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Speed up loading client CA list

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Do not attempt to load and print all trusted CAs unless we need them to
invoke SSL_CTX_set_client_CA_list(3). Loading all trusted CAs can be
slow, especially if there are many. The CAdir format allows OpenSSL to
only load them on demand, avoiding this overhead.

Additionally, SSL_CTX_load_verify_locations(3) supports file formats
that SSL_load_client_CA_file(3) and SSL_add_*_cert_subjects_to_stack(3)
do not support, for example certificates in the BEGIN TRUSTED
CERTIFICATE format. Valid configurations with older stunnel versions
that point to such a file would otherwise needlessly start failing.

Additionally, use SSL_load_client_CA_file(3) to load certificates from
a file rather than SSL_add_file_cert_subjects_to_stack(3), since the
former uses a hashtable for deduplication, but the latter relies on
a sorted STACK_OF(X509_NAME). The sorting is exceptionally slow in
OpenSSL, because the comparison function for X509_NAMEs converts them to
DER involving a memory allocation, which is already expensive, but even
more expensive when used with stunnel's custom allocator functions.

An upstream PR openssl/openssl#25056 will eventually fix this, but it
will take quite a while for this to arrive on users' systems, and it
will likely not be backported into older affected versions of OpenSSL or
their forks.

(cherry picked from commit a154e02ce9)

Resolves: RHEL-46411
Resolves: RHEL-50154
Signed-off-by: Clemens Lang <cllang@redhat.com>
This commit is contained in:
Clemens Lang 2024-08-01 14:36:43 +02:00
parent 0334b7c96b
commit 8e69cc0314
2 changed files with 115 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

107
stunnel-5.72-speed-up-loading-client-CA-list.patch Normal file
View File

@ -0,0 +1,107 @@
From 5f0b818f62720d5bd8b8c9c631604ddb4c992be7 Mon Sep 17 00:00:00 2001
From: Clemens Lang <cllang@redhat.com>
Date: Wed, 31 Jul 2024 15:35:24 +0200
Subject: [PATCH] src/verify.c: Speed up loading client CA list
Do not attempt to load and print all trusted CAs unless we need them to
invoke SSL_CTX_set_client_CA_list(3). Loading all trusted CAs can be
slow, especially if there are many. The CAdir format allows OpenSSL to
only load them on demand, avoiding this overhead.
Additionally, SSL_CTX_load_verify_locations(3) supports file formats
that SSL_load_client_CA_file(3) and SSL_add_*_cert_subjects_to_stack(3)
do not support, for example certificates in the BEGIN TRUSTED
CERTIFICATE format. Valid configurations with older stunnel versions
that point to such a file would otherwise needlessly start failing.
Additionally, use SSL_load_client_CA_file(3) to load certificates from
a file rather than SSL_add_file_cert_subjects_to_stack(3), since the
former uses a hashtable for deduplication, but the latter relies on
a sorted STACK_OF(X509_NAME). The sorting is exceptionally slow in
OpenSSL, because the comparison function for X509_NAMEs converts them to
DER involving a memory allocation, which is already expensive, but even
more expensive when used with stunnel's custom allocator functions.
An upstream PR openssl/openssl#25056 will eventually fix this, but it
will take quite a while for this to arrive on users' systems, and it
will likely not be backported into older affected versions of OpenSSL or
their forks.
Related: RHEL-50154
Related: RHEL-46411
Signed-off-by: Clemens Lang <cllang@redhat.com>
---
src/verify.c | 42 ++++++++++++++++++++++++++++--------------
1 file changed, 28 insertions(+), 14 deletions(-)
diff --git a/src/verify.c b/src/verify.c
index 56ab130..d1d3849 100644
--- a/src/verify.c
+++ b/src/verify.c
@@ -95,10 +95,35 @@ NOEXPORT int init_ca(SERVICE_OPTIONS *section) {
if(!SSL_CTX_load_verify_locations(section->ctx,
section->ca_file, section->ca_dir)) {
sslerror("SSL_CTX_load_verify_locations");
+ return 1; /* FAILED */
}
}
- ca_dn=sk_X509_NAME_new_null();
+ /* Do not attempt to load and print all trusted CAs unless we need them to
+ invoke SSL_CTX_set_client_CA_list(3). Loading all trusted CAs can be
+ slow, especially if there are many. The CAdir format allows OpenSSL to
+ only load them on demand.
+ Additionally, SSL_CTX_load_verify_locations(3) supports file formats
+ that SSL_load_client_CA_file(3) and SSL_add_*_cert_subjects_to_stack(3)
+ do not support, for example certificates in the BEGIN TRUSTED
+ CERTIFICATE format. Valid configurations with older stunnel versions
+ that point to such a file would otherwise needlessly start failing. */
+ if(section->option.client)
+ return 0; /* OK */
+
+ if(section->ca_file)
+ /* SSL_load_client_CA_file is a lot faster than
+ SSL_add_file_cert_subjects_to_stack(). Use it for ca_file if
+ specified, then add the rest of the certificates to this stack. */
+ ca_dn=SSL_load_client_CA_file(section->ca_file);
+
+ if (!ca_dn)
+ /* ca_file not set, or SSL_load_client_CA_file(3) failed. */
+ ca_dn=sk_X509_NAME_new_null();
+
+ /* client CA list initialization from directory */
+ if(section->ca_dir)
+ SSL_add_dir_cert_subjects_to_stack(ca_dn, section->ca_dir);
#ifndef OPENSSL_NO_ENGINE
/* CA and client CA list initialization with the engine */
@@ -115,24 +140,13 @@ NOEXPORT int init_ca(SERVICE_OPTIONS *section) {
}
#endif
- /* client CA list initialization with the file and/or directory */
- if(section->ca_file)
- SSL_add_file_cert_subjects_to_stack(ca_dn, section->ca_file);
- if(section->ca_dir)
- SSL_add_dir_cert_subjects_to_stack(ca_dn, section->ca_dir);
-
if(!sk_X509_NAME_num(ca_dn)) {
sk_X509_NAME_pop_free(ca_dn, X509_NAME_free);
return 1; /* FAILED */
}
- if(section->option.client) {
- print_CA_list("Configured trusted server CA", ca_dn);
- sk_X509_NAME_pop_free(ca_dn, X509_NAME_free);
- } else { /* only set the client CA list on the server */
- print_CA_list("Configured trusted client CA", ca_dn);
- SSL_CTX_set_client_CA_list(section->ctx, ca_dn);
- }
+ print_CA_list("Configured trusted client CA", ca_dn);
+ SSL_CTX_set_client_CA_list(section->ctx, ca_dn);
return 0; /* OK */
}
--
2.45.2

