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 simplar to the generic
request extension, so incude 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: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/fuse/dev.c | 2 ++
fs/fuse/dir.c | 66 ++++++++++++++++++++++-----------------
fs/fuse/fuse_i.h | 6 ++--
include/uapi/linux/fuse.h | 28 ++++++++++++++++-
4 files changed, 71 insertions(+), 31 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c73d9c4132f6..c77eea4f636b 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -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);
}
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index aa67869e3444..c227ce87b100 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -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);
- 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 = get_create_ext(&args, entry, mode);
+ if (err)
+ goto out_put_forget_req;
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;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index d339b1ace887..31e2ca0d2788 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -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);
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index e3c54109bae9..c71f12429e3d 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -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 */
--
2.38.1
