diff options
Diffstat (limited to 'common-session.c')
| -rw-r--r-- | common-session.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/common-session.c b/common-session.c index e8dc650..b8ea6f7 100644 --- a/common-session.c +++ b/common-session.c @@ -229,13 +229,11 @@ void session_identification() { /* write our version string, this blocks */ if (atomicio(write, ses.sock, LOCAL_IDENT "\r\n", strlen(LOCAL_IDENT "\r\n")) == DROPBEAR_FAILURE) { - dropbear_exit("Error writing ident string"); + ses.remoteclosed(); } - /* We allow up to 9 lines before the actual version string, to - * account for wrappers/cruft etc. According to the spec only the client - * needs to handle this, but no harm in letting the server handle it too */ - for (i = 0; i < 10; i++) { + /* If they send more than 50 lines, something is wrong */ + for (i = 0; i < 50; i++) { len = ident_readln(ses.sock, linebuf, sizeof(linebuf)); if (len < 0 && errno != EINTR) { @@ -252,13 +250,19 @@ void session_identification() { if (!done) { TRACE(("err: %s for '%s'\n", strerror(errno), linebuf)) - dropbear_exit("Failed to get remote version"); + ses.remoteclosed(); } else { /* linebuf is already null terminated */ ses.remoteident = m_malloc(len); memcpy(ses.remoteident, linebuf, len); } + /* Shall assume that 2.x will be backwards compatible. */ + if (strncmp(ses.remoteident, "SSH-2.", 6) != 0 + && strncmp(ses.remoteident, "SSH-1.99-", 9) != 0) { + dropbear_exit("Incompatible remote version '%s'", ses.remoteident); + } + TRACE(("remoteident: %s", ses.remoteident)) } |