archive_ppmd7.c: avoid possible integer overflow (security)

Found by LGTM.com code analysis

diff --git a/libarchive/archive_ppmd7.c b/libarchive/archive_ppmd7.c
index d0bacc68cd7c653cbdd78f0b0f4a19851fa06b17..4029395b4c7f456816538e3b9a40ce092e85e406 100644 (file)
--- a/libarchive/archive_ppmd7.c
+++ b/libarchive/archive_ppmd7.c
@@ -1000,7 +1000,7 @@ static void RangeEnc_ShiftLow(CPpmd7z_RangeEnc *p)
 
 static void RangeEnc_Encode(CPpmd7z_RangeEnc *p, UInt32 start, UInt32 size, UInt32 total)
 {
-  p->Low += start * (p->Range /= total);
+  p->Low += (UInt64)start * (UInt64)(p->Range /= total);
   p->Range *= size;
   while (p->Range < kTopValue)
   {