Mandatory Surgeon Guenther's Warning: This code could not possibly be

correct because it doesn't zerofill the front of usecs, but that's the
way I found it.
a more thorough emulation of the old code, but with fewer whacky snprintf
pointer arithmetic antics. ok beck guenther

2 files changed, 48 insertions, 48 deletions

diff --git a/src/lib/libcrypto/ts/ts_rsp_sign.c b/src/lib/libcrypto/ts/ts_rsp_sign.c
index b0f023c9d2..235c0a8476 100644
--- a/src/lib/libcrypto/ts/ts_rsp_sign.c
+++ b/src/lib/libcrypto/ts/ts_rsp_sign.c
@@ -953,8 +953,9 @@ TS_RESP_set_genTime_with_precision(ASN1_GENERALIZEDTIME *asn1_time,
         time_t time_sec = (time_t) sec;
         struct tm *tm = NULL;   
         char genTime_str[17 + TS_MAX_CLOCK_PRECISION_DIGITS];
-        char *p = genTime_str;
-        char *p_end = genTime_str + sizeof(genTime_str);
+        char usecstr[TS_MAX_CLOCK_PRECISION_DIGITS + 2];
+        char *p;
+        int rv;
 
         if (precision > TS_MAX_CLOCK_PRECISION_DIGITS)
                 goto err;
@@ -970,18 +971,7 @@ TS_RESP_set_genTime_with_precision(ASN1_GENERALIZEDTIME *asn1_time,
          * meet the rfc3161 requirement: "GeneralizedTime syntax can include 
          * fraction-of-second details". 
          */                   
-        p += BIO_snprintf(p, p_end - p,
-                          "%04d%02d%02d%02d%02d%02d",
-                          tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, 
-                          tm->tm_hour, tm->tm_min, tm->tm_sec);
-        if (precision > 0)
-        {
-                /* Add fraction of seconds (leave space for dot and null). */
-                BIO_snprintf(p, 2 + precision, ".%ld", usec);
-                /* We cannot use the snprintf return value, 
-                   because it might have been truncated. */
-                p += strlen(p);
-
+        if (precision > 0) {
                 /* To make things a bit harder, X.690 | ISO/IEC 8825-1 provides
                    the following restrictions for a DER-encoding, which OpenSSL
                    (specifically ASN1_GENERALIZEDTIME_check() function) doesn't 
@@ -993,16 +983,26 @@ TS_RESP_set_genTime_with_precision(ASN1_GENERALIZEDTIME *asn1_time,
                    if the elements correspond to 0, they MUST be wholly
                    omitted, and the decimal point element also MUST be
                    omitted." */
-                /* Remove trailing zeros. The dot guarantees the exit
-                   condition of this loop even if all the digits are zero. */
-                while (*--p == '0')
-                        /* empty */;
-                /* p points to either the dot or the last non-zero digit. */
-                if (*p != '.') ++p;
-                }
-        /* Add the trailing Z and the terminating null. */
-        *p++ = 'Z';
-        *p++ = '\0';
+                (void)snprintf(usecstr, sizeof(usecstr), ".%ld", usec);
+                /* truncate and trim trailing 0 */
+                usecstr[precision + 1] = '\0';
+                p = usecstr + strlen(usecstr) - 1;
+                while (p > usecstr && *p == '0')
+                        *p-- = '\0';
+                /* if we've reached the beginning, delete the . too */
+                if (p == usecstr)
+                        *p = '\0';
+
+        } else {
+                /* empty */
+                usecstr[0] = '\0';
+        }
+        rv = snprintf(genTime_str, sizeof(genTime_str),
+            "%04d%02d%02d%02d%02d%02d%sZ",
+            tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, 
+            tm->tm_hour, tm->tm_min, tm->tm_sec, usecstr);
+        if (rv == -1 || rv >= sizeof(genTime_str))
+                goto err;
 
