Merge pull request #1940 from stephentoub/fix_bi_overrun

stephentoub · stephentoub · commit 795753133dbe · 2015-06-05T19:10:30.000-04:00
Fix buffer overrun in BigIntegerCalculator.Subtract
diff --git a/src/System.Runtime.Numerics/src/System/Numerics/BigIntegerCalculator.AddSub.cs b/src/System.Runtime.Numerics/src/System/Numerics/BigIntegerCalculator.AddSub.cs
@@ -197,7 +197,7 @@ private unsafe static void Subtract(uint* left, int leftLength,
                 bits[i] = (uint)digit;
                 carry = digit >> 32;
             }
-            bits[i] = (uint)carry;
+            Debug.Assert(carry == 0);
         }
 
         [SecuritySafeCritical]

Original file line number	Diff line number	Diff line change
`@@ -197,7 +197,7 @@ private unsafe static void Subtract(uint* left, int leftLength,`
`197`	`197`	`bits[i] = (uint)digit;`
`198`	`198`	`carry = digit >> 32;`
`199`	`199`	`}`
`200`		`- bits[i] = (uint)carry;`
	`200`	`+ Debug.Assert(carry == 0);`
`201`	`201`	`}`
`202`	`202`
`203`	`203`	`[SecuritySafeCritical]`