[Qemu-devel] [PULL 33/36] ppc/spapr: Fix buffer overflow in spapr_populate_drconf_memory()

[David Gibson]

From: Thomas Huth <address@hidden>

The buffer that is allocated in spapr_populate_drconf_memory()
is used for setting both, the "ibm,dynamic-memory" and the
"ibm,associativity-lookup-arrays" property. However, only the
size of the first one is taken into account when allocating the
memory. So if the length of the second property is larger than
the length of the first one, we run into a buffer overflow here!
Fix it by taking the length of the second property into account,
too.

Fixes: "spapr: Support ibm,dynamic-reconfiguration-memory" patch
Signed-off-by: Thomas Huth <address@hidden>
Reviewed-by: David Gibson <address@hidden>
Signed-off-by: David Gibson <address@hidden>
---
 hw/ppc/spapr.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 59fc814..1333375 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -725,9 +725,12 @@ static int spapr_populate_drconf_memory(sPAPRMachineState 
*spapr, void *fdt)
     uint32_t *int_buf, *cur_index, buf_len;
     int nr_nodes = nb_numa_nodes ? nb_numa_nodes : 1;
 
-    /* Allocate enough buffer size to fit in ibm,dynamic-memory */
-    buf_len = nr_lmbs * SPAPR_DR_LMB_LIST_ENTRY_SIZE * sizeof(uint32_t) +
-                sizeof(uint32_t);
+    /*
+     * Allocate enough buffer size to fit in ibm,dynamic-memory
+     * or ibm,associativity-lookup-arrays
+     */
+    buf_len = MAX(nr_lmbs * SPAPR_DR_LMB_LIST_ENTRY_SIZE + 1, nr_nodes * 4 + 2)
+              * sizeof(uint32_t);
     cur_index = int_buf = g_malloc0(buf_len);
 
     offset = fdt_add_subnode(fdt, 0, "ibm,dynamic-reconfiguration-memory");
-- 
2.4.3