Steve French <smfrench@xxxxxxxxx> writes:
> smb3: fix possible access to uninitialized pointer to DACL
>
> dacl_ptr can be null so we must check for it (ie if dacloffset is
> set) everywhere dacl_ptr is
> used in build_sec_desc - and we were missing one check
>
> Addresses-Coverity: 1475598 ("Explicit null dereference")
Looks OK since dacl_ptr is only set if dacloffset is set but it would
be clearer if you check for dacl_ptr directly no? Any reason you are
checking this way?
I think this is clearer, unless I'm missing something:
ndacl_ptr->num_aces = dacl_ptr ? dacl_ptr->num_aces : 0;
>
>
> --
> Thanks,
>
> Steve
> From ec06cb04376e5abc927a9b85dd768ce8728965bb Mon Sep 17 00:00:00 2001
> From: Steve French <stfrench@xxxxxxxxxxxxx>
> Date: Tue, 22 Jun 2021 17:54:50 -0500
> Subject: [PATCH] smb3: fix possible access to uninitialized pointer to DACL
>
> dacl_ptr can be null so we must check for it everywhere it is
> used in build_sec_desc.
>
> Addresses-Coverity: 1475598 ("Explicit null dereference")
> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
> ---
> fs/cifs/cifsacl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
> index 784407f9280f..25a8139336fa 100644
> --- a/fs/cifs/cifsacl.c
> +++ b/fs/cifs/cifsacl.c
> @@ -1308,7 +1308,7 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
> ndacl_ptr = (struct cifs_acl *)((char *)pnntsd + ndacloffset);
> ndacl_ptr->revision =
> dacloffset ? dacl_ptr->revision : cpu_to_le16(ACL_REVISION);
> - ndacl_ptr->num_aces = dacl_ptr->num_aces;
> + ndacl_ptr->num_aces = dacloffset ? dacl_ptr->num_aces : 0;
>
> if (uid_valid(uid)) { /* chown */
> uid_t id;
> --
> 2.30.2
>
--
Aurélien Aptel / SUSE Labs Samba Team
GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg, DE
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 247165 (AG München)
