X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=imap.c;h=cb87eda5378f258f20955c3524f2f84c6d29cd0e;hb=2629c4511c68729d98acfd08637c1f00d3807f49;hp=89d486c3e39de956fb67900f4d92bb8ec5ff2fda;hpb=dca4a906d60a197b09159bc8d8a16625b1790215;p=~andy%2Ffetchmail

diff --git a/imap.c b/imap.c
index 89d486c3..cb87eda5 100644
--- a/imap.c
+++ b/imap.c
@@ -8,6 +8,7 @@
 #include  "config.h"
 #include  <stdio.h>
 #include  <string.h>
+#include  <strings.h>
 #include  <ctype.h>
 #if defined(STDC_HEADERS)
 #include  <stdlib.h>
@@ -74,7 +75,9 @@ static int imap_untagged_response(int sock, const char *buf)
     }
     else if (strstr(buf, " EXISTS"))
     {
-	count = atoi(buf+2);
+	char *t; unsigned long u;
+	errno = 0;
+	u = strtoul(buf+2, &t, 10);
 	/*
 	 * Don't trust the message count passed by the server.
 	 * Without this check, it might be possible to do a
@@ -82,11 +85,15 @@ static int imap_untagged_response(int sock, const char *buf)
 	 * count, and allocate a malloc area that would overlap
 	 * a portion of the stack.
 	 */
-	if ((unsigned)count > INT_MAX/sizeof(int))
+	if (errno /* strtoul failed */
+		|| t == buf+2 /* no valid data */
+		|| u > (unsigned long)(INT_MAX/sizeof(int)) /* too large */)
 	{
-	    report(stderr, GT_("bogus message count!"));
+	    report(stderr, GT_("bogus message count in \"%s\"!"), buf);
 	    return(PS_PROTOCOL);
 	}
+	count = u; /* safe as long as count <= INT_MAX - checked above */
+
 	if ((recentcount = count - oldcount) < 0)
 	    recentcount = 0;
 
@@ -117,14 +124,22 @@ static int imap_untagged_response(int sock, const char *buf)
 # if 0
     else if (strstr(buf, " RECENT"))
     {
+	/* fixme: use strto[u]l and error checking */
 	recentcount = atoi(buf+2);
     }
 # endif
     else if (strstr(buf, " EXPUNGE"))
     {
+	unsigned long u; char *t;
 	/* the response "* 10 EXPUNGE" means that the currently
 	 * tenth (i.e. only one) message has been deleted */
-	if (atoi(buf+2) > 0)
+	errno = 0;
+	u = strtoul(buf+2, &t, 10);
+	if (errno /* conversion error */ || t == buf+2 /* no number found */) {
+	    report(stderr, GT_("bogus EXPUNGE count in \"%s\"!"), buf);
+	    return PS_PROTOCOL;
+	}
+	if (u > 0)
 	{
 	    if (count > 0)
 		count--;
@@ -164,7 +179,7 @@ static int imap_untagged_response(int sock, const char *buf)
     return(PS_SUCCESS);
 }
 
-static int imap_response(int sock, char *argbuf)
+static int imap_response(int sock, char *argbuf, struct RecvSplit *rs)
 /* parse command response */
 {
     char buf[MSGBUFSIZE+1];
@@ -173,7 +188,11 @@ static int imap_response(int sock, char *argbuf)
 	int	ok;
 	char	*cp;
 
-	if ((ok = gen_recv(sock, buf, sizeof(buf))))
+	if (rs)
+	    ok = gen_recv_split(sock, buf, sizeof(buf), rs);
+	else
+	    ok = gen_recv(sock, buf, sizeof(buf));
+	if (ok != PS_SUCCESS)
 	    return(ok);
 
 	/* all tokens in responses are caseblind */
@@ -254,7 +273,7 @@ static int imap_ok(int sock, char *argbuf)
 {
     int ok;
 
-    while ((ok = imap_response(sock, argbuf)) == PS_UNTAGGED)
+    while ((ok = imap_response(sock, argbuf, NULL)) == PS_UNTAGGED)
 	; /* wait for the tagged response */
     return(ok);
 }
@@ -275,57 +294,13 @@ static int imap_ok(int sock, char *argbuf)
 
 static int do_imap_ntlm(int sock, struct query *ctl)
 {
-    tSmbNtlmAuthRequest request;
-    tSmbNtlmAuthChallenge challenge;
-    tSmbNtlmAuthResponse response;
-
-    char msgbuf[2048];
-    int result,len;
+    int result;
 
     gen_send(sock, "AUTHENTICATE NTLM");
 
