[Xen-devel] [PATCH v7 05/25] xen/arm: check for multiboot nodes only under /chosen

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Make sure to only look for multiboot compatible nodes only under
/chosen, not under any other paths (depth <= 3).

Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>

---

Changes in v7:
- set path size to 92, treat -FDT_ERR_NOSPACE as erro

Changes in v6:
- do not proceed if fdt_get_path returns error != -FDT_ERR_NOSPACE
- remove sizeof, use hardcoded value

Changes in v5:
- add patch
- add check on return value of fdt_get_path
---
 xen/arch/arm/bootfdt.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 8eba42c..b1d226f 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -173,7 +173,15 @@ static void __init process_multiboot_node(const void *fdt, 
int node,
     bootmodule_kind kind;
     paddr_t start, size;
     const char *cmdline;
-    int len;
+    /* sizeof("/chosen/") + DT_MAX_NAME + '/' + DT_MAX_NAME + '/0' => 92 */
+    int len = 92;
+    char path[92];
+    int ret;
+
+    /* Check that the node is under "/chosen" (first 7 chars of path) */
+    ret = fdt_get_path(fdt, node, path, len);
+    if ( ret != 0 || strncmp(path, "/chosen", 7) )
+        return;
 
     prop = fdt_get_property(fdt, node, "reg", &len);
     if ( !prop )
@@ -286,8 +294,8 @@ static int __init early_scan_node(const void *fdt,
 {
     if ( device_tree_node_matches(fdt, node, "memory") )
         process_memory_node(fdt, node, name, address_cells, size_cells);
-    else if ( device_tree_node_compatible(fdt, node, "xen,multiboot-module" ) 
||
-              device_tree_node_compatible(fdt, node, "multiboot,module" ))
+    else if ( depth <= 3 && (device_tree_node_compatible(fdt, node, 
"xen,multiboot-module" ) ||
+              device_tree_node_compatible(fdt, node, "multiboot,module" )))
         process_multiboot_node(fdt, node, name, address_cells, size_cells);
     else if ( depth == 1 && device_tree_node_matches(fdt, node, "chosen") )
         process_chosen_node(fdt, node, name, address_cells, size_cells);
-- 
1.9.1


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