Only reads and writes need to allocate memory correspondent to the request length. Other requests can be sent to the storage without allocating any memory, and thus any request length is acceptable.
Reported-by: Sitsofe Wheeler <[email protected]> Cc: [email protected] Reviewed-by: Max Reitz <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> --- nbd/server.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 8752885..c41af0d 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -818,13 +818,6 @@ static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *reque goto out; } - if (request->len > NBD_MAX_BUFFER_SIZE) { - LOG("len (%u) is larger than max len (%u)", - request->len, NBD_MAX_BUFFER_SIZE); - rc = -EINVAL; - goto out; - } - if ((request->from + request->len) < request->from) { LOG("integer overflow detected! " "you're probably being attacked"); @@ -836,6 +829,13 @@ static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *reque command = request->type & NBD_CMD_MASK_COMMAND; if (command == NBD_CMD_READ || command == NBD_CMD_WRITE) { + if (request->len > NBD_MAX_BUFFER_SIZE) { + LOG("len (%u) is larger than max len (%u)", + request->len, NBD_MAX_BUFFER_SIZE); + rc = -EINVAL; + goto out; + } + req->data = blk_blockalign(client->exp->blk, request->len); } if (command == NBD_CMD_WRITE) { -- 1.8.3.1
