Raise an error on syscall failure in tls_retry_write_records

[openssl.git] / doc / man3 / EVP_DigestVerifyInit.pod

diff --git a/doc/man3/EVP_DigestVerifyInit.pod b/doc/man3/EVP_DigestVerifyInit.pod
index 398146b5b8eda5b26761120eaaf3d64bb7b22755..84401a8c8030eabf3817a792436781864a6d231b 100644 (file)
--- a/doc/man3/EVP_DigestVerifyInit.pod
+++ b/doc/man3/EVP_DigestVerifyInit.pod
@@ -18,7 +18,7 @@ EVP_DigestVerifyFinal, EVP_DigestVerify - EVP signature verification functions
  int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
  int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig,
                            size_t siglen);
- int EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char *sigret,
+ int EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char *sig,
                       size_t siglen, const unsigned char *tbs, size_t tbslen);
 
 =head1 DESCRIPTION
@@ -41,9 +41,9 @@ be used for the actual signing. See L<provider(7)/Implicit fetch> for
 more information about implicit fetches.
 
 The OpenSSL default and legacy providers support fetching digests and can fetch
-those digests from any available provider. The OpenSSL fips provider also
+those digests from any available provider. The OpenSSL FIPS provider also
 supports fetching digests but will only fetch digests that are themselves
-implemented inside the fips provider.
+implemented inside the FIPS provider.
 
 B<ctx> must be created with EVP_MD_CTX_new() before calling this function. If
 B<pctx> is not NULL, the EVP_PKEY_CTX of the verification operation will be
@@ -154,13 +154,27 @@ external circumstances (see L<RAND(7)>), the operation will fail.
 
 The call to EVP_DigestVerifyFinal() internally finalizes a copy of the digest
 context. This means that EVP_VerifyUpdate() and EVP_VerifyFinal() can
-be called later to digest and verify additional data.
+be called later to digest and verify additional data. Applications may disable
+this behavior by setting the EVP_MD_CTX_FLAG_FINALISE context flag via
+L<EVP_MD_CTX_set_flags(3)>.
+
+Note that not all providers support continuation, in case the selected
+provider does not allow to duplicate contexts EVP_DigestVerifyFinal() will
+finalize the digest context and attempting to process additional data via
+EVP_DigestVerifyUpdate() will result in an error.
 
 EVP_DigestVerifyInit() and EVP_DigestVerifyInit_ex() functions can be called
 multiple times on a context and the parameters set by previous calls should be
 preserved if the I<pkey> parameter is NULL. The call then just resets the state
 of the I<ctx>.
 
+EVP_DigestVerify() can only be called once, and cannot be used again without
+reinitialising the B<EVP_MD_CTX> by calling EVP_DigestVerifyInit_ex().
+
+Ignoring failure returns of EVP_DigestVerifyInit() and EVP_DigestVerifyInit_ex()
+functions can lead to subsequent undefined behavior when calling
+EVP_DigestVerifyUpdate(), EVP_DigestVerifyFinal(), or EVP_DigestVerify().
+
 =head1 SEE ALSO
 
 L<EVP_DigestSignInit(3)>,
@@ -182,7 +196,7 @@ EVP_DigestVerifyUpdate() was converted from a macro to a function in OpenSSL
 
 =head1 COPYRIGHT
 
-Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2006-2023 The OpenSSL Project Authors. All Rights Reserved.
 
 Licensed under the Apache License 2.0 (the "License").  You may not use
 this file except in compliance with the License.  You can obtain a copy