netdev - [PATCH net-next 1/1] smc: some potential use after free bugs

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Date:   Mon, 30 Jan 2017 10:55:04 +0100
From:   Ursula Braun <ubraun@...ux.vnet.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
        ubraun@...ux.vnet.ibm.com, dan.carpenter@...cle.com
Subject: [PATCH net-next 1/1] smc: some potential use after free bugs

From: Dan Carpenter <dan.carpenter@...cle.com>

Say we got really unlucky and these failed on the last iteration, then
it could lead to a use after free bug.

Fixes: cd6851f30386 ("smc: remote memory buffers (RMBs)")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Ursula Braun <ubraun@...ux.vnet.ibm.com>
---
 net/smc/smc_core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 8b1d343..0eac633 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -532,6 +532,7 @@ int smc_sndbuf_create(struct smc_sock *smc)
 						__GFP_NORETRY);
 		if (!sndbuf_desc->cpu_addr) {
 			kfree(sndbuf_desc);
+			sndbuf_desc = NULL;
 			/* if send buffer allocation has failed,
 			 * try a smaller one
 			 */
@@ -543,6 +544,7 @@ int smc_sndbuf_create(struct smc_sock *smc)
 		if (rc) {
 			kfree(sndbuf_desc->cpu_addr);
 			kfree(sndbuf_desc);
+			sndbuf_desc = NULL;
 			continue; /* if mapping failed, try smaller one */
 		}
 		sndbuf_desc->used = 1;
@@ -596,6 +598,7 @@ int smc_rmb_create(struct smc_sock *smc)
 					     __GFP_NORETRY);
 		if (!rmb_desc->cpu_addr) {
 			kfree(rmb_desc);
+			rmb_desc = NULL;
 			/* if RMB allocation has failed,
 			 * try a smaller one
 			 */
@@ -607,6 +610,7 @@ int smc_rmb_create(struct smc_sock *smc)
 		if (rc) {
 			kfree(rmb_desc->cpu_addr);
 			kfree(rmb_desc);
+			rmb_desc = NULL;
 			continue; /* if mapping failed, try smaller one */
 		}
 		rc = smc_ib_get_memory_region(lgr->lnk[SMC_SINGLE_LINK].roce_pd,
@@ -619,6 +623,7 @@ int smc_rmb_create(struct smc_sock *smc)
 					 DMA_FROM_DEVICE);
 			kfree(rmb_desc->cpu_addr);
 			kfree(rmb_desc);
+			rmb_desc = NULL;
 			continue;
 		}
 		rmb_desc->used = 1;
-- 
2.8.4