From d845c96128a40ca5802c0840ae190fa0af7d4735 Mon Sep 17 00:00:00 2001 From: Narayan Kamath Date: Thu, 4 Jun 2015 13:20:27 +0100 Subject: Add an installd command to link files Given a pair of absolute paths {from_path, to_path} , check that they are both valid apk subpaths (eg. /data/app/package/foo) and link(2) to_path to from_path. This is required by staged installs, where we link existing apks and oat files to their staging location. bug: 20889739 Change-Id: I3b5e3b43677af68be59308121a4409caaa6a72f0 --- cmds/installd/commands.cpp | 25 +++++++++++++++++++++++++ cmds/installd/installd.cpp | 9 ++++++++- cmds/installd/installd.h | 2 ++ cmds/installd/utils.cpp | 24 ++++++++++++++++-------- 4 files changed, 51 insertions(+), 9 deletions(-) (limited to 'cmds') diff --git a/cmds/installd/commands.cpp b/cmds/installd/commands.cpp index 99da968..ebd71a0 100644 --- a/cmds/installd/commands.cpp +++ b/cmds/installd/commands.cpp @@ -1778,6 +1778,31 @@ int rm_package_dir(const char* apk_path) return delete_dir_contents(apk_path, 1 /* also_delete_dir */ , NULL /* exclusion_predicate */); } +int link_file(const char* relative_path, const char* from_base, const char* to_base) { + char from_path[PKG_PATH_MAX]; + char to_path[PKG_PATH_MAX]; + snprintf(from_path, PKG_PATH_MAX, "%s/%s", from_base, relative_path); + snprintf(to_path, PKG_PATH_MAX, "%s/%s", to_base, relative_path); + + if (validate_apk_path_subdirs(from_path)) { + ALOGE("invalid app data sub-path '%s' (bad prefix)\n", from_path); + return -1; + } + + if (validate_apk_path_subdirs(to_path)) { + ALOGE("invalid app data sub-path '%s' (bad prefix)\n", to_path); + return -1; + } + + const int ret = link(from_path, to_path); + if (ret < 0) { + ALOGE("link(%s, %s) failed : %s", from_path, to_path, strerror(errno)); + return -1; + } + + return 0; +} + int calculate_oat_file_path(char path[PKG_PATH_MAX], const char *oat_dir, const char *apk_path, const char *instruction_set) { char *file_name_start; diff --git a/cmds/installd/installd.cpp b/cmds/installd/installd.cpp index 01e7cdd..297b3a1 100644 --- a/cmds/installd/installd.cpp +++ b/cmds/installd/installd.cpp @@ -179,6 +179,12 @@ static int do_rm_package_dir(char **arg, char reply[REPLY_MAX] __unused) return rm_package_dir(arg[0]); } +static int do_link_file(char **arg, char reply[REPLY_MAX] __unused) +{ + /* relative_path, from_base, to_base */ + return link_file(arg[0], arg[1], arg[2]); +} + struct cmdinfo { const char *name; unsigned numargs; @@ -209,7 +215,8 @@ struct cmdinfo cmds[] = { { "idmap", 3, do_idmap }, { "restorecondata", 4, do_restorecon_data }, { "createoatdir", 2, do_create_oat_dir }, - { "rmpackagedir", 1, do_rm_package_dir}, + { "rmpackagedir", 1, do_rm_package_dir }, + { "linkfile", 3, do_link_file } }; static int readx(int s, void *_buf, int count) diff --git a/cmds/installd/installd.h b/cmds/installd/installd.h index ce6c857..744ed3a 100644 --- a/cmds/installd/installd.h +++ b/cmds/installd/installd.h @@ -203,6 +203,7 @@ int get_path_from_string(dir_rec_t* rec, const char* path); int copy_and_append(dir_rec_t* dst, const dir_rec_t* src, const char* suffix); int validate_apk_path(const char *path); +int validate_apk_path_subdirs(const char *path); int append_and_increment(char** dst, const char* src, size_t* dst_size); @@ -254,3 +255,4 @@ int calculate_oat_file_path(char path[PKG_PATH_MAX], const char *oat_dir, const const char *instruction_set); int move_package_dir(char path[PKG_PATH_MAX], const char *oat_dir, const char *apk_path, const char *instruction_set); +int link_file(const char *relative_path, const char *from_base, const char *to_base); diff --git a/cmds/installd/utils.cpp b/cmds/installd/utils.cpp index 3f679a2..7db3fb9 100644 --- a/cmds/installd/utils.cpp +++ b/cmds/installd/utils.cpp @@ -1043,15 +1043,13 @@ int copy_and_append(dir_rec_t* dst, const dir_rec_t* src, const char* suffix) { } /** - * Check whether path points to a valid path for an APK file. Only one level of - * subdirectory names is allowed. Returns -1 when an invalid path is encountered - * and 0 when a valid path is encountered. + * Check whether path points to a valid path for an APK file. The path must + * begin with a whitelisted prefix path and must be no deeper than |maxSubdirs| within + * that path. Returns -1 when an invalid path is encountered and 0 when a valid path + * is encountered. */ -int validate_apk_path(const char *path) -{ +static int validate_apk_path_internal(const char *path, int maxSubdirs) { const dir_rec_t* dir = NULL; - int maxSubdirs = 1; - if (!strncmp(path, android_app_dir.path, android_app_dir.len)) { dir = &android_app_dir; } else if (!strncmp(path, android_app_private_dir.path, android_app_private_dir.len)) { @@ -1060,7 +1058,9 @@ int validate_apk_path(const char *path) dir = &android_asec_dir; } else if (!strncmp(path, android_mnt_expand_dir.path, android_mnt_expand_dir.len)) { dir = &android_mnt_expand_dir; - maxSubdirs = 2; + if (maxSubdirs < 2) { + maxSubdirs = 2; + } } else { return -1; } @@ -1068,6 +1068,14 @@ int validate_apk_path(const char *path) return validate_path(dir, path, maxSubdirs); } +int validate_apk_path(const char* path) { + return validate_apk_path_internal(path, 1 /* maxSubdirs */); +} + +int validate_apk_path_subdirs(const char* path) { + return validate_apk_path_internal(path, 3 /* maxSubdirs */); +} + int append_and_increment(char** dst, const char* src, size_t* dst_size) { ssize_t ret = strlcpy(*dst, src, *dst_size); if (ret < 0 || (size_t) ret >= *dst_size) { -- cgit v1.1