Avoid use of unchecked sprintf in libraries. Use asprintf if the

output buffer is allocated according to the size of data to be
written, or snprintf otherwise.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@19703 dc483132-0cff-0310-8789-dd5450dbe970

37 files changed, 306 insertions, 302 deletions

diff --git a/src/lib/gssapi/generic/disp_major_status.c b/src/lib/gssapi/generic/disp_major_status.c
index 218370d142..0648192a19 100644
--- a/src/lib/gssapi/generic/disp_major_status.c
+++ b/src/lib/gssapi/generic/disp_major_status.c
@@ -115,11 +115,8 @@ display_unknown(kind, value, buffer)
 {
    char *str;
 
-   if ((str =
-	(char *) xmalloc(strlen(unknown_error)+strlen(kind)+7)) == NULL)
-      return(0);
-
-   sprintf(str, unknown_error, kind, value);
+   if (asprintf(&str, unknown_error, kind, value) < 0)
+       return(0);
 
    buffer->length = strlen(str);
    buffer->value = str;
diff --git a/src/lib/gssapi/mechglue/oid_ops.c b/src/lib/gssapi/mechglue/oid_ops.c
index 5c2ceb321c..2dfbfeae76 100644
--- a/src/lib/gssapi/mechglue/oid_ops.c
+++ b/src/lib/gssapi/mechglue/oid_ops.c
@@ -249,9 +249,9 @@ generic_gss_oid_to_str(minor_status, oid, oid_str)
     numshift = 0;
     cp = (unsigned char *) oid->elements;
     number = (unsigned long) cp[0];
-    sprintf(numstr, "%lu ", (unsigned long)number/40);
+    snprintf(numstr, sizeof(numstr), "%lu ", (unsigned long)number/40);
     string_length += strlen(numstr);
-    sprintf(numstr, "%lu ", (unsigned long)number%40);
+    snprintf(numstr, sizeof(numstr), "%lu ", (unsigned long)number%40);
     string_length += strlen(numstr);
     for (i=1; i<oid->length; i++) {
 	if ((OM_uint32) (numshift+7) < (sizeof (OM_uint32)*8)) {/* XXX */
@@ -262,7 +262,7 @@ generic_gss_oid_to_str(minor_status, oid, oid_str)
 	    return(GSS_S_FAILURE);
 	}
 	if ((cp[i] & 0x80) == 0) {
-	    sprintf(numstr, "%lu ", (unsigned long)number);
+	    snprintf(numstr, sizeof(numstr), "%lu ", (unsigned long)number);
 	    string_length += strlen(numstr);
 	    number = 0;
 	    numshift = 0;
@@ -276,16 +276,16 @@ generic_gss_oid_to_str(minor_status, oid, oid_str)
     if ((bp = (char *) malloc(string_length))) {
 	strcpy(bp, "{ ");
 	number = (OM_uint32) cp[0];
-	sprintf(numstr, "%lu ", (unsigned long)number/40);
+	snprintf(numstr, sizeof(numstr), "%lu ", (unsigned long)number/40);
 	strcat(bp, numstr);
-	sprintf(numstr, "%lu ", (unsigned long)number%40);
+	snprintf(numstr, sizeof(numstr), "%lu ", (unsigned long)number%40);
 	strcat(bp, numstr);
 	number = 0;
 	cp = (unsigned char *) oid->elements;
 	for (i=1; i<oid->length; i++) {
 	    number = (number << 7) | (cp[i] & 0x7f);
 	    if ((cp[i] & 0x80) == 0) {
-		sprintf(numstr, "%lu ", (unsigned long)number);
+		snprintf(numstr, sizeof(numstr), "%lu ", (unsigned long)number);
 		strcat(bp, numstr);
 		number = 0;
 	    }
diff --git a/src/lib/kadm5/alt_prof.c b/src/lib/kadm5/alt_prof.c
index 5567b0c244..6802090d56 100644
--- a/src/lib/kadm5/alt_prof.c
+++ b/src/lib/kadm5/alt_prof.c
@@ -468,20 +468,17 @@ krb5_error_code kadm5_get_config_params(context, use_kdc_config,
      * admin database name and lockfile are now always derived from dbname
      */
     if (params.mask & KADM5_CONFIG_DBNAME) {
-	 params.admin_dbname = (char *) malloc(strlen(params.dbname) + 7);
-	 if (params.admin_dbname) {
-	      sprintf(params.admin_dbname, "%s.kadm5", params.dbname);
-	      params.mask |= KADM5_CONFIG_ADBNAME;
-	 }
+	if (asprintf(&params.admin_dbname, "%s.kadm5", params.dbname) > 0)
+	    params.mask |= KADM5_CONFIG_ADBNAME;
+	else
+	    params.admin_dbname = NULL;
     }
 
     if (params.mask & KADM5_CONFIG_ADBNAME) {
-	 params.admin_lockfile = (char *) malloc(strlen(params.admin_dbname)
-						 + 6);
-	 if (params.admin_lockfile) {
-	      sprintf(params.admin_lockfile, "%s.lock", params.admin_dbname);
-	      params.mask |= KADM5_CONFIG_ADB_LOCKFILE;
-	 }
+	if (asprintf(&params.admin_lockfile, "%s.lock", params.admin_dbname) > 0)
+	    params.mask |= KADM5_CONFIG_ADB_LOCKFILE;
+	else
+	    params.admin_lockfile = NULL;
     }
     
     /* Get the value for the admin (policy) database lock file*/
@@ -816,7 +813,7 @@ kadm5_get_admin_service_name(krb5_context ctx,
 	ret = ENOMEM;
 	goto err_params;
     }
-    sprintf(admin_name, "kadmin/%s", hp->h_name);
+    snprintf(admin_name, maxlen, "kadmin/%s", hp->h_name);
 
 err_params:
     kadm5_free_config_params(ctx, &params_out);
diff --git a/src/lib/kadm5/chpass_util.c b/src/lib/kadm5/chpass_util.c
index dc6ebb61b3..8f6f8c5d70 100644
--- a/src/lib/kadm5/chpass_util.c
+++ b/src/lib/kadm5/chpass_util.c
@@ -139,12 +139,13 @@ kadm5_ret_t _kadm5_chpass_principal_util(void *server_handle,
   if ((code != KADM5_PASS_Q_TOOSHORT) && 
       (code != KADM5_PASS_REUSE) &&(code != KADM5_PASS_Q_CLASS) && 
       (code != KADM5_PASS_Q_DICT) && (code != KADM5_PASS_TOOSOON)) {
-    /* Can't get more info for other errors */
-    sprintf(buffer, "%s %s", error_message(code), 
-	    string_text(CHPASS_UTIL_WHILE_TRYING_TO_CHANGE));
-    sprintf(msg_ret, "%s\n%s\n", string_text(CHPASS_UTIL_PASSWORD_NOT_CHANGED), 
-	    buffer);
-    return(code);
+      /* Can't get more info for other errors */
+      snprintf(buffer, sizeof(buffer), "%s %s", error_message(code), 
+	       string_text(CHPASS_UTIL_WHILE_TRYING_TO_CHANGE));
+      snprintf(msg_ret, msg_len, "%s\n%s\n",
+	       string_text(CHPASS_UTIL_PASSWORD_NOT_CHANGED), 
+	       buffer);
+      return(code);
   }
 
   /* Ok, we have a password quality error. Return a good message */
@@ -200,31 +201,31 @@ kadm5_ret_t _kadm5_chpass_principal_util(void *server_handle,
   code2 = kadm5_get_policy(lhandle, princ_ent.policy,
 			   &policy_ent);
   if (code2 != 0) {
-    sprintf(msg_ret, "%s %s\n%s %s\n\n%s\n ", error_message(code2), 
-	    string_text(CHPASS_UTIL_GET_POLICY_INFO),
-	    error_message(code),
-	    string_text(CHPASS_UTIL_WHILE_TRYING_TO_CHANGE),
-	    string_text(CHPASS_UTIL_PASSWORD_NOT_CHANGED));
-    (void) kadm5_free_principal_ent(lhandle, &princ_ent);
-    return(code);
+      snprintf(msg_ret, msg_len, "%s %s\n%s %s\n\n%s\n ", error_message(code2), 
+	       string_text(CHPASS_UTIL_GET_POLICY_INFO),
+	       error_message(code),
+	       string_text(CHPASS_UTIL_WHILE_TRYING_TO_CHANGE),
+	       string_text(CHPASS_UTIL_PASSWORD_NOT_CHANGED));
+      (void) kadm5_free_principal_ent(lhandle, &princ_ent);
+      return(code);
   }
   
   if (code == KADM5_PASS_Q_TOOSHORT) {
-    sprintf(msg_ret, string_text(CHPASS_UTIL_PASSWORD_TOO_SHORT), 
-	    policy_ent.pw_min_length);
-    (void) kadm5_free_principal_ent(lhandle, &princ_ent);
-    (void) kadm5_free_policy_ent(lhandle, &policy_ent);
-    return(code);
+      snprintf(msg_ret, msg_len, string_text(CHPASS_UTIL_PASSWORD_TOO_SHORT), 
+	       policy_ent.pw_min_length);
+      (void) kadm5_free_principal_ent(lhandle, &princ_ent);
+      (void) kadm5_free_policy_ent(lhandle, &policy_ent);
+      return(code);
   }
 