         /* Now call OpenSSL to check and set our genTime value */
         if (!asn1_time && !(asn1_time = M_ASN1_GENERALIZEDTIME_new()))
diff --git a/src/lib/libssl/src/crypto/ts/ts_rsp_sign.c b/src/lib/libssl/src/crypto/ts/ts_rsp_sign.c
index b0f023c9d2..235c0a8476 100644
--- a/src/lib/libssl/src/crypto/ts/ts_rsp_sign.c
+++ b/src/lib/libssl/src/crypto/ts/ts_rsp_sign.c
@@ -953,8 +953,9 @@ TS_RESP_set_genTime_with_precision(ASN1_GENERALIZEDTIME *asn1_time,
         time_t time_sec = (time_t) sec;
         struct tm *tm = NULL;   
         char genTime_str[17 + TS_MAX_CLOCK_PRECISION_DIGITS];
-        char *p = genTime_str;
-        char *p_end = genTime_str + sizeof(genTime_str);
+        char usecstr[TS_MAX_CLOCK_PRECISION_DIGITS + 2];
+        char *p;
+        int rv;
 
         if (precision > TS_MAX_CLOCK_PRECISION_DIGITS)
                 goto err;
@@ -970,18 +971,7 @@ TS_RESP_set_genTime_with_precision(ASN1_GENERALIZEDTIME *asn1_time,
          * meet the rfc3161 requirement: "GeneralizedTime syntax can include 
          * fraction-of-second details". 
          */                   
-        p += BIO_snprintf(p, p_end - p,
-                          "%04d%02d%02d%02d%02d%02d",
-                          tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, 
-                          tm->tm_hour, tm->tm_min, tm->tm_sec);
-        if (precision > 0)
-        {
-                /* Add fraction of seconds (leave space for dot and null). */
-                BIO_snprintf(p, 2 + precision, ".%ld", usec);
-                /* We cannot use the snprintf return value, 
-                   because it might have been truncated. */
-                p += strlen(p);
-
+        if (precision > 0) {
                 /* To make things a bit harder, X.690 | ISO/IEC 8825-1 provides
                    the following restrictions for a DER-encoding, which OpenSSL
                    (specifically ASN1_GENERALIZEDTIME_check() function) doesn't 
@@ -993,16 +983,26 @@ TS_RESP_set_genTime_with_precision(ASN1_GENERALIZEDTIME *asn1_time,
                    if the elements correspond to 0, they MUST be wholly
                    omitted, and the decimal point element also MUST be
                    omitted." */
-                /* Remove trailing zeros. The dot guarantees the exit
-                   condition of this loop even if all the digits are zero. */
-                while (*--p == '0')
-                        /* empty */;
-                /* p points to either the dot or the last non-zero digit. */
-                if (*p != '.') ++p;
-                }
-        /* Add the trailing Z and the terminating null. */
-        *p++ = 'Z';
-        *p++ = '\0';
+                (void)snprintf(usecstr, sizeof(usecstr), ".%ld", usec);
+                /* truncate and trim trailing 0 */
+                usecstr[precision + 1] = '\0';
+                p = usecstr + strlen(usecstr) - 1;
+                while (p > usecstr && *p == '0')
+                        *p-- = '\0';
+                /* if we've reached the beginning, delete the . too */
+                if (p == usecstr)
+                        *p = '\0';
+
+        } else {
+                /* empty */
+                usecstr[0] = '\0';
+        }
+        rv = snprintf(genTime_str, sizeof(genTime_str),
+            "%04d%02d%02d%02d%02d%02d%sZ",
+            tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, 
+            tm->tm_hour, tm->tm_min, tm->tm_sec, usecstr);
+        if (rv == -1 || rv >= sizeof(genTime_str))
+                goto err;
 
         /* Now call OpenSSL to check and set our genTime value */
         if (!asn1_time && !(asn1_time = M_ASN1_GENERALIZEDTIME_new()))