[Qemu-devel] [PATCH] hw/pci-host/bonito: Avoid buffer overrun for bad LDMA/COP accesses

[Peter Maydell <peter.maydell@linaro.org>]

The LDMA and COP memory regions represent four 32 bit registers
each, but the memory regions themselves are 0x100 bytes large.
Add guards to the read and write accessors so that bogus accesses
beyond the four defined registers don't just run off the end of
the bonldma and boncop structs and into whatever lies beyond.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I don't have a fulong2e image, so this is compile tested only...

 hw/pci-host/bonito.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/hw/pci-host/bonito.c b/hw/pci-host/bonito.c
index 3a731fe..4139a2c 100644
--- a/hw/pci-host/bonito.c
+++ b/hw/pci-host/bonito.c
@@ -355,6 +355,10 @@ static uint64_t bonito_ldma_readl(void *opaque, hwaddr addr,
     uint32_t val;
     PCIBonitoState *s = opaque;
 
+    if (addr >= sizeof(s->bonldma)) {
+        return 0;
+    }
+
     val = ((uint32_t *)(&s->bonldma))[addr/sizeof(uint32_t)];
 
     return val;
@@ -365,6 +369,10 @@ static void bonito_ldma_writel(void *opaque, hwaddr addr,
 {
     PCIBonitoState *s = opaque;
 
+    if (addr >= sizeof(s->bonldma)) {
+        return;
+    }
+
     ((uint32_t *)(&s->bonldma))[addr/sizeof(uint32_t)] = val & 0xffffffff;
 }
 
@@ -384,6 +392,10 @@ static uint64_t bonito_cop_readl(void *opaque, hwaddr addr,
     uint32_t val;
     PCIBonitoState *s = opaque;
 
+    if (addr >= sizeof(s->boncop)) {
+        return 0;
+    }
+
     val = ((uint32_t *)(&s->boncop))[addr/sizeof(uint32_t)];
 
     return val;
@@ -394,6 +406,10 @@ static void bonito_cop_writel(void *opaque, hwaddr addr,
 {
     PCIBonitoState *s = opaque;
 
+    if (addr >= sizeof(s->boncop)) {
+        return;
+    }
+
     ((uint32_t *)(&s->boncop))[addr/sizeof(uint32_t)] = val & 0xffffffff;
 }
 
-- 
1.9.1