libcutils: fs_config() add check /vendor/etc/fs_config_*
Add reading of vendor file-system config files
/vendor/etc/fs_config_dirs and /vendor/etc/fs_config_files.
Order of interpretation (for dirs and files respectively):
- /system/etc/fs_config_dirs or /system/etc/fs_config_files
- /vendor/etc/fs_config_dirs or /vendor/etc/fs_config_files
- internal android_dirs[] or android_files[] structures.
No restrictions are placed on the vendor file-system config files,
although the developer is advised to restrict the scope to the /vendor
file-system since the intent is to provide support only for
customized portions of vendor.img.
Test: full build and install smoke test and inspection
Bug: 36071012
Change-Id: I4077bd6afcda2ee16189b2eb3c322af15205bbb9
diff --git a/libcutils/fs_config.c b/libcutils/fs_config.c
index 696df26..7a2301d 100644
--- a/libcutils/fs_config.c
+++ b/libcutils/fs_config.c
@@ -110,8 +110,20 @@
** way up to the root. Prefixes ending in * denotes wildcard
** and will allow partial matches.
*/
-static const char conf_dir[] = "/system/etc/fs_config_dirs";
-static const char conf_file[] = "/system/etc/fs_config_files";
+static const char sys_conf_dir[] = "/system/etc/fs_config_dirs";
+static const char sys_conf_file[] = "/system/etc/fs_config_files";
+/* No restrictions are placed on the vendor file-system config files,
+ * although the developer is advised to restrict the scope to the /vendor
+ * file-system since the intent is to provide support for customized
+ * portions of a separate vendor.img. Has to remain open so that
+ * customization can also land on /system/vendor. We expect build-time
+ * checking or filtering when constructing /vendor/etc/fs_config_* files.
+ */
+static const char ven_conf_dir[] = "/vendor/etc/fs_config_dirs";
+static const char ven_conf_file[] = "/vendor/etc/fs_config_files";
+static const char* conf[][2] = {
+ {sys_conf_file, sys_conf_dir}, {ven_conf_file, ven_conf_dir},
+};
static const struct fs_path_config android_files[] = {
/* clang-format off */
@@ -135,8 +147,8 @@
{ 00700, AID_ROOT, AID_ROOT, 0, "system/bin/secilc" },
{ 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" },
{ 00600, AID_ROOT, AID_ROOT, 0, "system/build.prop" },
- { 00444, AID_ROOT, AID_ROOT, 0, conf_dir + 1 },
- { 00444, AID_ROOT, AID_ROOT, 0, conf_file + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, sys_conf_dir + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, sys_conf_file + 1 },
{ 00440, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.rc" },
{ 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.sh" },
{ 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.ril" },
@@ -145,6 +157,8 @@
{ 00440, AID_ROOT, AID_ROOT, 0, "system/etc/recovery.img" },
{ 00600, AID_ROOT, AID_ROOT, 0, "vendor/build.prop" },
{ 00600, AID_ROOT, AID_ROOT, 0, "vendor/default.prop" },
+ { 00444, AID_ROOT, AID_ROOT, 0, ven_conf_dir + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, ven_conf_file + 1 },
/* the following two files are INTENTIONALLY set-uid, but they
* are NOT included on user builds. */
@@ -209,7 +223,7 @@
/* clang-format on */
};
-static int fs_config_open(int dir, const char* target_out_path) {
+static int fs_config_open(int dir, int which, const char* target_out_path) {
int fd = -1;
if (target_out_path && *target_out_path) {
@@ -223,13 +237,13 @@
if (target_out_path[target_out_path_len] == '/') {
skip_len++;
}
- if (asprintf(&name, "%s%s", target_out_path, (dir ? conf_dir : conf_file) + skip_len) != -1) {
+ if (asprintf(&name, "%s%s", target_out_path, conf[which][dir] + skip_len) != -1) {
fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_BINARY));
free(name);
}
}
if (fd < 0) {
- fd = TEMP_FAILURE_RETRY(open(dir ? conf_dir : conf_file, O_RDONLY | O_BINARY));
+ fd = TEMP_FAILURE_RETRY(open(conf[which][dir], O_RDONLY | O_BINARY));
}
return fd;
}
@@ -254,8 +268,7 @@
void fs_config(const char* path, int dir, const char* target_out_path, unsigned* uid, unsigned* gid,
unsigned* mode, uint64_t* capabilities) {
const struct fs_path_config* pc;
- size_t plen;
- int fd;
+ size_t which, plen;
if (path[0] == '/') {
path++;
@@ -263,32 +276,34 @@
plen = strlen(path);
- fd = fs_config_open(dir, target_out_path);
- if (fd >= 0) {
+ for (which = 0; which < (sizeof(conf) / sizeof(conf[0])); ++which) {
struct fs_path_config_from_file header;
+ int fd = fs_config_open(dir, which, target_out_path);
+ if (fd < 0) continue;
+
while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) {
char* prefix;
uint16_t host_len = get2LE((const uint8_t*)&header.len);
ssize_t len, remainder = host_len - sizeof(header);
if (remainder <= 0) {
- ALOGE("%s len is corrupted", dir ? conf_dir : conf_file);
+ ALOGE("%s len is corrupted", conf[which][dir]);
break;
}
prefix = calloc(1, remainder);
if (!prefix) {
- ALOGE("%s out of memory", dir ? conf_dir : conf_file);
+ ALOGE("%s out of memory", conf[which][dir]);
break;
}
if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) {
free(prefix);
- ALOGE("%s prefix is truncated", dir ? conf_dir : conf_file);
+ ALOGE("%s prefix is truncated", conf[which][dir]);
break;
}
len = strnlen(prefix, remainder);
if (len >= remainder) { /* missing a terminating null */
free(prefix);
- ALOGE("%s is corrupted", dir ? conf_dir : conf_file);
+ ALOGE("%s is corrupted", conf[which][dir]);
break;
}
if (fs_config_cmp(dir, prefix, len, path, plen)) {