Commit 47695810 authored by Matt Caswell's avatar Matt Caswell
Browse files

Document that HMAC() with a NULL md is not thread safe 



Fixes #3541

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3553)
parent 867a9170

doc/man3/HMAC.pod

+2 −1
Original line number Diff line number Diff line
@@ -60,7 +60,8 @@ B<key_len> bytes long. 
It places the result in B<md> (which must have space for the output of

the hash function, which is no more than B<EVP_MAX_MD_SIZE> bytes).

If B<md> is NULL, the digest is placed in a static array.  The size of

the output is placed in B<md_len>, unless it is B<NULL>.

the output is placed in B<md_len>, unless it is B<NULL>. Note: passing a NULL

value for B<md>  to use the static array is not thread safe.



B<evp_md> can be EVP_sha1(), EVP_ripemd160() etc.