From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+1lNuHCuY9PJNqSIq4Fu2S4FnPodW2SvaWGjXntVU23GnyQvTkgwv2w5nrytmm49HmjVDJ ARC-Seal: i=1; a=rsa-sha256; t=1523981076; cv=none; d=google.com; s=arc-20160816; b=XheSS//oqTUZf6oMgU60LbhC9/UtmUeFW1MTbZGd1GJX2SMzF5wuxJwdJLyiipBQVL AmxtEWNeC454p4d6cMmIetd5f4IRd0LsBK0fxLV1bIZJ7FiDsC+bBobDSE9CQ0S2GpdW HoGM4ykhPCR0F4m2cHzs0mL+aIbFsRID5kLvOdYkDkMW3l6w3w0dMPSpvzO0+LUitY6a iL3pVlMdVL9Kks1lGhvZT/wxGfaCbQiv7dhQTev+18BqbM0lELRqBEsIC76uWlm5luvF yU/3mx2zw4ZosfvuHXeGeojiCdb8FRofcTRH94n3sRGh1h7dHvbwKZ+aInsk9/QdFDu+ KWbQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=4VWMIaV9XnJ9xfeAEDv+ZA8bIMr7iO7k3cF5KUaZX4w=; b=z6h22BXqqJ+T0wlg/T/g41vo/lqAXZsR+YXMYS2w0BaLjr/eo21BeKMz0xx91SMTil N4a+5aMOk4ZHioExrzykRVEY0Ls7DjLvnUvWK3vZerHAbVpe4qzZ4DSJN9U7FU/R2kh5 d4MLc+XmsyJMxfe1D2b0Ir35BF60H9t97cD5fa94gDf8HkVJ+rcjAFyXth1YoK8OftAd u8D9pfFeIabp8PNcrDT1vztvArfnRy6oEFsMh+pGbSVJJ4Ko4MoYudVAC1gfTsHUNa8E XIR00AsOpiVXWyCfDQTMy7wMReTvCIv2tJtrPrNvk/Q3Px/RLwt1OnBN4tYl/GOMtJab vG5w== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 46.44.180.42 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 46.44.180.42 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tejaswi Tanikella , "David S. Miller" Subject: [PATCH 4.15 05/53] slip: Check if rstate is initialized before uncompressing Date: Tue, 17 Apr 2018 17:58:30 +0200 Message-Id: <20180417155723.313038973@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180417155723.091120060@linuxfoundation.org> References: <20180417155723.091120060@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598009735919872133?= X-GMAIL-MSGID: =?utf-8?q?1598009981459093325?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tejaswi Tanikella [ Upstream commit 3f01ddb962dc506916c243f9524e8bef97119b77 ] On receiving a packet the state index points to the rstate which must be used to fill up IP and TCP headers. But if the state index points to a rstate which is unitialized, i.e. filled with zeros, it gets stuck in an infinite loop inside ip_fast_csum trying to compute the ip checsum of a header with zero length. 89.666953: <2> [] slhc_uncompress+0x464/0x468 89.666965: <2> [] ppp_receive_nonmp_frame+0x3b4/0x65c 89.666978: <2> [] ppp_receive_frame+0x64/0x7e0 89.666991: <2> [] ppp_input+0x104/0x198 89.667005: <2> [] pppopns_recv_core+0x238/0x370 89.667027: <2> [] __sk_receive_skb+0xdc/0x250 89.667040: <2> [] pppopns_recv+0x44/0x60 89.667053: <2> [] __sock_queue_rcv_skb+0x16c/0x24c 89.667065: <2> [] sock_queue_rcv_skb+0x2c/0x38 89.667085: <2> [] raw_rcv+0x124/0x154 89.667098: <2> [] raw_local_deliver+0x1e0/0x22c 89.667117: <2> [] ip_local_deliver_finish+0x70/0x24c 89.667131: <2> [] ip_local_deliver+0x100/0x10c ./scripts/faddr2line vmlinux slhc_uncompress+0x464/0x468 output: ip_fast_csum at arch/arm64/include/asm/checksum.h:40 (inlined by) slhc_uncompress at drivers/net/slip/slhc.c:615 Adding a variable to indicate if the current rstate is initialized. If such a packet arrives, move to toss state. Signed-off-by: Tejaswi Tanikella Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/slip/slhc.c | 5 +++++ include/net/slhc_vj.h | 1 + 2 files changed, 6 insertions(+) --- a/drivers/net/slip/slhc.c +++ b/drivers/net/slip/slhc.c @@ -509,6 +509,10 @@ slhc_uncompress(struct slcompress *comp, if(x < 0 || x > comp->rslot_limit) goto bad; + /* Check if the cstate is initialized */ + if (!comp->rstate[x].initialized) + goto bad; + comp->flags &=~ SLF_TOSS; comp->recv_current = x; } else { @@ -673,6 +677,7 @@ slhc_remember(struct slcompress *comp, u if (cs->cs_tcp.doff > 5) memcpy(cs->cs_tcpopt, icp + ihl*4 + sizeof(struct tcphdr), (cs->cs_tcp.doff - 5) * 4); cs->cs_hsize = ihl*2 + cs->cs_tcp.doff*2; + cs->initialized = true; /* Put headers back on packet * Neither header checksum is recalculated */ --- a/include/net/slhc_vj.h +++ b/include/net/slhc_vj.h @@ -127,6 +127,7 @@ typedef __u32 int32; */ struct cstate { byte_t cs_this; /* connection id number (xmit) */ + bool initialized; /* true if initialized */ struct cstate *next; /* next in ring (xmit) */ struct iphdr cs_ip; /* ip/tcp hdr from most recent packet */ struct tcphdr cs_tcp;