diff options
author | djm@openbsd.org <djm@openbsd.org> | 2018-07-04 13:49:31 +0000 |
---|---|---|
committer | Damien Miller <djm@mindrot.org> | 2018-07-04 23:51:52 +1000 |
commit | 312d2f2861a2598ed08587cb6c45c0e98a85408f (patch) | |
tree | e3bdc4facef48a89cd76fa793d9e70211b7ff8d2 | |
parent | 303af5803bd74bf05d375c04e1a83b40c30b2be5 (diff) |
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
-rw-r--r-- | compat.c | 18 | ||||
-rw-r--r-- | kex.c | 95 | ||||
-rw-r--r-- | kex.h | 4 | ||||
-rw-r--r-- | match.c | 36 | ||||
-rw-r--r-- | match.h | 5 | ||||
-rw-r--r-- | readconf.c | 38 | ||||
-rw-r--r-- | servconf.c | 32 | ||||
-rw-r--r-- | ssh_config.5 | 8 | ||||
-rw-r--r-- | sshconnect2.c | 10 | ||||
-rw-r--r-- | sshd_config.5 | 8 |
10 files changed, 187 insertions, 67 deletions
@@ -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@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') @@ -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 */ @@ -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]); @@ -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@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@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); +} @@ -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@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 *); @@ -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@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@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); @@ -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@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 |