lkml.org 
[lkml]   [2012]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[GIT] Bug fix for Yama
    Please pull this fix for a deadlock in the Yama LSM.

    The following changes since commit d9875690d9b89a866022ff49e3fcea892345ad92:
    Linus Torvalds (1):
    Linux 3.6-rc2

    are available in the git repository at:

    git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git for-linus

    Kees Cook (1):
    Yama: access task_struct->comm directly

    security/yama/yama_lsm.c | 10 ++--------
    1 file changed, 2 insertions(+), 8 deletions(-)
    commit 7612bfeecc197bbb6629842b5c6ff1967f0a9b70
    Author: Kees Cook <keescook@chromium.org>
    Date: Wed Aug 15 11:41:55 2012 -0700

    Yama: access task_struct->comm directly

    The core ptrace access checking routine holds a task lock, and when
    reporting a failure, Yama takes a separate task lock. To avoid a
    potential deadlock with two ptracers taking the opposite locks, do not
    use get_task_comm() and just use ->comm directly since accuracy is not
    important for the report.

    Reported-by: Fengguang Wu <fengguang.wu@intel.com>
    Suggested-by: Oleg Nesterov <oleg@redhat.com>
    CC: stable@vger.kernel.org
    Signed-off-by: Kees Cook <keescook@chromium.org>
    Acked-by: John Johansen <john.johansen@canonical.com>
    Signed-off-by: James Morris <james.l.morris@oracle.com>

    diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
    index d51b7c7..0cc99a3 100644
    --- a/security/yama/yama_lsm.c
    +++ b/security/yama/yama_lsm.c
    @@ -279,12 +279,9 @@ static int yama_ptrace_access_check(struct task_struct *child,
    }

    if (rc) {
    - char name[sizeof(current->comm)];
    printk_ratelimited(KERN_NOTICE
    "ptrace of pid %d was attempted by: %s (pid %d)\n",
    - child->pid,
    - get_task_comm(name, current),
    - current->pid);
    + child->pid, current->comm, current->pid);
    }

    return rc;
    @@ -319,12 +316,9 @@ static int yama_ptrace_traceme(struct task_struct *parent)
    }

    if (rc) {
    - char name[sizeof(current->comm)];
    printk_ratelimited(KERN_NOTICE
    "ptraceme of pid %d was attempted by: %s (pid %d)\n",
    - current->pid,
    - get_task_comm(name, parent),
    - parent->pid);
    + current->pid, parent->comm, parent->pid);
    }

    return rc;

    \
     
     \ /
      Last update: 2012-08-17 13:41    [from the cache]
    ©2003-2014 Jasper Spaans. hosted at Digital Ocean