Merge "Give secondary users read-only physical cards." into mnc-dev (d57125af) · Commits · e / os / android_system_core

sdcard/sdcard.c

+46 −25

Original line number	Diff line number	Diff line
		@@ -151,7 +151,7 @@ struct node {
		perm_t perm;
		userid_t userid;
		uid_t uid;
		mode_t mode;
		bool under_android;

		struct node next; / per-dir sibling list */
		struct node child; / first contained file by this dir */
		@@ -419,11 +419,20 @@ static void attr_from_stat(struct fuse* fuse, struct fuse_attr *attr,
		attr->gid = multiuser_get_uid(node->userid, fuse->gid);
		}

		/* Filter requested mode based on underlying file, and
		* pass through file type. */
		int visible_mode = node->mode;
		if (node->perm != PERM_PRE_ROOT) {
		visible_mode = visible_mode & ~fuse->mask;
		int visible_mode = 0775 & ~fuse->mask;
		if (node->perm == PERM_PRE_ROOT) {
		/* Top of multi-user view should always be visible to ensure
		* secondary users can traverse inside. */
		visible_mode = 0711;
		} else if (node->under_android) {
		/* Block "other" access to Android directories, since only apps
		* belonging to a specific user should be in there; we still
		* leave +x open for the default view. */
		if (fuse->gid == AID_SDCARD_RW) {
		visible_mode = visible_mode & ~0006;
		} else {
		visible_mode = visible_mode & ~0007;
		}
		}
		int owner_mode = s->st_mode & 0700;
		int filtered_mode = visible_mode & (owner_mode \| (owner_mode >> 3) \| (owner_mode >> 6));
		@@ -452,7 +461,7 @@ static void derive_permissions_locked(struct fuse* fuse, struct node *parent,
		node->perm = PERM_INHERIT;
		node->userid = parent->userid;
		node->uid = parent->uid;
		node->mode = parent->mode;
		node->under_android = parent->under_android;

		/* Derive custom permissions based on parent and current node */
		switch (parent->perm) {
		@@ -463,33 +472,28 @@ static void derive_permissions_locked(struct fuse* fuse, struct node *parent,
		/* Legacy internal layout places users at top level */
		node->perm = PERM_ROOT;
		node->userid = strtoul(node->name, NULL, 10);
		node->mode = 0771;
		break;
		case PERM_ROOT:
		/* Assume masked off by default. */
		node->mode = 0770;
		if (!strcasecmp(node->name, "Android")) {
		/* App-specific directories inside; let anyone traverse */
		node->perm = PERM_ANDROID;
		node->mode = 0771;
		node->under_android = true;
		}
		break;
		case PERM_ANDROID:
		if (!strcasecmp(node->name, "data")) {
		/* App-specific directories inside; let anyone traverse */
		node->perm = PERM_ANDROID_DATA;
		node->mode = 0771;
		} else if (!strcasecmp(node->name, "obb")) {
		/* App-specific directories inside; let anyone traverse */
		node->perm = PERM_ANDROID_OBB;
		node->mode = 0771;
		/* Single OBB directory is always shared */
		node->graft_path = fuse->global->obb_path;
		node->graft_pathlen = strlen(fuse->global->obb_path);
		} else if (!strcasecmp(node->name, "media")) {
		/* App-specific directories inside; let anyone traverse */
		node->perm = PERM_ANDROID_MEDIA;
		node->mode = 0771;
		}
		break;
		case PERM_ANDROID_DATA:
		@@ -499,7 +503,6 @@ static void derive_permissions_locked(struct fuse* fuse, struct node *parent,
		if (appid != 0) {
		node->uid = multiuser_get_uid(parent->userid, appid);
		}
		node->mode = 0770;
		break;
		}
		}
		@@ -1730,6 +1733,7 @@ static int usage() {
		ERROR("usage: sdcard [OPTIONS] <source_path> <label>\n"
		" -u: specify UID to run as\n"
		" -g: specify GID to run as\n"
		" -U: specify user ID that owns device\n"
		" -m: source_path is multi-user\n"
		" -w: runtime_write mount has full write access\n"
		"\n");
		@@ -1763,7 +1767,7 @@ static int fuse_setup(struct fuse* fuse, gid_t gid, mode_t mask) {
		}

