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    Subject[PATCH 3.16 281/328] pstore/ram: Fix failure-path memory leak in ramoops_init
    3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Kees Cook <keescook@chromium.org>

    commit bac6f6cda206ad7cbe0c73c35e494377ce9c4749 upstream.

    As reported by nixiaoming, with some minor clarifications:

    1) memory leak in ramoops_register_dummy():
    dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
    but no kfree() if platform_device_register_data() fails.

    2) memory leak in ramoops_init():
    Missing platform_device_unregister(dummy) and kfree(dummy_data)
    if platform_driver_register(&ramoops_driver) fails.

    I've clarified the purpose of ramoops_register_dummy(), and added a
    common cleanup routine for all three failure paths to call.

    Reported-by: nixiaoming <nixiaoming@huawei.com>
    Cc: Anton Vorontsov <anton@enomsg.org>
    Cc: Colin Cross <ccross@android.com>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Joel Fernandes <joelaf@google.com>
    Cc: Geliang Tang <geliangtang@gmail.com>
    Signed-off-by: Kees Cook <keescook@chromium.org>
    [bwh: Backported to 3.16: adjust context]
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    fs/pstore/ram.c | 29 +++++++++++++++++++++++++----
    1 file changed, 25 insertions(+), 4 deletions(-)

    --- a/fs/pstore/ram.c
    +++ b/fs/pstore/ram.c
    @@ -557,8 +557,22 @@ static struct platform_driver ramoops_dr
    },
    };

    -static void ramoops_register_dummy(void)
    +static inline void ramoops_unregister_dummy(void)
    {
    + platform_device_unregister(dummy);
    + dummy = NULL;
    +
    + kfree(dummy_data);
    + dummy_data = NULL;
    +}
    +
    +static void __init ramoops_register_dummy(void)
    +{
    + /*
    + * Prepare a dummy platform data structure to carry the module
    + * parameters. If mem_size isn't set, then there are no module
    + * parameters, and we can skip this.
    + */
    if (!mem_size)
    return;

    @@ -588,21 +602,28 @@ static void ramoops_register_dummy(void)
    if (IS_ERR(dummy)) {
    pr_info("could not create platform device: %ld\n",
    PTR_ERR(dummy));
    + dummy = NULL;
    + ramoops_unregister_dummy();
    }
    }

    static int __init ramoops_init(void)
    {
    + int ret;
    +
    ramoops_register_dummy();
    - return platform_driver_register(&ramoops_driver);
    + ret = platform_driver_register(&ramoops_driver);
    + if (ret != 0)
    + ramoops_unregister_dummy();
    +
    + return ret;
    }
    postcore_initcall(ramoops_init);

    static void __exit ramoops_exit(void)
    {
    platform_driver_unregister(&ramoops_driver);
    - platform_device_unregister(dummy);
    - kfree(dummy_data);
    + ramoops_unregister_dummy();
    }
    module_exit(ramoops_exit);

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