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libcutils: fs_config() add check /vendor/etc/fs_config_*

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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
This commit is contained in:
Mark Salyzyn 2017-03-20 08:15:40 -07:00
parent a45eae93f6
commit 9ceadcb0c4
1 changed files with 30 additions and 15 deletions
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45
libcutils/fs_config.c
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@ -110,8 +110,20 @@ static const struct fs_path_config android_dirs[] = {
** 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 @@ static const struct fs_path_config android_files[] = {
{ 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 @@ static const struct fs_path_config android_files[] = {
{ 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 @@ static const struct fs_path_config android_files[] = {
/* 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 @@ static int fs_config_open(int dir, const char* target_out_path) {
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 @@ static bool fs_config_cmp(bool dir, const char* prefix, size_t len, const char*
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 @@ void fs_config(const char* path, int dir, const char* target_out_path, unsigned*
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)) {