 /* Can't get more info for other errors */
 
   if (code == KADM5_PASS_Q_CLASS) {
-    sprintf(msg_ret, string_text(CHPASS_UTIL_TOO_FEW_CLASSES), 
-	    policy_ent.pw_min_classes);
-    (void) kadm5_free_principal_ent(lhandle, &princ_ent);
-    (void) kadm5_free_policy_ent(lhandle, &policy_ent);
-    return(code);
+      snprintf(msg_ret, msg_len, string_text(CHPASS_UTIL_TOO_FEW_CLASSES), 
+	       policy_ent.pw_min_classes);
+      (void) kadm5_free_principal_ent(lhandle, &princ_ent);
+      (void) kadm5_free_policy_ent(lhandle, &policy_ent);
+      return(code);
   }
 
   if (code == KADM5_PASS_TOOSOON) {
@@ -237,18 +238,19 @@ kadm5_ret_t _kadm5_chpass_principal_util(void *server_handle,
     if (*(ptr = &time_string[strlen(time_string)-1]) == '\n')
       *ptr = '\0';
 
-    sprintf(msg_ret, string_text(CHPASS_UTIL_PASSWORD_TOO_SOON), 
-	    time_string);
+    snprintf(msg_ret, msg_len, string_text(CHPASS_UTIL_PASSWORD_TOO_SOON), 
+	     time_string);
     (void) kadm5_free_principal_ent(lhandle, &princ_ent);
     (void) kadm5_free_policy_ent(lhandle, &policy_ent);
     return(code);
   }
 
   /* We should never get here, but just in case ... */
-  sprintf(buffer, "%s %s", error_message(code), 
-	  string_text(CHPASS_UTIL_WHILE_TRYING_TO_CHANGE));
-  sprintf(msg_ret, "%s\n%s\n", string_text(CHPASS_UTIL_PASSWORD_NOT_CHANGED), 
-	  buffer);
+  snprintf(buffer, sizeof(buffer), "%s %s", error_message(code), 
+	   string_text(CHPASS_UTIL_WHILE_TRYING_TO_CHANGE));
+  snprintf(msg_ret, msg_len, "%s\n%s\n",
+	   string_text(CHPASS_UTIL_PASSWORD_NOT_CHANGED), 
+	   buffer);
   (void) kadm5_free_principal_ent(lhandle, &princ_ent);
   (void) kadm5_free_policy_ent(lhandle, &policy_ent);
   return(code);
diff --git a/src/lib/kadm5/clnt/client_init.c b/src/lib/kadm5/clnt/client_init.c
index 92cb715b29..bdef3e2934 100644
--- a/src/lib/kadm5/clnt/client_init.c
+++ b/src/lib/kadm5/clnt/client_init.c
@@ -405,23 +405,21 @@ kadm5_get_init_creds(kadm5_server_handle_t handle,
 
      if (init_type == INIT_CREDS) {
 	  ccache = ccache_in;
-	  handle->cache_name = (char *)
-	       malloc(strlen(krb5_cc_get_type(handle->context, ccache)) +
-		      strlen(krb5_cc_get_name(handle->context, ccache)) + 2);
-	  if (handle->cache_name == NULL) {
-	       code = ENOMEM;
-	       goto error;
+	  if (asprintf(&handle->cache_name, "%s:%s",
+		       krb5_cc_get_type(handle->context, ccache),
+		       krb5_cc_get_name(handle->context, ccache)) < 0) {
+	      handle->cache_name = NULL;
+	      code = ENOMEM;
+	      goto error;
 	  }
-	  sprintf(handle->cache_name, "%s:%s",
-		  krb5_cc_get_type(handle->context, ccache),
-		  krb5_cc_get_name(handle->context, ccache));
      } else {
 	  static int counter = 0;
 
-	  handle->cache_name = malloc(sizeof("MEMORY:kadm5_")
-				      + 3*sizeof(counter));
-	  sprintf(handle->cache_name, "MEMORY:kadm5_%u", counter++);
-
+	  if (asprintf(&handle->cache_name, "MEMORY:kadm5_%u", counter++) < 0) {
+	      handle->cache_name = NULL;
+	      code = ENOMEM;
+	      goto error;
+	  }
 	  code = krb5_cc_resolve(handle->context, handle->cache_name,
 				 &ccache);
 	  if (code) 
@@ -477,6 +475,7 @@ kadm5_gic_iter(kadm5_server_handle_t handle,
      krb5_keytab kt;
      krb5_get_init_creds_opt opt;
      krb5_creds mcreds, outcreds;
+     int n;
 
      ctx = handle->context;
      kt = NULL;
@@ -487,20 +486,17 @@ kadm5_gic_iter(kadm5_server_handle_t handle,
 
      code = ENOMEM;
      if (realm) {
-          if ((strlen(svcname) + strlen(realm) + 1) >= full_svcname_len)
-	       goto error;
-	  sprintf(full_svcname, "%s@%s", svcname, realm);
+	 n = snprintf(full_svcname, full_svcname_len, "%s@%s",
+		      svcname, realm);
+	 if (n < 0 || n >= full_svcname_len)
+	     goto error;
      } else {
-	  /* krb5_princ_realm(client) is not null terminated */
-          if ((strlen(svcname) + krb5_princ_realm(ctx, client)->length + 1)
-	      >= full_svcname_len)
-	       goto error;
-
-	  strcpy(full_svcname, svcname);
-	  strcat(full_svcname, "@");
-	  strncat(full_svcname,
-		  krb5_princ_realm(ctx, client)->data,
-		  krb5_princ_realm(ctx, client)->length);
+	 /* krb5_princ_realm(client) is not null terminated */
+	 n = snprintf(full_svcname, full_svcname_len, "%s@%.*s",
+		      svcname, krb5_princ_realm(ctx, client)->length,
+		      krb5_princ_realm(ctx, client)->data);
+	 if (n < 0 || n >= full_svcname_len)
+	     goto error;
      }
 
      if (init_type != INIT_CREDS)
diff --git a/src/lib/kadm5/logger.c b/src/lib/kadm5/logger.c
index 86abf48e99..dabb399c17 100644
--- a/src/lib/kadm5/logger.c
+++ b/src/lib/kadm5/logger.c
@@ -189,7 +189,7 @@ klog_com_err_proc(const char *whoami, long int code, const char *format, va_list
     char	*syslogp;
 
     /* Make the header */
-    sprintf(outbuf, "%s: ", whoami);
+    snprintf(outbuf, sizeof(outbuf), "%s: ", whoami);
     /*
      * Squirrel away address after header for syslog since syslog makes
      * a header
@@ -844,13 +844,13 @@ klog_vsyslog(int priority, const char *format, va_list arglist)
     cp += 15;
 #endif	/* HAVE_STRFTIME */
 #ifdef VERBOSE_LOGS
-    sprintf(cp, " %s %s[%ld](%s): ",
-	    log_control.log_hostname ? log_control.log_hostname : "", 
-	    log_control.log_whoami ? log_control.log_whoami : "", 
-	    (long) getpid(),
-	    severity2string(priority));
+    snprintf(cp, sizeof(outbuf) - (cp-outbuf), " %s %s[%ld](%s): ",
+	     log_control.log_hostname ? log_control.log_hostname : "", 
+	     log_control.log_whoami ? log_control.log_whoami : "", 
+	     (long) getpid(),
+	     severity2string(priority));
 #else
-    sprintf(cp, " ");
+    snprintf(cp, sizeof(outbuf) - (cp-outbuf), " ");
 #endif
     syslogp = &outbuf[strlen(outbuf)];
 
diff --git a/src/lib/kadm5/srv/server_kdb.c b/src/lib/kadm5/srv/server_kdb.c
index 6392ef10d7..700b53a66a 100644
--- a/src/lib/kadm5/srv/server_kdb.c
+++ b/src/lib/kadm5/srv/server_kdb.c
@@ -113,11 +113,10 @@ krb5_error_code kdb_init_hist(kadm5_server_handle_t handle, char *r)
 	realm = r;
     }
 
