[PATCH net 5/6] net/smc: check smcd_v2_ext_offset when receiving proposal msg
From: Guangguan Wang <hidden>
Date: 2024-11-28 12:14:52
Also in:
linux-rdma, linux-s390, lkml
Subsystem:
networking [general], shared memory communications (smc) sockets, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, D. Wythe, Dust Li, Sidraya Jayagond, Wenjia Zhang, Linus Torvalds
When receiving proposal msg in server, the field smcd_v2_ext_offset in
proposal msg is from the remote client and can not be fully trusted.
Once the value of smcd_v2_ext_offset exceed the max value, there has
the chance to access wrong address, and crash may happen.
This patch checks the value of smcd_v2_ext_offset before using it.
Fixes: 5c21c4ccafe8 ("net/smc: determine accepted ISM devices")
Signed-off-by: Guangguan Wang <redacted>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: D. Wythe <alibuda@linux.alibaba.com>
---
net/smc/af_smc.c | 2 ++
net/smc/smc_clc.h | 8 +++++++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 5bfd38eaee3a..ef4e0ff6beed 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c@@ -2147,6 +2147,8 @@ static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc, pclc_smcd = smc_get_clc_msg_smcd(pclc); smc_v2_ext = smc_get_clc_v2_ext(pclc); smcd_v2_ext = smc_get_clc_smcd_v2_ext(smc_v2_ext); + if (!pclc_smcd || !smc_v2_ext || !smcd_v2_ext) + goto not_found; mutex_lock(&smcd_dev_list.mutex); if (pclc_smcd->ism.chid) {
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index 23afa4df862e..767289925410 100644
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h@@ -400,9 +400,15 @@ smc_get_clc_v2_ext(struct smc_clc_msg_proposal *prop) static inline struct smc_clc_smcd_v2_extension * smc_get_clc_smcd_v2_ext(struct smc_clc_v2_extension *prop_v2ext) { + u16 max_offset = offsetof(struct smc_clc_msg_proposal_area, pclc_smcd_v2_ext) - + offsetof(struct smc_clc_msg_proposal_area, pclc_v2_ext) - + offsetof(struct smc_clc_v2_extension, hdr) - + offsetofend(struct smc_clnt_opts_area_hdr, smcd_v2_ext_offset); + if (!prop_v2ext) return NULL; - if (!ntohs(prop_v2ext->hdr.smcd_v2_ext_offset)) + if (!ntohs(prop_v2ext->hdr.smcd_v2_ext_offset) || + ntohs(prop_v2ext->hdr.smcd_v2_ext_offset) > max_offset) return NULL; return (struct smc_clc_smcd_v2_extension *)
--
2.24.3 (Apple Git-128)