| From | Luis Henriques <> | Subject | [PATCH 3.11 062/182] IB/nes: Return an error on ib_copy_from_udata() failure instead of NULL | Date | Thu, 24 Apr 2014 09:49:47 +0100 |
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3.11.10.9 -stable review patch. If anyone has any objections, please let me know.
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From: Yann Droneaud <ydroneaud@opteya.com>
commit 9d194d1025f463392feafa26ff8c2d8247f71be1 upstream.
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: https://www.gitorious.org/opteya/coccib/source/75ebf2c1033c64c1d81df13e4ae44ee99c989eba:ib_copy_udata.cocci Link: http://marc.info/?i=cover.1394485254.git.ydroneaud@opteya.com Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/infiniband/hw/nes/nes_verbs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c index 5b53ca5..09999cd 100644 --- a/drivers/infiniband/hw/nes/nes_verbs.c +++ b/drivers/infiniband/hw/nes/nes_verbs.c @@ -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; -- 1.9.1
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