From e18ec3a7019ebcf631d1fe67459964ffbc442315 Mon Sep 17 00:00:00 2001
From: Janos SUTO <sj@acts.hu>
Date: Fri, 2 Mar 2018 22:46:48 +0100
Subject: [PATCH] revised smtp protocol handling

Signed-off-by: Janos SUTO <sj@acts.hu>
---
 src/config.h            |  4 +-
 src/defs.h              |  2 +-
 src/misc.c              | 66 +++++++++++++------------------
 src/misc.h              |  3 +-
 src/session.c           | 88 ++++++++++++++++++++---------------------
 src/smtp.c              | 62 +++++------------------------
 src/smtp.h              |  2 +-
 unit_tests/check_misc.c | 46 ---------------------
 8 files changed, 86 insertions(+), 187 deletions(-)

diff --git a/src/config.h b/src/config.h
index e022a47e..b67b3e12 100644
--- a/src/config.h
+++ b/src/config.h
@@ -9,9 +9,9 @@
 #include "piler-config.h"
 #include "params.h"
 
-#define VERSION "1.3.3"
+#define VERSION "1.3.4"
 
-#define BUILD 990
+#define BUILD 991
 
 #define HOSTID "mailarchiver"
 
diff --git a/src/defs.h b/src/defs.h
index 75911f57..129c56b7 100644
--- a/src/defs.h
+++ b/src/defs.h
@@ -383,7 +383,7 @@ struct smtp_session {
    char ttmpfile[SMALLBUFSIZE];
    char mailfrom[SMALLBUFSIZE];
    char rcptto[MAX_RCPT_TO][SMALLBUFSIZE];
-   char buf[SMALLBUFSIZE];
+   char buf[MAXBUFSIZE];
    char remote_host[INET6_ADDRSTRLEN];
    time_t lasttime;
    int protocol_state;
diff --git a/src/misc.c b/src/misc.c
index 9643acdc..37191c62 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -84,44 +84,6 @@ long tvdiff(struct timeval a, struct timeval b){
 }
 
 
-/*
- * search something in a buffer
- */
-
-int searchStringInBuffer(char *s, int len1, char *what, int len2){
-   int i, k, r;
-
-   for(i=0; i<len1; i++){
-      r = 0;
-
-      for(k=0; k<len2; k++){
-         if(*(s+i+k) == *(what+k))
-            r++;
-      }
-
-      if(r == len2)
-         return i;
-   }
-
-   return -1;
-}
-
-
-int search_char_backward(char *buf, int buflen, char c){
-   int n, m;
-
-   m = buflen - 1 - 5;
-   if(m < 0) m = 0;
-
-   for(n=m; n<buflen; n++){
-      if(*(buf + n) == c){
-         return n;
-      }
-   }
-   return -1;
-}
-
-
 /*
  * count a character in buffer
  */
@@ -739,6 +701,34 @@ void move_email(struct smtp_session *session){
 }
 
 
+int read_one_line(char *s, int c, char *buf, int buflen, int *rc){
+   int i=0;
+
+   *rc = ERR;
+
+   memset(buf, 0, buflen);
+
+   if(s == NULL){
+      return i;
+   }
+
+   for(; *s; s++){
+      if(i<buflen-2){
+         buf[i] = *s;
+         i++;
+
+         if(*s == c){
+            *rc = OK;
+            break;
+         }
+      }
+      else break;
+   }
+
+   return i;
+}
+
+
 #ifndef _GNU_SOURCE
 char *strcasestr(const char *s, const char *find){
    char c, sc;
diff --git a/src/misc.h b/src/misc.h
index 08d9c728..592c5fcb 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -19,8 +19,6 @@ int get_build();
 void get_extractor_list();
 void __fatal(char *s);
 long tvdiff(struct timeval a, struct timeval b);
-int searchStringInBuffer(char *s, int len1, char *what, int len2);
-int search_char_backward(char *buf, int buflen, char c);
 int countCharacterInBuffer(char *p, char c);
 void replaceCharacterInBuffer(char *p, char from, char to);
 char *split(char *str, int ch, char *buf, int buflen, int *result);
@@ -51,6 +49,7 @@ int create_and_bind(char *listen_addr, int listen_port);
 int can_i_write_directory(char *dir);
 
 void move_email(struct smtp_session *session);
+int read_one_line(char *s, int c, char *buf, int buflen, int *rc);
 
 #ifndef _GNU_SOURCE
    char *strcasestr(const char *s, const char *find);
diff --git a/src/session.c b/src/session.c
index 04ede38f..3279cdd6 100644
--- a/src/session.c
+++ b/src/session.c
@@ -126,7 +126,7 @@ void init_smtp_session(struct smtp_session *session, int slot, int sd, struct co
    session->num_of_rcpt_to = 0;
    for(i=0; i<MAX_RCPT_TO; i++) memset(session->rcptto[i], 0, SMALLBUFSIZE);
 
