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    Subject[38/68] KEYS: Fix bug in keyctl_session_to_parent() if parent has no session keyring
    2.6.32-stable review patch.  If anyone has any objections, please let us know.


    From: David Howells <>

    commit 3d96406c7da1ed5811ea52a3b0905f4f0e295376 upstream.

    Fix a bug in keyctl_session_to_parent() whereby it tries to check the ownership
    of the parent process's session keyring whether or not the parent has a session
    keyring [CVE-2010-2960].

    This results in the following oops:

    BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
    IP: [<ffffffff811ae4dd>] keyctl_session_to_parent+0x251/0x443
    Call Trace:
    [<ffffffff811ae2f3>] ? keyctl_session_to_parent+0x67/0x443
    [<ffffffff8109d286>] ? __do_fault+0x24b/0x3d0
    [<ffffffff811af98c>] sys_keyctl+0xb4/0xb8
    [<ffffffff81001eab>] system_call_fastpath+0x16/0x1b

    if the parent process has no session keyring.

    If the system is using pam_keyinit then it mostly protected against this as all
    processes derived from a login will have inherited the session keyring created
    by pam_keyinit during the log in procedure.

    To test this, pam_keyinit calls need to be commented out in /etc/pam.d/.

    Reported-by: Tavis Ormandy <>
    Signed-off-by: David Howells <>
    Acked-by: Tavis Ormandy <>
    Cc: dann frazier <>
    Signed-off-by: Linus Torvalds <>
    Signed-off-by: Greg Kroah-Hartman <>

    security/keys/keyctl.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- a/security/keys/keyctl.c
    +++ b/security/keys/keyctl.c
    @@ -1292,7 +1292,8 @@ long keyctl_session_to_parent(void)
    goto not_permitted;

    /* the keyrings must have the same UID */
    - if (pcred ->tgcred->session_keyring->uid != mycred->euid ||
    + if ((pcred->tgcred->session_keyring &&
    + pcred->tgcred->session_keyring->uid != mycred->euid) ||
    mycred->tgcred->session_keyring->uid != mycred->euid)
    goto not_permitted;

     \ /
      Last update: 2010-09-27 20:09    [W:0.028 / U:36.972 seconds]
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