Merge remote-tracking branch 'upstream-public/pr/2753' into development
diff --git a/ChangeLog b/ChangeLog
index 550352f..d847692 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -93,6 +93,9 @@
    * Fix the build on ARMv5TE in ARM mode to not use assembly instructions
      that are only available in Thumb mode. Fix contributed by Aurelien Jarno
      in #2169.
+   * Fix propagation of restart contexts in restartable EC operations.
+     This could previously lead to segmentation faults in builds using an
+     address-sanitizer and enabling but not using MBEDTLS_ECP_RESTARTABLE.
 
 Changes
    * Server's RSA certificate in certs.c was SHA-1 signed. In the default
diff --git a/library/ecdsa.c b/library/ecdsa.c
index dc19384..58e1a5f 100644
--- a/library/ecdsa.c
+++ b/library/ecdsa.c
@@ -172,11 +172,11 @@
 }
 #endif /* MBEDTLS_ECDSA_DETERMINISTIC */
 
-#define ECDSA_RS_ECP    &rs_ctx->ecp
+#define ECDSA_RS_ECP    ( rs_ctx == NULL ? NULL : &rs_ctx->ecp )
 
 /* Utility macro for checking and updating ops budget */
 #define ECDSA_BUDGET( ops )   \
-    MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, &rs_ctx->ecp, ops ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, ECDSA_RS_ECP, ops ) );
 
 /* Call this when entering a function that needs its own sub-context */
 #define ECDSA_RS_ENTER( SUB )   do {                                 \