openssl: CURLSSLOPT_NO_PARTIALCHAIN can disable partial cert chains

Closes #4655

2 files changed, 22 insertions, 17 deletions

diff --git a/docs/libcurl/opts/CURLOPT_SSL_OPTIONS.3 b/docs/libcurl/opts/CURLOPT_SSL_OPTIONS.3
index ace496abc..fd8504fb6 100644
--- a/docs/libcurl/opts/CURLOPT_SSL_OPTIONS.3
+++ b/docs/libcurl/opts/CURLOPT_SSL_OPTIONS.3
@@ -28,23 +28,27 @@ CURLOPT_SSL_OPTIONS \- set SSL behavior options
 
 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_OPTIONS, long bitmask);
 .SH DESCRIPTION
-Pass a long with a bitmask to tell libcurl about specific SSL behaviors.
-
-\fICURLSSLOPT_ALLOW_BEAST\fP tells libcurl to not attempt to use any
-workarounds for a security flaw in the SSL3 and TLS1.0 protocols.  If this
-option isn't used or this bit is set to 0, the SSL layer libcurl uses may use a
-work-around for this flaw although it might cause interoperability problems
-with some (older) SSL implementations. WARNING: avoiding this work-around
-lessens the security, and by setting this option to 1 you ask for exactly that.
-This option is only supported for DarwinSSL, NSS and OpenSSL.
-
-Added in 7.44.0:
-
-\fICURLSSLOPT_NO_REVOKE\fP tells libcurl to disable certificate revocation
-checks for those SSL backends where such behavior is present. This option is
-only supported for Schannel (the native Windows SSL library), with an
-exception in the case of Windows' Untrusted Publishers blacklist which it
-seems can't be bypassed.
+Pass a long with a bitmask to tell libcurl about specific SSL
+behaviors. Available bits:
+.IP CURLSSLOPT_ALLOW_BEAST
+Tells libcurl to not attempt to use any workarounds for a security flaw in the
+SSL3 and TLS1.0 protocols.  If this option isn't used or this bit is set to 0,
+the SSL layer libcurl uses may use a work-around for this flaw although it
+might cause interoperability problems with some (older) SSL
+implementations. WARNING: avoiding this work-around lessens the security, and
+by setting this option to 1 you ask for exactly that.  This option is only
+supported for DarwinSSL, NSS and OpenSSL.
+.IP CURLSSLOPT_NO_REVOKE
+Tells libcurl to disable certificate revocation checks for those SSL backends
+where such behavior is present. This option is only supported for Schannel
+(the native Windows SSL library), with an exception in the case of Windows'
+Untrusted Publishers blacklist which it seems can't be bypassed. (Added in
+7.44.0)
+.IP CURLSSLOPT_NO_PARTIALCHAIN
+Tells libcurl to not accept "partial" certificate chains, which it otherwise
+does by default. This option is only supported for OpenSSL and will fail the
+certificate verification if the chain ends with an intermediate certificate
+and not with a root cert. (Added in 7.68.0)
 .SH DEFAULT
 0
 .SH PROTOCOLS
diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions
index 29013b148..18f04bd70 100644
--- a/docs/libcurl/symbols-in-versions
+++ b/docs/libcurl/symbols-in-versions
@@ -738,6 +738,7 @@ CURLSSLBACKEND_SCHANNEL         7.34.0
 CURLSSLBACKEND_SECURETRANSPORT  7.64.1
 CURLSSLBACKEND_WOLFSSL          7.49.0
 CURLSSLOPT_ALLOW_BEAST          7.25.0
+CURLSSLOPT_NO_PARTIALCHAIN      7.68.0
 CURLSSLOPT_NO_REVOKE            7.44.0
 CURLSSLSET_NO_BACKENDS          7.56.0
 CURLSSLSET_OK                   7.56.0