net/smc: check smcd_v2_ext_offset when receiving proposal msg
[ 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: 5c21c4ccaf
("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>
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@ -2096,6 +2096,8 @@ static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc,
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pclc_smcd = smc_get_clc_msg_smcd(pclc);
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smc_v2_ext = smc_get_clc_v2_ext(pclc);
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smcd_v2_ext = smc_get_clc_smcd_v2_ext(smc_v2_ext);
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if (!pclc_smcd || !smc_v2_ext || !smcd_v2_ext)
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goto not_found;
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mutex_lock(&smcd_dev_list.mutex);
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if (pclc_smcd->ism.chid)
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@ -361,9 +361,15 @@ smc_get_clc_v2_ext(struct smc_clc_msg_proposal *prop)
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static inline struct smc_clc_smcd_v2_extension *
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smc_get_clc_smcd_v2_ext(struct smc_clc_v2_extension *prop_v2ext)
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{
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u16 max_offset = offsetof(struct smc_clc_msg_proposal_area, pclc_smcd_v2_ext) -
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offsetof(struct smc_clc_msg_proposal_area, pclc_v2_ext) -
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offsetof(struct smc_clc_v2_extension, hdr) -
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offsetofend(struct smc_clnt_opts_area_hdr, smcd_v2_ext_offset);
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if (!prop_v2ext)
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return NULL;
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if (!ntohs(prop_v2ext->hdr.smcd_v2_ext_offset))
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if (!ntohs(prop_v2ext->hdr.smcd_v2_ext_offset) ||
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ntohs(prop_v2ext->hdr.smcd_v2_ext_offset) > max_offset)
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return NULL;
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return (struct smc_clc_smcd_v2_extension *)
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