File 0198-xhci-apply-limits-to-loops.patch of Package qemu-linux-user.6838

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File 0198-xhci-apply-limits-to-loops.patch of Package qemu-linux-user.6838

From d5f5cbf72396152324bf4565ffbbaecf469cae91 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Mon, 6 Feb 2017 13:21:09 +0100
Subject: [PATCH] xhci: apply limits to loops
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

Limits should be big enough that normal guest should not hit it.
Add a tracepoint to log them, just in case.  Also, while being
at it, log the existing link trb limit too.

Reported-by: 李强 <liqiang6-s@360.cn>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1486383669-6421-1-git-send-email-kraxel@redhat.com
(cherry picked from commit f89b60f6e5fee3923bedf80e82b4e5efc1bb156b)
[BR: BSC#1025109 CVE-2017-5973]
Signed-off-by: Bruce Rogers <brogers@suse.com>

Conflicts:
	hw/usb/hcd-xhci.c
	hw/usb/trace-events
---
 hw/usb/hcd-xhci.c | 15 ++++++++++++++-
 trace-events      |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 4e9dea52cf..74ae2dc313 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -54,6 +54,8 @@
 #define ER_FULL_HACK
 
 #define TRB_LINK_LIMIT  4
+#define COMMAND_LIMIT   256
+#define TRANSFER_LIMIT  256
 
 #define LEN_CAP         0x40
 #define LEN_OPER        (0x400 + 0x10 * MAXPORTS)
@@ -1029,6 +1031,7 @@ static TRBType xhci_ring_fetch(XHCIState *xhci, XHCIRing *ring, XHCITRB *trb,
             return type;
         } else {
             if (++link_cnt > TRB_LINK_LIMIT) {
+                trace_usb_xhci_enforced_limit("trb-link");
                 return 0;
             }
             ring->dequeue = xhci_mask64(trb->parameter);
@@ -2101,6 +2104,7 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid,
     XHCIRing *ring;
     USBEndpoint *ep = NULL;
     uint64_t mfindex;
+    unsigned int count = 0;
     int length;
     int i;
 
@@ -2238,6 +2242,10 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid,
             epctx->retry = xfer;
             break;
         }
+        if (count++ > TRANSFER_LIMIT) {
+            trace_usb_xhci_enforced_limit("transfers");
+            break;
+        }
     }
 
     ep = xhci_epid_to_usbep(xhci, slotid, epid);
@@ -2708,7 +2716,7 @@ static void xhci_process_commands(XHCIState *xhci)
     TRBType type;
     XHCIEvent event = {ER_COMMAND_COMPLETE, CC_SUCCESS};
     dma_addr_t addr;
-    unsigned int i, slotid = 0;
+    unsigned int i, slotid = 0, count = 0;
 
     DPRINTF("xhci_process_commands()\n");
     if (!xhci_running(xhci)) {
@@ -2822,6 +2830,11 @@ static void xhci_process_commands(XHCIState *xhci)
         }
         event.slotid = slotid;
         xhci_event(xhci, &event, 0);
+
+        if (count++ > COMMAND_LIMIT) {
+            trace_usb_xhci_enforced_limit("commands");
+            return;
+        }
     }
 }
 
diff --git a/trace-events b/trace-events
index 8350743878..9f3f2af0d8 100644
--- a/trace-events
+++ b/trace-events
@@ -489,6 +489,7 @@ usb_xhci_xfer_retry(void *xfer) "%p"
 usb_xhci_xfer_success(void *xfer, uint32_t bytes) "%p: len %d"
 usb_xhci_xfer_error(void *xfer, uint32_t ret) "%p: ret %d"
 usb_xhci_unimplemented(const char *item, int nr) "%s (0x%x)"
+usb_xhci_enforced_limit(const char *item) "%s"
 
 # hw/usb/desc.c
 usb_desc_device(int addr, int len, int ret) "dev %d query device, len %d, ret %d"

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File 0198-xhci-apply-limits-to-loops.patch of Package qemu-linux-user.6838

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