm Exp $ */
/*
* Copyright (c) 1995 Tatu Ylonen <ylo at cs.hut.fi>, Espoo, Finland
* All rights reserved
@@ -190,15 +190,29 @@ option_clear_or_none(const char *o)
static void
assemble_algorithms(ServerOptions *o)
{
- if (kex_assemble_names(KEX_SERVER_ENCRYPT, &o->ciphers) != 0 ||
- kex_assemble_names(KEX_SERVER_MAC, &o->macs) != 0 ||
- kex_assemble_names(KEX_SERVER_KEX, &o->kex_algorithms) != 0 ||
- kex_assemble_names(KEX_DEFAULT_PK_ALG,
- &o->hostkeyalgorithms) != 0 ||
- kex_assemble_names(KEX_DEFAULT_PK_ALG,
- &o->hostbased_key_types) != 0 ||
- kex_assemble_names(KEX_DEFAULT_PK_ALG, &o->pubkey_key_types) != 0)
+ char *all_cipher, *all_mac, *all_kex, *all_key;
+
+ all_cipher = cipher_alg_list(',', 0);
+ all_mac = mac_alg_list(',');
+ all_kex = kex_alg_list(',');
+ all_key = sshkey_alg_list(0, 0, 1, ',');
+ if (kex_assemble_names(&o->ciphers,
+ KEX_SERVER_ENCRYPT, all_cipher) != 0 ||
+ kex_assemble_names(&o->macs,
+ KEX_SERVER_MAC, all_mac) != 0 ||
+ kex_assemble_names(&o->kex_algorithms,
+ KEX_SERVER_KEX, all_kex) != 0 ||
+ kex_assemble_names(&o->hostkeyalgorithms,
+ KEX_DEFAULT_PK_ALG, all_key) != 0 ||
+ kex_assemble_names(&o->hostbased_key_types,
+ KEX_DEFAULT_PK_ALG, all_key) != 0 ||
+ kex_assemble_names(&o->pubkey_key_types,
+ KEX_DEFAULT_PK_ALG, all_key) != 0)
fatal("kex_assemble_names failed");
+ free(all_cipher);
+ free(all_mac);
+ free(all_kex);
+ free(all_key);
}
static void
diff --git a/ssh_config.5 b/ssh_config.5
index eff9c5e6..df94d60d 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -33,8 +33,8 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.\" $OpenBSD: ssh_config.5,v 1.278 2018/07/03 11:39:54 djm Exp $
-.Dd $Mdocdate: July 3 2018 $
+.\" $OpenBSD: ssh_config.5,v 1.279 2018/07/04 13:49:31 djm Exp $
+.Dd $Mdocdate: July 4 2018 $
.Dt SSH_CONFIG 5
.Os
.Sh NAME
@@ -757,7 +757,7 @@ or
(the default).
.It Cm HostbasedKeyTypes
Specifies the key types that will be used for hostbased authentication
-as a comma-separated pattern list.
+as a comma-separated list of patterns.
Alternately if the specified value begins with a
.Sq +
character, then the specified key types will be appended to the default set
@@ -1242,7 +1242,7 @@ The default is
.Cm no .
.It Cm PubkeyAcceptedKeyTypes
Specifies the key types that will be used for public key authentication
-as a comma-separated pattern list.
+as a comma-separated list of patterns.
Alternately if the specified value begins with a
.Sq +
character, then the key types after it will be appended to the default
diff --git a/sshconnect2.c b/sshconnect2.c
index db95cb21..f3ccd53a 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.274 2018/07/03 13:20:25 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.275 2018/07/04 13:49:31 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Damien Miller. All rights reserved.
@@ -158,7 +158,7 @@ void
ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
{
char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
- char *s;
+ char *s, *all_key;
struct kex *kex;
int r;
@@ -178,9 +178,11 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
myproposal[PROPOSAL_MAC_ALGS_CTOS] =
myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
if (options.hostkeyalgorithms != NULL) {
- if (kex_assemble_names(KEX_DEFAULT_PK_ALG,
- &options.hostkeyalgorithms) != 0)
+ all_key = sshkey_alg_list(0, 0, 1, ',');
+ if (kex_assemble_names(&options.hostkeyalgorithms,
+ KEX_DEFAULT_PK_ALG, all_key) != 0)
fatal("%s: kex_assemble_namelist", __func__);
+ free(all_key);
myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
compat_pkalg_proposal(options.hostkeyalgorithms);
} else {
diff --git a/sshd_config.5 b/sshd_config.5
index cc019ec7..aa888796 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,8 +33,8 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.\" $OpenBSD: sshd_config.5,v 1.279 2018/07/03 11:39:54 djm Exp $
-.Dd $Mdocdate: July 3 2018 $
+.\" $OpenBSD: sshd_config.5,v 1.280 2018/07/04 13:49:31 djm Exp $
+.Dd $Mdocdate: July 4 2018 $
.Dt SSHD_CONFIG 5
.Os
.Sh NAME
@@ -659,7 +659,7 @@ The default is
.Cm yes .
.It Cm HostbasedAcceptedKeyTypes
Specifies the key types that will be accepted for hostbased authentication
-as a comma-separated pattern list.
+as a list of comma-separated patterns.
Alternately if the specified value begins with a
.Sq +
character, then the specified key types will be appended to the default set
@@ -1386,7 +1386,7 @@ The default is
.Cm yes .
.It Cm PubkeyAcceptedKeyTypes
Specifies the key types that will be accepted for public key authentication
-as a comma-separated pattern list.
+as a list of comma-separated patterns.
Alternately if the specified value begins with a
.Sq +
character, then the specified key types will be appended to the default set
--
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