1. 20 Sep, 2019 1 commit
    • Ian Lance Taylor's avatar
      runtime: avoid overflow in markrootBlock · 66e562cc
      Ian Lance Taylor authored
      In a position independent executable the data or BSS may be located
      close to the end of memory. If it is placed closer than
      rootBlockBytes, then the calculations in markrootBlock would overflow,
      and the test that ensures that n is not larger than n0 would fail.
      This would then cause scanblock to scan data that it shouldn't,
      using an effectively random ptrmask, leading to program crashes.
      
      No test because the only way to test it is to build a PIE and convince
      the kernel to put the data section near the end of memory, and I don't
      know how to do that. Or perhaps we could use a linker script, but that
      is painful.
      
      The new code is algebraically identical to the original code, but
      avoids the potential overflow of b+rootBlockBytes.
      
      Change-Id: Ieb4e5465174bb762b063d2491caeaa745017345e
      Reviewed-on: https://go-review.googlesource.com/c/go/+/195717
      Run-TryBot: Ian Lance Taylor <iant@golang.org>
      TryBot-Result: Gobot Gobot <gobot@golang.org>
      Reviewed-by: default avatarAustin Clements <austin@google.com>
      66e562cc
  2. 19 Sep, 2019 12 commits
  3. 18 Sep, 2019 24 commits
  4. 17 Sep, 2019 3 commits