From 05a980ba4bd3de0540771000955bd3235ad17acd Mon Sep 17 00:00:00 2001 From: Holger Weiss Date: Sat, 15 Sep 2007 14:25:56 +0000 Subject: Properly handle SMTP server responses which are split into multiple packets (noted by Chris Adams on nagiosplug-help@). TODO: The new recvline()/recvlines() functions should buffer received data instead of reading one byte at a time and they should be moved to netutils.c so that other plugins can use them, too. git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1780 f882894a-f735-0410-b71e-b25c423dba1c --- plugins/check_smtp.c | 90 +++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 72 insertions(+), 18 deletions(-) (limited to 'plugins/check_smtp.c') diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c index 8d392cc6..79c7cd35 100644 --- a/plugins/check_smtp.c +++ b/plugins/check_smtp.c @@ -40,6 +40,8 @@ const char *revision = "$Revision$"; const char *copyright = "2000-2006"; const char *email = "nagiosplug-devel@lists.sourceforge.net"; +#include + #include "common.h" #include "netutils.h" #include "utils.h" @@ -75,6 +77,8 @@ int validate_arguments (void); void print_help (void); void print_usage (void); void smtp_quit(void); +int recvline(char *, size_t); +int recvlines(char *, size_t); int my_close(void); #include "regex.h" @@ -116,7 +120,6 @@ char buffer[MAX_INPUT_BUFFER]; enum { TCP_PROTOCOL = 1, UDP_PROTOCOL = 2, - MAXBUF = 1024 }; /* written by lauri alanko */ @@ -222,7 +225,7 @@ main (int argc, char **argv) /* watch for the SMTP connection string and */ /* return a WARNING status if we couldn't read any data */ - if (recv (sd, buffer, MAX_INPUT_BUFFER - 1, 0) == -1) { + if (recvlines(buffer, MAX_INPUT_BUFFER) <= 0) { printf (_("recv() failed\n")); result = STATE_WARNING; } @@ -246,11 +249,10 @@ main (int argc, char **argv) send(sd, helocmd, strlen(helocmd), 0); /* allow for response to helo command to reach us */ - if(read (sd, buffer, MAXBUF - 1) < 0){ + if (recvlines(buffer, MAX_INPUT_BUFFER) <= 0) { printf (_("recv() failed\n")); return STATE_WARNING; } else if(use_ehlo){ - buffer[MAXBUF-1]='\0'; if(strstr(buffer, "250 STARTTLS") != NULL || strstr(buffer, "250-STARTTLS") != NULL){ supports_tls=TRUE; @@ -268,7 +270,7 @@ main (int argc, char **argv) /* send the STARTTLS command */ send(sd, SMTP_STARTTLS, strlen(SMTP_STARTTLS), 0); - recv(sd,buffer, MAX_INPUT_BUFFER-1, 0); /* wait for it */ + recvlines(buffer, MAX_INPUT_BUFFER); /* wait for it */ if (!strstr (buffer, server_expect)) { printf (_("Server does not support STARTTLS\n")); smtp_quit(); @@ -302,13 +304,12 @@ main (int argc, char **argv) } if (verbose) printf(_("sent %s"), helocmd); - if ((n = my_recv(buffer, MAX_INPUT_BUFFER - 1)) <= 0) { + if ((n = recvlines(buffer, MAX_INPUT_BUFFER)) <= 0) { printf("%s\n", _("SMTP UNKNOWN - Cannot read EHLO response via TLS.")); my_close(); return STATE_UNKNOWN; } if (verbose) { - buffer[n] = '\0'; printf("%s", buffer); } @@ -337,16 +338,14 @@ main (int argc, char **argv) */ if (smtp_use_dummycmd) { my_send(cmd_str, strlen(cmd_str)); - my_recv(buffer, MAX_INPUT_BUFFER-1); - if (verbose) + if (recvlines(buffer, MAX_INPUT_BUFFER) >= 1 && verbose) printf("%s", buffer); } while (n < ncommands) { asprintf (&cmd_str, "%s%s", commands[n], "\r\n"); my_send(cmd_str, strlen(cmd_str)); - my_recv(buffer, MAX_INPUT_BUFFER-1); - if (verbose) + if (recvlines(buffer, MAX_INPUT_BUFFER) >= 1 && verbose) printf("%s", buffer); strip (buffer); if (n < nresponses) { @@ -395,12 +394,11 @@ main (int argc, char **argv) if (verbose) printf (_("sent %s\n"), "AUTH LOGIN"); - if((ret = my_recv(buffer, MAXBUF - 1)) < 0){ + if ((ret = recvlines(buffer, MAX_INPUT_BUFFER)) <= 0) { asprintf(&error_msg, _("recv() failed after AUTH LOGIN, ")); result = STATE_WARNING; break; } - buffer[ret] = 0; if (verbose) printf (_("received %s\n"), buffer); @@ -417,12 +415,11 @@ main (int argc, char **argv) if (verbose) printf (_("sent %s\n"), abuf); - if ((ret = my_recv(buffer, MAX_INPUT_BUFFER-1)) == -1) { + if ((ret = recvlines(buffer, MAX_INPUT_BUFFER)) <= 0) { result = STATE_CRITICAL; asprintf(&error_msg, _("recv() failed after sending authuser, ")); break; } - buffer[ret] = 0; if (verbose) { printf (_("received %s\n"), buffer); } @@ -438,12 +435,11 @@ main (int argc, char **argv) if (verbose) { printf (_("sent %s\n"), abuf); } - if ((ret = my_recv(buffer, MAX_INPUT_BUFFER-1)) == -1) { + if ((ret = recvlines(buffer, MAX_INPUT_BUFFER)) <= 0) { result = STATE_CRITICAL; asprintf(&error_msg, _("recv() failed after sending authpass, ")); break; } - buffer[ret] = 0; if (verbose) { printf (_("received %s\n"), buffer); } @@ -715,7 +711,7 @@ smtp_quit(void) printf(_("sent %s\n"), "QUIT"); /* read the response but don't care about problems */ - bytes = my_recv(buffer, MAXBUF - 1); + bytes = recvlines(buffer, MAX_INPUT_BUFFER); if (verbose) { if (bytes < 0) printf(_("recv() failed after QUIT.")); @@ -729,6 +725,64 @@ smtp_quit(void) } +/* + * Receive one line, copy it into buf and nul-terminate it. Returns the + * number of bytes written to buf (excluding the '\0') or 0 on EOF or <0 on + * error. + * + * TODO: Reading one byte at a time is very inefficient. Replace this by a + * function which buffers the data, move that to netutils.c and change + * check_smtp and other plugins to use that. Also, remove (\r)\n. + */ +int +recvline(char *buf, size_t bufsize) +{ + int result; + unsigned i; + + for (i = result = 0; i < bufsize - 1; i++) { + if ((result = my_recv(&buf[i], 1)) != 1) + break; + if (buf[i] == '\n') { + buf[++i] = '\0'; + return i; + } + } + return (result == 1 || i == 0) ? -2 : result; /* -2 if out of space */ +} + + +/* + * Receive one or more lines, copy them into buf and nul-terminate it. Returns + * the number of bytes written to buf (excluding the '\0') or 0 on EOF or <0 on + * error. Works for all protocols which format multiline replies as follows: + * + * ``The format for multiline replies requires that every line, except the last, + * begin with the reply code, followed immediately by a hyphen, `-' (also known + * as minus), followed by text. The last line will begin with the reply code, + * followed immediately by , optionally some text, and . As noted + * above, servers SHOULD send the if subsequent text is not sent, but + * clients MUST be prepared for it to be omitted.'' (RFC 2821, 4.2.1) + * + * TODO: Move this to netutils.c. Also, remove \r and possibly the final \n. + */ +int +recvlines(char *buf, size_t bufsize) +{ + int result, i; + + for (i = 0; /* forever */; i += result) + if (!((result = recvline(buf + i, bufsize - i)) > 3 && + isdigit((int)buf[i]) && + isdigit((int)buf[i + 1]) && + isdigit((int)buf[i + 2]) && + buf[i + 3] == '-')) + break; + + return (result <= 0) ? result : result + i; +} + + int my_close (void) { -- cgit v1.2.3