apps/s_server: Add missing check for BIO_new

As the potential failure of the BIO_new(), it should be better to check the return value and return error if fails in order to avoid the dereference of NULL pointer.
And because 'bio_s_msg' is checked before being used everytime, which has no need to add the check.
But 'bio_s_out' is not.
And since the check 'if (bio_s_out == NULL)' is redundant, it can be removed to make the code succincter.
Also the 'sbio' and so forth should be checked like the other places in the same file.

Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17710)

1 files changed, 50 insertions, 4 deletions

diff --git a/apps/s_server.c b/apps/s_server.c
index 3646dd1dbd..45c112345f 100644
--- a/apps/s_server.c
+++ b/apps/s_server.c
@@ -1817,10 +1817,13 @@ int s_server_main(int argc, char *argv[])
             if (s_msg && bio_s_msg == NULL)
                 bio_s_msg = dup_bio_out(FORMAT_TEXT);
         } else {
-            if (bio_s_out == NULL)
-                bio_s_out = dup_bio_out(FORMAT_TEXT);
+            bio_s_out = dup_bio_out(FORMAT_TEXT);
         }
     }
+
+    if (bio_s_out == NULL)
+        goto end;
+
     if (nocert) {
         s_cert_file = NULL;
         s_key_file = NULL;
@@ -2362,6 +2365,11 @@ static int sv_body(int s, int stype, int prot, unsigned char *context)
         else
 # endif
             sbio = BIO_new_dgram(s, BIO_NOCLOSE);
+        if (sbio == NULL) {
+            BIO_printf(bio_err, "Unable to create BIO\n");
+            ERR_print_errors(bio_err);
+            goto err;
+        }
 
         if (enable_timeouts) {
             timeout.tv_sec = 0;
@@ -2411,6 +2419,13 @@ static int sv_body(int s, int stype, int prot, unsigned char *context)
         BIO *test;
 
         test = BIO_new(BIO_f_nbio_test());
+        if (test == NULL) {
+            BIO_printf(bio_err, "Unable to create BIO\n");
+            ret = -1;
+            BIO_free(sbio);
+            goto err;
+        }
+
         sbio = BIO_push(test, sbio);
     }
 
@@ -2997,6 +3012,9 @@ static int www_body(int s, int stype, int prot, unsigned char *context)
     int width;
     fd_set readfds;
     const char *opmode;
+#ifdef CHARSET_EBCDIC
+    BIO *filter;
+#endif
 
     /* Set width for a select call if needed */
     width = s + 1;
@@ -3036,10 +3054,21 @@ static int www_body(int s, int stype, int prot, unsigned char *context)
     }
 
     sbio = BIO_new_socket(s, BIO_NOCLOSE);
+    if (sbio == NULL) {
+        SSL_free(con);
+        goto err;
+    }
+
     if (s_nbio_test) {
         BIO *test;
 
         test = BIO_new(BIO_f_nbio_test());
+        if (test == NULL) {
+            SSL_free(con);
+            BIO_free(sbio);
+            goto err;
+        }
+
         sbio = BIO_push(test, sbio);
     }
     SSL_set_bio(con, sbio, sbio);
@@ -3050,7 +3079,11 @@ static int www_body(int s, int stype, int prot, unsigned char *context)
     BIO_push(io, ssl_bio);
     ssl_bio = NULL;
 #ifdef CHARSET_EBCDIC
-    io = BIO_push(BIO_new(BIO_f_ebcdic_filter()), io);
+    filter = BIO_new(BIO_f_ebcdic_filter());
+    if (filter == NULL)
+        goto err;
+
+    io = BIO_push(filter, io);
 #endif
 
     if (s_debug) {
@@ -3414,6 +3447,9 @@ static int rev_body(int s, int stype, int prot, unsigned char *context)
     int ret = 1;
     SSL *con;
     BIO *io, *ssl_bio, *sbio;
+#ifdef CHARSET_EBCDIC
+    BIO *filter;
+#endif
 
     /* as we use BIO_gets(), and it always null terminates data, we need
      * to allocate 1 byte longer buffer to fit the full 2^14 byte record */
@@ -3443,6 +3479,12 @@ static int rev_body(int s, int stype, int prot, unsigned char *context)
     }
 
     sbio = BIO_new_socket(s, BIO_NOCLOSE);
+    if (sbio == NULL) {
+        SSL_free(con);
+        ERR_print_errors(bio_err);
+        goto err;
+    }
+
     SSL_set_bio(con, sbio, sbio);
     SSL_set_accept_state(con);
 
@@ -3451,7 +3493,11 @@ static int rev_body(int s, int stype, int prot, unsigned char *context)
     BIO_push(io, ssl_bio);
     ssl_bio = NULL;
 #ifdef CHARSET_EBCDIC
-    io = BIO_push(BIO_new(BIO_f_ebcdic_filter()), io);
+    filter = BIO_new(BIO_f_ebcdic_filter());
+    if (filter == NULL)
+        goto err;
+
+    io = BIO_push(filter, io);
 #endif
 
     if (s_debug) {