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Fix #2614
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Currently `compare_server_name_to_cert()` only indicates whether the server's host name matches a wildcard name in the certificate. So, it does not indicate if the certificate includes a wildcard name that does not match the server's host name. As a result, if a certificate includes the names "api.sub.example.tld" and "*.api.sub.example.tld," then a wildcard certificate warning will be issued for host names such as www.api.sub.example.tld, but not for api.sub.example.tld.

This commit changes `compare_server_name_to_cert()` to indicate whether the certificate is a wildcard certificate in addition to providing information about how the certificate matches the server's host name. Functions that use this function's response are then changed to extract the information they need (matching or wildcard) from the return value.
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@dcooper16
dcooper16 committed Jan 17, 2025
1 parent daf0671 commit 95b6258
Showing 1 changed file with 31 additions and 16 deletions.
47 changes: 31 additions & 16 deletions testssl.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -8386,12 +8386,14 @@ wildcard_match()
# 8, if the server name provided is a wildcard match against the CN
# 9, if the server name provided matches a name in the SAN AND is a wildcard match against the CN
# 10, if the server name provided is a wildcard match against the CN AND a name in the SAN
#
# Add 128 to the return value if the CN or a DNS name in the SAN is a wildcard.

compare_server_name_to_cert() {
local cert="$1"
local servername cns cn dns_sans ip_sans san dercert tag
local srv_id="" xmppaddr=""
local -i i len len1 cn_match=0
local -i i len len1 cn_match=0 wildcard_cert=0
local -i subret=0 # no error condition, passing results

HAS_DNS_SANS=false
Expand Down Expand Up @@ -8536,10 +8538,16 @@ compare_server_name_to_cert() {
fi

# Check whether any of the DNS names in the certificate are wildcard names
# that match the servername
# and if they match the servername
if [[ $subret -eq 0 ]]; then
while read san; do
[[ -n "$san" ]] || continue
is_wildcard "$san"
if [[ $? -eq 0 ]]; then
wildcard_cert=128
else
continue
fi
wildcard_match "$servername" "$san"
[[ $? -eq 0 ]] && subret=2 && break
done <<< "$dns_sans"
Expand All @@ -8555,13 +8563,20 @@ compare_server_name_to_cert() {
# Check whether the CN matches the servername
[[ $(toupper "$cn") == "$servername" ]] && cn_match=4 && break

# Check whether the CN is a wildcard name that matches the servername
# Check whether the CN is a wildcard name and if it matches the servername
# NOTE: Don't stop loop on a wildcard match in case there is another CN
# that is an exact match.
is_wildcard "$cn"
if [[ $? -eq 0 ]]; then
wildcard_cert=128
else
continue
fi
wildcard_match "$servername" "$cn"
[[ $? -eq 0 ]] && cn_match=8
done <<< "$cns"
subret+=$cn_match
subret+=$wildcard_cert
return $subret
}

Expand Down Expand Up @@ -9456,7 +9471,7 @@ certificate_info() {
# supported by the client.
has_dns_sans=$HAS_DNS_SANS

case $trust_sni in
case $((trust_sni%128)) in
0) trustfinding="certificate does not match supplied URI"
set_grade_cap "M" "Domain name mismatch"
;;
Expand All @@ -9483,10 +9498,10 @@ certificate_info() {
;;
esac

