From 96675cbb757a83b57c12565acc9c7ab49d5d1aeb Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Fri, 6 May 2011 03:27:18 +0000 Subject: [PATCH] dccp: handle invalid feature options length A length of zero (after subtracting two for the type and len fields) for the DCCPO_{CHANGE,CONFIRM}_{L,R} options will cause an underflow due to the subtraction. The subsequent code may read past the end of the options value buffer when parsing. I'm unsure of what the consequences of this might be, but it's probably not good. Signed-off-by: Dan Rosenberg Cc: stable@kernel.org Acked-by: Gerrit Renker Signed-off-by: David S. Miller --- net/dccp/options.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/dccp/options.c b/net/dccp/options.c index f06ffcfc8d712..4b2ab657ac8e6 100644 --- a/net/dccp/options.c +++ b/net/dccp/options.c @@ -123,6 +123,8 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R: if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */ break; + if (len == 0) + goto out_invalid_option; rc = dccp_feat_parse_options(sk, dreq, mandatory, opt, *value, value + 1, len - 1); if (rc) -- 2.39.5