imap-send: move common code into function host_matches()
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> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Beat Bolli committed
Mar 11, 2026 at 23:10 UTC
6392a0b75d979ba8e23c85d57b85779aace25370
1 file changed
+9
-7
imap-send.c
+9
-7
@@ -219,8 +219,14 @@ static int ssl_socket_connect(struct imap_socket *sock UNUSED,
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#else
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-static int host_matches(const char *host, const char *pattern)
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+static int host_matches(const char *host, const ASN1_STRING *asn1_str)
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{
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+ const char *pattern = (const char *)ASN1_STRING_get0_data(asn1_str);
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+
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+ /* embedded NUL characters may open a security hole */
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+ if (memchr(pattern, '\0', ASN1_STRING_length(asn1_str)))
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+ return 0;
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+
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if (pattern[0] == '*' && pattern[1] == '.') {
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pattern += 2;
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if (!(host = strchr(host, '.')))
@@ -252,10 +258,7 @@ static int verify_hostname(X509 *cert, const char *hostname)
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GENERAL_NAME *subj_alt_name = sk_GENERAL_NAME_value(subj_alt_names, i);
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ASN1_STRING *subj_alt_str = GENERAL_NAME_get0_value(subj_alt_name, &ntype);
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- if (ntype == GEN_DNS &&
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- strlen((const char *)ASN1_STRING_get0_data(subj_alt_str)) ==
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- ASN1_STRING_length(subj_alt_str) &&
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- host_matches(hostname, (const char *)ASN1_STRING_get0_data(subj_alt_str)))
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+ if (ntype == GEN_DNS && host_matches(hostname, subj_alt_str))
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found = 1;
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}
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sk_GENERAL_NAME_pop_free(subj_alt_names, GENERAL_NAME_free);
@@ -270,8 +273,7 @@ static int verify_hostname(X509 *cert, const char *hostname)
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(cname_entry = X509_NAME_get_entry(subj, i)) == NULL ||
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(cname = X509_NAME_ENTRY_get_data(cname_entry)) == NULL)
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return error("cannot get certificate common name");
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- if (strlen((const char *)ASN1_STRING_get0_data(cname)) == ASN1_STRING_length(cname) &&
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- host_matches(hostname, (const char *)ASN1_STRING_get0_data(cname)))
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+ if (host_matches(hostname, cname))
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return 0;
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return error("certificate owner '%s' does not match hostname '%s'",
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ASN1_STRING_get0_data(cname), hostname);