use strlcat() strlcpy() and slprintf() whenever possible to avoid any

chance of a buffer overflow

authenticate.c

@@ -28,7 +28,6 @@ static void base64_encode(char *buf, int len, char *out)
 	char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 	int bit_offset, byte_offset, idx, i;
 	unsigned char *d = (unsigned char *)buf;
-	char *p;
 	int bytes = (len*8 + 5)/6;
 
 	memset(out, 0, bytes+1);
@@ -56,7 +55,7 @@ static void gen_challenge(char *addr, char *challenge)
 
 	memset(input, 0, sizeof(input));
 
-	strncpy((char *)input, addr, 16);
+	strlcpy((char *)input, addr, 16);
 	gettimeofday(&tv, NULL);
 	SIVAL(input, 16, tv.tv_sec);
 	SIVAL(input, 20, tv.tv_usec);
@@ -74,8 +73,8 @@ static int get_secret(int module, char *user, char *secret, int len)
 {
 	char *fname = lp_secrets_file(module);
 	int fd, found=0;
-	char line[1024];
-	char *p, *pass;
+	char line[MAXPATHLEN];
+	char *p, *pass=NULL;
 
 	if (!fname || !*fname) return 0;
 
@@ -137,7 +136,7 @@ int auth_server(int fd, int module, char *addr, char *leader)
 	char *users = lp_auth_users(module);
 	char challenge[16];
 	char b64_challenge[30];
-	char line[1024];
+	char line[MAXPATHLEN];
 	char user[100];
 	char secret[100];
 	char pass[30];

clientserver.c

@@ -30,7 +30,7 @@ int start_socket_client(char *host, char *path, int argc, char *argv[])
 	int fd, i;
 	char *sargs[MAX_ARGS];
 	int sargc=0;
-	char line[1024];
+	char line[MAXPATHLEN];
 	char *p, *user=NULL;
 	extern int remote_version;
 
@@ -102,13 +102,12 @@ static int rsync_module(int fd, int i)
 	int argc=0;
 	char *argv[MAX_ARGS];
 	char **argp;
-	char line[1024];
+	char line[MAXPATHLEN];
 	uid_t uid;
 	gid_t gid;
 	char *p;
 	char *addr = client_addr(fd);
 	char *host = client_name(fd);
-	char *auth;
 	char *name = lp_name(i);
 	int start_glob=0;
 
@@ -201,17 +200,13 @@ static int rsync_module(int fd, int i)
 
 		p = line;
 
-		if (start_glob && strncmp(p, name, strlen(name)) == 0) {
-			p += strlen(name);
-			if (!*p) p = ".";
-		}
-
 		argv[argc] = strdup(p);
 		if (!argv[argc]) {
 			return -1;
 		}
 
 		if (start_glob) {
+			rprintf(FINFO,"transferring %s\n",p);
 			glob_expand(name, argv, &argc, MAX_ARGS);
 		} else {
 			argc++;
@@ -331,6 +326,8 @@ int daemon_main(void)
 
 	become_daemon();
 
+	rprintf(FINFO,"rsyncd version %s starting\n",VERSION);
+
 	start_accept_loop(rsync_port, start_daemon);
 	return -1;
 }

exclude.c

@@ -205,8 +205,8 @@ void add_cvs_excludes(void)
     add_exclude(cvs_ignore_list[i]);
 
   if ((p=getenv("HOME")) && strlen(p) < (MAXPATHLEN-12)) {
-    sprintf(fname,"%s/.cvsignore",p);
-    add_exclude_file(fname,0);
+	  slprintf(fname,sizeof(fname)-1, "%s/.cvsignore",p);
+	  add_exclude_file(fname,0);
   }
 
   add_exclude_line(getenv("CVSIGNORE"));

flist.c

@@ -521,7 +521,7 @@ static void send_directory(int f,struct file_list *flist,char *dir)
 			closedir(d);
 			return;
 		}
-		strcat(fname,"/");
+		strlcat(fname,"/", MAXPATHLEN-1);
 		l++;
 	}
 	p = fname + strlen(fname);
@@ -585,7 +585,7 @@ struct file_list *send_file_list(int f,int argc,char *argv[])
 
 		l = strlen(fname);
 		if (l != 1 && fname[l-1] == '/') {
-			strcat(fname,".");
+			strlcat(fname,".",MAXPATHLEN-1);
 		}
 
 		if (link_stat(fname,&st) != 0) {
@@ -878,7 +878,7 @@ char *f_name(struct file_struct *f)
 	n = (n+1)%10;
 
