commit 07cb422cbb552744ac7cd13507fa4933de98ab15
Author: Jaroslav Suchanek <jaroslav.sucha...@gmail.com>
AuthorDate: Sat Nov 9 19:47:55 2019 +0100
Commit: Oswald Buddenhagen <o...@users.sf.net>
CommitDate: Tue Aug 4 14:49:58 2020 +0200
Add support for specifying cipher string used for ssl connection
Some distributions (e.g. Fedora) added support for system wide crypto
policies. This is supported in most common crypto libraries including
OpenSSL. Applications can override this policy using their own cipher
string. This commit adds support for specifying the cipher string in
the mbsync configuration.
For example, to exclude Diffie-Hellman, the user can specify
CipherString "DEFAULT:!DH"
in the IMAP Account's configuration.
NEWS | 2 ++
src/drv_imap.c | 2 ++
src/mbsync.1 | 7 +++++++
src/socket.c | 5 +++++
src/socket.h | 1 +
5 files changed, 17 insertions(+)
diff --git a/NEWS b/NEWS
index ef795a8..18e4f13 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ The 'isync' compatibility wrapper was removed.
The IMAP '$Forwarded' / Maildir 'P' (passed) flag is supported now.
+Support for configuring a TLS cipher string was added.
+
[1.3.0]
Network timeout handling has been added.
diff --git a/src/drv_imap.c b/src/drv_imap.c
index e2d5fce..b6f7278 100644
--- a/src/drv_imap.c
+++ b/src/drv_imap.c
@@ -3295,6 +3295,8 @@ imap_parse_store( conffile_t *cfg, store_conf_t **storep )
cfg->file, cfg->line,
server->sconf.client_keyfile );
cfg->err = 1;
}
+ } else if (!strcasecmp( "CipherString", cfg->cmd )) {
+ server->sconf.cipher_string = nfstrdup( cfg->val );
} else if (!strcasecmp( "SSLType", cfg->cmd )) {
if (!strcasecmp( "None", cfg->val )) {
server->ssl_type = SSL_None;
diff --git a/src/mbsync.1 b/src/mbsync.1
index c8c8736..325385f 100644
--- a/src/mbsync.1
+++ b/src/mbsync.1
@@ -414,6 +414,13 @@ so it is unlikely that you need this option.
File containing the private key corresponding to \fBClientCertificate\fR.
.
.TP
+\fBCipherString\fR \fIstring\fR
+Specify OpenSSL cipher string for connections secured with TLS up to
+version 1.2 (but not 1.3 and above).
+The format is described in \fBciphers\fR\|(1).
+(Default: empty, which implies system wide policy).
+.
+.TP
\fBPipelineDepth\fR \fIdepth\fR
Maximum number of IMAP commands which can be simultaneously in flight.
Setting this to \fI1\fR disables pipelining.
diff --git a/src/socket.c b/src/socket.c
index 4034d9d..feb6511 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -263,6 +263,11 @@ init_ssl_ctx( const server_conf_t *conf )
SSL_CTX_set_options( mconf->SSLContext, options );
+ if (conf->cipher_string && !SSL_CTX_set_cipher_list( mconf->SSLContext,
conf->cipher_string )) {
+ print_ssl_errors( "setting cipher string '%s'",
conf->cipher_string );
+ return 0;
+ }
+
if (conf->cert_file && !SSL_CTX_load_verify_locations(
mconf->SSLContext, conf->cert_file, 0 )) {
print_ssl_errors( "loading certificate file '%s'",
conf->cert_file );
return 0;
diff --git a/src/socket.h b/src/socket.h
index d760c56..f8f25b1 100644
--- a/src/socket.h
+++ b/src/socket.h
@@ -49,6 +49,7 @@ typedef struct {
char *cert_file;
char *client_certfile;
char *client_keyfile;
+ char *cipher_string;
char system_certs;
char ssl_versions;
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