6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Guangguan Wang guangguan.wang@linux.alibaba.com
[ Upstream commit 9ab332deb671d8f7e66d82a2ff2b3f715bc3a4ad ]
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 guangguan.wang@linux.alibaba.com Reviewed-by: Wen Gu guwen@linux.alibaba.com Reviewed-by: D. Wythe alibuda@linux.alibaba.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 5d96f9de5b5d..6cc7b846cff1 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 2ff423224a59..1a7676227f16 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 *)