Merge pull request #6403 from kareem-wolfssl/gh6387

Fix wolfssl_asn1_time_to_tm setting unexpected fields in tm struct.

Author: JacobBarthelmeh

src/ssl_asn1.c

@@ -3652,6 +3652,9 @@ static int wolfssl_asn1_time_to_tm(const WOLFSSL_ASN1_TIME* asnTime,
     const unsigned char* asn1TimeBuf;
     int asn1TimeBufLen;
     int i = 0;
+#ifdef XMKTIME
+    struct tm localTm = {0};
+#endif
 
     /* Get the string buffer - fixed array, can't fail. */
     asn1TimeBuf = wolfSSL_ASN1_TIME_get_data(asnTime);
@@ -3706,8 +3709,13 @@ static int wolfssl_asn1_time_to_tm(const WOLFSSL_ASN1_TIME* asnTime,
         tm->tm_sec  += (asn1TimeBuf[i] - '0');
 
     #ifdef XMKTIME
-        /* Call XMKTIME on tm to get tm_wday and tm_yday fields populated. */
-        XMKTIME(tm);
+        XMEMCPY(&localTm, tm, sizeof(struct tm));
+        /* Call XMKTIME on tm to get tm_wday and tm_yday fields populated.
+           Note that localTm is used here to avoid modifying other fields,
+           such as tm_isdst/tm_gmtoff. */
+        XMKTIME(&localTm);
+        tm->tm_wday = localTm.tm_wday;
+        tm->tm_yday = localTm.tm_yday;
     #endif
     }
 

tests/api.c

@@ -33143,6 +33143,7 @@ static int test_wolfSSL_ASN1_TIME_to_tm(void)
       defined(OPENSSL_ALL)) && !defined(NO_ASN_TIME)
     ASN1_TIME asnTime;
     struct tm tm;
+    time_t testTime = 1683926567; /* Fri May 12 09:22:47 PM UTC 2023 */
 
     XMEMSET(&asnTime, 0, sizeof(ASN1_TIME));
     AssertIntEQ(ASN1_TIME_set_string(&asnTime, "000222211515Z"), 1);
@@ -33188,6 +33189,22 @@ static int test_wolfSSL_ASN1_TIME_to_tm(void)
     AssertIntEQ(ASN1_TIME_set_string(&asnTime, "20000222211515U"), 1);
     AssertIntEQ(ASN1_TIME_to_tm(&asnTime, &tm), 0);
 
+#ifdef XMKTIME
+    AssertNotNull(ASN1_TIME_adj(&asnTime, testTime, 0, 0));
+    AssertIntEQ(ASN1_TIME_to_tm(&asnTime, &tm), 1);
+    AssertIntEQ(tm.tm_sec, 47);
+    AssertIntEQ(tm.tm_min, 22);
+    AssertIntEQ(tm.tm_hour, 21);
+    AssertIntEQ(tm.tm_mday, 12);
+    AssertIntEQ(tm.tm_mon, 4);
+    AssertIntEQ(tm.tm_year, 123);
+    AssertIntEQ(tm.tm_wday, 5);
+    AssertIntEQ(tm.tm_yday, 131);
+    /* Confirm that when used with a tm struct from ASN1_TIME_adj, all other
+       fields are zeroed out as expected. */
+    AssertIntEQ(tm.tm_isdst, 0);
+#endif
+
     res = TEST_RES_CHECK(1);
 #endif
     return res;