Fix to make sure a double free cannot occur (ZD 21093)

dgarske · dgarske · commit 5fdf32dec649 · 2026-03-19T17:03:09.000-07:00
diff --git a/wolfcrypt/src/asn.c b/wolfcrypt/src/asn.c
@@ -18413,6 +18413,7 @@ void FreeSignatureCtx(SignatureCtx* sigCtx)
                 if (sigCtx->key.ecc->nb_ctx != NULL) {
                     XFREE(sigCtx->key.ecc->nb_ctx, sigCtx->heap,
                           DYNAMIC_TYPE_TMP_BUFFER);
+                    sigCtx->key.ecc->nb_ctx = NULL;
                 }
             #endif /* WC_ECC_NONBLOCK && WOLFSSL_ASYNC_CRYPT_SW &&
                       WC_ASYNC_ENABLE_ECC */
@@ -18488,6 +18489,7 @@ void FreeSignatureCtx(SignatureCtx* sigCtx)
     #ifndef WOLFSSL_NO_MALLOC
         sigCtx->key.ptr = NULL;
     #endif
+        sigCtx->keyOID = 0; /* mark key as freed (guards re-entry without malloc) */
     }
 #endif /* !NO_ASN_CRYPT */
 

Original file line number	Diff line number	Diff line change
`@@ -18413,6 +18413,7 @@ void FreeSignatureCtx(SignatureCtx* sigCtx)`
`18413`	`18413`	`if (sigCtx->key.ecc->nb_ctx != NULL) {`
`18414`	`18414`	`XFREE(sigCtx->key.ecc->nb_ctx, sigCtx->heap,`
`18415`	`18415`	`DYNAMIC_TYPE_TMP_BUFFER);`
	`18416`	`+ sigCtx->key.ecc->nb_ctx = NULL;`
`18416`	`18417`	`}`
`18417`	`18418`	`#endif /* WC_ECC_NONBLOCK && WOLFSSL_ASYNC_CRYPT_SW &&`
`18418`	`18419`	`WC_ASYNC_ENABLE_ECC */`
`@@ -18488,6 +18489,7 @@ void FreeSignatureCtx(SignatureCtx* sigCtx)`
`18488`	`18489`	`#ifndef WOLFSSL_NO_MALLOC`
`18489`	`18490`	`sigCtx->key.ptr = NULL;`
`18490`	`18491`	`#endif`
	`18492`	`+ sigCtx->keyOID = 0; /* mark key as freed (guards re-entry without malloc) */`
`18491`	`18493`	`}`
`18492`	`18494`	`#endif /* !NO_ASN_CRYPT */`
`18493`	`18495`