[PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

[PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

[Dan Carpenter]

The clean up is handled by the caller, rpcrdma_buffer_create(), so this
call to rpcrdma_sendctxs_destroy() leads to a double free.

Fixes: ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 net/sunrpc/xprtrdma/verbs.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 3dde05892c8e..4994e75945b8 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -845,17 +845,13 @@ static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
 	for (i = 0; i <= buf->rb_sc_last; i++) {
 		sc = rpcrdma_sendctx_create(&r_xprt->rx_ia);
 		if (!sc)
-			goto out_destroy;
+			return -ENOMEM;
 
 		sc->sc_xprt = r_xprt;
 		buf->rb_sc_ctxs[i] = sc;
 	}
 
 	return 0;
-
-out_destroy:
-	rpcrdma_sendctxs_destroy(buf);
-	return -ENOMEM;
 }
 
 /* The sendctx queue is not guaranteed to have a size that is a
-- 
2.17.1

Re: [PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

[Chuck Lever]

> On Jan 5, 2019, at 8:06 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> 
> The clean up is handled by the caller, rpcrdma_buffer_create(), so this
> call to rpcrdma_sendctxs_destroy() leads to a double free.

True. This fix is adequate, but I'm wondering if rpcrdma_sendctxs_destroy
should be made more careful about being called twice. Hm.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>


> Fixes: ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> net/sunrpc/xprtrdma/verbs.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 3dde05892c8e..4994e75945b8 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -845,17 +845,13 @@ static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
> 	for (i = 0; i <= buf->rb_sc_last; i++) {
> 		sc = rpcrdma_sendctx_create(&r_xprt->rx_ia);
> 		if (!sc)
> -			goto out_destroy;
> +			return -ENOMEM;
> 
> 		sc->sc_xprt = r_xprt;
> 		buf->rb_sc_ctxs[i] = sc;
> 	}
> 
> 	return 0;
> -
> -out_destroy:
> -	rpcrdma_sendctxs_destroy(buf);
> -	return -ENOMEM;
> }
> 
> /* The sendctx queue is not guaranteed to have a size that is a
> -- 
> 2.17.1
> 

--
Chuck Lever

Re: [PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

[Bruce Fields]

On Sat, Jan 05, 2019 at 11:24:45AM -0500, Chuck Lever wrote:
> 
> > On Jan 5, 2019, at 8:06 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> > 
> > The clean up is handled by the caller, rpcrdma_buffer_create(), so this
> > call to rpcrdma_sendctxs_destroy() leads to a double free.
> 
> True. This fix is adequate, but I'm wondering if rpcrdma_sendctxs_destroy
> should be made more careful about being called twice. Hm.
> 
> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>

I'm assuming Trond or Anna will pick this up.--b.

> 
> 
> > Fixes: ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > net/sunrpc/xprtrdma/verbs.c | 6 +-----
> > 1 file changed, 1 insertion(+), 5 deletions(-)
> > 
> > diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> > index 3dde05892c8e..4994e75945b8 100644
> > --- a/net/sunrpc/xprtrdma/verbs.c
> > +++ b/net/sunrpc/xprtrdma/verbs.c
> > @@ -845,17 +845,13 @@ static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
> > 	for (i = 0; i <= buf->rb_sc_last; i++) {
> > 		sc = rpcrdma_sendctx_create(&r_xprt->rx_ia);
> > 		if (!sc)
> > -			goto out_destroy;
> > +			return -ENOMEM;
> > 
> > 		sc->sc_xprt = r_xprt;
> > 		buf->rb_sc_ctxs[i] = sc;
> > 	}
> > 
> > 	return 0;
> > -
> > -out_destroy:
> > -	rpcrdma_sendctxs_destroy(buf);
> > -	return -ENOMEM;
> > }
> > 
> > /* The sendctx queue is not guaranteed to have a size that is a
> > -- 
> > 2.17.1
> > 
> 
> --
> Chuck Lever
> 
> 

Re: [PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

[Dan Carpenter]

On Sat, Jan 05, 2019 at 11:24:45AM -0500, Chuck Lever wrote:
> 
> > On Jan 5, 2019, at 8:06 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> > 
> > The clean up is handled by the caller, rpcrdma_buffer_create(), so this
> > call to rpcrdma_sendctxs_destroy() leads to a double free.
> 
> True. This fix is adequate, but I'm wondering if rpcrdma_sendctxs_destroy
> should be made more careful about being called twice. Hm.
> 

I actually wrote the patch like that originally, but then this way made
for an easier patch description so I re-wrote it.  Let me send the other
patch and you can apply that or both if you want.

regards,
dan carpenter

[PATCH] xprtrdma: Make rpcrdma_sendctxs_destroy() more robust

[Dan Carpenter]

There was a double free in the error handling here recently.  It was
a bit subtle which function was supposed to call rpcrdma_sendctxs_destroy()
so it was called in both.

