[Gptfdisk-general] [PATCH 4/4] seek: detect and complain about seek overflows

[Cody P S. <de...@co...>]

---
 diskio-unix.cc | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/diskio-unix.cc b/diskio-unix.cc
index 71b4387..4a835a5 100644
--- a/diskio-unix.cc
+++ b/diskio-unix.cc
@@ -280,7 +280,12 @@ int DiskIO::Seek(uint64_t sector) {
    } // if
 
    if (isOpen) {
-      seekTo = sector * (uint64_t) GetBlockSize();
+      uint64_t b = (uint64_t) GetBlockSize();
+      if (UINT64_MAX / b <= sector) {
+         cerr << "Overflow in seek calculation: " << b << " * " << sector << endl;
+         return 0;
+      }
+      seekTo = sector * b;
       sought = lseek64(fd, seekTo, SEEK_SET);
       if (sought != seekTo) {
          retval = 0;
-- 
2.4.3