From 380b5ae0a1e4a68bfb098319a7ab86d3d34c2fcb Mon Sep 17 00:00:00 2001 From: Sean Bright Date: Mon, 16 Apr 2018 15:13:58 -0400 Subject: [PATCH 1/1] AST-2018-007: iostreams potential DoS when client connection closed prematurely Before Asterisk sends an HTTP response (at least in the case of errors), it attempts to read & discard the content of the request. If the client lies about the Content-Length, or the connection is closed from the client side before "Content-Length" bytes are sent, the request handling thread will busy loop. ASTERISK-27807 Change-Id: I945c5fc888ed92be625b8c35039fc6d2aa89c762 --- main/iostream.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/main/iostream.c b/main/iostream.c index 4cddd43b6b..20188cb7a0 100644 --- a/main/iostream.c +++ b/main/iostream.c @@ -197,11 +197,18 @@ static ssize_t iostream_read(struct ast_iostream *stream, void *buf, size_t size } } break; + case SSL_ERROR_SYSCALL: + /* Some non-recoverable I/O error occurred. The OpenSSL error queue may + * contain more information on the error. For socket I/O on Unix systems, + * consult errno for details. */ + ast_debug(1, "TLS non-recoverable I/O error occurred: %s, %s\n", ERR_error_string(sslerr, err), + ssl_error_to_string(sslerr, res)); + return -1; default: /* Report EOF for an undecoded SSL or transport error. */ ast_debug(1, "TLS transport or SSL error reading data: %s, %s\n", ERR_error_string(sslerr, err), ssl_error_to_string(sslerr, res)); - return 0; + return -1; } if (!ms) { /* Report EOF for a timeout */ @@ -317,7 +324,7 @@ ssize_t ast_iostream_discard(struct ast_iostream *stream, size_t size) while (remaining) { ret = ast_iostream_read(stream, buf, remaining > sizeof(buf) ? sizeof(buf) : remaining); - if (ret < 0) { + if (ret <= 0) { return ret; } remaining -= ret; -- 2.19.0