This patch makes it so we can call rpcrdma_sendctxs_destroy() twice
in a row without crashing.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 net/sunrpc/xprtrdma/verbs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 7749a2bf6887..d05f4885548d 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -802,9 +802,12 @@ static void rpcrdma_sendctxs_destroy(struct rpcrdma_buffer *buf)
 {
 	unsigned long i;
 
+	if (!buf->rb_sc_ctxs)
+		return;
 	for (i = 0; i <= buf->rb_sc_last; i++)
 		kfree(buf->rb_sc_ctxs[i]);
 	kfree(buf->rb_sc_ctxs);
+	buf->rb_sc_ctxs = NULL;
 }
 
 static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
-- 
2.17.1

Re: [PATCH] xprtrdma: Make rpcrdma_sendctxs_destroy() more robust

[Chuck Lever]

> On Jan 7, 2019, at 2:08 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> 
> There was a double free in the error handling here recently.  It was
> a bit subtle which function was supposed to call rpcrdma_sendctxs_destroy()
> so it was called in both.
> 
> This patch makes it so we can call rpcrdma_sendctxs_destroy() twice
> in a row without crashing.

Belt-and-braces. I think the other patch "must" be applied, and this
one "should" be applied.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>


> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> net/sunrpc/xprtrdma/verbs.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 7749a2bf6887..d05f4885548d 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -802,9 +802,12 @@ static void rpcrdma_sendctxs_destroy(struct rpcrdma_buffer *buf)
> {
> 	unsigned long i;
> 
> +	if (!buf->rb_sc_ctxs)
> +		return;
> 	for (i = 0; i <= buf->rb_sc_last; i++)
> 		kfree(buf->rb_sc_ctxs[i]);
> 	kfree(buf->rb_sc_ctxs);
> +	buf->rb_sc_ctxs = NULL;
> }
> 
> static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
> -- 
> 2.17.1
> 

--
Chuck Lever

Re: [PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

[Schumaker, Anna]

On Mon, 2019-01-07 at 12:22 -0500, Bruce Fields wrote:
> On Sat, Jan 05, 2019 at 11:24:45AM -0500, Chuck Lever wrote:
> > > On Jan 5, 2019, at 8:06 AM, Dan Carpenter <dan.carpenter@oracle.com>
> > > wrote:
> > > 
> > > The clean up is handled by the caller, rpcrdma_buffer_create(), so this
> > > call to rpcrdma_sendctxs_destroy() leads to a double free.
> > 
> > True. This fix is adequate, but I'm wondering if rpcrdma_sendctxs_destroy
> > should be made more careful about being called twice. Hm.
> > 
> > Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
> 
> I'm assuming Trond or Anna will pick this up.--b.

Yeah, I'll take this one and 1/2 for a 5.0-rc.  I might save the additional
cleanup patch Dan sent for 5.1

Anna

> 
> > 
> > > Fixes: ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send
> > > arguments")
> > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > ---
> > > net/sunrpc/xprtrdma/verbs.c | 6 +-----
> > > 1 file changed, 1 insertion(+), 5 deletions(-)
> > > 
> > > diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> > > index 3dde05892c8e..4994e75945b8 100644
> > > --- a/net/sunrpc/xprtrdma/verbs.c
> > > +++ b/net/sunrpc/xprtrdma/verbs.c
> > > @@ -845,17 +845,13 @@ static int rpcrdma_sendctxs_create(struct
> > > rpcrdma_xprt *r_xprt)
> > > 	for (i = 0; i <= buf->rb_sc_last; i++) {
> > > 		sc = rpcrdma_sendctx_create(&r_xprt->rx_ia);
> > > 		if (!sc)
> > > -			goto out_destroy;
> > > +			return -ENOMEM;
> > > 
> > > 		sc->sc_xprt = r_xprt;
> > > 		buf->rb_sc_ctxs[i] = sc;
> > > 	}
> > > 
> > > 	return 0;
> > > -
> > > -out_destroy:
> > > -	rpcrdma_sendctxs_destroy(buf);
> > > -	return -ENOMEM;
> > > }
> > > 
> > > /* The sendctx queue is not guaranteed to have a size that is a
> > > -- 
> > > 2.17.1
> > > 
> > 
> > --
> > Chuck Lever
> > 
> >