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

[Ursula Braun]

From: Dan Carpenter <dan.carpen...@oracle.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.carpen...@oracle.com>
Signed-off-by: Ursula Braun <ubr...@linux.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