Don't hold a lock when calling a callback in ossl_namemap_doall_names

We don't want to hold a read lock when calling a user supplied callback.
That callback could do anything so the risk of a deadlock is high.
Instead we collect all the names first inside the read lock, and then
subsequently call the user callback outside the read lock.

Fixes #14225

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14250)

1 files changed, 7 insertions, 5 deletions

diff --git a/crypto/store/store_meth.c b/crypto/store/store_meth.c
index d66b30f0ad..04f7249ddc 100644
--- a/crypto/store/store_meth.c
+++ b/crypto/store/store_meth.c
@@ -452,17 +452,19 @@ void OSSL_STORE_LOADER_do_all_provided(OSSL_LIB_CTX *libctx,
                           &data);
 }
 
-void OSSL_STORE_LOADER_names_do_all(const OSSL_STORE_LOADER *loader,
-                                    void (*fn)(const char *name, void *data),
-                                    void *data)
+int OSSL_STORE_LOADER_names_do_all(const OSSL_STORE_LOADER *loader,
+                                   void (*fn)(const char *name, void *data),
+                                   void *data)
 {
     if (loader == NULL)
-        return;
+        return 0;
 
     if (loader->prov != NULL) {
         OSSL_LIB_CTX *libctx = ossl_provider_libctx(loader->prov);
         OSSL_NAMEMAP *namemap = ossl_namemap_stored(libctx);
 
-        ossl_namemap_doall_names(namemap, loader->scheme_id, fn, data);
+        return ossl_namemap_doall_names(namemap, loader->scheme_id, fn, data);
     }
+
+    return 1;
 }