File hw-pvrdma-number-of-page-table-entries-t.patch of Package qemu.42056

From: Yuval Shaia <yuval.shaia.ml@gmail.com>
Date: Wed, 1 Mar 2023 16:29:26 +0200
Subject: hw/pvrdma: number of page table entries the driver must not exceed
 the table size (bsc#1209554, CVE-2023-1544)

Guest driver allocates and initialize page tables to be used as a ring
of descriptors for CQ and async events.
The page table that represents the ring, along with the number of pages
in the page table is passed to the device.
Currently our device supports only one page table for a ring.

Let's make sure that the number of page table entries the driver
reports, do not exceeds the one page table size.

Reported-by: Soul Chen <soulchen8650@gmail.com>
Signed-off-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
Fixes: CVE-2023-1544
Message-ID: <20230301142926.18686-1-yuval.shaia.ml@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 85fc35afa93c7320d1641d344d0c5dfbe341d087)
References: bsc#1209554 (CVE-2023-1544)
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
---
 hw/rdma/vmw/pvrdma_main.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
index e31d223897d8902394b95877cb41..67b51147e0478c437335ed4bf441 100644
--- a/hw/rdma/vmw/pvrdma_main.c
+++ b/hw/rdma/vmw/pvrdma_main.c
@@ -89,19 +89,33 @@ static int init_dev_ring(PvrdmaRing *ring, struct pvrdma_ring **ring_state,
                          dma_addr_t dir_addr, uint32_t num_pages)
 {
     uint64_t *dir, *tbl;
-    int rc = 0;
+    int max_pages, rc = 0;
 
     if (!num_pages) {
         rdma_error_report("Ring pages count must be strictly positive");
         return -EINVAL;
     }
 
+    /*
+     * Make sure we can satisfy the requested number of pages in a single
+     * TARGET_PAGE_SIZE sized page table (taking into account that first entry
+     * is reserved for ring-state)
+     */
+    max_pages = TARGET_PAGE_SIZE / sizeof(dma_addr_t) - 1;
+    if (num_pages > max_pages) {
+        rdma_error_report("Maximum pages on a single directory must not exceed %d\n",
+                          max_pages);
+        return -EINVAL;
+    }
+
     dir = rdma_pci_dma_map(pci_dev, dir_addr, TARGET_PAGE_SIZE);
     if (!dir) {
         rdma_error_report("Failed to map to page directory (ring %s)", name);
         rc = -ENOMEM;
         goto out;
     }
+
+    /* We support only one page table for a ring */
     tbl = rdma_pci_dma_map(pci_dev, dir[0], TARGET_PAGE_SIZE);
     if (!tbl) {
         rdma_error_report("Failed to map to page table (ring %s)", name);