From a18385c6866da4d69f46b64626ae5d60b4cf4a66 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: 2018-10-19 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 6caf1db38..c5dd617ef 100644 --- a/servconf.c +++ b/servconf.c @@ -182,6 +182,7 @@ initialize_server_options(ServerOptions *options) options->fingerprint_hash = -1; options->disable_forwarding = -1; options->expose_userauth_info = -1; + options->debian_banner = -1; } /* Returns 1 if a string option is unset or set to "none" or 0 otherwise. */ @@ -417,6 +418,8 @@ fill_default_server_options(ServerOptions *options) options->disable_forwarding = 0; if (options->expose_userauth_info == -1) options->expose_userauth_info = 0; + if (options->debian_banner == -1) + options->debian_banner = 1; assemble_algorithms(options); @@ -504,6 +507,7 @@ typedef enum { sStreamLocalBindMask, sStreamLocalBindUnlink, sAllowStreamLocalForwarding, sFingerprintHash, sDisableForwarding, sExposeAuthInfo, sRDomain, + sDebianBanner, sDeprecated, sIgnore, sUnsupported } ServerOpCodes; @@ -661,6 +665,7 @@ static struct { { "exposeauthinfo", sExposeAuthInfo, SSHCFG_ALL }, { "rdomain", sRDomain, SSHCFG_ALL }, { "casignaturealgorithms", sCASignatureAlgorithms, SSHCFG_ALL }, + { "debianbanner", sDebianBanner, SSHCFG_GLOBAL }, { NULL, sBadOption, 0 } }; @@ -2173,6 +2178,10 @@ process_server_config_line(ServerOptions *options, char *line, *charptr = xstrdup(arg); break; + case sDebianBanner: + intptr = &options->debian_banner; + goto parse_flag; + case sDeprecated: case sIgnore: case sUnsupported: diff --git a/servconf.h b/servconf.h index 3b76da816..4e3c54042 100644 --- a/servconf.h +++ b/servconf.h @@ -212,6 +212,8 @@ typedef struct { int fingerprint_hash; int expose_userauth_info; u_int64_t timing_secret; + + int debian_banner; } ServerOptions; /* Information about the incoming connection as used by Match */ diff --git a/sshd.c b/sshd.c index 9481272fc..d7e77d343 100644 --- a/sshd.c +++ b/sshd.c @@ -384,7 +384,8 @@ sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out) char remote_version[256]; /* Must be at least as big as buf. */ xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n", - PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_RELEASE, + PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, + options.debian_banner ? SSH_RELEASE : SSH_RELEASE_MINIMUM, *options.version_addendum == '\0' ? "" : " ", options.version_addendum); diff --git a/sshd_config.5 b/sshd_config.5 index e7e55dd71..37e6be38f 100644 --- a/sshd_config.5 +++ b/sshd_config.5 @@ -543,6 +543,11 @@ or .Cm no . The default is .Cm yes . +.It Cm DebianBanner +Specifies whether the distribution-specified extra version suffix is +included during initial protocol handshake. +The default is +.Cm yes . .It Cm DenyGroups This keyword can be followed by a list of group name patterns, separated by spaces.