-    if ((hist_name = (char *) malloc(strlen(KADM5_HIST_PRINCIPAL) +
-				     strlen(realm) + 2)) == NULL)
+    if (asprintf(&hist_name, "%s@%s", KADM5_HIST_PRINCIPAL, realm) < 0) {
+	hist_name = NULL;
 	goto done;
-
-    (void) sprintf(hist_name, "%s@%s", KADM5_HIST_PRINCIPAL, realm);
+    }
 
     if ((ret = krb5_parse_name(handle->context, hist_name, &hist_princ)))
 	goto done;
diff --git a/src/lib/kdb/kdb5.c b/src/lib/kdb/kdb5.c
index a20af6b175..2b6ed2c642 100644
--- a/src/lib/kdb/kdb5.c
+++ b/src/lib/kdb/kdb5.c
@@ -269,8 +269,9 @@ kdb_load_library(krb5_context kcontext, char *lib_name, db_library * lib)
     } else
 #endif
     {
-	sprintf(buf, "Program not built to support %s database type\n",
-		lib_name);
+	snprintf(buf, sizeof(buf),
+		 "Program not built to support %s database type\n",
+		 lib_name);
 	status = KRB5_KDB_DBTYPE_NOSUP;
 	krb5_db_set_err(kcontext, krb5_err_have_str, status, buf);
 	goto clean_n_exit;
@@ -282,8 +283,9 @@ kdb_load_library(krb5_context kcontext, char *lib_name, db_library * lib)
 
     if ((status = (*lib)->vftabl.init_library())) {
 	/* ERROR. library not initialized cleanly */
-	sprintf(buf, "%s library initialization failed, error code %ld\n",
-		lib_name, status);
+	snprintf(buf, sizeof(buf),
+		 "%s library initialization failed, error code %ld\n",
+		 lib_name, status);
 	status = KRB5_KDB_DBTYPE_INIT;
 	krb5_db_set_err(kcontext, krb5_err_have_str, status, buf);
 	goto clean_n_exit;
diff --git a/src/lib/krb4/CCache-glue.c b/src/lib/krb4/CCache-glue.c
index 2ccbb153a1..a078c9f697 100644
--- a/src/lib/krb4/CCache-glue.c
+++ b/src/lib/krb4/CCache-glue.c
@@ -93,7 +93,7 @@ krb_in_tkt (
 	err = cc_initialize (&cc_context, ccapi_version_3, &cc_version, NULL);
     
 	if (err == ccNoError) {
-        sprintf (principal, "%s%s%s@%s", pname, (pinst [0] == '\0') ? "" : ".", pinst, realm);
+	    snprintf (principal, sizeof(principal), "%s%s%s@%s", pname, (pinst [0] == '\0') ? "" : ".", pinst, realm);
 	}
     
 	if (err == ccNoError) {
diff --git a/src/lib/krb4/RealmsConfig-glue.c b/src/lib/krb4/RealmsConfig-glue.c
index 740d881c41..df663adb56 100644
--- a/src/lib/krb4/RealmsConfig-glue.c
+++ b/src/lib/krb4/RealmsConfig-glue.c
@@ -473,7 +473,7 @@ krb_get_krbhst(
 	    return KFAILURE;
 	if (strlen(entry->host) + 6 >= MAXHOSTNAMELEN)
 	    return KFAILURE;
-	sprintf(host, "%s:%d", entry->host, entry->port);
+	snprintf(host, MAXHOSTNAMELEN, "%s:%d", entry->host, entry->port);
 	return KSUCCESS;
     }
 #endif
diff --git a/src/lib/krb4/klog.c b/src/lib/krb4/klog.c
index da48efeb2c..4e9661a891 100644
--- a/src/lib/krb4/klog.c
+++ b/src/lib/krb4/klog.c
@@ -91,7 +91,7 @@ char * klog(type,format,a1,a2,a3,a4,a5,a6,a7,a8,a9,a0)
         logtype_array[L_ERR_UNK] = 1;
     }
 
-    (void) sprintf(logtxt,format,a1,a2,a3,a4,a5,a6,a7,a8,a9,a0);
+    (void) snprintf(logtxt,sizeof(logtxt),format,a1,a2,a3,a4,a5,a6,a7,a8,a9,a0);
 
     if (!logtype_array[type])
 	return(logtxt);
diff --git a/src/lib/krb4/password_to_key.c b/src/lib/krb4/password_to_key.c
index c6e60d98cd..d5ca7a5ccc 100644
--- a/src/lib/krb4/password_to_key.c
+++ b/src/lib/krb4/password_to_key.c
@@ -35,6 +35,8 @@
 #include "krb.h"
 #include "krb4int.h"
 
+#include "k5-platform.h"
+
 /*
  * passwd_to_key(): given a password, return a DES key.
  * There are extra arguments here which (used to be?)
@@ -107,17 +109,15 @@ krb5_passwd_to_key(
     char	*passwd,
     C_Block	key)
 {
-    size_t	len, tlen;
     char	*p;
 
     if (user && instance && realm && passwd) {
-        len = MAX_K_NAME_SZ + strlen(passwd) + 1;
-	tlen = strlen(passwd) + strlen(realm) + strlen(user) + strlen(instance) + 1;
-	if (tlen > len)
+	if (strlen(realm) + strlen(user) + strlen(instance) > MAX_K_NAME_SZ)
+	    /* XXX Is this right?  The old code returned 0, which is
+	       also what it returns after sucessfully generating a
+	       key.  The other error path returns -1.  */
 	    return 0;
-        p = malloc (tlen);
-        if (p != NULL) {
-            sprintf (p, "%s%s%s%s", passwd, realm, user, instance);
+	if (asprintf(&p, "%s%s%s%s", passwd, realm, user, instance) >= 0) {
             des_string_to_key (p, key);
             free (p);
             return 0;
diff --git a/src/lib/krb4/stime.c b/src/lib/krb4/stime.c
index 92c86895e8..f73c6f5201 100644
--- a/src/lib/krb4/stime.c
+++ b/src/lib/krb4/stime.c
@@ -49,9 +49,9 @@ char *krb_stime(t)
 
     adjusted_time = *t - CONVERT_TIME_EPOCH;
     tm = localtime(&adjusted_time);
-    (void) sprintf(st,"%2d-%s-%d %02d:%02d:%02d",tm->tm_mday,
-                   month_sname(tm->tm_mon + 1),1900+tm->tm_year,
-                   tm->tm_hour, tm->tm_min, tm->tm_sec);
+    (void) snprintf(st,sizeof(st),"%2d-%s-%d %02d:%02d:%02d",tm->tm_mday,
+		    month_sname(tm->tm_mon + 1),1900+tm->tm_year,
+		    tm->tm_hour, tm->tm_min, tm->tm_sec);
     return st;
 }
 
diff --git a/src/lib/krb4/tkt_string.c b/src/lib/krb4/tkt_string.c
index 123596ca24..f6ed927b74 100644
--- a/src/lib/krb4/tkt_string.c
+++ b/src/lib/krb4/tkt_string.c
@@ -74,7 +74,8 @@ const char *tkt_string()
 	} else {
 	    /* 32 bits of signed integer will always fit in 11 characters
 	     (including the sign), so no need to worry about overflow */
-	    (void) sprintf(krb_ticket_string, "%s%d",TKT_ROOT,(int) getuid());
+	    (void) snprintf(krb_ticket_string, sizeof(krb_ticket_string),
+			    "%s%d",TKT_ROOT,(int) getuid());
         }
     }
     return krb_ticket_string;
diff --git a/src/lib/krb5/asn.1/asn1_encode.c b/src/lib/krb5/asn.1/asn1_encode.c
index c5e3452b85..5ef2a3efa8 100644
--- a/src/lib/krb5/asn.1/asn1_encode.c
+++ b/src/lib/krb5/asn.1/asn1_encode.c
@@ -261,9 +261,12 @@ asn1_error_code asn1_encode_generaltime(asn1buf *buf, time_t val,
 	  gtime->tm_mday > 31 || gtime->tm_hour > 23 ||
 	  gtime->tm_min > 59 || gtime->tm_sec > 59)
 	  return ASN1_BAD_GMTIME;
-      sprintf(s, "%04d%02d%02d%02d%02d%02dZ",
-	      1900+gtime->tm_year, gtime->tm_mon+1, gtime->tm_mday,
-	      gtime->tm_hour, gtime->tm_min, gtime->tm_sec);
+      if (snprintf(s, sizeof(s), "%04d%02d%02d%02d%02d%02dZ",
+		   1900+gtime->tm_year, gtime->tm_mon+1, gtime->tm_mday,
+		   gtime->tm_hour, gtime->tm_min, gtime->tm_sec)
+	  >= sizeof(s))
+	  /* Shouldn't be possible given above tests.  */
+	  return ASN1_BAD_GMTIME;
       sp = s;
   }
 
diff --git a/src/lib/krb5/ccache/ccapi/stdcc.c b/src/lib/krb5/ccache/ccapi/stdcc.c
index babfea48b4..8f98ef7dbe 100644
--- a/src/lib/krb5/ccache/ccapi/stdcc.c
+++ b/src/lib/krb5/ccache/ccapi/stdcc.c
@@ -1060,7 +1060,7 @@ krb5_error_code KRB5_CALLCONV  krb5_stdcc_generate_new
 	
   	/* create a unique name */
   	cc_get_change_time(gCntrlBlock, &change_time);
-  	sprintf(name, "gen_new_cache%d", change_time);
+  	snprintf(name, 256, "gen_new_cache%d", change_time);
   	
