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authorTejaswi Tanikella <tejaswit@codeaurora.org>2018-04-11 16:34:47 +0530
committerDavid S. Miller <davem@davemloft.net>2018-04-11 10:33:46 -0400
commit3f01ddb962dc506916c243f9524e8bef97119b77 (patch)
tree60eee083e1987d0abe884bd00e2a14133b10066b /drivers/net
parentfed56079e76461765f1e21c214bd1b614b7981e8 (diff)
downloadlinux-3f01ddb962dc506916c243f9524e8bef97119b77.tar.bz2
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> [<ffffff9dd3e94d38>] slhc_uncompress+0x464/0x468 89.666965: <2> [<ffffff9dd3e87d88>] ppp_receive_nonmp_frame+0x3b4/0x65c 89.666978: <2> [<ffffff9dd3e89dd4>] ppp_receive_frame+0x64/0x7e0 89.666991: <2> [<ffffff9dd3e8a708>] ppp_input+0x104/0x198 89.667005: <2> [<ffffff9dd3e93868>] pppopns_recv_core+0x238/0x370 89.667027: <2> [<ffffff9dd4428fc8>] __sk_receive_skb+0xdc/0x250 89.667040: <2> [<ffffff9dd3e939e4>] pppopns_recv+0x44/0x60 89.667053: <2> [<ffffff9dd4426848>] __sock_queue_rcv_skb+0x16c/0x24c 89.667065: <2> [<ffffff9dd4426954>] sock_queue_rcv_skb+0x2c/0x38 89.667085: <2> [<ffffff9dd44f7358>] raw_rcv+0x124/0x154 89.667098: <2> [<ffffff9dd44f7568>] raw_local_deliver+0x1e0/0x22c 89.667117: <2> [<ffffff9dd44c8ba0>] ip_local_deliver_finish+0x70/0x24c 89.667131: <2> [<ffffff9dd44c92f4>] 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 <tejaswit@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/slip/slhc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
index 5782733959f0..f4e93f5fc204 100644
--- a/drivers/net/slip/slhc.c
+++ b/drivers/net/slip/slhc.c
@@ -509,6 +509,10 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
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, unsigned char *icp, int isize)
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
*/