From 1cbbbb90ae1a4f88f8090e1fdecee007b8d360f8 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sun, 9 Feb 2014 16:10:06 +0000 Subject: Add DebianBanner server configuration option Setting this to "no" causes sshd to omit the Debian revision from its initial protocol handshake, for those scared by package-versioning.patch. Bug-Debian: http://bugs.debian.org/562048 Forwarded: not-needed Last-Update: 2015-11-29 Patch-Name: debian-banner.patch --- servconf.c | 9 +++++++++ servconf.h | 2 ++ sshd.c | 3 ++- sshd_config.5 | 5 +++++ 4 files changed, 18 insertions(+), 1 deletion(-) diff --git a/servconf.c b/servconf.c index ed3a88d..a778f44 100644 --- a/servconf.c +++ b/servconf.c @@ -171,6 +171,7 @@ initialize_server_options(ServerOptions *options) options->ip_qos_bulk = -1; options->version_addendum = NULL; options->fingerprint_hash = -1; + options->debian_banner = -1; } /* Returns 1 if a string option is unset or set to "none" or 0 otherwise. */ @@ -347,6 +348,8 @@ fill_default_server_options(ServerOptions *options) options->fwd_opts.streamlocal_bind_unlink = 0; if (options->fingerprint_hash == -1) options->fingerprint_hash = SSH_FP_HASH_DEFAULT; + if (options->debian_banner == -1) + options->debian_banner = 1; if (kex_assemble_names(KEX_SERVER_ENCRYPT, &options->ciphers) != 0 || kex_assemble_names(KEX_SERVER_MAC, &options->macs) != 0 || @@ -430,6 +433,7 @@ typedef enum { sAuthenticationMethods, sHostKeyAgent, sPermitUserRC, sStreamLocalBindMask, sStreamLocalBindUnlink, sAllowStreamLocalForwarding, sFingerprintHash, + sDebianBanner, sDeprecated, sUnsupported } ServerOpCodes; @@ -577,6 +581,7 @@ static struct { { "streamlocalbindunlink", sStreamLocalBindUnlink, SSHCFG_ALL }, { "allowstreamlocalforwarding", sAllowStreamLocalForwarding, SSHCFG_ALL }, { "fingerprinthash", sFingerprintHash, SSHCFG_GLOBAL }, + { "debianbanner", sDebianBanner, SSHCFG_GLOBAL }, { NULL, sBadOption, 0 } }; @@ -1867,6 +1872,10 @@ process_server_config_line(ServerOptions *options, char *line, options->fingerprint_hash = value; break; + case sDebianBanner: + intptr = &options->debian_banner; + goto parse_int; + case sDeprecated: logit("%s line %d: Deprecated option %s", filename, linenum, arg); diff --git a/servconf.h b/servconf.h index 778ba17..161fa37 100644 --- a/servconf.h +++ b/servconf.h @@ -197,6 +197,8 @@ typedef struct { char *auth_methods[MAX_AUTH_METHODS]; int fingerprint_hash; + + int debian_banner; } ServerOptions; /* Information about the incoming connection as used by Match */ diff --git a/sshd.c b/sshd.c index 189d34a..8d17521 100644 --- a/sshd.c +++ b/sshd.c @@ -443,7 +443,8 @@ sshd_exchange_identification(int sock_in, int sock_out) } xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s", - major, minor, SSH_RELEASE, + major, minor, + options.debian_banner ? SSH_RELEASE : SSH_RELEASE_MINIMUM, *options.version_addendum == '\0' ? "" : " ", options.version_addendum, newline); diff --git a/sshd_config.5 b/sshd_config.5 index c8ee35d..b149bd3 100644 --- a/sshd_config.5 +++ b/sshd_config.5 @@ -533,6 +533,11 @@ or .Dq no . The default is .Dq delayed . +.It Cm DebianBanner +Specifies whether the distribution-specified extra version suffix is +included during initial protocol handshake. +The default is +.Dq yes . .It Cm DenyGroups This keyword can be followed by a list of group name patterns, separated by spaces.