From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Mon, 27 Jan 2020 19:01:14 +0000
Subject: [PATCH] virtiofsd: passthrough_ll: add ino_map to hide lo_inode
pointers
Do not expose lo_inode pointers to clients.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit 92fb57b83cdbfc4bf53c0c46a3d0bcbc36e64126)
---
tools/virtiofsd/passthrough_ll.c | 144 ++++++++++++++++++++++++-------
1 file changed, 114 insertions(+), 30 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index e83a976587..a3ebf74eab 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -57,8 +57,8 @@
#include "passthrough_helpers.h"
/*
- * We are re-using pointers to our `struct lo_inode` and `struct
- * lo_dirp` elements as inodes. This means that we must be able to
+ * We are re-using pointers to our `struct lo_inode`
+ * elements as inodes. This means that we must be able to
* store uintptr_t values in a fuse_ino_t variable. The following
* incantation checks this condition at compile time.
*/
@@ -76,7 +76,7 @@ struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct {
struct lo_map_elem {
union {
- /* Element values will go here... */
+ struct lo_inode *inode;
ssize_t freelist;
};
bool in_use;
@@ -97,6 +97,7 @@ struct lo_inode {
ino_t ino;
dev_t dev;
uint64_t refcount; /* protected by lo->mutex */
+ fuse_ino_t fuse_ino;
};
struct lo_cred {
@@ -121,6 +122,7 @@ struct lo_data {
int cache;
int timeout_set;
struct lo_inode root; /* protected by lo->mutex */
+ struct lo_map ino_map; /* protected by lo->mutex */
};
static const struct fuse_opt lo_opts[] = {
@@ -145,14 +147,14 @@ static struct lo_data *lo_data(fuse_req_t req)
return (struct lo_data *)fuse_req_userdata(req);
}
-__attribute__((unused)) static void lo_map_init(struct lo_map *map)
+static void lo_map_init(struct lo_map *map)
{
map->elems = NULL;
map->nelems = 0;
map->freelist = -1;
}
-__attribute__((unused)) static void lo_map_destroy(struct lo_map *map)
+static void lo_map_destroy(struct lo_map *map)
{
free(map->elems);
}
@@ -183,8 +185,7 @@ static int lo_map_grow(struct lo_map *map, size_t new_nelems)
return 1;
}
-__attribute__((unused)) static struct lo_map_elem *
-lo_map_alloc_elem(struct lo_map *map)
+static struct lo_map_elem *lo_map_alloc_elem(struct lo_map *map)
{
struct lo_map_elem *elem;
@@ -200,8 +201,7 @@ lo_map_alloc_elem(struct lo_map *map)
return elem;
}
-__attribute__((unused)) static struct lo_map_elem *
-lo_map_reserve(struct lo_map *map, size_t key)
+static struct lo_map_elem *lo_map_reserve(struct lo_map *map, size_t key)
{
ssize_t *prev;
@@ -222,8 +222,7 @@ lo_map_reserve(struct lo_map *map, size_t key)
return NULL;
}
-__attribute__((unused)) static struct lo_map_elem *
-lo_map_get(struct lo_map *map, size_t key)
+static struct lo_map_elem *lo_map_get(struct lo_map *map, size_t key)
{
if (key >= map->nelems) {
return NULL;
@@ -234,8 +233,7 @@ lo_map_get(struct lo_map *map, size_t key)
return &map->elems[key];
}
-__attribute__((unused)) static void lo_map_remove(struct lo_map *map,
- size_t key)
+static void lo_map_remove(struct lo_map *map, size_t key)
{
struct lo_map_elem *elem;
@@ -254,18 +252,40 @@ __attribute__((unused)) static void lo_map_remove(struct lo_map *map,
map->freelist = key;
}
+/* Assumes lo->mutex is held */
+static ssize_t lo_add_inode_mapping(fuse_req_t req, struct lo_inode *inode)
+{
+ struct lo_map_elem *elem;
+
+ elem = lo_map_alloc_elem(&lo_data(req)->ino_map);
+ if (!elem) {
+ return -1;
+ }
+
+ elem->inode = inode;
+ return elem - lo_data(req)->ino_map.elems;
+}
+
static struct lo_inode *lo_inode(fuse_req_t req, fuse_ino_t ino)
{
- if (ino == FUSE_ROOT_ID) {
- return &lo_data(req)->root;
- } else {
- return (struct lo_inode *)(uintptr_t)ino;
+ struct lo_data *lo = lo_data(req);
+ struct lo_map_elem *elem;
+
+ pthread_mutex_lock(&lo->mutex);
+ elem = lo_map_get(&lo->ino_map, ino);
+ pthread_mutex_unlock(&lo->mutex);
+
+ if (!elem) {
+ return NULL;
}
+
+ return elem->inode;
}
static int lo_fd(fuse_req_t req, fuse_ino_t ino)
{
- return lo_inode(req, ino)->fd;
+ struct lo_inode *inode = lo_inode(req, ino);
+ return inode ? inode->fd : -1;
}
static bool lo_debug(fuse_req_t req)
@@ -337,10 +357,18 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
{
int saverr;
char procname[64];
- struct lo_inode *inode = lo_inode(req, ino);
- int ifd = inode->fd;
+ struct lo_inode *inode;
+ int ifd;
int res;
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
+ ifd = inode->fd;
+
if (valid & FUSE_SET_ATTR_MODE) {
if (fi) {
res = fchmod(fi->fh, attr->st_mode);
