Add a new `init_security` field to `fuse_conn` that controls whether we
initialize security when a new inode is created. Also add a
`FUSE_SECURITY_CTX` flag that can be set in the `flags` field of the
`fuse_init_out` struct that controls when the `init_security` field is
set.
When set to true, get the security context for a newly created inode via
`security_dentry_init_security` and append it to the create, mkdir,
mknod, and symlink requests. The server should use this context by
writing it to `/proc/thread-self/attr/fscreate` before creating the
requested inode.
Calling security hooks is needed for `setfscreatecon` to work since it
is applied as part of the selinux security hook.
Signed-off-by: Chirantan Ekbote <chirantan@xxxxxxxxxxxx>
---
Changes in v2:
* Added the FUSE_SECURITY_CTX flag for init_out responses.
* Switched to security_dentry_init_security.
* Send security context with create, mknod, mkdir, and symlink
requests instead of applying it after creation.
fs/fuse/dir.c | 99 +++++++++++++++++++++++++++++++++++++--
fs/fuse/fuse_i.h | 3 ++
fs/fuse/inode.c | 5 +-
include/uapi/linux/fuse.h | 8 +++-
4 files changed, 110 insertions(+), 5 deletions(-)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index ee190119f45cc..86bc073bb4f0a 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -16,6 +16,9 @@
#include <linux/xattr.h>
#include <linux/iversion.h>
#include <linux/posix_acl.h>
+#include <linux/security.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
static void fuse_advise_use_readdirplus(struct inode *dir)
{
@@ -442,6 +445,8 @@ 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 = 0;
/* Userspace expects S_IFREG in create mode */
BUG_ON((mode & S_IFMT) != S_IFREG);
@@ -477,6 +482,21 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
args.out_args[0].value = &outentry;
args.out_args[1].size = sizeof(outopen);
args.out_args[1].value = &outopen;
+
+ if (fc->init_security) {
+ err = security_dentry_init_security(entry, mode, &entry->d_name,
+ &security_ctx,
+ &security_ctxlen);
+ if (err)
+ goto out_put_forget_req;
+
+ if (security_ctxlen > 0) {
+ args.in_numargs = 3;
+ args.in_args[2].size = security_ctxlen;
+ args.in_args[2].value = security_ctx;
+ }
+ }
+
err = fuse_simple_request(fc, &args);
if (err)
goto out_free_ff;
@@ -513,6 +533,8 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
return err;
out_free_ff:
+ if (security_ctxlen > 0)
+ kfree(security_ctx);
fuse_file_free(ff);
out_put_forget_req:
kfree(forget);
@@ -629,6 +651,9 @@ static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
{
struct fuse_mknod_in inarg;
struct fuse_conn *fc = get_fuse_conn(dir);
+ void *security_ctx = NULL;
+ u32 security_ctxlen = 0;
+ int ret;
FUSE_ARGS(args);
if (!fc->dont_mask)
@@ -644,7 +669,27 @@ static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
- return create_new_entry(fc, &args, dir, entry, mode);
+
+ if (fc->init_security) {
+ ret = security_dentry_init_security(entry, mode, &entry->d_name,
+ &security_ctx,
+ &security_ctxlen);
+ if (ret)
+ goto out;
+
+ if (security_ctxlen > 0) {
+ args.in_numargs = 3;
+ args.in_args[2].size = security_ctxlen;
+ args.in_args[2].value = security_ctx;
+ }
+ }
+
+ ret = create_new_entry(fc, &args, dir, entry, mode);
+
+ if (security_ctxlen > 0)
+ kfree(security_ctx);
+out:
+ return ret;
}
static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
@@ -657,6 +702,9 @@ static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
{
struct fuse_mkdir_in inarg;
struct fuse_conn *fc = get_fuse_conn(dir);
+ void *security_ctx = NULL;
+ u32 security_ctxlen = 0;
+ int ret;
FUSE_ARGS(args);
if (!fc->dont_mask)
@@ -671,7 +719,28 @@ static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
- return create_new_entry(fc, &args, dir, entry, S_IFDIR);
+
+ if (fc->init_security) {
+ ret = security_dentry_init_security(entry, S_IFDIR,
+ &entry->d_name,
