ANDROID: Sdcardfs: Move gid derivation under flag

This moves the code to adjust the gid/uid of lower filesystem
files under the mount flag derive_gid.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: I44eaad4ef67c7fcfda3b6ea3502afab94442610c
Bug: 63245673

diff --git a/fs/sdcardfs/derived_perm.c b/fs/sdcardfs/derived_perm.c
index 1239d1c..fffaad4 100644 (file)
--- a/fs/sdcardfs/derived_perm.c
+++ b/fs/sdcardfs/derived_perm.c
@@ -176,6 +176,9 @@ void fixup_lower_ownership(struct dentry *dentry, const char *name)
        gid_t gid = sbi->options.fs_low_gid;
        struct iattr newattrs;
 
+       if (!sbi->options.gid_derivation)
+               return;
+
        info = SDCARDFS_I(d_inode(dentry));
        info_d = info->data;
        perm = info_d->perm;

diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index 70a4e3c..5e919e2 100644 (file)
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -34,10 +34,14 @@ const struct cred *override_fsids(struct sdcardfs_sb_info *sbi,
        if (!cred)
                return NULL;
 
-       if (data->under_obb)
-               uid = AID_MEDIA_OBB;
-       else
-               uid = multiuser_get_uid(data->userid, sbi->options.fs_low_uid);
+       if (sbi->options.gid_derivation) {
+               if (data->under_obb)
+                       uid = AID_MEDIA_OBB;
+               else
+                       uid = multiuser_get_uid(data->userid, sbi->options.fs_low_uid);
+       } else {
+               uid = 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);
 

diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
index 80825b2..0a2b516 100644 (file)
--- a/fs/sdcardfs/main.c
+++ b/fs/sdcardfs/main.c
@@ -32,6 +32,7 @@ enum {
        Opt_multiuser,
        Opt_userid,
        Opt_reserved_mb,
+       Opt_gid_derivation,
        Opt_err,
 };
 
@@ -43,6 +44,7 @@ static const match_table_t sdcardfs_tokens = {
        {Opt_mask, "mask=%u"},
        {Opt_userid, "userid=%d"},
        {Opt_multiuser, "multiuser"},
+       {Opt_gid_derivation, "derive_gid"},
        {Opt_reserved_mb, "reserved_mb=%u"},
        {Opt_err, NULL}
 };
@@ -64,6 +66,8 @@ static int parse_options(struct super_block *sb, char *options, int silent,
        vfsopts->gid = 0;
        /* by default, 0MB is reserved */
        opts->reserved_mb = 0;
+       /* by default, gid derivation is off */
+       opts->gid_derivation = false;
 
        *debug = 0;
 
@@ -115,6 +119,9 @@ static int parse_options(struct super_block *sb, char *options, int silent,
                                return 0;
                        opts->reserved_mb = option;
                        break;
+               case Opt_gid_derivation:
+                       opts->gid_derivation = true;
+                       break;
                /* unknown option */
                default:
                        if (!silent)

diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h
index 4e0ce49..d1d8bab 100644 (file)
--- a/fs/sdcardfs/sdcardfs.h
+++ b/fs/sdcardfs/sdcardfs.h
@@ -219,6 +219,7 @@ struct sdcardfs_mount_options {
        gid_t fs_low_gid;
        userid_t fs_user_id;
        bool multiuser;
+       bool gid_derivation;
        unsigned int reserved_mb;
 };
 

diff --git a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c
index 7f4539b..b89947d 100644 (file)
--- a/fs/sdcardfs/super.c
+++ b/fs/sdcardfs/super.c
@@ -302,6 +302,8 @@ static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m,
                seq_printf(m, ",mask=%u", vfsopts->mask);
        if (opts->fs_user_id)
                seq_printf(m, ",userid=%u", opts->fs_user_id);
+       if (opts->gid_derivation)
+               seq_puts(m, ",derive_gid");
        if (opts->reserved_mb != 0)
                seq_printf(m, ",reserved=%uMB", opts->reserved_mb);