1. 18 Dec, 2021 1 commit
    • Chuck Lever's avatar
      NFSD: Fix READDIR buffer overflow · 53b1119a
      Chuck Lever authored
      If a client sends a READDIR count argument that is too small (say,
      zero), then the buffer size calculation in the new init_dirlist
      helper functions results in an underflow, allowing the XDR stream
      functions to write beyond the actual buffer.
      
      This calculation has always been suspect. NFSD has never sanity-
      checked the READDIR count argument, but the old entry encoders
      managed the problem correctly.
      
      With the commits below, entry encoding changed, exposing the
      underflow to the pointer arithmetic in xdr_reserve_space().
      
      Modern NFS clients attempt to retrieve as much data as possible
      for each READDIR request. Also, we have no unit tests that
      exercise the behavior of READDIR at the lower bound of @count
      values. Thus this case was missed during testing.
      Reported-by: default avatarAnatoly Trosinenko <anatoly.trosinenko@gmail.com>
      Fixes: f5dcccd6 ("NFSD: Update the NFSv2 READDIR entry encoder to use struct xdr_stream")
      Fixes: 7f87fc2d ("NFSD: Update NFSv3 READDIR entry encoders to use struct xdr_stream")
      Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      53b1119a
  2. 12 Dec, 2021 14 commits
  3. 11 Dec, 2021 25 commits