   	/* create the new cache */
   	err = cc_create(gCntrlBlock, name, name, CC_CRED_V5, 0L,
diff --git a/src/lib/krb5/ccache/ser_cc.c b/src/lib/krb5/ccache/ser_cc.c
index a7d34f93d1..d2abf532d4 100644
--- a/src/lib/krb5/ccache/ser_cc.c
+++ b/src/lib/krb5/ccache/ser_cc.c
@@ -120,13 +120,13 @@ krb5_ccache_externalize(krb5_context kcontext, krb5_pointer arg, krb5_octet **bu
 	    fnamep = krb5_cc_get_name(kcontext, ccache);
 	    namelen += (strlen(fnamep)+1);
 
-	    if ((ccname = (char *) malloc(namelen))) {
-		/* Format the ccache name. */
-		if (ccache->ops && ccache->ops->prefix)
-		    sprintf(ccname, "%s:%s", ccache->ops->prefix, fnamep);
-		else
-		    strcpy(ccname, fnamep);
+	    if (ccache->ops && ccache->ops->prefix) {
+		if (asprintf(&ccname, "%s:%s", ccache->ops->prefix, fnamep) < 0)
+		    ccname = NULL;
+	    } else
+		ccname = strdup(fnamep);
 
+	    if (ccname) {
 		/* Put the length of the file name */
 		(void) krb5_ser_pack_int32((krb5_int32) strlen(ccname),
 					   &bp, &remain);
diff --git a/src/lib/krb5/ccache/t_cc.c b/src/lib/krb5/ccache/t_cc.c
index 393ac92cde..862411509b 100644
--- a/src/lib/krb5/ccache/t_cc.c
+++ b/src/lib/krb5/ccache/t_cc.c
@@ -170,7 +170,7 @@ static void cc_test(krb5_context context, const char *name, int flags)
 
      {
        /* Copy the cache test*/
-       sprintf(newcache, "%s.new", name);
+       snprintf(newcache, sizeof(newcache), "%s.new", name);
        kret = krb5_cc_resolve(context, newcache, &id2);
        CHECK(kret, "resolve of new cache");
        
@@ -212,12 +212,11 @@ static void cc_test(krb5_context context, const char *name, int flags)
  */
 static int check_registered(krb5_context context, const char *prefix)
 {
-
   char name[300];
   krb5_error_code kret;
   krb5_ccache id;
 
-  sprintf(name, "%s/tmp/cctest.%ld", prefix, (long) getpid());
+  snprintf(name, sizeof(name), "%s/tmp/cctest.%ld", prefix, (long) getpid());
 
   kret = krb5_cc_resolve(context, name, &id);
   if(kret != KRB5_OK) {
@@ -242,7 +241,7 @@ static void do_test(krb5_context context, const char *prefix)
 {
   char name[300];
 
-  sprintf(name, "%s/tmp/cctest.%ld", prefix, (long) getpid());
+  snprintf(name, sizeof(name), "%s/tmp/cctest.%ld", prefix, (long) getpid());
   printf("Starting test on %s\n", name);
   cc_test (context, name, 0);
   cc_test (context, name, !0);
diff --git a/src/lib/krb5/keytab/kt_file.c b/src/lib/krb5/keytab/kt_file.c
index df0a80501f..2652c00aff 100644
--- a/src/lib/krb5/keytab/kt_file.c
+++ b/src/lib/krb5/keytab/kt_file.c
@@ -607,14 +607,13 @@ krb5_ktf_keytab_externalize(krb5_context kcontext, krb5_pointer arg, krb5_octet
 		fnamep = ktfile_def_name;
 	    namelen += (strlen(fnamep)+1);
 
-	    if ((ktname = (char *) malloc(namelen))) {
-		/* Format the keytab name. */
-		if (keytab->ops && keytab->ops->prefix)
-		    sprintf(ktname, "%s:%s", keytab->ops->prefix, fnamep);
-
-		else
-		    strcpy(ktname, fnamep);
+	    if (keytab->ops && keytab->ops->prefix) {
+		if (asprintf(&ktname, "%s:%s", keytab->ops->prefix, fnamep) < 0)
+		    ktname = NULL;
+	    } else
+		ktname = strdup(fnamep);
 
+	    if (ktname) {
 		/* Fill in the file-specific keytab information. */
 		if (ktdata) {
 		    if (ktdata->openf) {
diff --git a/src/lib/krb5/krb/gic_pwd.c b/src/lib/krb5/krb/gic_pwd.c
index 02d344c5df..dd3f011d9a 100644
--- a/src/lib/krb5/krb/gic_pwd.c
+++ b/src/lib/krb5/krb/gic_pwd.c
@@ -257,10 +257,12 @@ krb5_get_init_creds_password(krb5_context context,
 
       if (strcmp(pw0.data, pw1.data) != 0) {
 	 ret = KRB5_LIBOS_BADPWDMATCH;
-	 sprintf(banner, "%s.  Please try again.", error_message(ret));
+	 snprintf(banner, sizeof(banner),
+		  "%s.  Please try again.", error_message(ret));
       } else if (pw0.length == 0) {
 	 ret = KRB5_CHPW_PWDNULL;
-	 sprintf(banner, "%s.  Please try again.", error_message(ret));
+	 snprintf(banner, sizeof(banner),
+		  "%s.  Please try again.", error_message(ret));
       } else {
 	 int result_code;
 	 krb5_data code_string;
@@ -295,11 +297,11 @@ krb5_get_init_creds_password(krb5_context context,
 	 if (result_string.length > (sizeof(banner)-100))
 	    result_string.length = sizeof(banner)-100;
 
-	 sprintf(banner, "%.*s%s%.*s.  Please try again.\n",
-		 (int) code_string.length, code_string.data,
-		 result_string.length ? ": " : "",
-		 (int) result_string.length,
-		 result_string.data ? result_string.data : "");
+	 snprintf(banner, sizeof(banner), "%.*s%s%.*s.  Please try again.\n",
+		  (int) code_string.length, code_string.data,
+		  result_string.length ? ": " : "",
+		  (int) result_string.length,
+		  result_string.data ? result_string.data : "");
 
 	 krb5_xfree(code_string.data);
 	 krb5_xfree(result_string.data);
@@ -340,14 +342,16 @@ cleanup:
 	  ((hours = ((as_reply->enc_part2->key_exp-now)/(60*60))) <= 7*24) &&
 	  (hours >= 0)) {
 	 if (hours < 1)
-	    sprintf(banner,
-		    "Warning: Your password will expire in less than one hour.");
+	     snprintf(banner, sizeof(banner),
+		      "Warning: Your password will expire in less than one hour.");
 	 else if (hours <= 48)
-	    sprintf(banner, "Warning: Your password will expire in %d hour%s.",
-		    hours, (hours == 1)?"":"s");
+	     snprintf(banner, sizeof(banner),
+		      "Warning: Your password will expire in %d hour%s.",
+		      hours, (hours == 1)?"":"s");
 	 else
-	    sprintf(banner, "Warning: Your password will expire in %d days.",
-		    hours/24);
+	     snprintf(banner, sizeof(banner),
+		      "Warning: Your password will expire in %d days.",
+		      hours/24);
 
 	 /* ignore an error here */
          /* PROMPTER_INVOCATION */
@@ -376,17 +380,17 @@ cleanup:
 	       delta = (*last_req)->value - now;
 
 	       if (delta < 3600)
-		  sprintf(banner,
-		    "Warning: Your password will expire in less than one "
-		     "hour on %s", ts);
+		   snprintf(banner, sizeof(banner),
+			    "Warning: Your password will expire in less than one hour on %s",
+			    ts);
 	       else if (delta < 86400*2)
-		  sprintf(banner,
-		     "Warning: Your password will expire in %d hour%s on %s",
-		     delta / 3600, delta < 7200 ? "" : "s", ts);
+		   snprintf(banner, sizeof(banner),
+			    "Warning: Your password will expire in %d hour%s on %s",
+			    delta / 3600, delta < 7200 ? "" : "s", ts);
 	       else
-		  sprintf(banner,
-		     "Warning: Your password will expire in %d days on %s",
-		     delta / 86400, ts);
+		   snprintf(banner, sizeof(banner),
+			    "Warning: Your password will expire in %d days on %s",
+			    delta / 86400, ts);
 	       /* ignore an error here */
 	       /* PROMPTER_INVOCATION */
 	       (*prompter)(context, data, 0, banner, 0, 0);
diff --git a/src/lib/krb5/krb/preauth2.c b/src/lib/krb5/krb/preauth2.c
index f59b899c60..7be2becfeb 100644
--- a/src/lib/krb5/krb/preauth2.c
+++ b/src/lib/krb5/krb/preauth2.c
@@ -799,21 +799,21 @@ krb5_error_code pa_sam(krb5_context context,
 			prompter_data, salt, s2kparams, as_key, gak_data)))
 	   return(ret);
     }
-    sprintf(name, "%.*s",
-	    SAMDATA(sam_challenge->sam_type_name, "SAM Authentication",
-		    sizeof(name) - 1));
+    snprintf(name, sizeof(name), "%.*s",
+	     SAMDATA(sam_challenge->sam_type_name, "SAM Authentication",
+		     sizeof(name) - 1));
 
