[PATCH 5.4 061/203] RDMA/hns: Prevent undefined behavior in hns_roce_set_user_sq_size()

Greg Kroah-Hartman
2020-01-16T23:46:56Z

From: Jason Gunthorpe <jgg@mellanox.com>

commit 515f60004ed985d2b2f03659365752e0b6142986 upstream.

The "ucmd->log_sq_bb_count" variable is a user controlled variable in the
0-255 range. If we shift more than then number of bits in an int then
it's undefined behavior (it shift wraps), and potentially the int could
become negative.

Fixes: 9a4435375cd1 ("IB/hns: Add driver files for hns RoCE driver")
Link: https://lore.kernel.org/r/20190608092514.GC28890@mwanda
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/hw/hns/hns_roce_qp.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/hw/hns/hns_roce_qp.c
+++ b/drivers/infiniband/hw/hns/hns_roce_qp.c
@@ -332,9 +332,8 @@ static int check_sq_size_with_integrity(
u8 max_sq_stride = ilog2(roundup_sq_stride);

/* Sanity check SQ size before proceeding */
- if ((u32)(1 << ucmd->log_sq_bb_count) > hr_dev->caps.max_wqes ||
- ucmd->log_sq_stride > max_sq_stride ||
- ucmd->log_sq_stride < HNS_ROCE_IB_MIN_SQ_STRIDE) {
+ if (ucmd->log_sq_stride > max_sq_stride ||
+ ucmd->log_sq_stride < HNS_ROCE_IB_MIN_SQ_STRIDE) {
ibdev_err(&hr_dev->ib_dev, "check SQ size error!\n");
return -EINVAL;
}
@@ -358,13 +357,16 @@ static int hns_roce_set_user_sq_size(str
u32 max_cnt;
int ret;

+ if (check_shl_overflow(1, ucmd->log_sq_bb_count, &hr_qp->sq.wqe_cnt) ||
+ hr_qp->sq.wqe_cnt > hr_dev->caps.max_wqes)
+ return -EINVAL;
+
ret = check_sq_size_with_integrity(hr_dev, cap, ucmd);
if (ret) {
ibdev_err(&hr_dev->ib_dev, "Sanity check sq size failed\n");
return ret;
}

- hr_qp->sq.wqe_cnt = 1 << ucmd->log_sq_bb_count;
hr_qp->sq.wqe_shift = ucmd->log_sq_stride;

max_cnt = max(1U, cap->max_send_sge);