From ee7d68c9fe11ab965be124bbfd571280d2eef22b Mon Sep 17 00:00:00 2001
From: John Safranek <john@wolfssl.com>
Date: Tue, 12 May 2026 15:56:06 -0700
Subject: [PATCH] Convert FatFS date/time to Unix timestamp in SFTP

- Add TimeTo32_FatFS() to decode FatFS fdate/ftime fields via mktime()
- Use converted timestamp for atime/mtime instead of raw fdate
---
 src/wolfsftp.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 4 deletions(-)

diff --git a/src/wolfsftp.c b/src/wolfsftp.c
index 0e62d87cf..094b4f8de 100644
--- a/src/wolfsftp.c
+++ b/src/wolfsftp.c
@@ -4850,6 +4850,54 @@ static int SFTP_GetAttributes_Handle(WOLFSSH* ssh, byte* handle, int handleSz,
 
 #elif defined(WOLFSSH_FATFS)
 
+/*
+ * fdate
+ * The date when the file was modified or the directory was created.
+ *     bit15:9
+ *         Year origin from 1980 (0..127)
+ *     bit8:5
+ *         Month (1..12)
+ *     bit4:0
+ *         Day (1..31)
+ *
+ * ftime
+ * The time when the file was modified or the directory was created.
+ *     bit15:11
+ *         Hour (0..23)
+ *     bit10:5
+ *         Minute (0..59)
+ *     bit4:0
+ *         Second / 2 (0..29)
+ *
+ * mktime() expects month from 0 to 11. FatFS months
+ * are saved as 1 to 12. Hence 1 is being deducted to
+ * make it compatible with Unix time stamp.
+ */
+#define WS_GETDAY(d) ((d) & 0x001f)
+#define WS_GETMON(d) ((((d) >> 5) & 0x000f) - 1)
+#define WS_GETYEAR(d) (((d) >> 9) & 0x007f)
+#define WS_GETHOUR(t) (((t) >> 11) & 0x001f)
+#define WS_GETMIN(t)  (((t) >> 5 ) & 0x003f)
+#define WS_GETSEC(t)  (((t) << 1 ) & 0x003f)
+
+#ifndef NO_WOLFSSH_MKTIME
+/* convert nucleus date and time shorts to word32
+ * returns results in Unix time stamp */
+static word32 TimeTo32_FatFS(word16 d, word16 t)
+{
+    struct tm tmp = {0};
+
+    tmp.tm_mday = WS_GETDAY(d);
+    tmp.tm_mon  = WS_GETMON(d);
+    tmp.tm_year = WS_GETYEAR(d);
+    tmp.tm_hour = WS_GETHOUR(t);
+    tmp.tm_min  = WS_GETMIN(t);
+    tmp.tm_sec  = WS_GETSEC(t);
+
+    return mktime(&tmp);
+}
+#endif /* NO_WOLFSSH_MKTIME */
+
 /* FatFs has its own structure for file attributes */
 
 static int SFTP_GetAttributes(void* fs, const char* fileName,
@@ -4907,10 +4955,13 @@ static int SFTP_GetAttributes(void* fs, const char* fileName,
     }
 
 #ifndef NO_WOLFSSH_MKTIME
-    /* get file times */
-    atr->flags |= WOLFSSH_FILEATRB_TIME;
-    atr->atime = info.fdate;
-    atr->mtime = info.fdate;
+    {
+        /* get file times */
+        word32 daytime = TimeTo32_FatFS(info.fdate, info.ftime);
+        atr->flags |= WOLFSSH_FILEATRB_TIME;
+        atr->atime = daytime;
+        atr->mtime = daytime;
+    }
 #endif /* NO_WOLFSSH_MKTIME */
     return WS_SUCCESS;
 }