FROMGIT: libfdt: fdt_path_offset_namelen: Reject empty path
Reject empty paths and negative lengths, according to the DT spec v0.4:
The convention for specifying a device path is:
/node-name-1/node-name-2/node-name-N
The path to the root node is /.
This prevents the access to path[0] from ever being out-of-bounds.
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Message-ID: <20231010092822.qo2nxc3g47t26dqs@google.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Test: N/A
Change-Id: I8efee39a06fa62f1f057a975e8133a295be0a656
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index 7912463..53db8ce 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -263,6 +263,9 @@
FDT_RO_PROBE(fdt);
+ if (!can_assume(VALID_INPUT) && namelen <= 0)
+ return -FDT_ERR_BADPATH;
+
/* see if we have an alias */
if (*path != '/') {
const char *q = memchr(path, '/', end - p);
diff --git a/tests/path_offset.c b/tests/path_offset.c
index 82527d4..07e9d65 100644
--- a/tests/path_offset.c
+++ b/tests/path_offset.c
@@ -48,10 +48,13 @@
verbose_printf("Checking offset of \"%s\" is %d...\n", path, offset);
rc = fdt_path_offset(fdt, path);
+ if (rc == offset)
+ return;
+
if (rc < 0)
FAIL("fdt_path_offset(\"%s\") failed: %s",
path, fdt_strerror(rc));
- if (rc != offset)
+ else
FAIL("fdt_path_offset(\"%s\") returned incorrect offset"
" %d instead of %d", path, rc, offset);
}
@@ -102,6 +105,7 @@
check_path_offset(fdt, "/subnode@2/subsubnode", subsubnode2_offset2);
/* Test paths with extraneous separators */
+ check_path_offset(fdt, "", -FDT_ERR_BADPATH);
check_path_offset(fdt, "//", 0);
check_path_offset(fdt, "///", 0);
check_path_offset(fdt, "//subnode@1", subnode1_offset);
@@ -110,6 +114,8 @@
check_path_offset(fdt, "/subnode@2////subsubnode", subsubnode2_offset2);
/* Test fdt_path_offset_namelen() */
+ check_path_offset_namelen(fdt, "/subnode@1", -1, -FDT_ERR_BADPATH);
+ check_path_offset_namelen(fdt, "/subnode@1", 0, -FDT_ERR_BADPATH);
check_path_offset_namelen(fdt, "/subnode@1", 1, 0);
check_path_offset_namelen(fdt, "/subnode@1/subsubnode", 10, subnode1_offset);
check_path_offset_namelen(fdt, "/subnode@1/subsubnode", 11, subnode1_offset);