-    sprintf(banner, "%.*s",
-	    SAMDATA(sam_challenge->sam_challenge_label,
-		    sam_challenge_banner(sam_challenge->sam_type),
-		    sizeof(banner)-1));
+    snprintf(banner, sizeof(banner), "%.*s",
+	     SAMDATA(sam_challenge->sam_challenge_label,
+		     sam_challenge_banner(sam_challenge->sam_type),
+		     sizeof(banner)-1));
 
     /* sprintf(prompt, "Challenge is [%s], %s: ", challenge, prompt); */
-    sprintf(prompt, "%s%.*s%s%.*s",
-	    sam_challenge->sam_challenge.length?"Challenge is [":"",
-	    SAMDATA(sam_challenge->sam_challenge, "", 20),
-	    sam_challenge->sam_challenge.length?"], ":"",
-	    SAMDATA(sam_challenge->sam_response_prompt, "passcode", 55));
+    snprintf(prompt, sizeof(prompt), "%s%.*s%s%.*s",
+	     sam_challenge->sam_challenge.length?"Challenge is [":"",
+	     SAMDATA(sam_challenge->sam_challenge, "", 20),
+	     sam_challenge->sam_challenge.length?"], ":"",
+	     SAMDATA(sam_challenge->sam_response_prompt, "passcode", 55));
 
     response_data.data = response;
     response_data.length = sizeof(response);
@@ -1064,20 +1064,20 @@ krb5_error_code pa_sam_2(krb5_context context,
 	}
    }
 
-   sprintf(name, "%.*s",
+   snprintf(name, sizeof(name), "%.*s",
 	SAMDATA(sc2b->sam_type_name, "SAM Authentication",
 	sizeof(name) - 1));
 
-   sprintf(banner, "%.*s",
-	SAMDATA(sc2b->sam_challenge_label,
-	sam_challenge_banner(sc2b->sam_type),
-	sizeof(banner)-1));
+   snprintf(banner, sizeof(banner), "%.*s",
+	    SAMDATA(sc2b->sam_challenge_label,
+		    sam_challenge_banner(sc2b->sam_type),
+		    sizeof(banner)-1));
 
-   sprintf(prompt, "%s%.*s%s%.*s",
-	sc2b->sam_challenge.length?"Challenge is [":"",
-	SAMDATA(sc2b->sam_challenge, "", 20),
-	sc2b->sam_challenge.length?"], ":"",
-	SAMDATA(sc2b->sam_response_prompt, "passcode", 55));
+   snprintf(prompt, sizeof(prompt), "%s%.*s%s%.*s",
+	    sc2b->sam_challenge.length?"Challenge is [":"",
+	    SAMDATA(sc2b->sam_challenge, "", 20),
+	    sc2b->sam_challenge.length?"], ":"",
+	    SAMDATA(sc2b->sam_response_prompt, "passcode", 55));
 
    response_data.data = response;
    response_data.length = sizeof(response);
diff --git a/src/lib/krb5/krb/srv_rcache.c b/src/lib/krb5/krb/srv_rcache.c
index f88df5ee5f..c8cbe72bc0 100644
--- a/src/lib/krb5/krb/srv_rcache.c
+++ b/src/lib/krb5/krb/srv_rcache.c
@@ -84,7 +84,7 @@ krb5_get_server_rcache(krb5_context context, const krb5_data *piece,
 	    continue;
 	}
 	if (!isvalidrcname((int) piece->data[i])) {
-	    sprintf(tmp, "%03o", piece->data[i]);
+	    snprintf(tmp, sizeof(tmp), "%03o", piece->data[i]);
 	    cachename[p++] = '-';
 	    cachename[p++] = tmp[0];
 	    cachename[p++] = tmp[1];
diff --git a/src/lib/krb5/krb/str_conv.c b/src/lib/krb5/krb/str_conv.c
index d0a11db28f..a650496fc3 100644
--- a/src/lib/krb5/krb/str_conv.c
+++ b/src/lib/krb5/krb/str_conv.c
@@ -264,9 +264,9 @@ krb5_timestamp_to_sfstring(krb5_timestamp timestamp, char *buffer, size_t buflen
     if (!ndone) {
 #define sftime_default_len	2+1+2+1+4+1+2+1+2+1
 	if (buflen >= sftime_default_len) {
-	    sprintf(buffer, "%02d/%02d/%4d %02d:%02d",
-		    tmp->tm_mday, tmp->tm_mon+1, 1900+tmp->tm_year,
-		    tmp->tm_hour, tmp->tm_min);
+	    snprintf(buffer, buflen, "%02d/%02d/%4d %02d:%02d",
+		     tmp->tm_mday, tmp->tm_mon+1, 1900+tmp->tm_year,
+		     tmp->tm_hour, tmp->tm_min);
 	    ndone = strlen(buffer);
 	}
     }
@@ -309,14 +309,14 @@ krb5_deltat_to_string(krb5_deltat deltat, char *buffer, size_t buflen)
 
     memset (tmpbuf, 0, sizeof (tmpbuf));
     if (days == 0)
-	sprintf(buffer, "%d:%02d:%02d", hours, minutes, seconds);
+	snprintf(buffer, buflen, "%d:%02d:%02d", hours, minutes, seconds);
     else if (hours || minutes || seconds)
-	sprintf(buffer, "%d %s %02d:%02d:%02d", days,
-		(days > 1) ? "days" : "day",
-		hours, minutes, seconds);
+	snprintf(buffer, buflen, "%d %s %02d:%02d:%02d", days,
+		 (days > 1) ? "days" : "day",
+		 hours, minutes, seconds);
     else
-	sprintf(buffer, "%d %s", days,
-		(days > 1) ? "days" : "day");
+	snprintf(buffer, buflen, "%d %s", days,
+		 (days > 1) ? "days" : "day");
     if (tmpbuf[sizeof(tmpbuf)-1] != 0)
 	/* Something must be very wrong with my math above, or the
 	   assumptions going into it...  */
diff --git a/src/lib/krb5/krb/t_ser.c b/src/lib/krb5/krb/t_ser.c
index d62bceeb71..383b6708db 100644
--- a/src/lib/krb5/krb/t_ser.c
+++ b/src/lib/krb5/krb/t_ser.c
@@ -203,7 +203,7 @@ ser_kcontext_test(krb5_context kcontext, int verbose)
     profile_t		sprofile;
     char		dbname[128];
 
-    sprintf(dbname, "temp_%d", (int) getpid());
+    snprintf(dbname, sizeof(dbname), "temp_%d", (int) getpid());
     sprofile = kcontext->profile;
     kcontext->profile = (profile_t) NULL;
     if (!(kret = ser_data(verbose, "> Context with no profile",
@@ -320,7 +320,8 @@ ser_acontext_test(krb5_context kcontext, int verbose)
 		 */
 		memset(&aent, 0, sizeof(aent));
 		aent.magic = KV5M_AUTHENTICATOR;
-		sprintf(clname, "help/me/%d@this.is.a.test", (int) getpid());
+		snprintf(clname, sizeof(clname),
+			 "help/me/%d@this.is.a.test", (int) getpid());
 		actx->authentp = &aent;
 		if (!(kret = krb5_parse_name(kcontext, clname,
 					     &aent.client)) &&
@@ -368,9 +369,10 @@ ser_ccache_test(krb5_context kcontext, int verbose)
     krb5_ccache		ccache;
     krb5_principal	principal;
 
-    sprintf(ccname, "temp_cc_%d", (int) getpid());
-    sprintf(princname, "zowie%d/instance%d@this.is.a.test",
-	    (int) getpid(), (int) getpid());
+    snprintf(ccname, sizeof(ccname), "temp_cc_%d", (int) getpid());
+    snprintf(princname, sizeof(princname),
+	     "zowie%d/instance%d@this.is.a.test",
+	     (int) getpid(), (int) getpid());
     if (!(kret = krb5_cc_resolve(kcontext, ccname, &ccache)) &&
 	!(kret = ser_data(verbose, "> Resolved default ccache",
 			  (krb5_pointer) ccache, KV5M_CCACHE)) &&
@@ -380,9 +382,9 @@ ser_ccache_test(krb5_context kcontext, int verbose)
 			  (krb5_pointer) ccache, KV5M_CCACHE)) &&
 	!(kret = krb5_cc_destroy(kcontext, ccache))) {
 	krb5_free_principal(kcontext, principal);
-	sprintf(ccname, "FILE:temp_cc_%d", (int) getpid());
-	sprintf(princname, "xxx%d/i%d@this.is.a.test",
-		(int) getpid(), (int) getpid());
+	snprintf(ccname, sizeof(ccname), "FILE:temp_cc_%d", (int) getpid());
+	snprintf(princname, sizeof(princname), "xxx%d/i%d@this.is.a.test",
+		 (int) getpid(), (int) getpid());
 	if (!(kret = krb5_cc_resolve(kcontext, ccname, &ccache)) &&
 	    !(kret = ser_data(verbose, "> Resolved FILE ccache",
 			      (krb5_pointer) ccache, KV5M_CCACHE)) &&
@@ -412,7 +414,7 @@ ser_keytab_test(krb5_context kcontext, int verbose)
     char		ccname[128];
     krb5_keytab		keytab;
 
