[lkml]   [2012]   [Mar]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 0/9] proc: protect /proc/<pid>/* files across execve
    On Sat, Mar 10, 2012 at 3:25 PM, Djalal Harouni <> wrote:
    > 1) Use the target exec_id to bind files to their exec_id task:
    > For the REG files /proc/<pid>/{environ,pagemap,mem} we set the exec_id
    > of the proc_file_private to the target task, and we continue with
    > permission checks at open time, later on each read/write call the
    > permission checks are done + check the target exec_id if it equals the
    > exec_id of the proc_file_private that was set at open time, in other words
    > we bind the file to its task's exec_id, this way new exec programs can not
    > operate on the passed fd.

    So the exec_id approach was totally broken when it was used for
    /proc/<pid>/mem, is there any reason to believe it's a good idea now?

    It's entirely predictable, and you can make the exec_id match by
    simply forking elsewhere and then passing the fd around using unix
    domain sockets, since the exec_id is just updated by incrementing a

    I would in general suggest strongly against using exec_id for anything
    that involves files. It isn't designed for that, it's designed for the
    whole "check the parent exec_id" thing for ptrace, where that whole
    "pass things around to another process" approach doesn't work.


     \ /
      Last update: 2012-03-11 01:05    [W:0.020 / U:0.048 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site