 	if (f->dirname) {
-		sprintf(p, "%s/%s", f->dirname, f->basename);
+		slprintf(p, MAXPATHLEN-1, "%s/%s", f->dirname, f->basename);
 	} else {
 		strlcpy(p, f->basename, MAXPATHLEN-1);
 	}

io.c

@@ -521,13 +521,7 @@ void io_printf(int fd, const char *format, ...)
 	int len;
 	
 	va_start(ap, format);
-
-#if HAVE_VSNPRINTF
-	len = vsnprintf(buf, sizeof(buf)-1, format, ap);
-#else
-	vsprintf(buf, format, ap);
-	len = strlen(buf);
-#endif
+	len = vslprintf(buf, sizeof(buf)-1, format, ap);
 	va_end(ap);
 
 	if (len < 0) exit_cleanup(1);

log.c

@@ -23,6 +23,7 @@
   */
 #include "rsync.h"
 
+
 /* this is the rsync debugging function. Call it with FINFO or FERROR */
 void rprintf(int fd, const char *format, ...)
 {
@@ -33,13 +34,7 @@ void rprintf(int fd, const char *format, ...)
 	extern int am_daemon;
 
 	va_start(ap, format);
-
-#if HAVE_VSNPRINTF
-	len = vsnprintf(buf, sizeof(buf)-1, format, ap);
-#else
-	vsprintf(buf, format, ap);
-	len = strlen(buf);
-#endif
+	len = vslprintf(buf, sizeof(buf)-1, format, ap);
 	va_end(ap);
 
 	if (len < 0) exit_cleanup(1);

main.c

@@ -190,7 +190,6 @@ static void do_server_sender(int f_in, int f_out, int argc,char *argv[])
 	struct file_list *flist;
 	char *dir = argv[0];
 	extern int relative_paths;
-	extern int am_daemon;
 	extern int recurse;
 
 	if (verbose > 2)

rsync.c

@@ -111,10 +111,7 @@ static int delete_file(char *fname)
 		if (strcmp(dname,".")==0 ||
 		    strcmp(dname,"..")==0)
 			continue;
-		strlcpy(buf, fname, (MAXPATHLEN-strlen(dname))-2);
-		strcat(buf, "/");
-		strcat(buf, dname);
-		buf[MAXPATHLEN-1] = 0;
+		slprintf(buf, sizeof(buf)-1, "%s/%s", fname, dname);
 		if (verbose > 0)
 			rprintf(FINFO,"deleting %s\n", buf);
 		if (delete_file(buf) != 0) {
@@ -831,7 +828,7 @@ int recv_files(int f_in,struct file_list *flist,char *local_name,int f_gen)
 		      close(fd1);
 		      continue;
 	      }
-	      sprintf(fnametmp,"%s/.%s.XXXXXX",tmpdir,f);
+	      slprintf(fnametmp,sizeof(fnametmp)-1, "%s/.%s.XXXXXX",tmpdir,f);
       } else {
 	      char *f = strrchr(fname,'/');
 
@@ -844,10 +841,10 @@ int recv_files(int f_in,struct file_list *flist,char *local_name,int f_gen)
 
 	      if (f) {
 		      *f = 0;
-		      sprintf(fnametmp,"%s/.%s.XXXXXX",fname,f+1);
+		      slprintf(fnametmp,sizeof(fnametmp)-1,"%s/.%s.XXXXXX",fname,f+1);
 		      *f = '/';
 	      } else {
-		      sprintf(fnametmp,".%s.XXXXXX",fname);
+		      slprintf(fnametmp,sizeof(fnametmp)-1,".%s.XXXXXX",fname);
 	      }
       }
       if (NULL == do_mktemp(fnametmp)) {
@@ -893,7 +890,7 @@ int recv_files(int f_in,struct file_list *flist,char *local_name,int f_gen)
 		rprintf(FERROR,"backup filename too long\n");
 		continue;
 	}
-	sprintf(fnamebak,"%s%s",fname,backup_suffix);
+	slprintf(fnamebak,sizeof(fnamebak)-1,"%s%s",fname,backup_suffix);
 	if (do_rename(fname,fnamebak) != 0 && errno != ENOENT) {
 	  rprintf(FERROR,"rename %s %s : %s\n",fname,fnamebak,strerror(errno));
 	  continue;
@@ -998,10 +995,10 @@ void send_files(struct file_list *flist,int f_out,int f_in)
 				  fname);
 			  return;
 		  }
-		  strcat(fname,"/");
+		  strlcat(fname,"/",MAXPATHLEN-1);
 		  offset = strlen(file->basedir)+1;
 	  }
-	  strncat(fname,f_name(file),MAXPATHLEN-strlen(fname));
+	  strlcat(fname,f_name(file),MAXPATHLEN-strlen(fname));
 	  
