From 3f01ddb962dc506916c243f9524e8bef97119b77 Mon Sep 17 00:00:00 2001 From: Tejaswi Tanikella Date: Wed, 11 Apr 2018 16:34:47 +0530 Subject: slip: Check if rstate is initialized before uncompressing 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 --- include/net/slhc_vj.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/slhc_vj.h') diff --git a/include/net/slhc_vj.h b/include/net/slhc_vj.h index 8716d5942b65..8fcf8908a694 100644 --- 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; -- cgit v1.2.3-59-g8ed1b