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    SubjectRe: [PATCH] ksys_mount: check for permissions before resource allocation
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    Date
    Just CC’ed to some of maintainers.

    $ perl scripts/get_maintainer.pl fs/0001-ksys_mount-check-for-permissions-before-resource-all.patch
    Alexander Viro <viro@zeniv.linux.org.uk> (maintainer:FILESYSTEMS (VFS and infrastructure))
    linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure))
    linux-kernel@vger.kernel.org (open list)

    > On Jun 5, 2018, at 6:00 AM, Ilya Matveychikov <matvejchikov@gmail.com> wrote:
    >
    > Early check for mount permissions prevents possible allocation of 3
    > pages from kmalloc() pool by unpriveledged user which can be used for
    > spraying the kernel heap.
    >
    > Signed-off-by: Ilya V. Matveychikov <matvejchikov@gmail.com>
    > ---
    > fs/namespace.c | 3 +++
    > 1 file changed, 3 insertions(+)
    >
    > diff --git a/fs/namespace.c b/fs/namespace.c
    > index 5f75969adff1..1ef8feb2de2a 100644
    > --- a/fs/namespace.c
    > +++ b/fs/namespace.c
    > @@ -3046,6 +3046,9 @@ int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
    > char *kernel_dev;
    > void *options;
    >
    > + if (!may_mount())
    > + return -EPERM;
    > +
    > kernel_type = copy_mount_string(type);
    > ret = PTR_ERR(kernel_type);
    > if (IS_ERR(kernel_type))
    > --
    > 2.17.0
    >

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