From 7e1d8445b57203211413259eeb53bb4a9400021a Mon Sep 17 00:00:00 2001 From: Matt Caswell Date: Tue, 13 Dec 2022 14:54:55 +0000 Subject: 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 Reviewed-by: Paul Dale Reviewed-by: Hugo Landau Reviewed-by: Tomas Mraz --- crypto/pem/pem_lib.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/crypto/pem/pem_lib.c b/crypto/pem/pem_lib.c index f9ff80162a..85c47fb627 100644 --- a/crypto/pem/pem_lib.c +++ b/crypto/pem/pem_lib.c @@ -989,7 +989,9 @@ int PEM_read_bio_ex(BIO *bp, char **name_out, char **header, out_free: pem_free(*header, flags, 0); + *header = NULL; pem_free(*data, flags, 0); + *data = NULL; end: EVP_ENCODE_CTX_free(ctx); pem_free(name, flags, 0); -- cgit v1.2.3