From: Joshua Rogers <MegaManSec@users.noreply.github.com>
Date: Sat, 11 Oct 2025 12:25:46 +0000 (+0800)
Subject: asn_mime: Harden multi_split() against pushing NULL if a section is empty
X-Git-Tag: 4.0-PRE-CLANG-FORMAT-WEBKIT~187
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50295c9c4ce890b44f7f308b83dbcb6107190c51;p=thirdparty%2Fopenssl.git

asn_mime: Harden multi_split() against pushing NULL if a section is empty

Signed-off-by: Joshua Rogers <MegaManSec@users.noreply.github.com>

Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28881)
---

diff --git a/crypto/asn1/asn_mime.c b/crypto/asn1/asn_mime.c
index c9bdfd98c84..f3511fedd7d 100644
--- a/crypto/asn1/asn_mime.c
+++ b/crypto/asn1/asn_mime.c
@@ -669,6 +669,12 @@ static int multi_split(BIO *bio, int flags, const char *bound, STACK_OF(BIO) **r
             first = 1;
             part++;
         } else if (state == 2) {
+            if (bpart == NULL) {
+                bpart = BIO_new(BIO_s_mem());
+                if (bpart == NULL)
+                    return 0;
+                BIO_set_mem_eof_return(bpart, 0);
+            }
             if (!sk_BIO_push(parts, bpart)) {
                 BIO_free(bpart);
                 return 0;