diff mbox series

[CIFS] Fix uninitialized pointer access to dacl_ptr in build_sec_desc

Message ID CAH2r5ms_paV2a7KZwWkmz25pn4iS2kEDErGpNapOWZ5Kd_bUNw@mail.gmail.com (mailing list archive)
State New, archived
Headers show
Series [CIFS] Fix uninitialized pointer access to dacl_ptr in build_sec_desc | expand

Commit Message

Steve French June 22, 2021, 11:02 p.m. UTC 
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")

Comments

Aurélien Aptel June 23, 2021, 11:41 a.m. UTC | #1 
Steve French <smfrench@gmail.com> 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@microsoft.com>
> 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@microsoft.com>
> ---
>  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
>
Steve French June 23, 2021, 2:17 p.m. UTC | #2 
On Wed, Jun 23, 2021 at 6:41 AM Aurélien Aptel <aaptel@suse.com> wrote:
>
> Steve French <smfrench@gmail.com> 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;

I agree that your suggestion is clearer but I was trying to match the
existing checks in the same code.
Will change both to your suggestion which is clearer.


> >
> >
> > --
> > Thanks,
> >
> > Steve
> > From ec06cb04376e5abc927a9b85dd768ce8728965bb Mon Sep 17 00:00:00 2001
> > From: Steve French <stfrench@microsoft.com>
> > 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@microsoft.com>
> > ---
> >  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)
>
Steve French June 24, 2021, 12:27 a.m. UTC | #3 
just changed the one place you noted (to keep the patch smaller) - see attached.


On Wed, Jun 23, 2021 at 9:17 AM Steve French <smfrench@gmail.com> wrote:
>
> On Wed, Jun 23, 2021 at 6:41 AM Aurélien Aptel <aaptel@suse.com> wrote:
> >
> > Steve French <smfrench@gmail.com> 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;
>
> I agree that your suggestion is clearer but I was trying to match the
> existing checks in the same code.
> Will change both to your suggestion which is clearer.
>
>
> > >
> > >
> > > --
> > > Thanks,
> > >
> > > Steve
> > > From ec06cb04376e5abc927a9b85dd768ce8728965bb Mon Sep 17 00:00:00 2001
> > > From: Steve French <stfrench@microsoft.com>
> > > 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@microsoft.com>
> > > ---
> > >  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)
> >
>
>
> --
> Thanks,
>
> Steve
diff mbox series

Patch

From ec06cb04376e5abc927a9b85dd768ce8728965bb Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
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@microsoft.com>
---
 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