It is currently possible to use a different configuration's signature and thus bypass the configuration check. Make sure that the configuration node that was hashed matches the one being checked, to catch this problem.
Also add a proper function comment to fit_config_check_sig() and make it static.
Signed-off-by: Simon Glass sjg@chromium.org ---
Changes in v2: None
common/image-sig.c | 36 +++++++++++++++++++++++++++++++++--- 1 file changed, 33 insertions(+), 3 deletions(-)
diff --git a/common/image-sig.c b/common/image-sig.c index 13ccd50bc5..03143a4040 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -359,20 +359,39 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, return 0; }
-int fit_config_check_sig(const void *fit, int noffset, int required_keynode, - char **err_msgp) +/** + * fit_config_check_sig() - Check the signature of a config + * + * @fit: FIT to check + * @noffset: Offset of configuration node (e.g. /configurations/conf-1) + * @required_keynode: Offset in the control FDT of the required key node, + * if any. If this is given, then the configuration wil not + * pass verification unless that key is used. If this is + * -1 then any signature will do. + * @conf_noffset: Offset of the configuration subnode being checked (e.g. + * /configurations/conf-1/kernel) + * @err_msgp: In the event of an error, this will be pointed to a + * help error string to display to the user. + * @return 0 if all verified ok, <0 on error + */ +static int fit_config_check_sig(const void *fit, int noffset, + int required_keynode, int conf_noffset, + char **err_msgp) { char * const exc_prop[] = {"data"}; const char *prop, *end, *name; struct image_sign_info info; const uint32_t *strings; + const char *config_name; uint8_t *fit_value; int fit_value_len; + bool found_config; int max_regions; int i, prop_len; char path[200]; int count;
+ config_name = fit_get_name(fit, conf_noffset, NULL); debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(), fit_get_name(fit, noffset, NULL), fit_get_name(gd_fdt_blob(), required_keynode, NULL)); @@ -413,9 +432,20 @@ int fit_config_check_sig(const void *fit, int noffset, int required_keynode, char *node_inc[count];
debug("Hash nodes (%d):\n", count); + found_config = false; for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) { debug(" '%s'\n", name); node_inc[i] = (char *)name; + if (!strncmp(FIT_CONFS_PATH, name, strlen(FIT_CONFS_PATH)) && + name[sizeof(FIT_CONFS_PATH) - 1] == '/' && + !strcmp(name + sizeof(FIT_CONFS_PATH), config_name)) { + debug(" (found config node %s)", config_name); + found_config = true; + } + } + if (!found_config) { + *err_msgp = "Selected config not in hashed nodes"; + return -1; }
/* @@ -483,7 +513,7 @@ static int fit_config_verify_sig(const void *fit, int conf_noffset, if (!strncmp(name, FIT_SIG_NODENAME, strlen(FIT_SIG_NODENAME))) { ret = fit_config_check_sig(fit, noffset, sig_offset, - &err_msg); + conf_noffset, &err_msg); if (ret) { puts("- "); } else {