8
stunnel.spec
View File

@ -32,6 +32,7 @@ Patch3: stunnel-5.69-system-ciphers.patch
Patch5: stunnel-5.69-default-tls-version.patch Patch5: stunnel-5.69-default-tls-version.patch
Patch6: stunnel-5.56-curves-doc-update.patch Patch6: stunnel-5.56-curves-doc-update.patch
Patch7: stunnel-5.71-Preserve-NO_TLSv1.-123-option-compatibility.patch Patch7: stunnel-5.71-Preserve-NO_TLSv1.-123-option-compatibility.patch
Patch8: stunnel-5.72-speed-up-loading-client-CA-list.patch
# util-linux is needed for rename # util-linux is needed for rename
BuildRequires: make BuildRequires: make
BuildRequires: gcc BuildRequires: gcc
@ -64,6 +65,7 @@ conjunction with imapd to create a TLS secure IMAP server.
%patch5 -p1 -b .default-tls-version %patch5 -p1 -b .default-tls-version
%patch6 -p1 -b .curves-doc-update %patch6 -p1 -b .curves-doc-update
%patch7 -p1 -b .preserve-no-tlsv1-123-option-compatibility %patch7 -p1 -b .preserve-no-tlsv1-123-option-compatibility
%patch8 -p1 -b .speed-up-loading-client-CA-list
# Fix the stack protector flag # Fix the stack protector flag
sed -i 's/-fstack-protector/-fstack-protector-strong/' configure sed -i 's/-fstack-protector/-fstack-protector-strong/' configure
@ -142,6 +144,12 @@ fi
%systemd_postun_with_restart %{name}.service %systemd_postun_with_restart %{name}.service
%changelog %changelog
* Wed Aug 07 2024 Clemens Lang <cllang@redhat.com> - 5.71-2
- Speed up loading client CA list from CAfile
Resolves: RHEL-46411
- Do not load all CAs in client mode to allow continued use of BEGIN TRUSTED CERTIFICATE format
Resolves: RHEL-50154
* Thu Oct 19 2023 Clemens Lang <cllang@redhat.com> - 5.71-2 * Thu Oct 19 2023 Clemens Lang <cllang@redhat.com> - 5.71-2
- Restore support for the NO_TLSv1.[123] values for the option directive - Restore support for the NO_TLSv1.[123] values for the option directive
Resolves: RHEL-2340 Resolves: RHEL-2340