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    Subject[PATCH 3.18 064/185] kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE
    Date
    3.18-stable review patch.  If anyone has any objections, please let me know.

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

    From: David Rientjes <rientjes@google.com>

    [ Upstream commit 88913bd8ea2a75d7e460a4bed5f75e1c32660d7e ]

    chan->n_subbufs is set by the user and relay_create_buf() does a kmalloc()
    of chan->n_subbufs * sizeof(size_t *).

    kmalloc_slab() will generate a warning when this fails if
    chan->subbufs * sizeof(size_t *) > KMALLOC_MAX_SIZE.

    Limit chan->n_subbufs to the maximum allowed kmalloc() size.

    Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802061216100.122576@chino.kir.corp.google.com
    Fixes: f6302f1bcd75 ("relay: prevent integer overflow in relay_open()")
    Signed-off-by: David Rientjes <rientjes@google.com>
    Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
    Cc: Jens Axboe <axboe@kernel.dk>
    Cc: Dave Jiang <dave.jiang@intel.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Dan Carpenter <dan.carpenter@oracle.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    kernel/relay.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/kernel/relay.c
    +++ b/kernel/relay.c
    @@ -166,7 +166,7 @@ static struct rchan_buf *relay_create_bu
    {
    struct rchan_buf *buf;

    - if (chan->n_subbufs > UINT_MAX / sizeof(size_t *))
    + if (chan->n_subbufs > KMALLOC_MAX_SIZE / sizeof(size_t *))
    return NULL;

    buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);

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