[PATCH v2 3/3] imap-send: move common code into function host_matches()
- From
Beat Bolli <dev+git@drbeat.li>
- Date
- Mar 11, 2026, 22:10 UTC
- Message-ID
- <20260311221027.1404476-4-dev+git@drbeat.li>
- In-Reply-To
- <20260311121107.1122387-1-dev+git@drbeat.li>
Move the ASN1_STRING access, the associated cast and the check for embedded NUL bytes into host_matches() to simplify both callers.
Reformulate the NUL check using memchr() and add a comment to make it more obvious what it is about.
Signed-off-by: Beat Bolli <dev+git@drbeat.li> --- imap-send.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/imap-send.c b/imap-send.c index 2a904314dd..af02c6a689 100644 --- a/imap-send.c +++ b/imap-send.c @@ -219,8 +219,14 @@ static int ssl_socket_connect(struct imap_socket *sock UNUSED, #else -static int host_matches(const char *host, const char *pattern) +static int host_matches(const char *host, const ASN1_STRING *asn1_str) { + const char *pattern = (const char *)ASN1_STRING_get0_data(asn1_str); + + /* embedded NUL characters may open a security hole */ + if (memchr(pattern, '\0', ASN1_STRING_length(asn1_str))) + return 0; + if (pattern[0] == '*' && pattern[1] == '.') { pattern += 2; if (!(host = strchr(host, '.'))) @@ -252,10 +258,7 @@ static int verify_hostname(X509 *cert, const char *hostname) GENERAL_NAME *subj_alt_name = sk_GENERAL_NAME_value(subj_alt_names, i); ASN1_STRING *subj_alt_str = GENERAL_NAME_get0_value(subj_alt_name, &ntype); - if (ntype == GEN_DNS && - strlen((const char *)ASN1_STRING_get0_data(subj_alt_str)) == - ASN1_STRING_length(subj_alt_str) && - host_matches(hostname, (const char *)ASN1_STRING_get0_data(subj_alt_str))) + if (ntype == GEN_DNS && host_matches(hostname, subj_alt_str)) found = 1; } sk_GENERAL_NAME_pop_free(subj_alt_names, GENERAL_NAME_free); @@ -270,8 +273,7 @@ static int verify_hostname(X509 *cert, const char *hostname) (cname_entry = X509_NAME_get_entry(subj, i)) == NULL || (cname = X509_NAME_ENTRY_get_data(cname_entry)) == NULL) return error("cannot get certificate common name"); - if (strlen((const char *)ASN1_STRING_get0_data(cname)) == ASN1_STRING_length(cname) && - host_matches(hostname, (const char *)ASN1_STRING_get0_data(cname))) + if (host_matches(hostname, cname)) return 0; return error("certificate owner '%s' does not match hostname '%s'", ASN1_STRING_get0_data(cname), hostname);
-- 2.51.0