Messages in this thread | | | Date | Wed, 24 Apr 2024 06:47:47 +1000 | Subject | Re: [PATCH][next] smb: smb2pdu.h: Avoid -Wflex-array-member-not-at-end warnings | From | "Gustavo A. R. Silva" <> |
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On 23/04/24 14:15, Steve French wrote: > This looks reasonably safe (running the usual regression tests on it now). > > Reminds me though that we have to be careful (e.g. the recent fix for > regression caused by cleanup).
mmh... it seems that the offending commit was never CC'd to the linux-hardening list, hence it wasn't reviewed by us.
After reviewing both, the offending commit and the fix, both seem to be wrong.
for __packed structs, you should use __struct_group():
__struct_group(network_open_info, group_name, __packed, struct_members);
The _packed in the commit 0268a7cc7fdc is not an attribute, it's the name for the group. So, it's not actually doing what the submitter thinks it does.
> > Thoughts about whether should be sent in rc6 or wait till 6.10? 51 > warnings does sound > distracting though so might be worth going in sooner rather than later.
There is actually no hurry. :)
Thanks -- Gustavo
> > commit 0268a7cc7fdc47d90b6c18859de7718d5059f6f1 > Author: Namjae Jeon <linkinjeon@kernel.org> > Date: Fri Apr 19 23:46:34 2024 +0900 > > ksmbd: common: use struct_group_attr instead of struct_group for > network_open_info > > 4byte padding cause the connection issue with the applications of MacOS. > smb2_close response size increases by 4 bytes by padding, And the smb > client of MacOS check it and stop the connection. This patch use > struct_group_attr instead of struct_group for network_open_info to use > __packed to avoid padding. > > > On Tue, Apr 23, 2024 at 1:58 PM Gustavo A. R. Silva > <gustavo@embeddedor.com> wrote: >> >> Hi all, >> >> Friendly ping: who can take this, please? >> >> Thanks >> -- >> Gustavo >> >> On 11/04/24 09:35, Gustavo A. R. Silva wrote: >>> -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting >>> ready to enable it globally. >>> >>> So, in order to avoid ending up with a flexible-array member in the >>> middle of multiple other structs, we use the `__struct_group()` helper >>> to separate the flexible array from the rest of the members in the >>> flexible structure, and use the tagged `struct create_context_hdr` >>> instead of `struct create_context`. >>> >>> So, with these changes, fix 51 of the following warnings[1]: >>> >>> fs/smb/client/../common/smb2pdu.h:1225:31: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] >>> >>> Link: https://gist.github.com/GustavoARSilva/772526a39be3dd4db39e71497f0a9893 [1] >>> Link: https://github.com/KSPP/linux/issues/202 >>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> >>> --- >>> fs/smb/client/smb2pdu.h | 12 ++++++------ >>> fs/smb/common/smb2pdu.h | 33 ++++++++++++++++++--------------- >>> fs/smb/server/smb2pdu.h | 18 +++++++++--------- >>> 3 files changed, 33 insertions(+), 30 deletions(-) >>> >>> diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h >>> index c72a3b2886b7..1a02bd9e0c00 100644 >>> --- a/fs/smb/client/smb2pdu.h >>> +++ b/fs/smb/client/smb2pdu.h >>> @@ -145,7 +145,7 @@ struct durable_context_v2 { >>> } __packed; >>> >>> struct create_durable_v2 { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct durable_context_v2 dcontext; >>> } __packed; >>> @@ -167,7 +167,7 @@ struct durable_reconnect_context_v2_rsp { >>> } __packed; >>> >>> struct create_durable_handle_reconnect_v2 { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct durable_reconnect_context_v2 dcontext; >>> __u8 Pad[4]; >>> @@ -175,7 +175,7 @@ struct create_durable_handle_reconnect_v2 { >>> >>> /* See MS-SMB2 2.2.13.2.5 */ >>> struct crt_twarp_ctxt { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le64 Timestamp; >>> >>> @@ -183,12 +183,12 @@ struct crt_twarp_ctxt { >>> >>> /* See MS-SMB2 2.2.13.2.9 */ >>> struct crt_query_id_ctxt { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> } __packed; >>> >>> struct crt_sd_ctxt { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct smb3_sd sd; >>> } __packed; >>> @@ -415,7 +415,7 @@ struct smb2_posix_info_parsed { >>> }; >>> >>> struct smb2_create_ea_ctx { >>> - struct create_context ctx; >>> + struct create_context_hdr ctx; >>> __u8 name[8]; >>> struct smb2_file_full_ea_info ea; >>> } __packed; >>> diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h >>> index 1b594307c9d5..eab9d49c63ba 100644 >>> --- a/fs/smb/common/smb2pdu.h >>> +++ b/fs/smb/common/smb2pdu.h >>> @@ -1171,12 +1171,15 @@ struct smb2_server_client_notification { >>> #define SMB2_CREATE_FLAG_REPARSEPOINT 0x01 >>> >>> struct create_context { >>> - __le32 Next; >>> - __le16 NameOffset; >>> - __le16 NameLength; >>> - __le16 Reserved; >>> - __le16 DataOffset; >>> - __le32 DataLength; >>> + /* New members must be added within the struct_group() macro below. */ >>> + __struct_group(create_context_hdr, hdr, __packed, >>> + __le32 Next; >>> + __le16 NameOffset; >>> + __le16 NameLength; >>> + __le16 Reserved; >>> + __le16 DataOffset; >>> + __le32 DataLength; >>> + ); >>> __u8 Buffer[]; >>> } __packed; >>> >>> @@ -1222,7 +1225,7 @@ struct smb2_create_rsp { >>> } __packed; >>> >>> struct create_posix { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[16]; >>> __le32 Mode; >>> __u32 Reserved; >>> @@ -1230,7 +1233,7 @@ struct create_posix { >>> >>> /* See MS-SMB2 2.2.13.2.3 and MS-SMB2 2.2.13.2.4 */ >>> struct create_durable { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> union { >>> __u8 Reserved[16]; >>> @@ -1243,14 +1246,14 @@ struct create_durable { >>> >>> /* See MS-SMB2 2.2.13.2.5 */ >>> struct create_mxac_req { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le64 Timestamp; >>> } __packed; >>> >>> /* See MS-SMB2 2.2.14.2.5 */ >>> struct create_mxac_rsp { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le32 QueryStatus; >>> __le32 MaximalAccess; >>> @@ -1286,13 +1289,13 @@ struct lease_context_v2 { >>> } __packed; >>> >>> struct create_lease { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct lease_context lcontext; >>> } __packed; >>> >>> struct create_lease_v2 { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct lease_context_v2 lcontext; >>> __u8 Pad[4]; >>> @@ -1300,7 +1303,7 @@ struct create_lease_v2 { >>> >>> /* See MS-SMB2 2.2.14.2.9 */ >>> struct create_disk_id_rsp { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le64 DiskFileId; >>> __le64 VolumeId; >>> @@ -1309,7 +1312,7 @@ struct create_disk_id_rsp { >>> >>> /* See MS-SMB2 2.2.13.2.13 */ >>> struct create_app_inst_id { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[16]; >>> __le32 StructureSize; /* Must be 20 */ >>> __u16 Reserved; >>> @@ -1318,7 +1321,7 @@ struct create_app_inst_id { >>> >>> /* See MS-SMB2 2.2.13.2.15 */ >>> struct create_app_inst_id_vers { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[16]; >>> __le32 StructureSize; /* Must be 24 */ >>> __u16 Reserved; >>> diff --git a/fs/smb/server/smb2pdu.h b/fs/smb/server/smb2pdu.h >>> index bd1d2a0e9203..643f5e1cfe35 100644 >>> --- a/fs/smb/server/smb2pdu.h >>> +++ b/fs/smb/server/smb2pdu.h >>> @@ -64,7 +64,7 @@ struct preauth_integrity_info { >>> #define SMB2_SESSION_TIMEOUT (10 * HZ) >>> >>> struct create_durable_req_v2 { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le32 Timeout; >>> __le32 Flags; >>> @@ -73,7 +73,7 @@ struct create_durable_req_v2 { >>> } __packed; >>> >>> struct create_durable_reconn_req { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> union { >>> __u8 Reserved[16]; >>> @@ -85,7 +85,7 @@ struct create_durable_reconn_req { >>> } __packed; >>> >>> struct create_durable_reconn_v2_req { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct { >>> __u64 PersistentFileId; >>> @@ -96,13 +96,13 @@ struct create_durable_reconn_v2_req { >>> } __packed; >>> >>> struct create_alloc_size_req { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le64 AllocationSize; >>> } __packed; >>> >>> struct create_durable_rsp { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> union { >>> __u8 Reserved[8]; >>> @@ -114,7 +114,7 @@ struct create_durable_rsp { >>> /* Flags */ >>> #define SMB2_DHANDLE_FLAG_PERSISTENT 0x00000002 >>> struct create_durable_v2_rsp { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> __le32 Timeout; >>> __le32 Flags; >>> @@ -122,7 +122,7 @@ struct create_durable_v2_rsp { >>> >>> /* equivalent of the contents of SMB3.1.1 POSIX open context response */ >>> struct create_posix_rsp { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[16]; >>> __le32 nlink; >>> __le32 reparse_tag; >>> @@ -381,13 +381,13 @@ struct smb2_ea_info { >>> } __packed; /* level 15 Query */ >>> >>> struct create_ea_buf_req { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct smb2_ea_info ea; >>> } __packed; >>> >>> struct create_sd_buf_req { >>> - struct create_context ccontext; >>> + struct create_context_hdr ccontext; >>> __u8 Name[8]; >>> struct smb_ntsd ntsd; >>> } __packed; >> > > > -- > Thanks, > > Steve
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