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    SubjectRe: [PATCH] proc: fix null pointer deref in proc_pid_permission()
    Hi,

    On Wed, Jan 11, 2012 at 01:47:05PM -0500, Xiaotian Feng wrote:
    > get_proc_task() can fail to search the task and return NULL, put_task_struct()
    > will then bomb the kernel with following oops:
    >
    > [ 1870.574045] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
    > [ 1870.574065] IP: [<ffffffff81217d34>] proc_pid_permission+0x64/0xe0
    > [ 1870.574088] PGD 112075067 PUD 112814067 PMD 0
    > [ 1870.574106] Oops: 0002 [#1] PREEMPT SMP
    >
    > This is a regression introduced by commit 0499680a, kernel should
    > return -ESRCH if get_proc_task() failed.

    Nice catch!

    However since this error is returned to userspace, shouldn't this be
    -ENOENT instead?

    -Kees

    --
    Kees Cook
    ChromeOS Security


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