diff mbox series

nfsd: fix memory leak in __cld_pipe_inprogress_downcall()

Message ID 20240216134541.31577-1-a.burakov@rosalinux.ru
State New
Headers
Series nfsd: fix memory leak in __cld_pipe_inprogress_downcall() |

Commit Message

Aleksandr Burakov Feb. 16, 2024, 1:45 p.m. UTC 
  Dynamic memory, referenced by 'princhash.data' and 'name.data', 
is allocated by calling function 'memdup_user' and lost 
at __cld_pipe_inprogress_downcall() function return

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 11a60d159259 ("nfsd: add a "GetVersion" upcall for nfsdcld")
Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
---
 fs/nfsd/nfs4recover.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Fedor Pchelkin Feb. 18, 2024, 6:06 p.m. UTC | #1 
Hello Aleksandr,

On 24/02/16 04:45PM, Aleksandr Burakov wrote:
> Dynamic memory, referenced by 'princhash.data' and 'name.data', 
> is allocated by calling function 'memdup_user' and lost 
> at __cld_pipe_inprogress_downcall() function return

It is not actually lost. If nfs4_client_to_reclaim() fails and thus
returns NULL - this error case is already properly handled.

If nfs4_client_to_reclaim() succeeds then reference to the memory in
question is passed to crp->cr_name.data and crp->cr_princhash.data
correspondingly, and crp->cr_strhash entry is added to the list associated
with nfsd_net. In this case the memory is supposed to be freed by
nfs4_remove_reclaim_record(). See comment for nfs4_client_to_reclaim().

So I think the patch just introduces a double-free.

> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 11a60d159259 ("nfsd: add a "GetVersion" upcall for nfsdcld")
> Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
> ---
>  fs/nfsd/nfs4recover.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> index 2c060e0b1604..02663484782d 100644
> --- a/fs/nfsd/nfs4recover.c
> +++ b/fs/nfsd/nfs4recover.c
> @@ -850,6 +850,8 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
>  			kfree(princhash.data);
>  			return -EFAULT;
>  		}
> +		kfree(name.data);
> +		kfree(princhash.data);
>  		return nn->client_tracking_ops->msglen;
>  	}
>  	return -EFAULT;
> -- 
> 2.25.1

--
Fedor
NeilBrown Feb. 18, 2024, 10:17 p.m. UTC | #2 
On Mon, 19 Feb 2024, Fedor Pchelkin wrote:
> Hello Aleksandr,
> 
> On 24/02/16 04:45PM, Aleksandr Burakov wrote:
> > Dynamic memory, referenced by 'princhash.data' and 'name.data', 
> > is allocated by calling function 'memdup_user' and lost 
> > at __cld_pipe_inprogress_downcall() function return
> 
> It is not actually lost. If nfs4_client_to_reclaim() fails and thus
> returns NULL - this error case is already properly handled.
> 
> If nfs4_client_to_reclaim() succeeds then reference to the memory in
> question is passed to crp->cr_name.data and crp->cr_princhash.data
> correspondingly, and crp->cr_strhash entry is added to the list associated
> with nfsd_net. In this case the memory is supposed to be freed by
> nfs4_remove_reclaim_record(). See comment for nfs4_client_to_reclaim().
> 
> So I think the patch just introduces a double-free.

Agreed - this patch is incorrect.

Thanks,
NeilBrown


> 
> > 
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: 11a60d159259 ("nfsd: add a "GetVersion" upcall for nfsdcld")
> > Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
> > ---
> >  fs/nfsd/nfs4recover.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> > index 2c060e0b1604..02663484782d 100644
> > --- a/fs/nfsd/nfs4recover.c
> > +++ b/fs/nfsd/nfs4recover.c
> > @@ -850,6 +850,8 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
> >  			kfree(princhash.data);
> >  			return -EFAULT;
> >  		}
> > +		kfree(name.data);
> > +		kfree(princhash.data);
> >  		return nn->client_tracking_ops->msglen;
> >  	}
> >  	return -EFAULT;
> > -- 
> > 2.25.1
> 
> --
> Fedor
> 
>
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 2c060e0b1604..02663484782d 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -850,6 +850,8 @@  __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
 			kfree(princhash.data);
 			return -EFAULT;
 		}
+		kfree(name.data);
+		kfree(princhash.data);
 		return nn->client_tracking_ops->msglen;
 	}
 	return -EFAULT;