From a114dc3c9af48a8f8ed22e738944a9c3e830a088 Mon Sep 17 00:00:00 2001
From Shao Denghui <[email protected]>
Date: Mon, 20 Feb 2023 21:59:31 +0800
Subject: [PATCH] [PATCH] Avoid dangling ptrs in header and data params for
 PEM_read_bio_ex In the event of a failure in PEM_read_bio_ex() we free the
 buffers we allocated for the header and data buffers. However we were not
 clearing the ptrs stored in *header and *data. Since, on success, the caller
 is responsible for freeing these ptrs this can potentially lead to a double
 free if the caller frees them even on failure.

Thanks to Dawei Wang for reporting this issue.

Based on a proposed patch by Kurt Roeckx.

CVE-2022-4450

Reference: https://github.com/openssl/openssl/commit/ee6243f3947107d655f6dee96f63861561a5aaeb

Reviewed-by: Paul Dale <[email protected]>
Reviewed-by: Tomas Mraz <[email protected]>

Signed-off-by: Shao Denghui <[email protected]>
---
 CryptoPkg/Library/OpensslLib/openssl/crypto/pem/pem_lib.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CryptoPkg/Library/OpensslLib/openssl/crypto/pem/pem_lib.c b/CryptoPkg/Library/OpensslLib/openssl/crypto/pem/pem_lib.c
index 64baf71..6c7c4fe 100644
--- a/CryptoPkg/Library/OpensslLib/openssl/crypto/pem/pem_lib.c
+++ b/CryptoPkg/Library/OpensslLib/openssl/crypto/pem/pem_lib.c
@@ -940,7 +940,9 @@ int PEM_read_bio_ex(BIO *bp, char **name_out, char **header,
     *data = pem_malloc(len, flags);
     if (*header == NULL || *data == NULL) {
         pem_free(*header, flags, 0);
+        *header = NULL;
         pem_free(*data, flags, 0);
+        *data = NULL;
         goto end;
     }
     BIO_read(headerB, *header, headerlen);
-- 
2.27.0