ssl_mail_client: Check return value of mbedtls_snprintf
The return value of snprintf() is the number of characters (excluding
the null terminator) which would have been written to the buffer if
enough space had been available. Thus, a return value of size or more
means the output was truncated.
Signed-off-by: Mingjie Shen <shen497@purdue.edu>
diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
index 72e12f0..512a610 100644
--- a/programs/ssl/ssl_mail_client.c
+++ b/programs/ssl/ssl_mail_client.c
@@ -724,6 +724,10 @@
fflush(stdout);
len = mbedtls_snprintf((char *) buf, sizeof(buf), "MAIL FROM:<%s>\r\n", opt.mail_from);
+ if (len < 0 || (size_t)len >= sizeof(buf)) {
+ mbedtls_printf(" failed\n ! mbedtls_snprintf encountered error or truncated output\n\n");
+ goto exit;
+ }
ret = write_ssl_and_get_response(&ssl, buf, len);
if (ret < 200 || ret > 299) {
mbedtls_printf(" failed\n ! server responded with %d\n\n", ret);
@@ -736,6 +740,10 @@
fflush(stdout);
len = mbedtls_snprintf((char *) buf, sizeof(buf), "RCPT TO:<%s>\r\n", opt.mail_to);
+ if (len < 0 || (size_t)len >= sizeof(buf)) {
+ mbedtls_printf(" failed\n ! mbedtls_snprintf encountered error or truncated output\n\n");
+ goto exit;
+ }
ret = write_ssl_and_get_response(&ssl, buf, len);
if (ret < 200 || ret > 299) {
mbedtls_printf(" failed\n ! server responded with %d\n\n", ret);
@@ -765,6 +773,10 @@
"Mbed TLS mail client example.\r\n"
"\r\n"
"Enjoy!", opt.mail_from);
+ if (len < 0 || (size_t)len >= sizeof(buf)) {
+ mbedtls_printf(" failed\n ! mbedtls_snprintf encountered error or truncated output\n\n");
+ goto exit;
+ }
ret = write_ssl_data(&ssl, buf, len);
len = sprintf((char *) buf, "\r\n.\r\n");