ANDROID: sdcardfs: Add default_normal option

The default_normal option causes mounts with the gid set to
AID_SDCARD_RW to have user specific gids, as in the normal case.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: I9619b8ac55f41415df943484dc8db1ea986cef6f
Bug: 64672411

diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index 5e919e2..c3763c5 100644 (file)
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -648,7 +648,7 @@ static int sdcardfs_permission(struct vfsmount *mnt, struct inode *inode, int ma
         */
        copy_attrs(&tmp, inode);
        tmp.i_uid = make_kuid(&init_user_ns, top->d_uid);
-       tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, top));
+       tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, inode->i_sb, top));
        tmp.i_mode = (inode->i_mode & S_IFMT)
                        | get_mode(mnt, SDCARDFS_I(inode), top);
        data_put(top);
@@ -727,7 +727,7 @@ static int sdcardfs_setattr(struct vfsmount *mnt, struct dentry *dentry, struct
         */
        copy_attrs(&tmp, inode);
        tmp.i_uid = make_kuid(&init_user_ns, top->d_uid);
-       tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, top));
+       tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, dentry->d_sb, top));
        tmp.i_mode = (inode->i_mode & S_IFMT)
                        | get_mode(mnt, SDCARDFS_I(inode), top);
        tmp.i_size = i_size_read(inode);
@@ -829,6 +829,7 @@ static int sdcardfs_fillattr(struct vfsmount *mnt,
 {
        struct sdcardfs_inode_info *info = SDCARDFS_I(inode);
        struct sdcardfs_inode_data *top = top_data_get(info);
+       struct super_block *sb = inode->i_sb;
 
        if (!top)
                return -EINVAL;
@@ -838,7 +839,7 @@ static int sdcardfs_fillattr(struct vfsmount *mnt,
        stat->mode = (inode->i_mode  & S_IFMT) | get_mode(mnt, info, top);
        stat->nlink = inode->i_nlink;
        stat->uid = make_kuid(&init_user_ns, top->d_uid);
-       stat->gid = make_kgid(&init_user_ns, get_gid(mnt, top));
+       stat->gid = make_kgid(&init_user_ns, get_gid(mnt, sb, top));
        stat->rdev = inode->i_rdev;
        stat->size = i_size_read(inode);
        stat->atime = inode->i_atime;

diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
index 0a2b516..ac27bb3 100644 (file)
--- a/fs/sdcardfs/main.c
+++ b/fs/sdcardfs/main.c
@@ -33,6 +33,7 @@ enum {
        Opt_userid,
        Opt_reserved_mb,
        Opt_gid_derivation,
+       Opt_default_normal,
        Opt_err,
 };
 
@@ -45,6 +46,7 @@ static const match_table_t sdcardfs_tokens = {
        {Opt_userid, "userid=%d"},
        {Opt_multiuser, "multiuser"},
        {Opt_gid_derivation, "derive_gid"},
+       {Opt_default_normal, "default_normal"},
        {Opt_reserved_mb, "reserved_mb=%u"},
        {Opt_err, NULL}
 };
@@ -68,6 +70,7 @@ static int parse_options(struct super_block *sb, char *options, int silent,
        opts->reserved_mb = 0;
        /* by default, gid derivation is off */
        opts->gid_derivation = false;
+       opts->default_normal = false;
 
        *debug = 0;
 
@@ -122,6 +125,9 @@ static int parse_options(struct super_block *sb, char *options, int silent,
                case Opt_gid_derivation:
                        opts->gid_derivation = true;
                        break;
+               case Opt_default_normal:
+                       opts->default_normal = true;
+                       break;
                /* unknown option */
                default:
                        if (!silent)
@@ -175,6 +181,7 @@ int parse_options_remount(struct super_block *sb, char *options, int silent,
                                return 0;
                        vfsopts->mask = option;
                        break;
+               case Opt_default_normal:
                case Opt_multiuser:
                case Opt_userid:
                case Opt_fsuid:

diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h
index d1d8bab..3da9fe9 100644 (file)
--- a/fs/sdcardfs/sdcardfs.h
+++ b/fs/sdcardfs/sdcardfs.h
@@ -220,6 +220,7 @@ struct sdcardfs_mount_options {
        userid_t fs_user_id;
        bool multiuser;
        bool gid_derivation;
+       bool default_normal;
        unsigned int reserved_mb;
 };
 
@@ -413,11 +414,13 @@ static inline void set_top(struct sdcardfs_inode_info *info,
 }
 
 static inline int get_gid(struct vfsmount *mnt,
+               struct super_block *sb,
                struct sdcardfs_inode_data *data)
 {
-       struct sdcardfs_vfsmount_options *opts = mnt->data;
+       struct sdcardfs_vfsmount_options *vfsopts = mnt->data;
+       struct sdcardfs_sb_info *sbi = SDCARDFS_SB(sb);
 
-       if (opts->gid == AID_SDCARD_RW)
+       if (vfsopts->gid == AID_SDCARD_RW && !sbi->options.default_normal)
                /* As an optimization, certain trusted system components only run
                 * as owner but operate across all users. Since we're now handing
                 * out the sdcard_rw GID only to trusted apps, we're okay relaxing
@@ -426,7 +429,7 @@ static inline int get_gid(struct vfsmount *mnt,
                 */
                return AID_SDCARD_RW;
        else
-               return multiuser_get_uid(data->userid, opts->gid);
+               return multiuser_get_uid(data->userid, vfsopts->gid);
 }
 
 static inline int get_mode(struct vfsmount *mnt,

diff --git a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c
index b89947d..87d6f83 100644 (file)
--- a/fs/sdcardfs/super.c
+++ b/fs/sdcardfs/super.c
@@ -304,6 +304,8 @@ static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m,
                seq_printf(m, ",userid=%u", opts->fs_user_id);
        if (opts->gid_derivation)
                seq_puts(m, ",derive_gid");
+       if (opts->default_normal)
+               seq_puts(m, ",default_normal");
        if (opts->reserved_mb != 0)
                seq_printf(m, ",reserved=%uMB", opts->reserved_mb);