Commit 15d937d7 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: add request extension 



Will need to add supplementary groups to create messages, so add the
general concept of a request extension.  A request extension is appended to
the end of the main request.  It has a header indicating the size and type
of the extension.

The create security context (fuse_secctx_*) is similar to the generic
request extension, so include that as well in a backward compatible manner.

Add the total extension length to the request header.  The offset of the
extension block within the request can be calculated by:

  inh->len - inh->total_extlen * 8

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 1b929c02

fs/fuse/dev.c

+2 −0
Original line number Diff line number Diff line
@@ -476,6 +476,8 @@ static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args) 
	req->in.h.opcode = args->opcode;

	req->in.h.nodeid = args->nodeid;

	req->args = args;

	if (args->is_ext)

		req->in.h.total_extlen = args->in_args[args->ext_idx].size / 8;

	if (args->end)

		__set_bit(FR_ASYNC, &req->flags);

}

fs/fuse/dir.c

+38 −28
Original line number Diff line number Diff line
@@ -466,7 +466,7 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, 
}



static int get_security_context(struct dentry *entry, umode_t mode,

				void **security_ctx, u32 *security_ctxlen)

				struct fuse_in_arg *ext)

{

	struct fuse_secctx *fctx;

	struct fuse_secctx_header *header;
@@ -513,14 +513,42 @@ static int get_security_context(struct dentry *entry, umode_t mode, 


		memcpy(ptr, ctx, ctxlen);

	}

	*security_ctxlen = total_len;

	*security_ctx = header;

	ext->size = total_len;

	ext->value = header;

	err = 0;

out_err:

	kfree(ctx);

	return err;

}



static int get_create_ext(struct fuse_args *args, struct dentry *dentry,

			  umode_t mode)

{

	struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);

	struct fuse_in_arg ext = { .size = 0, .value = NULL };

	int err = 0;



	if (fc->init_security)

		err = get_security_context(dentry, mode, &ext);



	if (!err && ext.size) {

		WARN_ON(args->in_numargs >= ARRAY_SIZE(args->in_args));

		args->is_ext = true;

		args->ext_idx = args->in_numargs++;

		args->in_args[args->ext_idx] = ext;

	} else {

		kfree(ext.value);

	}



	return err;

}



static void free_ext_value(struct fuse_args *args)

{

	if (args->is_ext)

		kfree(args->in_args[args->ext_idx].value);

}



/*

 * Atomic create+open operation

 *
@@ -541,8 +569,6 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, 
	struct fuse_entry_out outentry;

	struct fuse_inode *fi;

	struct fuse_file *ff;

	void *security_ctx = NULL;

	u32 security_ctxlen;

	bool trunc = flags & O_TRUNC;



	/* Userspace expects S_IFREG in create mode */
@@ -586,19 +612,12 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, 
	args.out_args[1].size = sizeof(outopen);

	args.out_args[1].value = &outopen;



	if (fm->fc->init_security) {

		err = get_security_context(entry, mode, &security_ctx,

					   &security_ctxlen);

	err = get_create_ext(&args, entry, mode);

	if (err)

		goto out_put_forget_req;



		args.in_numargs = 3;

		args.in_args[2].size = security_ctxlen;

		args.in_args[2].value = security_ctx;

	}



	err = fuse_simple_request(fm, &args);

	kfree(security_ctx);

	free_ext_value(&args);

	if (err)

		goto out_free_ff;
@@ -705,8 +724,6 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args, 
	struct dentry *d;

	int err;

	struct fuse_forget_link *forget;

	void *security_ctx = NULL;

	u32 security_ctxlen;



	if (fuse_is_bad(dir))

		return -EIO;
@@ -721,21 +738,14 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args, 
	args->out_args[0].size = sizeof(outarg);

	args->out_args[0].value = &outarg;



	if (fm->fc->init_security && args->opcode != FUSE_LINK) {

		err = get_security_context(entry, mode, &security_ctx,

					   &security_ctxlen);

	if (args->opcode != FUSE_LINK) {

		err = get_create_ext(args, entry, mode);

		if (err)

			goto out_put_forget_req;



		BUG_ON(args->in_numargs != 2);



		args->in_numargs = 3;

		args->in_args[2].size = security_ctxlen;

		args->in_args[2].value = security_ctx;

	}



	err = fuse_simple_request(fm, args);

	kfree(security_ctx);

	free_ext_value(args);

	if (err)

		goto out_put_forget_req;

fs/fuse/fuse_i.h

+4 −2
Original line number Diff line number Diff line
@@ -249,8 +249,9 @@ struct fuse_page_desc { 
struct fuse_args {

	uint64_t nodeid;

	uint32_t opcode;

	unsigned short in_numargs;

	unsigned short out_numargs;

	uint8_t in_numargs;

	uint8_t out_numargs;

	uint8_t ext_idx;

	bool force:1;

	bool noreply:1;

	bool nocreds:1;
@@ -261,6 +262,7 @@ struct fuse_args { 
	bool page_zeroing:1;

	bool page_replace:1;

	bool may_block:1;

	bool is_ext:1;

	struct fuse_in_arg in_args[3];

	struct fuse_arg out_args[2];

	void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error);

include/uapi/linux/fuse.h

+27 −1
Original line number Diff line number Diff line
@@ -201,6 +201,9 @@ 
 *  7.38

 *  - add FUSE_EXPIRE_ONLY flag to fuse_notify_inval_entry

 *  - add FOPEN_PARALLEL_DIRECT_WRITES

 *  - add total_extlen to fuse_in_header

 *  - add FUSE_MAX_NR_SECCTX

 *  - add extension header

 */



#ifndef _LINUX_FUSE_H
@@ -503,6 +506,15 @@ struct fuse_file_lock { 
 */

#define FUSE_EXPIRE_ONLY		(1 << 0)



/**

 * extension type

 * FUSE_MAX_NR_SECCTX: maximum value of &fuse_secctx_header.nr_secctx

 */

enum fuse_ext_type {

	/* Types 0..31 are reserved for fuse_secctx_header */

	FUSE_MAX_NR_SECCTX	= 31,

};



enum fuse_opcode {

	FUSE_LOOKUP		= 1,

	FUSE_FORGET		= 2,  /* no reply */
@@ -886,7 +898,8 @@ struct fuse_in_header { 
	uint32_t	uid;

	uint32_t	gid;

	uint32_t	pid;

	uint32_t	padding;

	uint16_t	total_extlen; /* length of extensions in 8byte units */

	uint16_t	padding;

};



struct fuse_out_header {
@@ -1047,4 +1060,17 @@ struct fuse_secctx_header { 
	uint32_t	nr_secctx;

};



/**

 * struct fuse_ext_header - extension header

 * @size: total size of this extension including this header

 * @type: type of extension

 *

 * This is made compatible with fuse_secctx_header by using type values >

 * FUSE_MAX_NR_SECCTX

 */

struct fuse_ext_header {

	uint32_t	size;

	uint32_t	type;

};



#endif /* _LINUX_FUSE_H */