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, 8 insertions, 3 deletions

diff --git a/doc/man3/EVP_DigestInit.pod b/doc/man3/EVP_DigestInit.pod
index 025bee4f46..c4cecad3a7 100644
--- a/doc/man3/EVP_DigestInit.pod
+++ b/doc/man3/EVP_DigestInit.pod
@@ -64,9 +64,9 @@ EVP_MD_do_all_provided
  const char *EVP_MD_name(const EVP_MD *md);
  int EVP_MD_number(const EVP_MD *md);
  int EVP_MD_is_a(const EVP_MD *md, const char *name);
- void EVP_MD_names_do_all(const EVP_MD *md,
-                          void (*fn)(const char *name, void *data),
-                          void *data);
+ int EVP_MD_names_do_all(const EVP_MD *md,
+                         void (*fn)(const char *name, void *data),
+                         void *data);
  const OSSL_PROVIDER *EVP_MD_provider(const EVP_MD *md);
  int EVP_MD_type(const EVP_MD *md);
  int EVP_MD_pkey_type(const EVP_MD *md);
@@ -542,6 +542,11 @@ Returns either an B<EVP_MD> structure or NULL if an error occurs.
 
 This function has no return value.
 
+=item EVP_MD_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.
+
 =back
 
 =head1 NOTES