+ &security_ctx,
+ &security_ctxlen);
+ if (ret)
+ goto out;
+
+ if (security_ctxlen > 0) {
+ args.in_numargs = 3;
+ args.in_args[2].size = security_ctxlen;
+ args.in_args[2].value = security_ctx;
+ }
+ }
+
+ ret = create_new_entry(fc, &args, dir, entry, S_IFDIR);
+
+ if (security_ctxlen > 0)
+ kfree(security_ctx);
+out:
+ return ret;
}
static int fuse_symlink(struct inode *dir, struct dentry *entry,
@@ -679,6 +748,9 @@ static int fuse_symlink(struct inode *dir, struct dentry *entry,
{
struct fuse_conn *fc = get_fuse_conn(dir);
unsigned len = strlen(link) + 1;
+ void *security_ctx = NULL;
+ u32 security_ctxlen = 0;
+ int ret;
FUSE_ARGS(args);
args.opcode = FUSE_SYMLINK;
@@ -687,7 +759,28 @@ static int fuse_symlink(struct inode *dir, struct dentry *entry,
args.in_args[0].value = entry->d_name.name;
args.in_args[1].size = len;
args.in_args[1].value = link;
- return create_new_entry(fc, &args, dir, entry, S_IFLNK);
+
+ if (fc->init_security) {
+ ret = security_dentry_init_security(entry, S_IFLNK,
+ &entry->d_name,
+ &security_ctx,
+ &security_ctxlen);
+ if (ret)
+ goto out;
+
+ if (security_ctxlen > 0) {
+ args.in_numargs = 3;
+ args.in_args[2].size = security_ctxlen;
+ args.in_args[2].value = security_ctx;
+ }
+ }
+
+ ret = create_new_entry(fc, &args, dir, entry, S_IFLNK);
+
+ if (security_ctxlen > 0)
+ kfree(security_ctx);
+out:
+ return ret;
}
void fuse_update_ctime(struct inode *inode)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index ca344bf714045..5ea9212b0a71c 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -719,6 +719,9 @@ struct fuse_conn {
/* Do not show mount options */
unsigned int no_mount_options:1;
+ /* Initialize security xattrs when creating a new inode */
+ unsigned int init_security : 1;
+
/** The number of requests waiting for completion */
atomic_t num_waiting;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 16aec32f7f3d7..1a311771c5555 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -951,6 +951,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_args *args,
min_t(unsigned int, FUSE_MAX_MAX_PAGES,
max_t(unsigned int, arg->max_pages, 1));
}
+ if (arg->flags & FUSE_SECURITY_CTX)
+ fc->init_security = 1;
} else {
ra_pages = fc->max_read / PAGE_SIZE;
fc->no_lock = 1;
@@ -988,7 +990,8 @@ void fuse_send_init(struct fuse_conn *fc)
FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
- FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA;
+ FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
+ FUSE_SECURITY_CTX;
ia->args.opcode = FUSE_INIT;
ia->args.in_numargs = 1;
ia->args.in_args[0].size = sizeof(ia->in);
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 373cada898159..00919c214149d 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -172,6 +172,10 @@
* - add FUSE_WRITE_KILL_PRIV flag
* - add FUSE_SETUPMAPPING and FUSE_REMOVEMAPPING
* - add map_alignment to fuse_init_out, add FUSE_MAP_ALIGNMENT flag
+ *
+ * 7.32
+ * - add FUSE_SECURITY_CTX flag for fuse_init_out
+ * - add security context to create, mkdir, and mknod requests
*/
#ifndef _LINUX_FUSE_H
@@ -207,7 +211,7 @@
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 31
+#define FUSE_KERNEL_MINOR_VERSION 32
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
@@ -314,6 +318,7 @@ struct fuse_file_lock {
* FUSE_NO_OPENDIR_SUPPORT: kernel supports zero-message opendir
* FUSE_EXPLICIT_INVAL_DATA: only invalidate cached pages on explicit request
* FUSE_MAP_ALIGNMENT: map_alignment field is valid
+ * FUSE_SECURITY_CTX: add security context to create, mkdir, symlink, and mknod
*/
#define FUSE_ASYNC_READ (1 << 0)
#define FUSE_POSIX_LOCKS (1 << 1)
@@ -342,6 +347,7 @@ struct fuse_file_lock {
#define FUSE_NO_OPENDIR_SUPPORT (1 << 24)
#define FUSE_EXPLICIT_INVAL_DATA (1 << 25)
#define FUSE_MAP_ALIGNMENT (1 << 26)
+#define FUSE_SECURITY_CTX (1 << 27)
/**
* CUSE INIT request/reply flags
--
2.27.0.278.ge193c7cf3a9-goog