-    sprintf(ccname, "temp_kt_%d", (int) getpid());
+    snprintf(ccname, sizeof(ccname), "temp_kt_%d", (int) getpid());
     if (!(kret = krb5_kt_resolve(kcontext, ccname, &keytab)) &&
 	!(kret = ser_data(verbose, "> Resolved default keytab",
 			  (krb5_pointer) keytab, KV5M_KEYTAB)) &&
@@ -422,7 +424,8 @@ ser_keytab_test(krb5_context kcontext, int verbose)
 	    !(kret = ser_data(verbose, "> Resolved FILE keytab",
 			      (krb5_pointer) keytab, KV5M_KEYTAB)) &&
 	    !(kret = krb5_kt_close(kcontext, keytab))) {
-	    sprintf(ccname, "WRFILE:temp_kt_%d", (int) getpid());
+	    snprintf(ccname, sizeof(ccname),
+		     "WRFILE:temp_kt_%d", (int) getpid());
 	    if (!(kret = krb5_kt_resolve(kcontext, ccname, &keytab)) &&
 		!(kret = ser_data(verbose, "> Resolved WRFILE keytab",
 				  (krb5_pointer) keytab, KV5M_KEYTAB)) &&
@@ -447,7 +450,7 @@ ser_rcache_test(krb5_context kcontext, int verbose)
     char		rcname[128];
     krb5_rcache		rcache;
 
-    sprintf(rcname, "dfl:temp_rc_%d", (int) getpid());
+    snprintf(rcname, sizeof(rcname), "dfl:temp_rc_%d", (int) getpid());
     if (!(kret = krb5_rc_resolve_full(kcontext, &rcache, rcname)) &&
 	!(kret = ser_data(verbose, "> Resolved FILE rcache",
 			  (krb5_pointer) rcache, KV5M_RCACHE)) &&
@@ -527,7 +530,9 @@ ser_princ_test(krb5_context kcontext, int verbose)
     krb5_principal	princ;
     char		pname[1024];
 
-    sprintf(pname, "the/quick/brown/fox/jumped/over/the/lazy/dog/%d@this.is.a.test", (int) getpid());
+    snprintf(pname, sizeof(pname),
+	     "the/quick/brown/fox/jumped/over/the/lazy/dog/%d@this.is.a.test",
+	     (int) getpid());
     if (!(kret = krb5_parse_name(kcontext, pname, &princ))) {
 	if (!(kret = ser_data(verbose, "> Principal",
 			      (krb5_pointer) princ, KV5M_PRINCIPAL))) {
diff --git a/src/lib/krb5/os/ccdefname.c b/src/lib/krb5/os/ccdefname.c
index d140b08967..8fa52f7b81 100644
--- a/src/lib/krb5/os/ccdefname.c
+++ b/src/lib/krb5/os/ccdefname.c
@@ -213,7 +213,8 @@ static krb5_error_code get_from_os(char *name_buf, int name_size)
 			result = ENOMEM;
 			goto cleanup;
 		} else {
-			sprintf (name_buf, "API:%s", default_name -> data);
+		    snprintf (name_buf, name_size, "API:%s",
+			      default_name -> data);
 		}
 	}
 	
@@ -233,8 +234,8 @@ cleanup:
 #if !(defined(_WIN32))
 static krb5_error_code get_from_os(char *name_buf, int name_size)
 {
-	sprintf(name_buf, "FILE:/tmp/krb5cc_%ld", (long) getuid());
-	return 0;
+    snprintf(name_buf, name_size, "FILE:/tmp/krb5cc_%ld", (long) getuid());
+    return 0;
 }
 #endif
 #endif
diff --git a/src/lib/krb5/os/dnssrv.c b/src/lib/krb5/os/dnssrv.c
index d1c96b291c..d726fb7e54 100644
--- a/src/lib/krb5/os/dnssrv.c
+++ b/src/lib/krb5/os/dnssrv.c
@@ -84,8 +84,10 @@ krb5int_make_srv_query_realm(const krb5_data *realm,
     if ( strlen(service) + strlen(protocol) + realm->length + 6 
          > MAXDNAME )
 	return 0;
-    sprintf(host, "%s.%s.%.*s", service, protocol, (int) realm->length,
-	    realm->data);
+    if (snprintf(host, sizeof(host), "%s.%s.%.*s",
+		 service, protocol, (int) realm->length,
+		 realm->data) >= sizeof(host))
+	return 0;
 
     /* Realm names don't (normally) end with ".", but if the query
        doesn't end with "." and doesn't get an answer as is, the
diff --git a/src/lib/krb5/os/gen_rname.c b/src/lib/krb5/os/gen_rname.c
index 7978a5dbcf..6098153386 100644
--- a/src/lib/krb5/os/gen_rname.c
+++ b/src/lib/krb5/os/gen_rname.c
@@ -36,14 +36,16 @@ krb5_gen_replay_name(krb5_context context, const krb5_address *address, const ch
 {
     char * tmp;
     int i;
+    int len;
 
-    if ((*string = malloc(strlen(uniq) + (address->length * 2) + 1)) == NULL)
+    len = strlen(uniq) + (address->length * 2) + 1;
+    if ((*string = malloc(len)) == NULL)
 	return ENOMEM;
 
-    sprintf(*string, "%s", uniq);
-    tmp = (*string) + strlen(uniq);
+    snprintf(*string, len, "%s", uniq);
+    tmp = *string + strlen(uniq);
     for (i = 0; i < address->length; i++) {
-	sprintf(tmp, "%.2x", address->contents[i] & 0xff);
+	snprintf(tmp, len - (tmp-*string), "%.2x", address->contents[i] & 0xff);
 	tmp += 2;
     }
     return 0;
diff --git a/src/lib/krb5/os/hst_realm.c b/src/lib/krb5/os/hst_realm.c
index 7e24b8d6de..9836378642 100644
--- a/src/lib/krb5/os/hst_realm.c
+++ b/src/lib/krb5/os/hst_realm.c
@@ -105,7 +105,8 @@ krb5_try_realm_txt_rr(const char *prefix, const char *name, char **realm)
     } else {
         if ( strlen(prefix) + strlen(name) + 3 > MAXDNAME )
             return KRB5_ERR_HOST_REALM_UNKNOWN;
-        sprintf(host,"%s.%s", prefix, name);
+        if (snprintf(host, sizeof(host), "%s.%s", prefix, name) >= sizeof(host))
+	    return KRB5_ERR_HOST_REALM_UNKNOWN;
 
         /* Realm names don't (normally) end with ".", but if the query
            doesn't end with "." and doesn't get an answer as is, the
diff --git a/src/lib/krb5/os/ktdefname.c b/src/lib/krb5/os/ktdefname.c
index 925b6e1b5b..28fac5deea 100644
--- a/src/lib/krb5/os/ktdefname.c
+++ b/src/lib/krb5/os/ktdefname.c
@@ -70,7 +70,7 @@ krb5_kt_default_name(krb5_context context, char *name, size_t namesize)
 	    defname[len]= '\0';
 	    if ( (len + strlen(krb5_defkeyname) + 1) > namesize )
 		return KRB5_CONFIG_NOTENUFSPACE;
-	    sprintf(name, krb5_defkeyname, defname);
+	    snprintf(name, namesize, krb5_defkeyname, defname);
 	}
 #else
 	if (namesize < (strlen(krb5_defkeyname)+1))
diff --git a/src/lib/krb5/os/locate_kdc.c b/src/lib/krb5/os/locate_kdc.c
index 566213d35f..f03568b36f 100644
--- a/src/lib/krb5/os/locate_kdc.c
+++ b/src/lib/krb5/os/locate_kdc.c
@@ -257,8 +257,11 @@ krb5int_add_host_to_list (struct addrlist *lp, const char *hostname,
 #ifdef AI_NUMERICSERV
     hint.ai_flags = AI_NUMERICSERV;
 #endif
-    sprintf(portbuf, "%d", ntohs(port));
-    sprintf(secportbuf, "%d", ntohs(secport));
+    if (snprintf(portbuf, sizeof(portbuf), "%d", ntohs(port)) >= sizeof(portbuf))
+	/* XXX */
+	return EINVAL;
+    if (snprintf(secportbuf, sizeof(secportbuf), "%d", ntohs(secport)) >= sizeof(secportbuf))
+	return EINVAL;
     err = getaddrinfo (hostname, portbuf, &hint, &addrs);
     if (err) {
 	Tprintf ("\tgetaddrinfo(\"%s\", \"%s\", ...)\n\treturns %d: %s\n",
diff --git a/src/lib/krb5/os/sendto_kdc.c b/src/lib/krb5/os/sendto_kdc.c
index a476ef400d..3be46de9fd 100644
--- a/src/lib/krb5/os/sendto_kdc.c
+++ b/src/lib/krb5/os/sendto_kdc.c
@@ -122,7 +122,7 @@ krb5int_debug_fprint (const char *fmt, ...)
 
