QUIC err handling: Save and restore error state

We save the error state from the thread that encountered
a permanent error condition caused by system or internal
error to the QUIC_CHANNEL.

Then we restore it whenever we are returning to a user
call when protocol is shutdown.

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21087)

2 files changed, 75 insertions, 0 deletions

diff --git a/doc/build.info b/doc/build.info
index 24d4050a45..7b96381240 100644
--- a/doc/build.info
+++ b/doc/build.info
@@ -1687,6 +1687,10 @@ DEPEND[html/man3/OSSL_ENCODER_to_bio.html]=man3/OSSL_ENCODER_to_bio.pod
 GENERATE[html/man3/OSSL_ENCODER_to_bio.html]=man3/OSSL_ENCODER_to_bio.pod
 DEPEND[man/man3/OSSL_ENCODER_to_bio.3]=man3/OSSL_ENCODER_to_bio.pod
 GENERATE[man/man3/OSSL_ENCODER_to_bio.3]=man3/OSSL_ENCODER_to_bio.pod
+DEPEND[html/man3/OSSL_ERR_STATE_save.html]=man3/OSSL_ERR_STATE_save.pod
+GENERATE[html/man3/OSSL_ERR_STATE_save.html]=man3/OSSL_ERR_STATE_save.pod
+DEPEND[man/man3/OSSL_ERR_STATE_save.3]=man3/OSSL_ERR_STATE_save.pod
+GENERATE[man/man3/OSSL_ERR_STATE_save.3]=man3/OSSL_ERR_STATE_save.pod
 DEPEND[html/man3/OSSL_ESS_check_signing_certs.html]=man3/OSSL_ESS_check_signing_certs.pod
 GENERATE[html/man3/OSSL_ESS_check_signing_certs.html]=man3/OSSL_ESS_check_signing_certs.pod
 DEPEND[man/man3/OSSL_ESS_check_signing_certs.3]=man3/OSSL_ESS_check_signing_certs.pod
@@ -3325,6 +3329,7 @@ html/man3/OSSL_ENCODER.html \
 html/man3/OSSL_ENCODER_CTX.html \
 html/man3/OSSL_ENCODER_CTX_new_for_pkey.html \
 html/man3/OSSL_ENCODER_to_bio.html \
+html/man3/OSSL_ERR_STATE_save.html \
 html/man3/OSSL_ESS_check_signing_certs.html \
 html/man3/OSSL_HPKE_CTX_new.html \
 html/man3/OSSL_HTTP_REQ_CTX.html \
@@ -3963,6 +3968,7 @@ man/man3/OSSL_ENCODER.3 \
 man/man3/OSSL_ENCODER_CTX.3 \
 man/man3/OSSL_ENCODER_CTX_new_for_pkey.3 \
 man/man3/OSSL_ENCODER_to_bio.3 \
+man/man3/OSSL_ERR_STATE_save.3 \
 man/man3/OSSL_ESS_check_signing_certs.3 \
 man/man3/OSSL_HPKE_CTX_new.3 \
 man/man3/OSSL_HTTP_REQ_CTX.3 \
diff --git a/doc/man3/OSSL_ERR_STATE_save.pod b/doc/man3/OSSL_ERR_STATE_save.pod
new file mode 100644
index 0000000000..79f3aba5f8
--- /dev/null
+++ b/doc/man3/OSSL_ERR_STATE_save.pod
@@ -0,0 +1,69 @@
+=pod
+
+=head1 NAME
+
+OSSL_ERR_STATE_new, OSSL_ERR_STATE_save, OSSL_ERR_STATE_restore,
+OSSL_ERR_STATE_free - saving and restoring error state
+
+=head1 SYNOPSIS
+
+ #include <openssl/err.h>
+
+ ERR_STATE *OSSL_ERR_STATE_new(void);
+ void OSSL_ERR_STATE_save(ERR_STATE *es);
+ void OSSL_ERR_STATE_restore(const ERR_STATE *es);
+ void OSSL_ERR_STATE_free(ERR_STATE *es);
+
+=head1 DESCRIPTION
+
+These functions save and restore the error state from the thread
+local error state to a preallocated error state structure.
+
+OSSL_ERR_STATE_new() allocates an empty error state structure to
+be used when saving and restoring thread error state.
+
+OSSL_ERR_STATE_save() saves the thread error state to I<es>. It
+subsequently clears the thread error state. Any previously saved
+state in I<es> is cleared prior to saving the new state.
+
+OSSL_ERR_STATE_restore() adds all the error entries from the
+saved state I<es> to the thread error state. Existing entries in
+the thread error state are not affected if there is enough space
+for all the added entries. Any allocated data in the saved error
+entries is duplicated on adding to the thread state.
+
+OSSL_ERR_STATE_free() frees the saved error state I<es>.
+
+=head1 RETURN VALUES
+
+OSSL_ERR_STATE_new() returns a pointer to the allocated ERR_STATE
+structure or NULL on error.
+
+OSSL_ERR_STATE_save(), OSSL_ERR_STATE_restore(), OSSL_ERR_STATE_free()
+do not return any values.
+
+=head1 NOTES
+
+OSSL_ERR_STATE_save() cannot fail as it takes over any allocated
+data from the thread error state.
+
+OSSL_ERR_STATE_restore() is a best effort function. The only failure
+that can happen during its operation is when memory allocation fails.
+Because it manipulates the thread error state it avoids raising memory
+errors on such failure. At worst the restored error entries will be
+missing the auxiliary error data.
+
+=head1 SEE ALSO
+
+L<ERR_raise(3)>, L<ERR_get_error(3)>, L<ERR_clear_error(3)>
+
+=head1 COPYRIGHT
+
+Copyright 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
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut