diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index abfede9483a3..e248948db9cf 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -167,10 +167,13 @@ struct fuse_release_args; /** * Reference to lower filesystem file for read/write operations handled in - * passthrough mode + * passthrough mode. + * This struct also tracks the credentials to be used for handling read/write + * operations. */ struct fuse_passthrough { struct file *filp; + struct cred *cred; }; /** FUSE specific file data */ diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c index 4ae0ed0ac4ea..401d3e33f880 100644 --- a/fs/fuse/passthrough.c +++ b/fs/fuse/passthrough.c @@ -64,6 +64,7 @@ ssize_t fuse_passthrough_read_iter(struct kiocb *iocb_fuse, struct iov_iter *iter) { ssize_t ret; + const struct cred *old_cred; struct file *fuse_filp = iocb_fuse->ki_filp; struct fuse_file *ff = fuse_filp->private_data; struct file *passthrough_filp = ff->passthrough.filp; @@ -71,6 +72,7 @@ ssize_t fuse_passthrough_read_iter(struct kiocb *iocb_fuse, if (!iov_iter_count(iter)) return 0; + old_cred = override_creds(ff->passthrough.cred); if (is_sync_kiocb(iocb_fuse)) { ret = vfs_iter_read(passthrough_filp, iter, &iocb_fuse->ki_pos, iocb_to_rw_flags(iocb_fuse->ki_flags, @@ -89,6 +91,7 @@ ssize_t fuse_passthrough_read_iter(struct kiocb *iocb_fuse, if (ret != -EIOCBQUEUED) fuse_aio_cleanup_handler(aio_req); } + revert_creds(old_cred); return ret; } @@ -97,6 +100,7 @@ ssize_t fuse_passthrough_write_iter(struct kiocb *iocb_fuse, struct iov_iter *iter) { ssize_t ret; + const struct cred *old_cred; struct file *fuse_filp = iocb_fuse->ki_filp; struct fuse_file *ff = fuse_filp->private_data; struct inode *fuse_inode = file_inode(fuse_filp); @@ -108,6 +112,7 @@ ssize_t fuse_passthrough_write_iter(struct kiocb *iocb_fuse, inode_lock(fuse_inode); + old_cred = override_creds(ff->passthrough.cred); if (is_sync_kiocb(iocb_fuse)) { file_start_write(passthrough_filp); ret = vfs_iter_write(passthrough_filp, iter, &iocb_fuse->ki_pos, @@ -136,6 +141,7 @@ ssize_t fuse_passthrough_write_iter(struct kiocb *iocb_fuse, fuse_aio_cleanup_handler(aio_req); } out: + revert_creds(old_cred); inode_unlock(fuse_inode); return ret; @@ -186,6 +192,7 @@ int fuse_passthrough_open(struct fuse_dev *fud, } passthrough->filp = passthrough_filp; + passthrough->cred = prepare_creds(); idr_preload(GFP_KERNEL); spin_lock(&fc->passthrough_req_lock); @@ -237,4 +244,8 @@ void fuse_passthrough_release(struct fuse_passthrough *passthrough) fput(passthrough->filp); passthrough->filp = NULL; } + if (passthrough->cred) { + put_cred(passthrough->cred); + passthrough->cred = NULL; + } }