| 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 |
| |
| |
| @@ -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); |
| } |