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Commit 9ceadcb0 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

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
parent a45eae93

libcutils/fs_config.c

+30 −15
Original line number Diff line number Diff line
@@ -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)) {