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IB/nes: Return an error on ib_copy_from_udata() failure instead of NULL

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In case of error while accessing to userspace memory, function
nes_create_qp() returns NULL instead of an error code wrapped through
ERR_PTR().  But NULL is not expected by ib_uverbs_create_qp(), as it
check for error with IS_ERR().

As page 0 is likely not mapped, it is going to trigger an Oops when
the kernel will try to dereference NULL pointer to access to struct
ib_qp's fields.

In some rare cases, page 0 could be mapped by userspace, which could
turn this bug to a vulnerability that could be exploited: the function
pointers in struct ib_device will be under userspace total control.

This was caught when using spatch (aka. coccinelle)
to rewrite calls to ib_copy_{from,to}_udata().

Link: https://www.gitorious.org/opteya/ib-hw-nes-create-qp-null
Link: 75ebf2c103:ib_copy_udata.cocci
Link: http://marc.info/?i=cover.1394485254.git.ydroneaud@opteya.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Yann Droneaud 2014-03-10 23:06:27 +01:00 committed by Roland Dreier
parent 06064a103f
commit 9d194d1025
1 changed files with 1 additions and 1 deletions
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2
drivers/infiniband/hw/nes/nes_verbs.c
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@ -1186,7 +1186,7 @@ static struct ib_qp *nes_create_qp(struct ib_pd *ibpd,
nes_free_resource(nesadapter, nesadapter->allocated_qps, qp_num);
kfree(nesqp->allocated_buffer);
nes_debug(NES_DBG_QP, "ib_copy_from_udata() Failed \n");
return NULL;
return ERR_PTR(-EFAULT);
}
if (req.user_wqe_buffers) {
virt_wqs = 1;