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xprtrdma: Double free in rpcrdma_sendctxs_create()

PATCH In review Dan Carpenter 4 participants 7 messages Jan 5, 2019 – Jan 7, 2019

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Dan Carpenter

author
#0 lore raw

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

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 <[email protected]>
---
 net/sunrpc/xprtrdma/verbs.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
net/sunrpc/xprtrdma/verbs.c +1 -5
index 3dde05892c8e..4994e75945b8 100644
@@ -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
Signature · 1 line
2.17.1
Reviewed-by on v1 2/2
#1 lore raw
Quoted 5 lines · 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.

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 <[email protected]>
Quoted 32 lines
Fixes ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments")
Signed-off-by Dan Carpenter <[email protected]>

---
net/sunrpc/xprtrdma/verbs.c | 6 +-----

1 file changed, 1 insertion(+), 5 deletions(-)
net/sunrpc/xprtrdma/verbs.c +1 -5
index 3dde05892c8e..4994e75945b8 100644
@@ -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
Signature · 1 line
2.17.1

--
Chuck Lever

#2 lore raw
Quoted 10 lines · Chuck Lever
Quoted 5 lines · 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.

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 <[email protected]>

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

Quoted 39 lines
Quoted 34 lines
Fixes ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments")
Signed-off-by Dan Carpenter <[email protected]>

---
net/sunrpc/xprtrdma/verbs.c | 6 +-----

1 file changed, 1 insertion(+), 5 deletions(-)
net/sunrpc/xprtrdma/verbs.c +1 -5
index 3dde05892c8e..4994e75945b8 100644
@@ -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
Signature · 1 line
2.17.1

--
Chuck Lever

author
#4 lore raw
In reply to Chuck Lever
Quoted 9 lines · Chuck Lever
Quoted 5 lines · 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.

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

author
#5 lore raw

PATCH 1/1 xprtrdma: Make rpcrdma_sendctxs_destroy() more robust

In reply to Chuck Lever

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 <[email protected]>
---
 net/sunrpc/xprtrdma/verbs.c | 3 +++
 1 file changed, 3 insertions(+)
net/sunrpc/xprtrdma/verbs.c +3 -0
index 7749a2bf6887..d05f4885548d 100644
@@ -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)
Signature · 1 line
2.17.1
Reviewed-by on v1 1/1
#6 lore raw

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

Quoted 10 lines · 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.

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

Reviewed-by Chuck Lever <[email protected]>
Quoted 25 lines
Signed-off-by Dan Carpenter <[email protected]>

---
net/sunrpc/xprtrdma/verbs.c | 3 +++

1 file changed, 3 insertions(+)
net/sunrpc/xprtrdma/verbs.c +3 -0
index 7749a2bf6887..d05f4885548d 100644
@@ -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)
Signature · 1 line
2.17.1

--
Chuck Lever

#3 lore raw
In reply to Bruce Fields

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