-    if ((result = gen_recv(sock, msgbuf, sizeof msgbuf)))
-	return result;
-  
-    if (msgbuf[0] != '+')
-	return PS_AUTHFAIL;
-  
-    buildSmbNtlmAuthRequest(&request,ctl->remotename,NULL);
-
-    if (outlevel >= O_DEBUG)
-	dumpSmbNtlmAuthRequest(stdout, &request);
-
-    memset(msgbuf,0,sizeof msgbuf);
-    to64frombits (msgbuf, &request, SmbLength(&request));
-  
-    if (outlevel >= O_MONITOR)
-	report(stdout, "IMAP> %s\n", msgbuf);
-  
-    strcat(msgbuf,"\r\n");
-    SockWrite (sock, msgbuf, strlen (msgbuf));
-
-    if ((gen_recv(sock, msgbuf, sizeof msgbuf)))
+    if ((result = ntlm_helper(sock, ctl, "IMAP")))
 	return result;
-  
-    len = from64tobits (&challenge, msgbuf, sizeof(challenge));
-    
-    if (outlevel >= O_DEBUG)
-	dumpSmbNtlmAuthChallenge(stdout, &challenge);
-    
-    buildSmbNtlmAuthResponse(&challenge, &response,ctl->remotename,ctl->password);
-  
-    if (outlevel >= O_DEBUG)
-	dumpSmbNtlmAuthResponse(stdout, &response);
-  
-    memset(msgbuf,0,sizeof msgbuf);
-    to64frombits (msgbuf, &response, SmbLength(&response));
-
-    if (outlevel >= O_MONITOR)
-	report(stdout, "IMAP> %s\n", msgbuf);
-      
-    strcat(msgbuf,"\r\n");
-    SockWrite (sock, msgbuf, strlen (msgbuf));
-  
+
     result = imap_ok (sock, NULL);
     if (result == PS_SUCCESS)
 	return PS_SUCCESS;
@@ -349,7 +324,7 @@ static void imap_canonicalize(char *result, char *raw, size_t maxlen)
     result[j] = '\0';
 }
 
-static void capa_probe(int sock, struct query *ctl)
+static int capa_probe(int sock, struct query *ctl)
 /* set capability variables from a CAPA probe */
 {
     int	ok;
@@ -385,6 +360,8 @@ static void capa_probe(int sock, struct query *ctl)
 	if (outlevel >= O_DEBUG)
 	    report(stdout, GT_("Protocol identified as IMAP2 or IMAP2BIS\n"));
     }
+    else
+	return ok;
 
     /* 
      * Handle idling.  We depend on coming through here on startup
@@ -402,9 +379,11 @@ static void capa_probe(int sock, struct query *ctl)
     }
 
     peek_capable = (imap_version >= IMAP4);
+
+    return PS_SUCCESS;
 }
 
-static int do_authcert (int sock, char *command, const char *name)
+static int do_authcert (int sock, const char *command, const char *name)
 /* do authentication "external" (authentication provided by client cert) */
 {
     char buf[256];
@@ -426,9 +405,6 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
 /* apply for connection authorization */
 {
     int ok = 0;
-#ifdef SSL_ENABLE
-    int got_tls = 0;
-#endif
     (void)greeting;
 
     /*
@@ -440,7 +416,8 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
     else
 	expunge_period = 1;
 
-    capa_probe(sock, ctl);
+    if ((ok = capa_probe(sock, ctl)))
+	return ok;
 
     /* 
      * If either (a) we saw a PREAUTH token in the greeting, or
@@ -462,16 +439,17 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
 	if (ctl->sslcommonname)
 	    commonname = ctl->sslcommonname;
 
