From 980ab18fbdf279a9771286b3ef6c997ed11def7a Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Thu, 6 Jul 2017 19:12:22 -0700 Subject: [PATCH] ANDROID: sdcardfs: override credential for ioctl to lower fs Otherwise, lower_fs->ioctl() fails due to inode_owner_or_capable(). Signed-off-by: Jaegeuk Kim Bug: 63260873 Change-Id: I623a6c7c5f8a3cbd7ec73ef89e18ddb093c43805 --- fs/sdcardfs/file.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/sdcardfs/file.c b/fs/sdcardfs/file.c index 6076c342dae6..5ac0b0bbb0ec 100644 --- a/fs/sdcardfs/file.c +++ b/fs/sdcardfs/file.c @@ -104,12 +104,19 @@ static long sdcardfs_unlocked_ioctl(struct file *file, unsigned int cmd, { long err = -ENOTTY; struct file *lower_file; + const struct cred *saved_cred = NULL; + struct dentry *dentry = file->f_path.dentry; + struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb); lower_file = sdcardfs_lower_file(file); /* XXX: use vfs_ioctl if/when VFS exports it */ if (!lower_file || !lower_file->f_op) goto out; + + /* save current_cred and override it */ + OVERRIDE_CRED(sbi, saved_cred, SDCARDFS_I(file_inode(file))); + if (lower_file->f_op->unlocked_ioctl) err = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg); @@ -117,6 +124,7 @@ static long sdcardfs_unlocked_ioctl(struct file *file, unsigned int cmd, if (!err) sdcardfs_copy_and_fix_attrs(file_inode(file), file_inode(lower_file)); + REVERT_CRED(saved_cred); out: return err; } @@ -127,15 +135,23 @@ static long sdcardfs_compat_ioctl(struct file *file, unsigned int cmd, { long err = -ENOTTY; struct file *lower_file; + const struct cred *saved_cred = NULL; + struct dentry *dentry = file->f_path.dentry; + struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb); lower_file = sdcardfs_lower_file(file); /* XXX: use vfs_ioctl if/when VFS exports it */ if (!lower_file || !lower_file->f_op) goto out; + + /* save current_cred and override it */ + OVERRIDE_CRED(sbi, saved_cred, SDCARDFS_I(file_inode(file))); + if (lower_file->f_op->compat_ioctl) err = lower_file->f_op->compat_ioctl(lower_file, cmd, arg); + REVERT_CRED(saved_cred); out: return err; }