diff options
Diffstat (limited to 'libfdt/fdt_ro.c')
| -rw-r--r-- | libfdt/fdt_ro.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index 87d736b..a62ec78 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -10,6 +10,14 @@ #include "libfdt_internal.h" +/* Check if a buffer contains a nul-terminated string. + * Used for checking property values which should be strings. + */ +static bool is_nul_string(const char *buf, const size_t buf_len) { + return buf_len > 0 && buf[buf_len - 1] == '\0' && + strnlen(buf, buf_len) == buf_len - 1; +} + static int fdt_nodename_eq_(const void *fdt, int offset, const char *s, int len) { @@ -531,13 +539,27 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset) const char *fdt_get_alias_namelen(const void *fdt, const char *name, int namelen) { + const char *prop; int aliasoffset; + int prop_len; aliasoffset = fdt_path_offset(fdt, "/aliases"); if (aliasoffset < 0) return NULL; - return fdt_getprop_namelen(fdt, aliasoffset, name, namelen, NULL); + prop = fdt_getprop_namelen(fdt, aliasoffset, name, namelen, &prop_len); + if (prop && !can_assume(VALID_INPUT)) { + /* Validate the alias value. From the devicetree spec v0.3: + * "An alias value is a device path and is encoded as a string. + * The value representes the full path to a node, ..." + * A full path must start at the root to prevent recursion. + */ + if (prop_len == 0 || *prop != '/' || !is_nul_string(prop, prop_len)) { + prop = NULL; + } + } + + return prop; } const char *fdt_get_alias(const void *fdt, const char *name) |