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, 6 insertions, 3 deletions

diff --git a/doc/man3/EVP_KEYMGMT.pod b/doc/man3/EVP_KEYMGMT.pod
index e47591b217..e103b58e90 100644
--- a/doc/man3/EVP_KEYMGMT.pod
+++ b/doc/man3/EVP_KEYMGMT.pod
@@ -35,9 +35,9 @@ EVP_KEYMGMT_gen_settable_params
  void EVP_KEYMGMT_do_all_provided(OSSL_LIB_CTX *libctx,
                                   void (*fn)(EVP_KEYMGMT *keymgmt, void *arg),
                                   void *arg);
- void EVP_KEYMGMT_names_do_all(const EVP_KEYMGMT *keymgmt,
-                               void (*fn)(const char *name, void *data),
-                               void *data);
+ int EVP_KEYMGMT_names_do_all(const EVP_KEYMGMT *keymgmt,
+                              void (*fn)(const char *name, void *data),
+                              void *data);
  const OSSL_PARAM *EVP_KEYMGMT_gettable_params(const EVP_KEYMGMT *keymgmt);
  const OSSL_PARAM *EVP_KEYMGMT_settable_params(const EVP_KEYMGMT *keymgmt);
  const OSSL_PARAM *EVP_KEYMGMT_gen_settable_params(const EVP_KEYMGMT *keymgmt);
@@ -110,6 +110,9 @@ error.
 
 EVP_KEYMGMT_up_ref() returns 1 on success, or 0 on error.
 
+EVP_KEYMGMT_names_do_all() returns 1 if the callback was called for all
+names. A return value of 0 means that the callback was not called for any names.
+
 EVP_KEYMGMT_free() doesn't return any value.
 
 EVP_KEYMGMT_provider() returns a pointer to a provider object, or NULL