-	if (strstr(capabilities, "STARTTLS"))
+	if (strstr(capabilities, "STARTTLS")
+		|| must_tls(ctl)) /* if TLS is mandatory, ignore capabilities */
 	{
 	    /* Use "tls1" rather than ctl->sslproto because tls1 is the only
 	     * protocol that will work with STARTTLS.  Don't need to worry
 	     * whether TLS is mandatory or opportunistic unless SSLOpen() fails
 	     * (see below). */
 	    if (gen_transact(sock, "STARTTLS") == PS_SUCCESS
-		    && SSLOpen(sock, ctl->sslcert, ctl->sslkey, "tls1", ctl->sslcertck,
-			ctl->sslcertpath, ctl->sslfingerprint, commonname,
-			ctl->server.pollname, &ctl->remotename) != -1)
+		    && (set_timeout(mytimeout), SSLOpen(sock, ctl->sslcert, ctl->sslkey, "tls1", ctl->sslcertck,
+			ctl->sslcertfile, ctl->sslcertpath, ctl->sslfingerprint, commonname,
+			ctl->server.pollname, &ctl->remotename)) != -1)
 	    {
 		/*
 		 * RFC 2595 says this:
@@ -486,22 +464,20 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
 		 * Now that we're confident in our TLS connection we can
 		 * guarantee a secure capability re-probe.
 		 */
-		got_tls = 1;
-		capa_probe(sock, ctl);
+		if ((ok = capa_probe(sock, ctl)))
+		    return ok;
 		if (outlevel >= O_VERBOSE)
 		{
 		    report(stdout, GT_("%s: upgrade to TLS succeeded.\n"), commonname);
 		}
-	    }
-	}
-
-	if (!got_tls) {
-	    if (must_tls(ctl)) {
+	    } else if (must_tls(ctl)) {
 		/* Config required TLS but we couldn't guarantee it, so we must
 		 * stop. */
+		set_timeout(0);
 		report(stderr, GT_("%s: upgrade to TLS failed.\n"), commonname);
 		return PS_SOCKET;
 	    } else {
+		set_timeout(0);
 		if (outlevel >= O_VERBOSE) {
 		    report(stdout, GT_("%s: opportunistic upgrade to TLS failed, trying to continue\n"), commonname);
 		}
@@ -529,7 +505,7 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
      * and IGNORE errors. */
     {
 	char *tmp = strstr(capabilities, " ID");
-	if (tmp && !isalnum(tmp[3]) && strstr(ctl->server.via ? ctl->server.via : ctl->server.pollname, "yahoo.com")) {
+	if (tmp && !isalnum((unsigned char)tmp[3]) && strstr(ctl->server.via ? ctl->server.via : ctl->server.pollname, "yahoo.com")) {
 		(void)gen_transact(sock, "ID (\"guid\" \"1\")");
 	}
     }
@@ -551,15 +527,13 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
     }
 
 #ifdef GSSAPI
-    if ((ctl->server.authenticate == A_ANY 
+    if (((ctl->server.authenticate == A_ANY && check_gss_creds("imap", ctl->server.truename) == PS_SUCCESS)
 	 || ctl->server.authenticate == A_GSSAPI)
 	&& strstr(capabilities, "AUTH=GSSAPI"))
     {
 	if ((ok = do_gssauth(sock, "AUTHENTICATE", "imap",
 			ctl->server.truename, ctl->remotename)))
 	{
-	    /* SASL cancellation of authentication */
-	    gen_send(sock, "*");
 	    if (ctl->server.authenticate != A_ANY)
                 return ok;
 	} else  {
@@ -596,8 +570,6 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
     {
 	if ((ok = do_cram_md5 (sock, "AUTHENTICATE", ctl, NULL)))
 	{
-	    /* SASL cancellation of authentication */
-	    gen_send(sock, "*");
 	    if(ctl->server.authenticate != A_ANY)
                 return ok;
 	}
@@ -633,8 +605,6 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
 	&& strstr (capabilities, "AUTH=NTLM")) {
 	if ((ok = do_imap_ntlm(sock, ctl)))
 	{
-	    /* SASL cancellation of authentication */
-	    gen_send(sock, "*");
 	    if(ctl->server.authenticate != A_ANY)
                 return ok;
 	}
@@ -688,8 +658,6 @@ static int imap_getauth(int sock, struct query *ctl, char *greeting)
 	free(remotename);
 	if (ok)
 	{
-	    /* SASL cancellation of authentication */
-	    gen_send(sock, "*");
 	    if(ctl->server.authenticate != A_ANY)
                 return ok;
 	}
@@ -798,13 +766,10 @@ static int imap_idle(int sock)
     return(ok);
 }
 
-/* maximum number of numbers we can process in "SEARCH" response */
-# define IMAP_SEARCH_MAX 1000
-
 static int imap_search(int sock, struct query *ctl, int count)
 /* search for unseen messages */
 {
-    int ok, first, last;
+    int ok;
     char buf[MSGBUFSIZE+1], *cp;
 
     /* Don't count deleted messages. Enabled only for IMAP4 servers or
@@ -814,29 +779,20 @@ static int imap_search(int sock, struct query *ctl, int count)
     flag skipdeleted = (imap_version >= IMAP4) && ctl->keep;
     const char *undeleted;
 
