From: Stefan Hajnoczi 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 Reviewed-by: Masayoshi Mizuma Signed-off-by: Dr. David Alan Gilbert (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); }