@@ -470,6 +498,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
inode->dev = e->attr.st_dev;
pthread_mutex_lock(&lo->mutex);
+ inode->fuse_ino = lo_add_inode_mapping(req, inode);
prev = &lo->root;
next = prev->next;
next->prev = inode;
@@ -478,7 +507,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
prev->next = inode;
pthread_mutex_unlock(&lo->mutex);
}
- e->ino = (uintptr_t)inode;
+ e->ino = inode->fuse_ino;
if (lo_debug(req)) {
fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n",
@@ -582,10 +611,16 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent,
{
int res;
int saverr;
- struct lo_inode *dir = lo_inode(req, parent);
+ struct lo_inode *dir;
struct fuse_entry_param e;
struct lo_cred old = {};
+ dir = lo_inode(req, parent);
+ if (!dir) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
saverr = ENOMEM;
saverr = lo_change_cred(req, &old);
@@ -663,10 +698,16 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent,
{
int res;
struct lo_data *lo = lo_data(req);
- struct lo_inode *inode = lo_inode(req, ino);
+ struct lo_inode *inode;
struct fuse_entry_param e;
int saverr;
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
memset(&e, 0, sizeof(struct fuse_entry_param));
e.attr_timeout = lo->timeout;
e.entry_timeout = lo->timeout;
@@ -684,7 +725,7 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent,
pthread_mutex_lock(&lo->mutex);
inode->refcount++;
pthread_mutex_unlock(&lo->mutex);
- e.ino = (uintptr_t)inode;
+ e.ino = inode->fuse_ino;
if (lo_debug(req)) {
fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n",
@@ -750,10 +791,10 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n)
next->prev = prev;
prev->next = next;
+ lo_map_remove(&lo->ino_map, inode->fuse_ino);
pthread_mutex_unlock(&lo->mutex);
close(inode->fd);
free(inode);
-
} else {
pthread_mutex_unlock(&lo->mutex);
}
@@ -762,7 +803,12 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n)
static void lo_forget_one(fuse_req_t req, fuse_ino_t ino, uint64_t nlookup)
{
struct lo_data *lo = lo_data(req);
- struct lo_inode *inode = lo_inode(req, ino);
+ struct lo_inode *inode;
+
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ return;
+ }
if (lo_debug(req)) {
fuse_log(FUSE_LOG_DEBUG, " forget %lli %lli -%lli\n",
@@ -1244,10 +1290,16 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
{
char *value = NULL;
char procname[64];
- struct lo_inode *inode = lo_inode(req, ino);
+ struct lo_inode *inode;
ssize_t ret;
int saverr;
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
saverr = ENOSYS;
if (!lo_data(req)->xattr) {
goto out;
@@ -1306,10 +1358,16 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
{
char *value = NULL;
char procname[64];
- struct lo_inode *inode = lo_inode(req, ino);
+ struct lo_inode *inode;
ssize_t ret;
int saverr;
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
saverr = ENOSYS;
if (!lo_data(req)->xattr) {
goto out;
@@ -1367,10 +1425,16 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
const char *value, size_t size, int flags)
{
char procname[64];
- struct lo_inode *inode = lo_inode(req, ino);
+ struct lo_inode *inode;
ssize_t ret;
int saverr;
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
saverr = ENOSYS;
if (!lo_data(req)->xattr) {
goto out;
@@ -1400,10 +1464,16 @@ out:
static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *name)
{
char procname[64];
- struct lo_inode *inode = lo_inode(req, ino);
+ struct lo_inode *inode;
ssize_t ret;
int saverr;
+ inode = lo_inode(req, ino);
+ if (!inode) {
+ fuse_reply_err(req, EBADF);
+ return;
+ }
+
saverr = ENOSYS;
if (!lo_data(req)->xattr) {
goto out;
@@ -1522,6 +1592,7 @@ int main(int argc, char *argv[])
struct fuse_session *se;
struct fuse_cmdline_opts opts;
struct lo_data lo = { .debug = 0, .writeback = 0 };
+ struct lo_map_elem *root_elem;
int ret = -1;
/* Don't mask creation mode, kernel already did that */
@@ -1530,8 +1601,19 @@ int main(int argc, char *argv[])
pthread_mutex_init(&lo.mutex, NULL);
lo.root.next = lo.root.prev = &lo.root;
lo.root.fd = -1;
+ lo.root.fuse_ino = FUSE_ROOT_ID;
lo.cache = CACHE_NORMAL;
+ /*
+ * Set up the ino map like this:
+ * [0] Reserved (will not be used)
+ * [1] Root inode
+ */
+ lo_map_init(&lo.ino_map);
+ lo_map_reserve(&lo.ino_map, 0)->in_use = false;
+ root_elem = lo_map_reserve(&lo.ino_map, lo.root.fuse_ino);
+ root_elem->inode = &lo.root;
+
if (fuse_parse_cmdline(&args, &opts) != 0) {
return 1;
}
@@ -1628,6 +1710,8 @@ err_out2:
err_out1:
fuse_opt_free_args(&args);
+ lo_map_destroy(&lo.ino_map);
+
if (lo.root.fd >= 0) {
close(lo.root.fd);
}