-    /* Skip range search if there are less than or equal to
-     * IMAP_SEARCH_MAX mails. */
-    flag skiprangesearch = (count <= IMAP_SEARCH_MAX);
+    /* structure to keep the end portion of the incomplete response */
+    struct RecvSplit rs;
 
     /* startcount is higher than count so that if there are no
      * unseen messages, imap_getsizes() will not need to do
      * anything! */
     startcount = count + 1;
 
-    for (first = 1, last = IMAP_SEARCH_MAX; first <= count; first += IMAP_SEARCH_MAX, last += IMAP_SEARCH_MAX)
+    for (;;)
     {
-	if (last > count)
-	    last = count;
-
-restartsearch:
 	undeleted = (skipdeleted ? " UNDELETED" : "");
-	if (skiprangesearch)
-	    gen_send(sock, "SEARCH UNSEEN%s", undeleted);
-	else if (last == first)
-	    gen_send(sock, "SEARCH %d UNSEEN%s", last, undeleted);
-	else
-	    gen_send(sock, "SEARCH %d:%d UNSEEN%s", first, last, undeleted);
-	while ((ok = imap_response(sock, buf)) == PS_UNTAGGED)
+	gen_send(sock, "SEARCH UNSEEN%s", undeleted);
+	gen_recv_split_init("* SEARCH", &rs);
+	while ((ok = imap_response(sock, buf, &rs)) == PS_UNTAGGED)
 	{
 	    if ((cp = strstr(buf, "* SEARCH")))
 	    {
@@ -854,7 +810,8 @@ restartsearch:
 
 			errno = 0;
 			um = strtoul(cp,&ep,10);
-			if (errno == 0 && um <= UINT_MAX && um <= (unsigned)count)
+			if (errno == 0 && ep > cp
+				&& um <= INT_MAX && um <= (unsigned)count)
 			{
 			    unseen_messages[unseen++] = um;
 			    if (outlevel >= O_DEBUG)
@@ -867,41 +824,28 @@ restartsearch:
 		}
 	    }
 	}
-	/* if there is a protocol error on the first loop, try a
-	 * different search command */
-	if (ok == PS_ERROR && first == 1)
+	if (ok != PS_ERROR) /* success or non-protocol error */
+	    return(ok);
+
+	/* there is a protocol error. try a different search command. */
+	if (skipdeleted)
 	{
-	    if (skipdeleted)
-	    {
-		/* retry with "SEARCH 1:1000 UNSEEN" */
-		skipdeleted = FALSE;
-		goto restartsearch;
-	    }
-	    if (!skiprangesearch)
-	    {
-		/* retry with "SEARCH UNSEEN" */
-		skiprangesearch = TRUE;
-		goto restartsearch;
-	    }
-	    /* try with "FETCH 1:n FLAGS" */
-	    goto fetchflags;
+	    /* retry with "SEARCH UNSEEN" */
+	    skipdeleted = FALSE;
+	    continue;
 	}
-	if (ok != PS_SUCCESS)
-	    return(ok);
-	/* loop back only when searching in range */
-	if (skiprangesearch)
-	    break;
+	/* try with "FETCH 1:n FLAGS" */
+	break;
     }
-    return(PS_SUCCESS);
 
-fetchflags:
     if (count == 1)
 	gen_send(sock, "FETCH %d FLAGS", count);
     else
 	gen_send(sock, "FETCH %d:%d FLAGS", 1, count);
-    while ((ok = imap_response(sock, buf)) == PS_UNTAGGED)
+    while ((ok = imap_response(sock, buf, NULL)) == PS_UNTAGGED)
     {
 	unsigned int num;
+	int consumed;
 
 	/* expected response format:
 	 * IMAP< * 1 FETCH (FLAGS (\Seen))
@@ -911,8 +855,10 @@ fetchflags:
 	 * IMAP< * 5 FETCH (UID 10 FLAGS (\Recent))
 	 */
 	if (unseen < count
-		&& sscanf(buf, "* %u FETCH ", &num) == 1
-		&& num >= 1 && num <= count
+		&& sscanf(buf, "* %u %n", &num, &consumed) == 1
+		&& 0 == strncasecmp(buf+consumed, "FETCH", 5)
+		&& isspace((unsigned char)buf[consumed+5])
+		&& num >= 1 && num <= (unsigned)count
 		&& strstr(buf, "FLAGS ")
 		&& !strstr(buf, "\\SEEN")
 		&& !strstr(buf, "\\DELETED"))
@@ -1107,20 +1053,23 @@ static int imap_getpartialsizes(int sock, int first, int last, int *sizes)
 	gen_send(sock, "FETCH %d:%d RFC822.SIZE", first, last);
     else /* no unseen messages! */
 	return(PS_SUCCESS);
-    while ((ok = imap_response(sock, buf)) == PS_UNTAGGED)
+    while ((ok = imap_response(sock, buf, NULL)) == PS_UNTAGGED)
     {
 	unsigned int size;
 	int num;
+	int consumed;
+	char *ptr;
 
