Fix the documentation for X509_cmp_timeframe

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28623)

diff --git a/doc/man3/X509_cmp_time.pod b/doc/man3/X509_cmp_time.pod
index 30a09f25f9fb82ef9cb10ebab7b8ef75222f3238..52b1722c9f25986b3c588acd3d0cc55ca3e5ffd4 100644 (file)
--- a/doc/man3/X509_cmp_time.pod
+++ b/doc/man3/X509_cmp_time.pod
@@ -61,13 +61,26 @@ X509_cmp_time() and X509_cmp_current_time() return -1 if I<asn1_time>
 is earlier than, or equal to, I<in_tm> (resp. current time), and 1
 otherwise. These methods return 0 on error.
 
-X509_cmp_timeframe() returns 0 if I<vpm> is not NULL and the verification
-parameters do not contain B<X509_V_FLAG_USE_CHECK_TIME>
-but do contain B<X509_V_FLAG_NO_CHECK_TIME>. Otherwise it returns
-1 if the end time is not NULL and the reference time (which has determined as
-stated above) is past the end time, -1 if the start time is not NULL and the
-reference time is before, else 0 to indicate that the reference time is in range
-(implying that the end time is not before the start time if both are present).
+X509_cmp_timeframe() compares a reference time to a start and end
+ASN1_TIME value range. The reference time is compared to the start
+value of the range inclusively, and to the end value of the range
+exclusively. The reference time used will retrieved from I<vpm> if the
+flag I<509_V_FLAG_USE_CHECK_TIME> is set in I<vpm>, otherwise it will
+be the current time. The start time used will be I<start> if it is non
+NULL, and a valid ASN1_TIME value, otherwise it will be infinitely in
+the past. The end time used will be I<end> if it is non NULL and a
+valid ASN1_TIME value, otherwise it will be infinitely in the
+future. 0 is returned unconditionally if the flag
+I<X509_V_FLAG_NO_CHECK_TIME> is set in I<vpm>. Otherwise 0 will be
+returned if the reference time is in the range of the start time and
+end time as described above. 1 is returned to indicate the reference
+time is after or equal to the end time. -1 is returned to indicate the
+reference time is before the start time. As this function treats
+invalid ASN1_TIME inputs as unlimited times, it should not be used to
+for temporal verification of certificates using untrusted inputs that
+have not been pre-validated to be correct ASN1_TIME values for a
+certificate as per RFC 5280, as invalid values will be accepted
+as valid forever.
 
 X509_time_adj(), X509_time_adj_ex() and X509_gmtime_adj() return a pointer to
 the updated ASN1_TIME structure, and NULL on error.