- djm@cvs.openbsd.org 2013/05/16 04:27:50

     [ssh_config.5 readconf.h readconf.c]
     add the ability to ignore specific unrecognised ssh_config options;
     bz#866; ok markus@

4 files changed, 45 insertions, 11 deletions

diff --git a/ChangeLog b/ChangeLog
index 186c43247..ae0f84777 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -33,6 +33,10 @@
      sshd.c] Add RekeyLimit to sshd with the same syntax as the client allowing
      rekeying based on traffic volume or time.  ok djm@, help & ok jmc@ for the man
      page.
+   - djm@cvs.openbsd.org 2013/05/16 04:27:50
+     [ssh_config.5 readconf.h readconf.c]
+     add the ability to ignore specific unrecognised ssh_config options;
+     bz#866; ok markus@
 
 20130510
  - (dtucker) [configure.ac] Enable -Wsizeof-pointer-memaccess if the compiler
diff --git a/readconf.c b/readconf.c
index d8898a029..51b23a3b8 100644
--- a/readconf.c
+++ b/readconf.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: readconf.c,v 1.198 2013/05/16 02:00:34 dtucker Exp $ */
+/* $OpenBSD: readconf.c,v 1.199 2013/05/16 04:27:50 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -134,8 +134,8 @@ typedef enum {
         oHashKnownHosts,
         oTunnel, oTunnelDevice, oLocalCommand, oPermitLocalCommand,
         oVisualHostKey, oUseRoaming, oZeroKnowledgePasswordAuthentication,
-        oKexAlgorithms, oIPQoS, oRequestTTY,
-        oDeprecated, oUnsupported
+        oKexAlgorithms, oIPQoS, oRequestTTY, oIgnoreUnknown,
+        oIgnoredUnknownOption, oDeprecated, oUnsupported
 } OpCodes;
 
 /* Textual representations of the tokens. */
@@ -246,6 +246,7 @@ static struct {
         { "kexalgorithms", oKexAlgorithms },
         { "ipqos", oIPQoS },
         { "requesttty", oRequestTTY },
+        { "ignoreunknown", oIgnoreUnknown },
 
         { NULL, oBadOption }
 };
@@ -351,14 +352,17 @@ add_identity_file(Options *options, const char *dir, const char *filename,
  */
 
 static OpCodes
-parse_token(const char *cp, const char *filename, int linenum)
+parse_token(const char *cp, const char *filename, int linenum,
+    const char *ignored_unknown)
 {
-        u_int i;
+        int i;
 
         for (i = 0; keywords[i].name; i++)
-                if (strcasecmp(cp, keywords[i].name) == 0)
+                if (strcmp(cp, keywords[i].name) == 0)
                         return keywords[i].opcode;
-
+        if (ignored_unknown != NULL && match_pattern_list(cp, ignored_unknown,
+            strlen(ignored_unknown), 1) == 1)
+                return oIgnoredUnknownOption;
         error("%s: line %d: Bad configuration option: %s",
             filename, linenum, cp);
         return oBadOption;
@@ -377,7 +381,7 @@ process_config_line(Options *options, const char *host,
 {
         char *s, **charptr, *endofnumber, *keyword, *arg, *arg2;
         char **cpptr, fwdarg[256];
-        u_int *uintptr, max_entries = 0;
+        u_int i, *uintptr, max_entries = 0;
         int negated, opcode, *intptr, value, value2, scale;
         LogLevel *log_level_ptr;
         long long orig, val64;
@@ -400,14 +404,22 @@ process_config_line(Options *options, const char *host,
                 keyword = strdelim(&s);
         if (keyword == NULL || !*keyword || *keyword == '\n' || *keyword == '#')
                 return 0;
+        /* Match lowercase keyword */
+        for (i = 0; i < strlen(keyword); i++)
+                keyword[i] = tolower(keyword[i]);
 
-        opcode = parse_token(keyword, filename, linenum);
+        opcode = parse_token(keyword, filename, linenum,
+            options->ignored_unknown);
 
         switch (opcode) {
         case oBadOption:
                 /* don't panic, but count bad options */
                 return -1;
                 /* NOTREACHED */
+        case oIgnoredUnknownOption:
+                debug("%s line %d: Ignored unknown option \"%s\"",
+                    filename, linenum, keyword);
+                return 0;
         case oConnectTimeout:
                 intptr = &options->connection_timeout;
 parse_time:
@@ -1077,6 +1089,10 @@ parse_int:
                         *intptr = value;
                 break;
 
+        case oIgnoreUnknown:
+                charptr = &options->ignored_unknown;
+                goto parse_string;
+
         case oDeprecated:
                 debug("%s line %d: Deprecated option \"%s\"",
                     filename, linenum, keyword);
@@ -1238,6 +1254,7 @@ initialize_options(Options * options)
         options->ip_qos_interactive = -1;
         options->ip_qos_bulk = -1;
         options->request_tty = -1;
+        options->ignored_unknown = NULL;
 }
 
 /*
diff --git a/readconf.h b/readconf.h
index e20573090..23fc500da 100644
--- a/readconf.h
+++ b/readconf.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: readconf.h,v 1.94 2013/05/16 02:00:34 dtucker Exp $ */
+/* $OpenBSD: readconf.h,v 1.95 2013/05/16 04:27:50 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -137,6 +137,8 @@ typedef struct {
         int     use_roaming;
 
         int     request_tty;
+
+        char    *ignored_unknown; /* Pattern list of unknown tokens to ignore */
 }       Options;
 
 #define SSHCTL_MASTER_NO        0
diff --git a/ssh_config.5 b/ssh_config.5
index 97897e00e..955afe351 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -33,7 +33,7 @@
 .\" (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 1.162 2013/05/16 02:00:34 dtucker Exp $
+.\" $OpenBSD: ssh_config.5,v 1.163 2013/05/16 04:27:50 djm Exp $
 .Dd $Mdocdate: May 16 2013 $
 .Dt SSH_CONFIG 5
 .Os
@@ -597,6 +597,17 @@ The default is the name given on the command line.
 Numeric IP addresses are also permitted (both on the command line and in
 .Cm HostName
 specifications).
+.It Cm IgnoreUnknown
+Specifies a pattern-list of unknown options to be ignored if they are
+encountered in configuration parsing.
+This may be used to suppress errors if
+.Nm
+contains options that are unrecognised by
+.Xr ssh 1 .
+It is recommended that
+.Cm IgnoreUnknown
+be listed early in the configuration file as it will not be applied
+to unknown options that appear before it.
 .It Cm IdentitiesOnly
 Specifies that
 .Xr ssh 1