-   memset(session->buf, 0, SMALLBUFSIZE);
+   memset(session->buf, 0, MAXBUFSIZE);
    memset(session->remote_host, 0, INET6_ADDRSTRLEN);
 
    reset_bdat_counters(session);
@@ -169,64 +169,64 @@ void tear_down_session(struct smtp_session **sessions, int slot, int *num_connec
 
 
 void handle_data(struct smtp_session *session, char *readbuf, int readlen, struct config *cfg){
-   char *p, puf[MAXBUFSIZE];
-   int result;
+   int puflen, rc, lines=0;
+   char *p, copybuf[BIGBUFSIZE+MAXBUFSIZE], puf[MAXBUFSIZE];
 
-   // process BDAT stuff
+   // if there's something in the saved buffer, then let's merge them
 
-   if(session->protocol_state == SMTP_STATE_BDAT){
-      if(session->bad == 1){
-         // something bad happened in the BDAT processing
-         return;
-      }
+   if(session->buflen > 0){
+      memset(copybuf, 0, sizeof(copybuf));
 
-      process_bdat(session, readbuf, readlen, cfg);
+      memcpy(copybuf, session->buf, session->buflen);
+      memcpy(&copybuf[session->buflen], readbuf, readlen);
+
+      session->buflen = 0;
+      memset(session->buf, 0, MAXBUFSIZE);
+
+      p = &copybuf[0];
    }
-
-   // process DATA
-
-   else if(session->protocol_state == SMTP_STATE_DATA){
-      process_data(session, readbuf, readlen);
-   }
-
-   // process other SMTP commands
-
    else {
-
-      if(session->buflen > 0){
-         snprintf(puf, sizeof(puf)-1, "%s%s", session->buf, readbuf);
-         snprintf(readbuf, BIGBUFSIZE-1, "%s", puf);
-
-         session->buflen = 0;
-         memset(session->buf, 0, SMALLBUFSIZE);
-      }
-
       p = readbuf;
+   }
 
-      do {
-         memset(puf, 0, sizeof(puf));
-         p = split(p, '\n', puf, sizeof(puf)-1, &result);
 
-         if(puf[0] == '\0') continue;
+   do {
+      puflen = read_one_line(p, '\n', puf, sizeof(puf)-1, &rc);
+      p += puflen;
 
-         if(result == 1){
-            process_smtp_command(session, puf, cfg);
+      lines++;
 
-            // if chunking is enabled and we have data after BDAT <len>
-            // then process the rest
-
-            if(session->cfg->enable_chunking == 1 && p && session->protocol_state == SMTP_STATE_BDAT){
-               process_bdat(session, p, strlen(p), cfg);
-               break;
+      if(rc == OK){
+         if(session->protocol_state == SMTP_STATE_BDAT){
+            if(session->bad == 1){
+               // something bad happened in the BDAT processing
+               return;
             }
+
+            process_bdat(session, puf, puflen, cfg);
+         }
+
+         else if(session->protocol_state == SMTP_STATE_DATA){
+            process_data(session, puf, puflen);
+         }
+
+         else {
+            process_smtp_command(session, puf, cfg);
+         }
+      }
+      else if(puflen > 0){
+         // if it's BDAT state, then don't buffer, rather give it to
+         // the BDAT processing function
+         if(session->protocol_state == SMTP_STATE_BDAT){
+            process_bdat(session, puf, puflen, cfg);
          }
          else {
-            snprintf(session->buf, SMALLBUFSIZE-1, "%s", puf);
-            session->buflen = strlen(puf);
+            snprintf(session->buf, MAXBUFSIZE-1, "%s", puf);
+            session->buflen = puflen;
          }
-      } while(p);
+      }
 
-   }
+   } while(puflen > 0);
 
 }
 
diff --git a/src/smtp.c b/src/smtp.c
index 850fe65d..171e789e 100644
--- a/src/smtp.c
+++ b/src/smtp.c
@@ -70,61 +70,17 @@ void process_smtp_command(struct smtp_session *session, char *buf, struct config
 }
 