		static void run(const char* source_path, const char* label, uid_t uid,
		gid_t gid, bool multi_user, bool full_write) {
		gid_t gid, userid_t userid, bool multi_user, bool full_write) {
		struct fuse_global global;
		struct fuse fuse_default;
		struct fuse fuse_read;
		@@ -1796,18 +1800,17 @@ static void run(const char* source_path, const char* label, uid_t uid,
		global.root.refcount = 2;
		global.root.namelen = strlen(source_path);
		global.root.name = strdup(source_path);
		global.root.userid = 0;
		global.root.userid = userid;
		global.root.uid = AID_ROOT;
		global.root.under_android = false;

		strcpy(global.source_path, source_path);

		if (multi_user) {
		global.root.perm = PERM_PRE_ROOT;
		global.root.mode = 0711;
		snprintf(global.obb_path, sizeof(global.obb_path), "%s/obb", source_path);
		} else {
		global.root.perm = PERM_ROOT;
		global.root.mode = 0771;
		snprintf(global.obb_path, sizeof(global.obb_path), "%s/Android/obb", source_path);
		}

		@@ -1833,12 +1836,26 @@ static void run(const char* source_path, const char* label, uid_t uid,

		umask(0);

		if (multi_user) {
		/* Multi-user storage is fully isolated per user, so "other"
		* permissions are completely masked off. */
		if (fuse_setup(&fuse_default, AID_SDCARD_RW, 0006)
		\|\| fuse_setup(&fuse_read, AID_EVERYBODY, 0027)
		\|\| fuse_setup(&fuse_write, AID_EVERYBODY, full_write ? 0007 : 0027)) {
		ERROR("failed to fuse_setup\n");
		exit(1);
		}
		} else {
		/* Physical storage is readable by all users on device, but
		* the Android directories are masked off to a single user
		* deep inside attr_from_stat(). */
		if (fuse_setup(&fuse_default, AID_SDCARD_RW, 0006)
		\|\| fuse_setup(&fuse_read, AID_EVERYBODY, full_write ? 0027 : 0022)
		\|\| fuse_setup(&fuse_write, AID_EVERYBODY, full_write ? 0007 : 0022)) {
		ERROR("failed to fuse_setup\n");
		exit(1);
		}
		}

		/* Drop privs */
		if (setgroups(sizeof(kGroups) / sizeof(kGroups[0]), kGroups) < 0) {
		@@ -1875,6 +1892,7 @@ int main(int argc, char **argv) {
		const char *label = NULL;
		uid_t uid = 0;
		gid_t gid = 0;
		userid_t userid = 0;
		bool multi_user = false;
		bool full_write = false;
		int i;
		@@ -1882,7 +1900,7 @@ int main(int argc, char **argv) {
		int fs_version;

		int opt;
		while ((opt = getopt(argc, argv, "u:g:mw")) != -1) {
		while ((opt = getopt(argc, argv, "u:g:U:mw")) != -1) {
		switch (opt) {
		case 'u':
		uid = strtoul(optarg, NULL, 10);
		@@ -1890,6 +1908,9 @@ int main(int argc, char **argv) {
		case 'g':
		gid = strtoul(optarg, NULL, 10);
		break;
		case 'U':
		userid = strtoul(optarg, NULL, 10);
		break;
		case 'm':
		multi_user = true;
		break;
		@@ -1938,6 +1959,6 @@ int main(int argc, char **argv) {
		sleep(1);
		}

		run(source_path, label, uid, gid, multi_user, full_write);
		run(source_path, label, uid, gid, userid, multi_user, full_write);
		return 1;
		}