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    Subject[PATCH v3 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot
    Date
    This adds PR_{GET,SET}_NO_NEW_PRIVS.  As an example of its use, it
    allows some unshare operations and (sometimes) chroot when no_new_privs
    is set. Another example is the experimental pam module here:

    http://web.mit.edu/luto/www/linux/

    After some impressively long mailing list threads, I still think that
    blocking setresuid, setuid, and capset in no_new_privs mode is
    unnecessary and overcomplicated. Additionally, blocking those calls
    will make my pam module either fail or become a giant security hole
    (depending on how carefully the core pam stuff is written -- I haven't
    checked).

    Changes from v2:
    - Rebased onto a very recent -linus tree.
    - Changed prctl numbering. (Needed because prctl 35 is now taken.)
    - Fixed a typo or two.
    - Removed explicit propagation of no_new_privs. dup_task_struct is enough.
    - Reworked the chroot patch. It now uses hopefully much more sane logic
    to decide whether the user is chrooted. It also checks that fs is not
    shared (which was a big security hole in the earlier version).

    For the git-inclined, this series is here:
    https://git.kernel.org/?p=linux/kernel/git/luto/linux.git;a=shortlog;h=refs/heads/security/no_new_privs/patch_v3

    Test it like this:

    ---- begin test case

    #include <sys/prctl.h>
    #include <stdio.h>
    #include <unistd.h>
    #include <errno.h>

    #define PR_SET_NO_NEW_PRIVS 36
    #define PR_GET_NO_NEW_PRIVS 37

    int main()
    {
    int nnp = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
    if (nnp == -EINVAL) {
    printf("Failed!\n");
    return 1;
    }

    printf("nnp was %d\n", nnp);

    if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) != 0) {
    printf("Failed!\n");
    return 1;
    }

    nnp = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
    if (nnp == -EINVAL) {
    printf("Failed!\n");
    return 1;
    }

    printf("nnp is %d\n", nnp);

    printf("here goes...\n");
    execlp("bash", "bash", NULL);
    printf("Failed to exec bash\n");
    return 1;
    }

    ---- end test case

    Andy Lutomirski (3):
    Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs
    Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs
    Allow unprivileged chroot when safe

    John Johansen (1):
    Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS

    fs/exec.c | 10 ++++++++-
    fs/open.c | 46 ++++++++++++++++++++++++++++++++++++++++++-
    include/linux/prctl.h | 15 ++++++++++++++
    include/linux/sched.h | 2 +
    include/linux/security.h | 1 +
    kernel/nsproxy.c | 8 ++++++-
    kernel/sys.c | 10 +++++++++
    security/apparmor/domain.c | 35 +++++++++++++++++++++++++++++++++
    security/commoncap.c | 7 ++++-
    security/selinux/hooks.c | 10 ++++++++-
    10 files changed, 137 insertions(+), 7 deletions(-)

    --
    1.7.7.6



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