Messages in this thread | | | Subject | Re: [PATCH 36/64] scsi: ibmvscsi: Avoid multi-field memset() overflow by aiming at srp | From | Tyrel Datwyler <> | Date | Fri, 30 Jul 2021 12:11:02 -0700 |
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On 7/28/21 8:35 PM, Martin K. Petersen wrote: > > Kees, > >> For example, change it to: >> >> + BUILD_BUG_ON(sizeof(evt_struct->iu.srp) != SRP_MAX_IU_LEN); >> + memset(&evt_struct->iu.srp, 0x00, sizeof(evt_struct->iu.srp)); >> srp_cmd = &evt_struct->iu.srp.cmd; >> - memset(srp_cmd, 0x00, SRP_MAX_IU_LEN); > >> For the moment, I'll leave the patch as-is unless you prefer having >> the BUILD_BUG_ON(). :) > > I'm OK with the BUILD_BUG_ON(). Hopefully Tyrel or Brian will chime in. >
All the other srp structs are at most 64 bytes and the size of the union is explicitly set to SRP_MAX_IU_LEN by the last field of the union.
union srp_iu { struct srp_login_req login_req; struct srp_login_rsp login_rsp; struct srp_login_rej login_rej; struct srp_i_logout i_logout; struct srp_t_logout t_logout; struct srp_tsk_mgmt tsk_mgmt; struct srp_cmd cmd; struct srp_rsp rsp; u8 reserved[SRP_MAX_IU_LEN]; };
So, in my mind if SRP_MAX_IU_LEN ever changes so does the size of the union making the BUILD_BUG_ON() superfluous. But it doesn't really hurt anything either.
-Tyrel
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