patch 9.0.2112: [security]: overflow in shift_line Commit: https://github.com/vim/vim/commit/6bf131888a3d1de62bbfa8a7ea03c0ddccfd496e Author: Christian Brabandt <cb@256bit.org> Date: Tue Nov 14 22:42:59 2023 +0100 patch 9.0.2112: [security]: overflow in shift_line Problem: [security]: overflow in shift_line Solution: allow a max indent of INT_MAX [security]: overflow in shift_line When shifting lines in operator pending mode and using a very large value, we may overflow the size of integer. Fix this by using a long variable, testing if the result would be larger than INT_MAX and if so, indent by INT_MAX value. Special case: We cannot use long here, since on 32bit architectures (or on Windows?), it typically cannot take larger values than a plain int, so we have to use long long count, decide whether the resulting multiplication of the shiftwidth value * amount is larger than INT_MAX and if so, we will store INT_MAX as possible larges value in the long long count variable. Then we can safely cast it back to int when calling the functions to set the indent (set_indent() or change_indent()). So this should be safe. Add a test that when using a huge value in operator pending mode for shifting, we will shift by INT_MAX closes: #13535 Signed-off-by: Christian Brabandt <cb@256bit.org>

--- a/src/ops.c
+++ b/src/ops.c
@@ -229,11 +229,11 @@ shift_line(
     int	amount,
     int call_changed_bytes)	// call changed_bytes()
 {
-    int		count;
+    long long	count;
     int		i, j;
     int		sw_val = (int)get_sw_value_indent(curbuf);
 
-    count = get_indent();	// get current indent
+    count = (long long)get_indent();	// get current indent
 
     if (round)			// round off indent
     {
@@ -260,14 +260,19 @@ shift_line(
 		count = 0;
 	}
 	else
-	    count += sw_val * amount;
+	{
+	    if ((long long)sw_val * (long long)amount > INT_MAX - count)
+		count = INT_MAX;
+	    else
+		count += (long long)sw_val * (long long)amount;
+	}
     }
 
     // Set new indent
     if (State & VREPLACE_FLAG)
-	change_indent(INDENT_SET, count, FALSE, NUL, call_changed_bytes);
+	change_indent(INDENT_SET, (int)count, FALSE, NUL, call_changed_bytes);
     else
-	(void)set_indent(count, call_changed_bytes ? SIN_CHANGED : 0);
+	(void)set_indent((int)count, call_changed_bytes ? SIN_CHANGED : 0);
 }
 
 /*