ANDROID: sdcardfs: Add GID Derivation to sdcardfs
This changes sdcardfs to modify the user and group in the
underlying filesystem depending on its usage. Ownership is
set by Android user, and package, as well as if the file is
under obb or cache. Other files can be labeled by extension.
Those values are set via the configfs interace.
To add an entry,
mkdir -p [configfs root]/sdcardfs/extensions/[gid]/[ext]
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 34262585
Change-Id: I4e030ce84f094a678376349b1a96923e5076a0f4
diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index 08965ac..c55505a 100644
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -22,16 +22,21 @@
#include <linux/fs_struct.h>
/* Do not directly use this function. Use OVERRIDE_CRED() instead. */
-const struct cred * override_fsids(struct sdcardfs_sb_info* sbi)
+const struct cred *override_fsids(struct sdcardfs_sb_info *sbi, struct sdcardfs_inode_info *info)
{
- struct cred * cred;
- const struct cred * old_cred;
+ struct cred *cred;
+ const struct cred *old_cred;
+ uid_t uid;
cred = prepare_creds();
if (!cred)
return NULL;
- cred->fsuid = make_kuid(&init_user_ns, sbi->options.fs_low_uid);
+ if (info->under_obb)
+ uid = AID_MEDIA_OBB;
+ else
+ uid = multiuser_get_uid(info->userid, sbi->options.fs_low_uid);
+ cred->fsuid = make_kuid(&init_user_ns, uid);
cred->fsgid = make_kgid(&init_user_ns, sbi->options.fs_low_gid);
old_cred = override_creds(cred);
@@ -40,9 +45,9 @@
}
/* Do not directly use this function, use REVERT_CRED() instead. */
-void revert_fsids(const struct cred * old_cred)
+void revert_fsids(const struct cred *old_cred)
{
- const struct cred * cur_cred;
+ const struct cred *cur_cred;
cur_cred = current->cred;
revert_creds(old_cred);
@@ -70,7 +75,7 @@
}
/* save current_cred and override it */
- OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
@@ -98,6 +103,7 @@
goto out;
fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
+ fixup_lower_ownership(dentry, dentry->d_name.name);
out:
current->fs = saved_fs;
@@ -171,7 +177,7 @@
}
/* save current_cred and override it */
- OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
@@ -279,7 +285,7 @@
}
/* save current_cred and override it */
- OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
/* check disk space */
if (!check_min_free_space(dentry, 0, 1)) {
@@ -343,9 +349,8 @@
fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
/* update number of links on parent directory */
set_nlink(dir, sdcardfs_lower_inode(dir)->i_nlink);
-
+ fixup_lower_ownership(dentry, dentry->d_name.name);
unlock_dir(lower_parent_dentry);
-
if ((!sbi->options.multiuser) && (!strcasecmp(dentry->d_name.name, "obb"))
&& (pi->perm == PERM_ANDROID) && (pi->userid == 0))
make_nomedia_in_obb = 1;
@@ -353,6 +358,8 @@
/* When creating /Android/data and /Android/obb, mark them as .nomedia */
if (make_nomedia_in_obb ||
((pi->perm == PERM_ANDROID) && (!strcasecmp(dentry->d_name.name, "data")))) {
+ REVERT_CRED(saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(d_inode(dentry)));
set_fs_pwd(current->fs, &lower_path);
touch_err = touch(".nomedia", 0664);
if (touch_err) {
@@ -390,7 +397,7 @@
}
/* save current_cred and override it */
- OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
/* sdcardfs_get_real_lower(): in case of remove an user's obb dentry
* the dentry on the original path should be deleted. */
@@ -483,7 +490,7 @@
}
/* save current_cred and override it */
- OVERRIDE_CRED(SDCARDFS_SB(old_dir->i_sb), saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(old_dir->i_sb), saved_cred, SDCARDFS_I(new_dir));
sdcardfs_get_real_lower(old_dentry, &lower_old_path);
sdcardfs_get_lower_path(new_dentry, &lower_new_path);
@@ -520,11 +527,10 @@
sdcardfs_copy_and_fix_attrs(old_dir, d_inode(lower_old_dir_dentry));
fsstack_copy_inode_size(old_dir, d_inode(lower_old_dir_dentry));
}
- /* At this point, not all dentry information has been moved, so
- * we pass along new_dentry for the name.*/
- get_derived_permission_new(new_dentry->d_parent, old_dentry, new_dentry);
+ get_derived_permission_new(new_dentry->d_parent, old_dentry, new_dentry->d_name.name);
fixup_tmp_permissions(d_inode(old_dentry));
- fixup_top_recursive(old_dentry);
+ fixup_lower_ownership(old_dentry, new_dentry->d_name.name);
+ drop_recursive(old_dentry); /* Can't fixup ownership recursively :( */
out:
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
dput(lower_old_dir_dentry);
@@ -756,7 +762,7 @@
goto out_err;
/* save current_cred and override it */
- OVERRIDE_CRED(SDCARDFS_SB(dentry->d_sb), saved_cred);
+ OVERRIDE_CRED(SDCARDFS_SB(dentry->d_sb), saved_cred, SDCARDFS_I(inode));
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;