From d63ce0d64c5abe9f285f14ce394660bfb9a16538 Mon Sep 17 00:00:00 2001 From: Chris Leech Date: Tue, 10 Nov 2020 14:14:11 -0800 Subject: check for TCP urgent pointer past end of frame CVE-2020-17437 --- iscsiuio/src/uip/uip.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/iscsiuio/src/uip/uip.c b/iscsiuio/src/uip/uip.c index 522fd9d..e0a7221 100644 --- a/iscsiuio/src/uip/uip.c +++ b/iscsiuio/src/uip/uip.c @@ -2095,11 +2095,16 @@ tcp_send_finack: } else { uip_urglen = 0; #else /* UIP_URGDATA > 0 */ - ustack->uip_appdata = - ((char *)ustack->uip_appdata) + - ((tcp_hdr->urgp[0] << 8) | tcp_hdr->urgp[1]); - ustack->uip_len -= - (tcp_hdr->urgp[0] << 8) | tcp_hdr->urgp[1]; + tmp16 = (tcp_hdr->urgp[0] << 8) | tcp_hdr->urgp[1]; + if (tmp16 <= ustack->uip_len) { + ustack->uip_appdata = ((char *)ustack->uip_appdata) + tmp16; + ustack->uip_len -= tmp16; + } else { + /* invalid urgent pointer length greater than frame */ + /* we're discarding urgent data anyway, throw it all out */ + ustack->uip_appdata = ((char *)ustack->uip_appdata) + ustack->uip_len; + ustack->uip_len = 0; + } #endif /* UIP_URGDATA > 0 */ } -- cgit v1.2.1