-	if (sscanf(buf, "* %d FETCH (RFC822.SIZE %u)", &num, &size) == 2
-	/* some servers (like mail.internode.on.net bld-mail04) return UID information here
-	 *
+	/* expected response formats:
 	 * IMAP> A0005 FETCH 1 RFC822.SIZE
+	 * IMAP< * 1 FETCH (RFC822.SIZE 1187)
 	 * IMAP< * 1 FETCH (UID 16 RFC822.SIZE 1447)
-	 * IMAP< A0005 OK FETCH completed
-	 *
 	 */
-		|| sscanf(buf, "* %d FETCH (UID %*s RFC822.SIZE %u)", &num, &size) == 2)
+	if (sscanf(buf, "* %d %n", &num, &consumed) == 1
+	    && 0 == strncasecmp(buf + consumed, "FETCH", 5)
+	    && isspace((unsigned char)buf[consumed + 5])
+		&& (ptr = strstr(buf, "RFC822.SIZE "))
+		&& sscanf(ptr, "RFC822.SIZE %u", &size) == 1)
 	{
 	    if (num >= first && num <= last)
 		sizes[num - first] = size;
@@ -1163,6 +1112,7 @@ static int imap_is_old(int sock, struct query *ctl, int number)
     return(seen);
 }
 
+#if 0
 static char *skip_token(char *ptr)
 {
     while(isspace((unsigned char)*ptr)) ptr++;
@@ -1170,12 +1120,15 @@ static char *skip_token(char *ptr)
     while(isspace((unsigned char)*ptr)) ptr++;
     return(ptr);
 }
+#endif
 
 static int imap_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
 /* request headers of nth message */
 {
     char buf [MSGBUFSIZE+1];
     int	num;
+    int ok;
+    char *ptr;
 
     (void)ctl;
     /* expunges change the fetch numbers */
@@ -1188,47 +1141,50 @@ static int imap_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
     gen_send(sock, "FETCH %d RFC822.HEADER", number);
 
     /* looking for FETCH response */
-    for (;;) 
+    if ((ok = imap_response(sock, buf, NULL)) == PS_UNTAGGED)
     {
-	int	ok;
-	char	*ptr;
-
-	if ((ok = gen_recv(sock, buf, sizeof(buf))))
-	    return(ok);
- 	ptr = skip_token(buf);	/* either "* " or "AXXXX " */
-	if (sscanf(ptr, "%d FETCH (RFC822.HEADER {%d}", &num, lenp) == 2
-	/* some servers (like mail.internode.on.net bld-mail04) return UID information here
-	 *
+		int consumed;
+	/* expected response formats:
 	 * IMAP> A0006 FETCH 1 RFC822.HEADER
+	 * IMAP< * 1 FETCH (RFC822.HEADER {1360}
 	 * IMAP< * 1 FETCH (UID 16 RFC822.HEADER {1360}
-	 * ...
-	 * IMAP< )
-	 * IMAP< A0006 OK FETCH completed
-	 *
+	 * IMAP< * 1 FETCH (UID 16 RFC822.SIZE 4029 RFC822.HEADER {1360}
 	 */
-		|| sscanf(ptr, "%d FETCH (UID %*s RFC822.HEADER {%d}", &num, lenp) == 2)
-	    break;
-	/* try to recover from chronically fucked-up M$ Exchange servers */
- 	else if (!strncmp(ptr, "NO", 2))
+	if (sscanf(buf, "* %d %n", &num, &consumed) == 1
+	    && 0 == strncasecmp(buf + consumed, "FETCH", 5)
+	    && isspace((unsigned char)buf[5+consumed])
+		&& num == number
+		&& (ptr = strstr(buf, "RFC822.HEADER"))
+		&& sscanf(ptr, "RFC822.HEADER {%d}%n", lenp, &consumed) == 1
+		&& ptr[consumed-1] == '}')
 	{
-	    /* wait for a tagged response */
-	    if (strstr (buf, "* NO"))
-		imap_ok (sock, 0);
- 	    return(PS_TRANSIENT);
+	    return(PS_SUCCESS);
 	}
- 	else if (!strncmp(ptr, "BAD", 3))
+
+	/* wait for a tagged response */
+	imap_ok (sock, 0);
+
+	/* try to recover for some responses */
+	if (!strncmp(buf, "* NO", 4) ||
+		!strncmp(buf, "* BAD", 5) ||
+		strstr(buf, "FETCH ()"))
 	{
-	    /* wait for a tagged response */
-	    if (strstr (buf, "* BAD"))
-		imap_ok (sock, 0);
- 	    return(PS_TRANSIENT);
+	    return(PS_TRANSIENT);
 	}
-    }
 