     va_start(args, fmt);
 
-#define putf(FMT,X)	(sprintf(tmpbuf,FMT,X),putstr(tmpbuf))
+#define putf(FMT,X)	(snprintf(tmpbuf,sizeof(tmpbuf),FMT,X),putstr(tmpbuf))
 
     for (; *fmt; fmt++) {
 	if (*fmt != '%') {
@@ -152,7 +152,7 @@ krb5int_debug_fprint (const char *fmt, ...)
 	case 'E':
 	    /* %E => krb5_error_code */
 	    kerr = va_arg(args, krb5_error_code);
-	    sprintf(tmpbuf, "%lu/", (unsigned long) kerr);
+	    snprintf(tmpbuf, sizeof(tmpbuf), "%lu/", (unsigned long) kerr);
 	    putstr(tmpbuf);
 	    p = error_message(kerr);
 	    putstr(p);
@@ -204,7 +204,7 @@ krb5int_debug_fprint (const char *fmt, ...)
 	    /* %t => struct timeval * */
 	    tv = va_arg(args, struct timeval *);
 	    if (tv) {
-		sprintf(tmpbuf, "%ld.%06ld",
+		snprintf(tmpbuf, sizeof(tmpbuf), "%ld.%06ld",
 			(long) tv->tv_sec, (long) tv->tv_usec);
 		putstr(tmpbuf);
 	    } else
@@ -226,7 +226,7 @@ krb5int_debug_fprint (const char *fmt, ...)
 	    else if (ai->ai_socktype == SOCK_STREAM)
 		strcpy(tmpbuf, "stream");
 	    else
-		sprintf(tmpbuf, "socktype%d", ai->ai_socktype);
+		snprintf(tmpbuf, sizeof(tmpbuf), "socktype%d", ai->ai_socktype);
 	    if (0 != getnameinfo (ai->ai_addr, ai->ai_addrlen,
 				  addrbuf, sizeof (addrbuf),
 				  portbuf, sizeof (portbuf),
@@ -234,9 +234,12 @@ krb5int_debug_fprint (const char *fmt, ...)
 		if (ai->ai_addr->sa_family == AF_UNSPEC)
 		    strcpy(tmpbuf + strlen(tmpbuf), " AF_UNSPEC");
 		else
-		    sprintf(tmpbuf + strlen(tmpbuf), " af%d", ai->ai_addr->sa_family);
+		    snprintf(tmpbuf + strlen(tmpbuf),
+			     sizeof(tmpbuf)-strlen(tmpbuf),
+			     " af%d", ai->ai_addr->sa_family);
 	    } else
-		sprintf(tmpbuf + strlen(tmpbuf), " %s.%s", addrbuf, portbuf);
+		snprintf(tmpbuf + strlen(tmpbuf), sizeof(tmpbuf)-strlen(tmpbuf),
+			 " %s.%s", addrbuf, portbuf);
 	    putstr(tmpbuf);
 	    break;
 	case 'D':
diff --git a/src/lib/krb5/rcache/rc_io.c b/src/lib/krb5/rcache/rc_io.c
index adc6a8c49c..32357283e3 100644
--- a/src/lib/krb5/rcache/rc_io.c
+++ b/src/lib/krb5/rcache/rc_io.c
@@ -76,8 +76,7 @@ krb5_rc_io_creat(krb5_context context, krb5_rc_iostuff *d, char **fn)
     size_t dirlen;
 
     GETDIR;
-    if (fn && *fn)
-    {
+    if (fn && *fn) {
 	if (!(d->fn = malloc(strlen(*fn) + dirlen + 1)))
 	    return KRB5_RC_IO_MALLOC;
 	(void) strcpy(d->fn, dir);
@@ -85,43 +84,34 @@ krb5_rc_io_creat(krb5_context context, krb5_rc_iostuff *d, char **fn)
 	(void) strcat(d->fn, *fn);
 	d->fd = THREEPARAMOPEN(d->fn, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL |
 			       O_BINARY, 0600);
-    }
-    else
-    {
-	/* %d is max 11 digits (-, 10 digits of 32-bit number)
-	 * 11 + /krb5_RC + aaa = 24, +6 for slop */
-	if (!(d->fn = malloc(30 + dirlen)))
+    } else {
+	if (asprintf(&d->fn, "%s%skrb5_RC%daaa",
+		     dir, PATH_SEPARATOR, (int) UNIQUE) < 0) {
+	    d->fn = NULL;
 	    return KRB5_RC_IO_MALLOC;
-	if (fn)
-	    if (!(*fn = malloc(35))) {
-		FREE(d->fn);
-		return KRB5_RC_IO_MALLOC;
-	    }
-	(void) sprintf(d->fn, "%s%skrb5_RC%d", dir, PATH_SEPARATOR,
-		       (int) UNIQUE);
-	c = d->fn + strlen(d->fn);
-	(void) strcpy(c, "aaa");
+	}
+	c = d->fn + strlen(d->fn) - 3;
 	while ((d->fd = THREEPARAMOPEN(d->fn, O_WRONLY | O_CREAT | O_TRUNC |
-				       O_EXCL | O_BINARY, 0600)) == -1)
-	{
-	    if ((c[2]++) == 'z')
-	    {
+				       O_EXCL | O_BINARY, 0600)) == -1)	{
+	    if ((c[2]++) == 'z') {
 		c[2] = 'a';
-		if ((c[1]++) == 'z')
-		{
+		if ((c[1]++) == 'z') {
 		    c[1] = 'a';
 		    if ((c[0]++) == 'z')
 			break; /* sigh */
 		}
 	    }
 	}
-	if (fn)
-	    (void) strcpy(*fn, d->fn + dirlen);
+	if (fn) {
+	    *fn = strdup(d->fn + dirlen);
+	    if (*fn == NULL) {
+		free(d->fn);
+		return KRB5_RC_IO_MALLOC;
+	    }
+	}
     }
-    if (d->fd == -1)
-    {
-	switch(errno)
-	{
+    if (d->fd == -1) {
+	switch(errno) {
 	case EFBIG:
 #ifdef EDQUOT
 	case EDQUOT:
diff --git a/src/lib/krb5/rcache/ser_rc.c b/src/lib/krb5/rcache/ser_rc.c
index 0b3d098a8a..af19edf7a6 100644
--- a/src/lib/krb5/rcache/ser_rc.c
+++ b/src/lib/krb5/rcache/ser_rc.c
@@ -121,13 +121,13 @@ krb5_rcache_externalize(krb5_context kcontext, krb5_pointer arg, krb5_octet **bu
 	    fnamep = krb5_rc_get_name(kcontext, rcache);
 	    namelen += (strlen(fnamep)+1);
 
-	    if ((rcname = (char *) malloc(namelen))) {
-		/* Format the rcache name. */
-		if (rcache->ops && rcache->ops->type)
-		    sprintf(rcname, "%s:%s", rcache->ops->type, fnamep);
-		else
-		    strcpy(rcname, fnamep);
+	    if (rcache->ops && rcache->ops->type) {
+		if (asprintf(&rcname, "%s:%s", rcache->ops->type, fnamep) < 0)
+		    rcname = NULL;
+	    } else
+		rcname = strdup(fnamep);
 
+	    if (rcname) {
 		/* Put the length of the file name */
 		(void) krb5_ser_pack_int32((krb5_int32) strlen(rcname),
 					   &bp, &remain);
diff --git a/src/lib/rpc/clnt_perror.c b/src/lib/rpc/clnt_perror.c
index 85935a8b00..0a52885a3d 100644
--- a/src/lib/rpc/clnt_perror.c
+++ b/src/lib/rpc/clnt_perror.c
@@ -81,9 +81,11 @@ clnt_sperror(CLIENT *rpch, char *s)
 	char *bufstart = get_buf();
 	char *str = bufstart;
 	char *strstart = str;
+	char *strend;
 
 	if (str == 0)
 		return (0);
+	strend = str + BUFSIZ;
 	CLNT_GETERR(rpch, &e);
 
 	strncpy (str, s, BUFSIZ - 1);
@@ -113,19 +115,19 @@ clnt_sperror(CLIENT *rpch, char *s)
 	case RPC_CANTSEND:
 	case RPC_CANTRECV:
 		/* 10 for the string */
-		if(str - bufstart + 10 + strlen(strerror(e.re_errno)) < BUFSIZ)
-		    (void) sprintf(str, "; errno = %s",
-				   strerror(e.re_errno)); 
+		if (str - bufstart + 10 + strlen(strerror(e.re_errno)) < BUFSIZ)
+		    (void) snprintf(str, strend-str, "; errno = %s",
+				    strerror(e.re_errno)); 
 		str += strlen(str);
 		break;
 
 	case RPC_VERSMISMATCH:
 		/* 33 for the string, 22 for the numbers */
 		if(str - bufstart + 33 + 22 < BUFSIZ)
-		    (void) sprintf(str,
-				   "; low version = %lu, high version = %lu", 
-				   (u_long) e.re_vers.low,
-				   (u_long) e.re_vers.high);
+		    (void) snprintf(str, strend-str,
+				    "; low version = %lu, high version = %lu", 
+				    (u_long) e.re_vers.low,
+				    (u_long) e.re_vers.high);
 		str += strlen(str);
 		break;
 