if [[ $trust_sni -eq 0 ]]; then
if [[ $((trust_sni%128)) -eq 0 ]]; then
pr_svrty_high "$trustfinding"
trust_sni_finding="HIGH"
elif [[ $trust_sni -eq 4 ]] || [[ $trust_sni -eq 8 ]]; then
elif [[ $((trust_sni%128)) -eq 4 ]] || [[ $((trust_sni%128)) -eq 8 ]]; then
if [[ $SERVICE == HTTP ]] || "$ASSUME_HTTP"; then
# https://bugs.chromium.org/p/chromium/issues/detail?id=308330
# https://bugzilla.mozilla.org/show_bug.cgi?id=1245280
Expand All @@ -9513,17 +9528,17 @@ certificate_info() {
# See issue #733.
if [[ -z "$sni_used" ]]; then
trustfinding_nosni=""
elif [[ $trust_sni -eq $trust_nosni && "$has_dns_sans" == "$has_dns_sans_nosni" ]] || \
[[ $trust_sni -eq 0 && $trust_nosni -eq 0 ]]; then
elif [[ $((trust_sni%128)) -eq $((trust_nosni%128)) && "$has_dns_sans" == "$has_dns_sans_nosni" ]] || \
[[ $((trust_sni%128)) -eq 0 && $((trust_nosni%128)) -eq 0 ]]; then
trustfinding_nosni=" (same w/o SNI)"
elif [[ $trust_nosni -eq 0 ]]; then
if [[ $trust_sni -eq 4 ]] || [[ $trust_sni -eq 8 ]]; then
elif [[ $((trust_nosni%128)) -eq 0 ]]; then
if [[ $((trust_sni%128)) -eq 4 ]] || [[ $((trust_sni%128)) -eq 8 ]]; then
trustfinding_nosni=" (w/o SNI: certificate does not match supplied URI)"
else
trustfinding_nosni=" (SNI mandatory)"
fi
elif [[ $trust_nosni -eq 4 ]] || [[ $trust_nosni -eq 8 ]] || [[ $trust_sni -eq 4 ]] || [[ $trust_sni -eq 8 ]]; then
case $trust_nosni in
elif [[ $((trust_nosni%128)) -eq 4 ]] || [[ $((trust_nosni%128)) -eq 8 ]] || [[ $((trust_sni%128)) -eq 4 ]] || [[ $((trust_sni%128)) -eq 8 ]]; then
case $((trust_nosni%128)) in
1) trustfinding_nosni=" (w/o SNI: Ok via SAN)" ;;
2) trustfinding_nosni=" (w/o SNI: Ok via SAN wildcard)" ;;
4) if "$has_dns_sans_nosni"; then
Expand All @@ -9543,12 +9558,12 @@ certificate_info() {
9) trustfinding_nosni=" (w/o SNI: Ok via CN wildcard and SAN)" ;;
10) trustfinding_nosni=" (w/o SNI: Ok via SAN wildcard and CN wildcard)" ;;
esac
elif [[ $trust_sni -ne 0 ]]; then
elif [[ $((trust_sni%128)) -ne 0 ]]; then
trustfinding_nosni=" (works w/o SNI)"
else
trustfinding_nosni=" (however, works w/o SNI)"
fi
if [[ -n "$sni_used" ]] || [[ $trust_nosni -eq 0 ]] || [[ $trust_nosni -ne 4 && $trust_nosni -ne 8 ]]; then
if [[ -n "$sni_used" ]] || [[ $((trust_nosni%128)) -eq 0 ]] || [[ $((trust_nosni%128)) -ne 4 && $((trust_nosni%128)) -ne 8 ]]; then
outln "$trustfinding_nosni"
elif [[ $SERVICE == HTTP ]] || "$ASSUME_HTTP"; then
prln_svrty_high "$trustfinding_nosni"
Expand All @@ -9558,7 +9573,7 @@ certificate_info() {

fileout "cert_trust${json_postfix}" "$trust_sni_finding" "${trustfinding}${trustfinding_nosni}"

if [[ "$trust_sni" =~ ^(2|6|8|9|10)$ ]] || [[ "$trust_nosni" =~ ^(2|6|8|9|10)$ ]]; then
if [[ $((trust_sni&128)) -eq 128 ]] || [[ $((trust_nosni&128)) -eq 128 ]]; then
out "${spaces}"
pr_svrty_low "wildcard certificate" ; outln " could be problematic, see other hosts at"
outln "${spaces}https://search.censys.io/search?resource=hosts&virtual_hosts=INCLUDE&q=$cert_fingerprint_sha2"
Expand Down Expand Up @@ -10164,7 +10179,7 @@ run_server_defaults() {
# $NODE being tested or if it has the same subject
# (CN and SAN) as other certificates for this host.
compare_server_name_to_cert "$HOSTCERT"
[[ $? -ne 0 ]] && success[n]=0 || success[n]=1
[[ $(($?%128)) -ne 0 ]] && success[n]=0 || success[n]=1

if [[ ${success[n]} -ne 0 ]]; then
cn_nosni="$(toupper "$(get_cn_from_cert $HOSTCERT)")"
Expand Down

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