-    if (num != number)
+	/* a response which does not match any of the above */
+	if (outlevel > O_SILENT)
+	    report(stderr, GT_("Incorrect FETCH response: %s.\n"), buf);
 	return(PS_ERROR);
-    else
-	return(PS_SUCCESS);
+    }
+    else if (ok == PS_SUCCESS)
+    {
+	/* an unexpected tagged response */
+	if (outlevel > O_SILENT)
+	    report(stderr, GT_("Incorrect FETCH response: %s.\n"), buf);
+	return(PS_TRANSIENT);
+    }
+    return(ok);
 }
 
 static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp)
@@ -1295,6 +1251,13 @@ static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp)
 	    return PS_SUCCESS;
     }
 
+    /* Understand the empty string. Seen on Yahoo. */
+    /* XXX FIXME: we should be able to handle strings here. */
+    if (strstr(buf+10, "\"\")")) {
+	    *lenp = 0;
+	    return PS_SUCCESS;
+    }
+
     /*
      * Try to extract a length from the FETCH response.  RFC2060 requires
      * it to be present, but at least one IMAP server (Novell GroupWise)
@@ -1302,15 +1265,21 @@ static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp)
      * server called dbmail that returns huge garbage lengths.
      */
     if ((cp = strchr(buf, '{'))) {
+	long l; char *t;
         errno = 0;
-	*lenp = (int)strtol(cp + 1, (char **)NULL, 10);
-        if (errno == ERANGE || *lenp < 0)
-            *lenp = -1;    /* length is too big/small for us to handle */
-    }
-    else
+	++ cp;
+	l = strtol(cp, &t, 10);
+        if (errno || t == cp || (t && !strchr(t, '}')) /* parse error */
+		    || l < 0 || l > INT_MAX /* range check */) {
+	    *lenp = -1;
+	} else {
+	    *lenp = l;
+	}
+    } else {
 	*lenp = -1;	/* missing length part in FETCH reponse */
+    }
 
-    return(PS_SUCCESS);
+    return PS_SUCCESS;
 }
 
 static int imap_trail(int sock, struct query *ctl, const char *tag)
@@ -1329,6 +1298,13 @@ static int imap_delete(int sock, struct query *ctl, int number)
 /* set delete flag for given message */
 {
     int	ok;
+    /* Select which flags to set on message deletion: */
+    const char delflags_seen[] = "\\Seen \\Deleted";
+    static const char *delflags;
+    /* Which environment variable to look for: */
+
+    /* DEFAULT since many fetchmail versions <= 6.3.X */
+    delflags = delflags_seen;
 
     (void)ctl;
     /* expunges change the fetch numbers */
@@ -1338,17 +1314,18 @@ static int imap_delete(int sock, struct query *ctl, int number)
      * Use SILENT if possible as a minor throughput optimization.
      * Note: this has been dropped from IMAP4rev1.
      *
-     * We set Seen because there are some IMAP servers (notably HP
-     * OpenMail) that do message-receipt DSNs, but only when the seen
-     * bit is set.  This is the appropriate time -- we get here right
+     * We set \Seen because there are some IMAP servers (notably HP
+     * OpenMail and MS Exchange) do message-receipt DSNs,
+     * but only when the seen bit gets set.
+     * This is the appropriate time -- we get here right
      * after the local SMTP response that says delivery was
      * successful.
      */
     if ((ok = gen_transact(sock,
 			imap_version == IMAP4 
-				? "STORE %d +FLAGS.SILENT (\\Seen \\Deleted)"
-				: "STORE %d +FLAGS (\\Seen \\Deleted)", 
-			number)))
+				? "STORE %d +FLAGS.SILENT (%s)"
+				: "STORE %d +FLAGS (%s)",
+			number, delflags)))
 	return(ok);
     else
 	deletions++;