[PATCH 2/2] ntdll: Fix integer overflow in RtlUniform.

[Jinoh Kang]

From: Jinoh Kang

The integer overflow bug in RtlUniform has been fixed since Windows
Vista.  Synchronize Wine's version accordingly.
---
 dlls/ntdll/rtl.c       | 23 ++---------------------
 dlls/ntdll/tests/rtl.c |  6 ------
 2 files changed, 2 insertions(+), 27 deletions(-)

diff --git a/dlls/ntdll/rtl.c b/dlls/ntdll/rtl.c
index 11067f44941..cbfdb0518a2 100644
--- a/dlls/ntdll/rtl.c
+++ b/dlls/ntdll/rtl.c
@@ -715,12 +715,7 @@ __ASM_GLOBAL_FUNC(NTDLL_RtlUshortByteSwap,
  *  It returns a random number uniformly distributed over [0..MAXLONG-1].
  *
  * NOTES
- *  Generates an uniform random number using D.H. Lehmer's 1948 algorithm.
- *  In our case the algorithm is:
- *
- *|  result = (*seed * 0x7fffffed + 0x7fffffc3) % MAXLONG;
- *|
- *|  *seed = result;
+ *  Generates an uniform random number using a linear congruential generator.
  *
  * DIFFERENCES
  *  The native documentation states that the random number is
@@ -732,21 +727,7 @@ ULONG WINAPI RtlUniform (PULONG seed)
 {
     ULONG result;

-   /*
-    * Instead of the algorithm stated above, we use the algorithm
-    * below, which is totally equivalent (see the tests), but does
-    * not use a division and therefore is faster.
-    */
-    result = *seed * 0xffffffed + 0x7fffffc3;
-    if (result == 0xffffffff || result == 0x7ffffffe) {
-	result = (result + 2) & MAXLONG;
-    } else if (result == 0x7fffffff) {
-	result = 0;
-    } else if ((result & 0x80000000) == 0) {
-	result = result + (~result & 1);
-    } else {
-	result = (result + (result & 1)) & MAXLONG;
-    } /* if */
+    result = ((ULONGLONG)*seed * 0x7fffffed + 0x7fffffc3) % MAXLONG;
     *seed = result;
     return result;
 }
diff --git a/dlls/ntdll/tests/rtl.c b/dlls/ntdll/tests/rtl.c
index 62cdd75f341..0c38f4c6bb3 100644
--- a/dlls/ntdll/tests/rtl.c
+++ b/dlls/ntdll/tests/rtl.c
@@ -380,7 +380,6 @@ static void test_RtlUniform(void)
     expected = 0x7fffffb1;
     result = RtlUniform(&seed);

-    todo_wine
     ok(result == expected,
         "RtlUniform(&seed (seed == 0x80000000)) returns %lx, expected %lx\n",
         result, expected);
@@ -393,7 +392,6 @@ static void test_RtlUniform(void)
     seed = 0x7fffffff;
     expected = 0x7fffffc3;
     result = RtlUniform(&seed);
-    todo_wine
     ok(result == expected,
         "RtlUniform(&seed (seed == 0x7fffffff)) returns %lx, expected %lx\n",
         result, expected);
@@ -423,11 +421,9 @@ static void test_RtlUniform(void)
         seed = num;
         expected = ((ULONGLONG)seed * 0x7fffffed + 0x7fffffc3) % MAXLONG;
         result = RtlUniform(&seed);
-        todo_wine_if(num >= 2)
         ok(result == expected,
                 "test: RtlUniform(&seed (seed == %lx)) returns %lx, expected %lx\n",
                 num, result, expected);
-        todo_wine_if(num >= 2)
         ok(seed == expected,
                 "test: RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx\n",
                 num, result, expected);
@@ -440,11 +436,9 @@ static void test_RtlUniform(void)
         expected = ((ULONGLONG)seed * 0x7fffffed + 0x7fffffc3) % 0x7fffffff;
         seed_bak = seed;
         result = RtlUniform(&seed);
-        todo_wine_if(seed_bak >= 2)
         ok(result == expected,
                 "test: %ld RtlUniform(&seed (seed == %lx)) returns %lx, expected %lx\n",
                 num, seed_bak, result, expected);
-        todo_wine_if(seed_bak >= 2)
         ok(seed == expected,
                 "test: %ld RtlUniform(&seed (seed == %lx)) sets seed to %lx, expected %lx\n",
                 num, seed_bak, result, expected);