CVE: CVE-2018-20216 Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=f1e2e38] Signed-off-by: Kai Kang From f1e2e38ee0136b7710a2caa347049818afd57a1b Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Thu, 13 Dec 2018 01:00:39 +0530 Subject: [PATCH] pvrdma: check return value from pvrdma_idx_ring_has_ routines pvrdma_idx_ring_has_[data/space] routines also return invalid index PVRDMA_INVALID_IDX[=-1], if ring has no data/space. Check return value from these routines to avoid plausible infinite loops. Reported-by: Li Qiang Signed-off-by: Prasad J Pandit Reviewed-by: Yuval Shaia Signed-off-by: Marcel Apfelbaum --- hw/rdma/vmw/pvrdma_dev_ring.c | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) diff --git a/hw/rdma/vmw/pvrdma_dev_ring.c b/hw/rdma/vmw/pvrdma_dev_ring.c index 01247fc041..e8e5b502f6 100644 --- a/hw/rdma/vmw/pvrdma_dev_ring.c +++ b/hw/rdma/vmw/pvrdma_dev_ring.c @@ -73,23 +73,16 @@ out: void *pvrdma_ring_next_elem_read(PvrdmaRing *ring) { + int e; unsigned int idx = 0, offset; - /* - pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail, - ring->ring_state->cons_head); - */ - - if (!pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx)) { + e = pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx); + if (e <= 0) { pr_dbg("No more data in ring\n"); return NULL; } offset = idx * ring->elem_sz; - /* - pr_dbg("idx=%d\n", idx); - pr_dbg("offset=%d\n", offset); - */ return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE); } @@ -105,20 +98,20 @@ void pvrdma_ring_read_inc(PvrdmaRing *ring) void *pvrdma_ring_next_elem_write(PvrdmaRing *ring) { - unsigned int idx, offset, tail; + int idx; + unsigned int offset, tail; - /* - pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail, - ring->ring_state->cons_head); - */ - - if (!pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail)) { + idx = pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail); + if (idx <= 0) { pr_dbg("CQ is full\n"); return NULL; } idx = pvrdma_idx(&ring->ring_state->prod_tail, ring->max_elems); - /* TODO: tail == idx */ + if (idx < 0 || tail != idx) { + pr_dbg("invalid idx\n"); + return NULL; + } offset = idx * ring->elem_sz; return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE); -- 2.20.1