commit e51bde06daff0ac92f0545ebe4406bda260542e5
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Tue Jun 03 11:22:55 2025 +0200
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Tue Jun 03 11:23:19 2025 +0200
tree 05d0e984356ebbd407db2da1c7fd840590b32a6c
parent 04fe95d95b1609b7a28e5665bd86066f58f00484

Fix possible UB in mbedtls_asn1_write_raw_buffer()

This is mostly unrelated to other commits in this PR, except for the
fact that one of the added X.509 tests revealed that with UBSan.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>

library/asn1write.c

diff --git a/library/asn1write.c b/library/asn1write.c
index 415357b..97f9db0 100644
--- a/library/asn1write.c
+++ b/library/asn1write.c
@@ -90,7 +90,9 @@
 
     len = size;
     (*p) -= len;
-    memcpy(*p, buf, len);
+    if (len != 0) {
+        memcpy(*p, buf, len);
+    }
 
     return (int) len;
 }