@@ -133,17 +135,17 @@ clnt_sperror(CLIENT *rpch, char *s)
 		err = auth_errmsg(e.re_why);
 		/* 8 for the string */
 		if(str - bufstart + 8 < BUFSIZ)
-		    (void) sprintf(str,"; why = ");
+		    (void) snprintf(str, strend-str, "; why = ");
 		str += strlen(str);
 		if (err != NULL) {
 			if(str - bufstart + strlen(err) < BUFSIZ)
-			    (void) sprintf(str, "%s",err);
+			    (void) snprintf(str, strend-str, "%s",err);
 		} else {
 		    /* 33 for the string, 11 for the number */
 		    if(str - bufstart + 33 + 11 < BUFSIZ)
-			(void) sprintf(str,
-				       "(unknown authentication error - %d)",
-				       (int) e.re_why);
+			(void) snprintf(str, strend-str,
+					"(unknown authentication error - %d)",
+					(int) e.re_why);
 		}
 		str += strlen(str);
 		break;
@@ -151,25 +153,25 @@ clnt_sperror(CLIENT *rpch, char *s)
 	case RPC_PROGVERSMISMATCH:
 		/* 33 for the string, 22 for the numbers */
 		if(str - bufstart + 33 + 22 < BUFSIZ)
-		    (void) sprintf(str,
-				   "; low version = %lu, high version = %lu",
-				   (u_long) e.re_vers.low,
-				   (u_long) e.re_vers.high);
+		    (void) snprintf(str, strend-str,
+				    "; low version = %lu, high version = %lu",
+				    (u_long) e.re_vers.low,
+				    (u_long) e.re_vers.high);
 		str += strlen(str);
 		break;
 
 	default:	/* unknown */
 		/* 14 for the string, 22 for the numbers */
 		if(str - bufstart + 14 + 22 < BUFSIZ)
-		    (void) sprintf(str,
-				   "; s1 = %lu, s2 = %lu",
-				   (u_long) e.re_lb.s1,
-				   (u_long) e.re_lb.s2);
+		    (void) snprintf(str, strend-str,
+				    "; s1 = %lu, s2 = %lu",
+				    (u_long) e.re_lb.s1,
+				    (u_long) e.re_lb.s2);
 		str += strlen(str);
 		break;
 	}
-	if(str - bufstart + 1 < BUFSIZ)
-	    (void) sprintf(str, "\n");
+	if (str - bufstart + 1 < BUFSIZ)
+	    (void) snprintf(str, strend-str, "\n");
 	return(strstart) ;
 }
 
@@ -252,10 +254,12 @@ char *
 clnt_spcreateerror(char *s)
 {
 	char *str = get_buf();
+	char *strend;
 
 	if (str == 0)
 		return(0);
-	(void) sprintf(str, "%s: ", s);
+	strend = str+BUFSIZ;
+	(void) snprintf(str, strend-str, "%s: ", s);
 	str[BUFSIZ - 1] = '\0';
 	(void) strncat(str, clnt_sperrno(rpc_createerr.cf_stat), BUFSIZ - 1);
 	switch (rpc_createerr.cf_stat) {
@@ -273,8 +277,9 @@ clnt_spcreateerror(char *s)
 		    if (m)
 			(void) strncat(str, m, BUFSIZ - 1 - strlen(str));
 		    else
-			(void) sprintf(&str[strlen(str)], "Error %d",
-				       rpc_createerr.cf_error.re_errno);
+			(void) snprintf(&str[strlen(str)], BUFSIZ - strlen(str),
+					"Error %d",
+					rpc_createerr.cf_error.re_errno);
 		}
 		break;
 
diff --git a/src/util/profile/prof_file.c b/src/util/profile/prof_file.c
index 265ccd6cf9..74d553ee63 100644
--- a/src/util/profile/prof_file.c
+++ b/src/util/profile/prof_file.c
@@ -407,15 +407,14 @@ static errcode_t write_data_to_file(prf_data_t data, const char *outfile,
 	retval = ENOMEM;
 	
 	new_file = old_file = 0;
-	new_file = malloc(strlen(outfile) + 5);
-	if (!new_file)
-		goto errout;
-	old_file = malloc(strlen(outfile) + 5);
-	if (!old_file)
-		goto errout;
-
-	sprintf(new_file, "%s.$$$", outfile);
-	sprintf(old_file, "%s.bak", outfile);
+	if (asprintf(&new_file, "%s.$$$", outfile) < 0) {
+	    new_file = NULL;
+	    goto errout;
+	}
+	if (asprintf(&old_file, "%s.bak", outfile) < 0) {
+	    old_file = NULL;
+	    goto errout;
+	}
 
 	errno = 0;
 
diff --git a/src/util/support/errors.c b/src/util/support/errors.c
index e2101a2a9f..94290f857a 100644
--- a/src/util/support/errors.c
+++ b/src/util/support/errors.c
@@ -125,7 +125,8 @@ krb5int_get_error (struct errinfo *ep, long code)
 		return r2;
 	}
     format_number:
-	sprintf (ep->scratch_buf, _("error %ld"), code);
+	snprintf (ep->scratch_buf, sizeof(ep->scratch_buf),
+		  _("error %ld"), code);
 	return ep->scratch_buf;
     }
     r = (char *) fptr(code);
diff --git a/src/util/support/plugins.c b/src/util/support/plugins.c
index b26726fab6..99d3aea570 100644
--- a/src/util/support/plugins.c
+++ b/src/util/support/plugins.c
@@ -49,6 +49,8 @@
 #include <unistd.h>
 #endif
 
+#include "k5-platform.h"
+
 #include <stdarg.h>
 static void Tprintf (const char *fmt, ...)
 {
@@ -377,15 +379,11 @@ krb5int_get_plugin_filenames (const char * const *filebases, char ***filenames)
     if (!err) {
         int j;
         for (i = 0; !err && (filebases[i] != NULL); i++) {
-            size_t baselen = strlen (filebases[i]);
             for (j = 0; !err && (fileexts[j] != NULL); j++) {
-                size_t len = baselen + strlen (fileexts[j]) + 2; /* '.' + NULL */
-                tempnames[i+j] = malloc (len * sizeof (char));
-                if (tempnames[i+j] == NULL) { 
-                    err = errno; 
-                } else {
-                    sprintf (tempnames[i+j], "%s%s", filebases[i], fileexts[j]);
-                }
+		if (asprintf(&tempnames[i+j], "%s%s", filebases[i], fileexts[j]) < 0) {
+		    tempnames[i+j] = NULL;
+		    err = errno;
+		}
             }
         }
     }
@@ -426,7 +424,6 @@ krb5int_open_plugin_dirs (const char * const *dirnames,
     }
     
     for (i = 0; !err && dirnames[i] != NULL; i++) {
-	size_t dirnamelen = strlen (dirnames[i]) + 1; /* '/' */
         if (filenames != NULL) {
             /* load plugins with names from filenames from each directory */
             int j;
@@ -436,11 +433,9 @@ krb5int_open_plugin_dirs (const char * const *dirnames,
 		char *filepath = NULL;
 		
 		if (!err) {
-		    filepath = malloc (dirnamelen + strlen (filenames[j]) + 1); /* NULL */
-		    if (filepath == NULL) { 
-			err = errno; 
-		    } else {
-			sprintf (filepath, "%s/%s", dirnames[i], filenames[j]);
+		    if (asprintf(&filepath, "%s/%s", dirnames[i], filenames[j]) < 0) {
+			filepath = NULL;
+			err = errno;
 		    }
 		}
 		
@@ -472,11 +467,9 @@ krb5int_open_plugin_dirs (const char * const *dirnames,
                 
 		if (!err) {
                     int len = NAMELEN (d);
-		    filepath = malloc (dirnamelen + len + 1); /* NULL */
-		    if (filepath == NULL) { 
-			err = errno; 
-		    } else {
-			sprintf (filepath, "%s/%*s", dirnames[i], len, d->d_name);
+		    if (asprintf(&filepath, "%s/%*s", dirnames[i], len, d->d_name) < 0) {
+			filepath = NULL;
+			err = errno;
 		    }
 		}