tequilaOS/platform_system_core
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Use Minijail for privilege dropping.

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Having so many copies of privilege-dropping code leads to errors.
De-duplicate this code and use Minijail for it.

Bug: 30156807

Change-Id: I36c85962b913a12efe5648a23cbacc5bcbb3853c
This commit is contained in:
Jorge Lucangeli Obes 2016-07-14 14:50:14 -04:00
parent a17427cb1e
commit c96f53e2fe
2 changed files with 15 additions and 11 deletions
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2
sdcard/Android.mk
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@ -5,7 +5,7 @@ include $(CLEAR_VARS)
LOCAL_SRC_FILES := sdcard.cpp fuse.cpp
LOCAL_MODULE := sdcard
LOCAL_CFLAGS := -Wall -Wno-unused-parameter -Werror
LOCAL_SHARED_LIBRARIES := libbase liblog libcutils libpackagelistparser
LOCAL_SHARED_LIBRARIES := libbase liblog libcutils libminijail libpackagelistparser
LOCAL_SANITIZE := integer
LOCAL_CLANG := true

24
sdcard/sdcard.cpp
View file

@ -36,6 +36,9 @@
#include <cutils/multiuser.h>
#include <packagelistparser/packagelistparser.h>
#include <libminijail.h>
#include <scoped_minijail.h>
#include <private/android_filesystem_config.h>
// README
@ -204,6 +207,15 @@ static int fuse_setup(struct fuse* fuse, gid_t gid, mode_t mask) {
return 0;
}
static void drop_privs(uid_t uid, gid_t gid) {
ScopedMinijail j(minijail_new());
minijail_set_supplementary_gids(j.get(), sizeof(kGroups) / sizeof(kGroups[0]), kGroups);
minijail_change_gid(j.get(), gid);
minijail_change_uid(j.get(), uid);
/* minijail_enter() will abort if priv-dropping fails. */
minijail_enter(j.get());
}
static void* start_handler(void* data) {
struct fuse_handler* handler = static_cast<fuse_handler*>(data);
handle_fuse_requests(handler);
@ -299,16 +311,8 @@ static void run(const char* source_path, const char* label, uid_t uid,
}
}
/* Drop privs. */
if (setgroups(sizeof(kGroups) / sizeof(kGroups[0]), kGroups) < 0) {
PLOG(FATAL) << "cannot setgroups";
}
if (setgid(gid) < 0) {
PLOG(FATAL) << "cannot setgid";
}
if (setuid(uid) < 0) {
PLOG(FATAL) << "cannot setuid";
}
// Will abort if priv-dropping fails.
drop_privs(uid, gid);
if (multi_user) {
fs_prepare_dir(global.obb_path, 0775, uid, gid);