5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guangguan Wang commit 9ab332deb671d8f7e66d82a2ff2b3f715bc3a4ad upstream. 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 Reviewed-by: Wen Gu Reviewed-by: D. Wythe Signed-off-by: David S. Miller [ jcao: drop the af_smc.c hunk, the !smcd_v2_ext test already there covers it; result matches the 5.15.y backport a36364d8d4fab ] Signed-off-by: Junjie Cao Signed-off-by: Sasha Levin --- net/smc/smc_clc.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h index a57a3489df4ae..f7f656b297f9c 100644 --- a/net/smc/smc_clc.h +++ b/net/smc/smc_clc.h @@ -306,9 +306,15 @@ 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 *) -- 2.53.0