updated the patch slightly by creating local variable for ace_count
and acl_size to avoid excessive endian conversions
On Mon, Nov 30, 2020 at 10:19 PM Steve French <smfrench@xxxxxxxxx> wrote:
>
> Updated patch with fixes for various endian sparse warnings
>
>
> On Mon, Nov 30, 2020 at 12:02 AM Steve French <smfrench@xxxxxxxxx> wrote:
> >
> > When mounting with "idsfromsid" mount option, Azure
> > corrupted the owner SIDs due to excessive padding
> > caused by placing the owner fields at the end of the
> > security descriptor on create. Placing owners at the
> > front of the security descriptor (rather than the end)
> > is also safer, as the number of ACEs (that follow it)
> > are variable.
> >
> > --
> > Thanks,
> >
> > Steve
>
>
>
> --
> Thanks,
>
> Steve
--
Thanks,
Steve
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 445e80862865..1b27d8d90607 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2272,17 +2272,15 @@ static struct crt_sd_ctxt *
create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
{
struct crt_sd_ctxt *buf;
- struct cifs_ace *pace;
- unsigned int sdlen, acelen;
+ __u8 *ptr, *aclptr;
+ unsigned int acelen, acl_size, ace_count;
unsigned int owner_offset = 0;
unsigned int group_offset = 0;
+ struct smb3_acl acl;
- *len = roundup(sizeof(struct crt_sd_ctxt) + (sizeof(struct cifs_ace) * 2), 8);
+ *len = roundup(sizeof(struct crt_sd_ctxt) + (sizeof(struct cifs_ace) * 4), 8);
if (set_owner) {
- /* offset fields are from beginning of security descriptor not of create context */
- owner_offset = sizeof(struct smb3_acl) + (sizeof(struct cifs_ace) * 2);
-
/* sizeof(struct owner_group_sids) is already multiple of 8 so no need to round */
*len += sizeof(struct owner_group_sids);
}
@@ -2291,26 +2289,22 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
if (buf == NULL)
return buf;
+ ptr = (__u8 *)&buf[1];
if (set_owner) {
+ /* offset fields are from beginning of security descriptor not of create context */
+ owner_offset = ptr - (__u8 *)&buf->sd;
buf->sd.OffsetOwner = cpu_to_le32(owner_offset);
- group_offset = owner_offset + sizeof(struct owner_sid);
+ group_offset = owner_offset + offsetof(struct owner_group_sids, group);
buf->sd.OffsetGroup = cpu_to_le32(group_offset);
+
+ setup_owner_group_sids(ptr);
+ ptr += sizeof(struct owner_group_sids);
} else {
buf->sd.OffsetOwner = 0;
buf->sd.OffsetGroup = 0;
}
- sdlen = sizeof(struct smb3_sd) + sizeof(struct smb3_acl) +
- 2 * sizeof(struct cifs_ace);
- if (set_owner) {
- sdlen += sizeof(struct owner_group_sids);
- setup_owner_group_sids(owner_offset + sizeof(struct create_context) + 8 /* name */
- + (char *)buf);
- }
-
- buf->ccontext.DataOffset = cpu_to_le16(offsetof
- (struct crt_sd_ctxt, sd));
- buf->ccontext.DataLength = cpu_to_le32(sdlen);
+ buf->ccontext.DataOffset = cpu_to_le16(offsetof(struct crt_sd_ctxt, sd));
buf->ccontext.NameOffset = cpu_to_le16(offsetof(struct crt_sd_ctxt, Name));
buf->ccontext.NameLength = cpu_to_le16(4);
/* SMB2_CREATE_SD_BUFFER_TOKEN is "SecD" */
@@ -2319,6 +2313,7 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
buf->Name[2] = 'c';
buf->Name[3] = 'D';
buf->sd.Revision = 1; /* Must be one see MS-DTYP 2.4.6 */
+
/*
* ACL is "self relative" ie ACL is stored in contiguous block of memory
* and "DP" ie the DACL is present
@@ -2326,28 +2321,39 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
buf->sd.Control = cpu_to_le16(ACL_CONTROL_SR | ACL_CONTROL_DP);
/* offset owner, group and Sbz1 and SACL are all zero */
- buf->sd.OffsetDacl = cpu_to_le32(sizeof(struct smb3_sd));
- buf->acl.AclRevision = ACL_REVISION; /* See 2.4.4.1 of MS-DTYP */
+ buf->sd.OffsetDacl = cpu_to_le32(ptr - (__u8 *)&buf->sd);
+ /* Ship the ACL for now. we will copy it into buf later. */
+ aclptr = ptr;
+ ptr += sizeof(struct cifs_acl);
+
+ acl.AclRevision = ACL_REVISION; /* See 2.4.4.1 of MS-DTYP */
/* create one ACE to hold the mode embedded in reserved special SID */
- pace = (struct cifs_ace *)(sizeof(struct crt_sd_ctxt) + (char *)buf);
- acelen = setup_special_mode_ACE(pace, (__u64)mode);
+ acelen = setup_special_mode_ACE((struct cifs_ace *)ptr, (__u64)mode);
+ ptr += acelen;
+ acl_size = acelen + sizeof(struct smb3_acl);
+ ace_count = 1;
if (set_owner) {
/* we do not need to reallocate buffer to add the two more ACEs. plenty of space */
- pace = (struct cifs_ace *)(acelen + (sizeof(struct crt_sd_ctxt) + (char *)buf));
- acelen += setup_special_user_owner_ACE(pace);
- /* it does not appear necessary to add an ACE for the NFS group SID */
- buf->acl.AceCount = cpu_to_le16(3);
- } else
- buf->acl.AceCount = cpu_to_le16(2);
+ acelen = setup_special_user_owner_ACE((struct cifs_ace *)ptr);
+ ptr += acelen;
+ acl_size += acelen;
+ ace_count += 1;
+ }
/* and one more ACE to allow access for authenticated users */
- pace = (struct cifs_ace *)(acelen + (sizeof(struct crt_sd_ctxt) +
- (char *)buf));
- acelen += setup_authusers_ACE(pace);
+ acelen = setup_authusers_ACE((struct cifs_ace *)ptr);
+ ptr += acelen;
+ acl_size += acelen;
+ ace_count += 1;
+
+ acl.AclSize = cpu_to_le16(acl_size);
+ acl.AceCount = cpu_to_le16(ace_count);
+ memcpy(aclptr, &acl, sizeof(struct cifs_acl));
- buf->acl.AclSize = cpu_to_le16(sizeof(struct cifs_acl) + acelen);
+ buf->ccontext.DataLength = cpu_to_le32(ptr - (__u8 *)&buf->sd);
+ *len = ptr - (__u8 *)buf;
return buf;
}
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index f05f9b12f689..fa57b03ca98c 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -963,8 +963,6 @@ struct crt_sd_ctxt {
struct create_context ccontext;
__u8 Name[8];
struct smb3_sd sd;
- struct smb3_acl acl;
- /* Followed by at least 4 ACEs */
} __packed;
