diff options
| author | Daniel Rosenberg <drosen@google.com> | 2017-04-24 16:11:03 -0700 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2017-04-27 12:33:08 +0200 |
| commit | 2cba78f1f68b8a486348cb49a620cd8c73804874 (patch) | |
| tree | 9af8dc91ee679325c53c432c8ed5775236cad4ff | |
| parent | 5fa8257e7d1c7755f8e10e01e438b5d5cf4b330a (diff) | |
ANDROID: sdcardfs: Avoid setting GIDs outside of valid ranges
When setting up the ownership of files on the lower filesystem,
ensure that these values are in reasonable ranges for apps. If
they aren't, default to AID_MEDIA_RW
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 37516160
Change-Id: I0bec76a61ac72aff0b993ab1ad04be8382178a00
| -rwxr-xr-x | fs/sdcardfs/derived_perm.c | 8 | ||||
| -rwxr-xr-x | fs/sdcardfs/multiuser.h | 7 |
2 files changed, 11 insertions, 4 deletions
diff --git a/fs/sdcardfs/derived_perm.c b/fs/sdcardfs/derived_perm.c index 7d6eb9ff8..41e3a7ab5 100755 --- a/fs/sdcardfs/derived_perm.c +++ b/fs/sdcardfs/derived_perm.c @@ -214,16 +214,16 @@ void fixup_lower_ownership(struct dentry *dentry, const char *name) gid = AID_MEDIA_OBB; break; case PERM_ANDROID_PACKAGE: - if (info->d_uid != 0) + if (uid_is_app(info->d_uid)) gid = multiuser_get_ext_gid(info->d_uid); else - gid = multiuser_get_uid(info->userid, uid); + gid = multiuser_get_uid(info->userid, AID_MEDIA_RW); break; case PERM_ANDROID_PACKAGE_CACHE: - if (info->d_uid != 0) + if (uid_is_app(info->d_uid)) gid = multiuser_get_ext_cache_gid(info->d_uid); else - gid = multiuser_get_uid(info->userid, uid); + gid = multiuser_get_uid(info->userid, AID_MEDIA_RW); break; case PERM_PRE_ROOT: default: diff --git a/fs/sdcardfs/multiuser.h b/fs/sdcardfs/multiuser.h index d0c925cda..85341e753 100755 --- a/fs/sdcardfs/multiuser.h +++ b/fs/sdcardfs/multiuser.h @@ -35,6 +35,13 @@ static inline uid_t multiuser_get_uid(userid_t user_id, appid_t app_id) return (user_id * AID_USER_OFFSET) + (app_id % AID_USER_OFFSET); } +static inline bool uid_is_app(uid_t uid) +{ + appid_t appid = uid % AID_USER_OFFSET; + + return appid >= AID_APP_START && appid <= AID_APP_END; +} + static inline gid_t multiuser_get_ext_cache_gid(uid_t uid) { return uid - AID_APP_START + AID_EXT_CACHE_GID_START; |