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| author | Pierre-Clément Tosi <ptosi@google.com> | 2023-10-10 10:28:22 +0100 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2023-10-11 11:37:24 +1100 |
| commit | 2283dd78eff5b37a092988e04fd873b040ad27c6 (patch) | |
| tree | 0246a9725024705edf5989eb7235c9e6043a5b31 | |
| parent | 79b9e326a162b15ca5758ee214e350f4f7c038fe (diff) | |
| download | dtc-2283dd78eff5b37a092988e04fd873b040ad27c6.tar.gz | |
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>
| -rw-r--r-- | libfdt/fdt_ro.c | 3 | ||||
| -rw-r--r-- | tests/path_offset.c | 8 |
2 files changed, 10 insertions, 1 deletions
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index 9fe2f49..b78c4e4 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -255,6 +255,9 @@ int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen) 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 8e657af..ad8db83 100644 --- a/tests/path_offset.c +++ b/tests/path_offset.c @@ -48,10 +48,13 @@ static void check_path_offset(void *fdt, const char *path, int offset) 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 @@ int main(int argc, char *argv[]) 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 @@ int main(int argc, char *argv[]) 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); |