upstream: better validate CASignatureAlgorithms in ssh_config and

sshd_config.

Previously this directive would accept certificate algorithm names, but
these were unusable in practice as OpenSSH does not support CA chains.

part of bz3577; ok dtucker@

OpenBSD-Commit-ID: a992d410c8a78ec982701bc3f91043dbdb359912
This commit is contained in:
djm@openbsd.org 2023-06-21 05:10:26 +00:00 committed by Damien Miller
parent 4e73cd0f4a
commit c1c2ca1365
No known key found for this signature in database
4 changed files with 22 additions and 9 deletions

View File

@ -1,4 +1,4 @@
/* $OpenBSD: readconf.c,v 1.376 2023/03/31 04:23:02 djm Exp $ */
/* $OpenBSD: readconf.c,v 1.377 2023/06/21 05:10:26 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -945,7 +945,7 @@ process_config_line_depth(Options *options, struct passwd *pw, const char *host,
char **cpptr, ***cppptr, fwdarg[256];
u_int i, *uintptr, uvalue, max_entries = 0;
int r, oactive, negated, opcode, *intptr, value, value2, cmdline = 0;
int remotefwd, dynamicfwd;
int remotefwd, dynamicfwd, ca_only = 0;
LogLevel *log_level_ptr;
SyslogFacility *log_facility_ptr;
long long val64;
@ -1441,6 +1441,7 @@ parse_int:
case oHostKeyAlgorithms:
charptr = &options->hostkeyalgorithms;
ca_only = 0;
parse_pubkey_algos:
arg = argv_next(&ac, &av);
if (!arg || *arg == '\0') {
@ -1450,7 +1451,7 @@ parse_pubkey_algos:
}
if (*arg != '-' &&
!sshkey_names_valid2(*arg == '+' || *arg == '^' ?
arg + 1 : arg, 1)) {
arg + 1 : arg, 1, ca_only)) {
error("%s line %d: Bad key types '%s'.",
filename, linenum, arg ? arg : "<NONE>");
goto out;
@ -1461,6 +1462,7 @@ parse_pubkey_algos:
case oCASignatureAlgorithms:
charptr = &options->ca_sign_algorithms;
ca_only = 1;
goto parse_pubkey_algos;
case oLogLevel:
@ -2117,10 +2119,12 @@ parse_pubkey_algos:
case oHostbasedAcceptedAlgorithms:
charptr = &options->hostbased_accepted_algos;
ca_only = 0;
goto parse_pubkey_algos;
case oPubkeyAcceptedAlgorithms:
charptr = &options->pubkey_accepted_algos;
ca_only = 0;
goto parse_pubkey_algos;
case oAddKeysToAgent:

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@ -1,5 +1,5 @@
/* $OpenBSD: servconf.c,v 1.394 2023/06/05 13:24:36 millert Exp $ */
/* $OpenBSD: servconf.c,v 1.395 2023/06/21 05:10:26 djm Exp $ */
/*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
@ -1333,6 +1333,7 @@ process_server_config_line_depth(ServerOptions *options, char *line,
{
char *str, ***chararrayptr, **charptr, *arg, *arg2, *p, *keyword;
int cmdline = 0, *intptr, value, value2, n, port, oactive, r, found;
int ca_only = 0;
SyslogFacility *log_facility_ptr;
LogLevel *log_level_ptr;
ServerOpCodes opcode;
@ -1574,6 +1575,7 @@ process_server_config_line_depth(ServerOptions *options, char *line,
case sHostbasedAcceptedAlgorithms:
charptr = &options->hostbased_accepted_algos;
ca_only = 0;
parse_pubkey_algos:
arg = argv_next(&ac, &av);
if (!arg || *arg == '\0')
@ -1581,7 +1583,7 @@ process_server_config_line_depth(ServerOptions *options, char *line,
filename, linenum);
if (*arg != '-' &&
!sshkey_names_valid2(*arg == '+' || *arg == '^' ?
arg + 1 : arg, 1))
arg + 1 : arg, 1, ca_only))
fatal("%s line %d: Bad key types '%s'.",
filename, linenum, arg ? arg : "<NONE>");
if (*activep && *charptr == NULL)
@ -1590,18 +1592,22 @@ process_server_config_line_depth(ServerOptions *options, char *line,
case sHostKeyAlgorithms:
charptr = &options->hostkeyalgorithms;
ca_only = 0;
goto parse_pubkey_algos;
case sCASignatureAlgorithms:
charptr = &options->ca_sign_algorithms;
ca_only = 1;
goto parse_pubkey_algos;
case sPubkeyAuthentication:
intptr = &options->pubkey_authentication;
ca_only = 0;
goto parse_flag;
case sPubkeyAcceptedAlgorithms:
charptr = &options->pubkey_accepted_algos;
ca_only = 0;
goto parse_pubkey_algos;
case sPubkeyAuthOptions:

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@ -1,4 +1,4 @@
/* $OpenBSD: sshkey.c,v 1.135 2023/03/31 03:22:49 djm Exp $ */
/* $OpenBSD: sshkey.c,v 1.136 2023/06/21 05:10:26 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Alexander von Gernler. All rights reserved.
@ -340,7 +340,7 @@ sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
}
int
sshkey_names_valid2(const char *names, int allow_wildcard)
sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only)
{
char *s, *cp, *p;
const struct sshkey_impl *impl;
@ -373,6 +373,9 @@ sshkey_names_valid2(const char *names, int allow_wildcard)
}
free(s);
return 0;
} else if (plain_only && sshkey_type_is_cert(type)) {
free(s);
return 0;
}
}
free(s);

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@ -1,4 +1,4 @@
/* $OpenBSD: sshkey.h,v 1.61 2022/10/28 00:44:44 djm Exp $ */
/* $OpenBSD: sshkey.h,v 1.62 2023/06/21 05:10:26 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
@ -264,7 +264,7 @@ int sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
int sshkey_ec_validate_private(const EC_KEY *);
const char *sshkey_ssh_name(const struct sshkey *);
const char *sshkey_ssh_name_plain(const struct sshkey *);
int sshkey_names_valid2(const char *, int);
int sshkey_names_valid2(const char *, int, int);
char *sshkey_alg_list(int, int, int, char);
int sshkey_from_blob(const u_char *, size_t, struct sshkey **);