From 0b0c60d540d5e88bff6cda9de9e62c1dc7cd5389 Mon Sep 17 00:00:00 2001
From: Christian Vogelgsang <chris@vogelgsang.org>
Date: Sun, 2 Feb 2025 17:19:51 +0100
Subject: [PATCH] limit Seek() to file size or return error

---
 amitools/vamos/lib/DosLibrary.py     | 14 +++++++++++---
 amitools/vamos/lib/dos/FileHandle.py | 17 +++++++++++++++--
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/amitools/vamos/lib/DosLibrary.py b/amitools/vamos/lib/DosLibrary.py
index b47217a0..01364db3 100644
--- a/amitools/vamos/lib/DosLibrary.py
+++ b/amitools/vamos/lib/DosLibrary.py
@@ -756,12 +756,20 @@ def Seek(self, ctx, fh_b_addr, pos, mode):
 
         old_pos = fh.tell()
         new_pos = fh.seek(pos, whence)
-        log_dos.info("Seek(%s, %06x, %s) -> old_pos=%06x", fh, pos, mode_str, old_pos)
-        if new_pos == -1:
+        log_dos.info(
+            "Seek(%s, %d, %s) -> old_pos=%d new_pos=%d",
+            fh,
+            pos,
+            mode_str,
+            old_pos,
+            new_pos,
+        )
+        if new_pos < 0:
             self.setioerr(ctx, ERROR_SEEK_ERROR)
+            return -1
         else:
             self.setioerr(ctx, 0)
-        return old_pos
+            return old_pos
 
     def FGetC(self, ctx, fh_b_addr):
         fh = self.file_mgr.get_by_b_addr(fh_b_addr, False)
diff --git a/amitools/vamos/lib/dos/FileHandle.py b/amitools/vamos/lib/dos/FileHandle.py
index af02df15..fc92f665 100644
--- a/amitools/vamos/lib/dos/FileHandle.py
+++ b/amitools/vamos/lib/dos/FileHandle.py
@@ -183,10 +183,23 @@ def tell(self):
     def seek(self, pos, whence):
         """set to position from whence
 
-        return -1 on error or new_pos
+        return -1 on error, -2 on too far or new_pos
         """
         try:
-            return self.obj.seek(pos, whence)
+            new_pos = self.obj.seek(pos, whence)
+
+            # we have to limit seek to file size
+            stat = os.stat(self.obj.fileno())
+            file_size = stat.st_size
+
+            # if seek to far then limit to file size
+            if new_pos > file_size:
+                # seek to end
+                self.obj.seek(file_size, 0)
+                return -2
+
+            return new_pos
+
         except IOError:
             return -1