 	  if (verbose > 2) 
 		  rprintf(FINFO,"send_files(%d,%s)\n",i,fname);

util.c

@@ -456,6 +456,21 @@ void strlcpy(char *d, char *s, int maxlen)
 	d[len] = 0;
 }
 
+/* like strncat but does not 0 fill the buffer and always null 
+   terminates (thus it can use maxlen+1 space in d) */
+void strlcat(char *d, char *s, int maxlen)
+{
+	int len1 = strlen(d);
+	int len2 = strlen(s);
+	if (len1+len2 > maxlen) {
+		len2 = maxlen-len1;
+	}
+	if (len2 > 0) {
+		memcpy(d+len1, s, len2);
+		d[len1+len2] = 0;
+	}
+}
+
 /* turn a user name into a uid */
 int name_to_uid(char *name, uid_t *uid)
 {
@@ -509,6 +524,7 @@ int lock_range(int fd, int offset, int len)
 static void glob_expand_one(char *s, char **argv, int *argc, int maxargs)
 {
 #ifndef HAVE_GLOB
+	if (!*s) s = ".";
 	argv[*argc] = strdup(s);
 	(*argc)++;
 	return;
@@ -516,6 +532,8 @@ static void glob_expand_one(char *s, char **argv, int *argc, int maxargs)
 	glob_t globbuf;
 	int i;
 
+	if (!*s) s = ".";
+
 	argv[*argc] = strdup(s);
 
 	memset(&globbuf, 0, sizeof(globbuf));
@@ -542,6 +560,10 @@ void glob_expand(char *base, char **argv, int *argc, int maxargs)
 
 	if (!s || !*s) return;
 
+	if (strncmp(s, base, strlen(base)) == 0) {
+		s += strlen(base);
+	}
+
 	s = strdup(s);
 	if (!s) out_of_memory("glob_expand");
 
@@ -551,7 +573,7 @@ void glob_expand(char *base, char **argv, int *argc, int maxargs)
 			/* split it at this point */
 			*(p-1) = 0;
 			glob_expand_one(q, argv, argc, maxargs);
-			q = p+strlen(base);
+			q = p+strlen(base)+1;
 		} else {
 			q++;
 		}
@@ -572,3 +594,74 @@ void strlower(char *s)
 		s++;
 	}
 }
+
+/* this is like vsnprintf but the 'n' limit does not include
+   the terminating null. So if you have a 1024 byte buffer then
+   pass 1023 for n */
+int vslprintf(char *str, int n, const char *format, va_list ap)
+{
+#ifdef HAVE_VSNPRINTF
+	int ret = vsnprintf(str, n, format, ap);
+	if (ret > n || ret < 0) {
+		str[n] = 0;
+		return -1;
+	}
+	str[ret] = 0;
+	return ret;
+#else
+	static char *buf;
+	static int len=MAXPATHLEN*8;
+	int ret;
+
+	/* this code is NOT a proper vsnprintf() implementation. It
+	   relies on the fact that all calls to slprintf() in rsync
+	   pass strings which have already been checked to be less
+	   than MAXPATHLEN in length and never more than 2 strings are
+	   concatenated. This means the above buffer is absolutely
+	   ample and can never be overflowed.
+
+	   In the future we would like to replace this with a proper
+	   vsnprintf() implementation but right now we need a solution
+	   that is secure and portable. This is it.  */
+
+	if (!buf) {
+		buf = malloc(len);
+		if (!buf) {
+			/* can't call debug or we would recurse */
+			exit(1);
+		}
+	}
+
+	ret = vsprintf(buf, format, ap);
+
+	if (ret < 0) {
+		str[0] = 0;
+		return -1;
+	}
+
+	if (ret < n) {
+		n = ret;
+	} else if (ret > n) {
+		ret = -1;
+	}
+
+	buf[n] = 0;
+	
+	memcpy(str, buf, n+1);
+
+	return ret;
+#endif
+}
+
+
+/* like snprintf but always null terminates */
+int slprintf(char *str, int n, char *format, ...)
+{
+	va_list ap;  
+	int ret;
+
+	va_start(ap, format);
+	ret = vslprintf(str,n,format,ap);
+	va_end(ap);
+	return ret;
+}