 
-void process_data(struct smtp_session *session, char *readbuf, int readlen){
-   char puf[SMALLBUFSIZE+BIGBUFSIZE];
-   int n, pos, len, writelen;
-
-   memset(puf, 0, sizeof(puf));
-   len = readlen;
-
-   if(session->buflen > 0){
-      memcpy(&puf[0], session->buf, session->buflen);
-      memcpy(&puf[session->buflen], readbuf, readlen);
-
-      len += session->buflen;
-   }
-   else {
-      memcpy(&puf[0], readbuf, readlen);
-   }
-
-   pos = searchStringInBuffer(&puf[0], len, SMTP_CMD_PERIOD, 5);
-
-   if(pos > 0){
-      if(write(session->fd, puf, pos) != -1){
-         session->tot_len += pos;
-         process_command_period(session);
-      }
-      else syslog(LOG_PRIORITY, "ERROR (line: %d): process_data(): failed to write %d bytes", __LINE__, pos);
-   }
-   else if(pos < 0){
-      n = search_char_backward(&puf[0], len, '\r');
-
-      if(n == -1 || len - n > 4){
-
-         if(n == -1) writelen = len;
-         else writelen = n-1;
-
-         if(writelen > 0){
-            if(write(session->fd, puf, writelen) != -1){
-               session->tot_len += writelen;
-            }
-            else syslog(LOG_PRIORITY, "ERROR (line: %d): process_data(): failed to write %d bytes", __LINE__, writelen);
-         }
-      }
-      else {
-         if(write(session->fd, puf, n) != -1){
-            session->tot_len += n;
-         }
-         else syslog(LOG_PRIORITY, "ERROR (line: %d) process_data(): failed to write %d bytes", __LINE__, n);
-
-         snprintf(session->buf, SMALLBUFSIZE-1, "%s", &puf[n]);
-         session->buflen = len - n;
-      }
-   }
-   else {
-      // The buffer contains only the CR-LF-DOT-CR-LF sequence
+void process_data(struct smtp_session *session, char *buf, int buflen){
+   if(strcmp(buf, ".\r\n") == 0){
       process_command_period(session);
    }
+   else {
+      // write line to file
+      if(write(session->fd, buf, buflen) != -1){
+         session->tot_len += buflen;
+      }
+      else syslog(LOG_PRIORITY, "ERROR (line: %d) process_data(): failed to write %d bytes", __LINE__, buflen);
+   }
 }
 
 
diff --git a/src/smtp.h b/src/smtp.h
index 5a429ff6..f4b0cb39 100644
--- a/src/smtp.h
+++ b/src/smtp.h
@@ -8,7 +8,7 @@
 #include <piler.h>
 
 void process_smtp_command(struct smtp_session *session, char *buf, struct config *cfg);
-void process_data(struct smtp_session *session, char *readbuf, int readlen);
+void process_data(struct smtp_session *session, char *buf, int buflen);
 
 void send_smtp_response(struct smtp_session *session, char *buf);
 void process_command_helo(struct smtp_session *session, char *buf, int buflen);
diff --git a/unit_tests/check_misc.c b/unit_tests/check_misc.c
index b1f4a7f1..96a5bb03 100644
--- a/unit_tests/check_misc.c
+++ b/unit_tests/check_misc.c
@@ -89,50 +89,6 @@ static void test_trim_buffer(){
 }
 
 
-static void test_search_string_in_buffer(){
-   unsigned int i;
-   int pos;
-   struct test_data_s_s_i test_data_s_s_i[] = {
-      { "ajaja\r\n.\r\n", SMTP_CMD_PERIOD, 5 },
-      { "ajaja\r\n.\r\ndhdjdhj", SMTP_CMD_PERIOD, 5 },
-      { "ajajadjdhj", "a", 0 },
-      { "ajajadjdhj", "aja", 0 },
-      { "ajajadjdhj", "jaja", 1 },
-      { "ajajadjdhj", "qqq", -1 },
-   };
-
-   TEST_HEADER();
-
-   for(i=0; i<sizeof(test_data_s_s_i)/sizeof(struct test_data_s_s_i); i++){
-      pos = searchStringInBuffer(test_data_s_s_i[i].s1, strlen(test_data_s_s_i[i].s1), test_data_s_s_i[i].s2, strlen(test_data_s_s_i[i].s2));
-      //printf("%s %s %d, %d\n", test_data_s_s_i[i].s1, test_data_s_s_i[i].s2, pos, test_data_s_s_i[i].result);
-      ASSERT(pos == test_data_s_s_i[i].result, test_data_s_s_i[i].s1);
-   }
-
-   TEST_FOOTER();
-}
-
-
-static void test_search_char_backward(){
-   unsigned int i;
-   int pos;
-   struct test_data_s_s_i test_data_s_s_i[] = {
-      { "abcdefghij\r\n.\r\n", "\r", 10 },
-      { "abcdefghij\n\n.\r\n", "\r", 13 },
-      { "abcdefghij\n\n.\n\n", "\r", -1 },
-   };
-
-   TEST_HEADER();
-
-   for(i=0; i<sizeof(test_data_s_s_i)/sizeof(struct test_data_s_s_i); i++){
-      pos = search_char_backward(test_data_s_s_i[i].s1, strlen(test_data_s_s_i[i].s1), test_data_s_s_i[i].s2[0]);
-      ASSERT(pos == test_data_s_s_i[i].result, test_data_s_s_i[i].s1);
-   }
-
-   TEST_FOOTER();
-}
-
-
 static void test_make_random_string(){
    unsigned int i;
    char buf[SMALLBUFSIZE];
@@ -229,8 +185,6 @@ int main(){
    test_extract_verp_address();
    test_extract_email();
    test_trim_buffer();
-   test_search_string_in_buffer();
-   test_search_char_backward();
    test_make_random_string();
    test_create_id();
    test_split();