From: Michael Bommarito <michael.bommarito@gmail.com> stable inclusion from stable-v6.6.143 commit 8ce96f1182644079249a24ac7e2ffc32e0301a46 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15911 CVE: CVE-2026-53225 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit f8373d7090b745728de66308deeecc67e8d319ce ] __sctp_rcv_asconf_lookup() in net/sctp/input.c only checks that the ASCONF chunk can hold the ADDIP header and a parameter header, then calls af->from_addr_param(), which reads the full address (16 bytes for IPv6) trusting the parameter's declared length. An unauthenticated peer can send a truncated trailing ASCONF chunk that declares an IPv6 address parameter but stops after the 4-byte parameter header; reached from the no-association lookup path, from_addr_param() then reads uninitialized bytes past the parameter. Impact: an unauthenticated SCTP peer makes the receive path read up to 16 bytes of uninitialized memory past a truncated ASCONF address parameter. The sibling __sctp_rcv_init_lookup() bounds parameters with sctp_walk_params(); this path open-codes the fetch and omits the bound. Verify the whole address parameter lies within the chunk before from_addr_param() reads it, the same class of fix as commit 51e5ad549c43 ("net: sctp: fix KMSAN uninit-value in sctp_inq_pop"). Fixes: df2185771439 ("[SCTP]: Update association lookup to look at ASCONF chunks as well") Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20260608122234.459098-1-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Ze Zuo <zuoze1@huawei.com> --- net/sctp/input.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/sctp/input.c b/net/sctp/input.c index 032a10d82302..df5b2187b8fa 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -1204,6 +1204,14 @@ static struct sctp_association *__sctp_rcv_asconf_lookup( /* Skip over the ADDIP header and find the Address parameter */ param = (union sctp_addr_param *)(asconf + 1); + /* The whole address parameter must lie within the chunk before + * af->from_addr_param() reads the variable-length address; otherwise a + * truncated trailing ASCONF chunk lets it read uninitialized bytes past + * the parameter. + */ + if (sizeof(*asconf) + ntohs(param->p.length) > ntohs(ch->length)) + return NULL; + af = sctp_get_af_specific(param_type2af(param->p.type)); if (unlikely(!af)) return NULL; -- 2.25.1