From: Alexander Aring <aahringo@xxxxxxxxxx> [ Upstream commit 4e006c7a6dac0ead4c1bf606000aa90a372fc253 ] This patch fixes a missing 8 byte for the header size calculation. The ipv6_rpl_srh_size() is used to check a skb_pull() on skb->data which points to skb_transport_header(). Currently we only check on the calculated addresses fields using CmprI and CmprE fields, see: https://www.rfc-editor.org/rfc/rfc6554#section-3 there is however a missing 8 byte inside the calculation which stands for the fields before the addresses field. Those 8 bytes are represented by sizeof(struct ipv6_rpl_sr_hdr) expression. Fixes: 8610c7c6e3bd ("net: ipv6: add support for rpl sr exthdr") Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx> Reported-by: maxpl0it <maxpl0it@xxxxxxxxxxxxxx> Reviewed-by: David Ahern <dsahern@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/ipv6/rpl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv6/rpl.c b/net/ipv6/rpl.c index 488aec9e1a74f..d1876f1922255 100644 --- a/net/ipv6/rpl.c +++ b/net/ipv6/rpl.c @@ -32,7 +32,8 @@ static void *ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr *hdr, int i) size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri, unsigned char cmpre) { - return (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre); + return sizeof(struct ipv6_rpl_sr_hdr) + (n * IPV6_PFXTAIL_LEN(cmpri)) + + IPV6_PFXTAIL_LEN(cmpre); } void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr, -- 2.39.2
