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authorCong Wang <xiyou.wangcong@gmail.com>2018-09-12 16:27:44 -0700
committerDoug Ledford <dledford@redhat.com>2018-09-13 13:04:13 -0400
commit5fe23f262e0548ca7f19fb79f89059a60d087d22 (patch)
tree33c44b6bd334656e0222fbf3fb4ee99306392cbf /drivers/infiniband
parent67e3816842fe6414d629c7515b955952ec40c7d7 (diff)
ucma: fix a use-after-free in ucma_resolve_ip()
There is a race condition between ucma_close() and ucma_resolve_ip(): CPU0 CPU1 ucma_resolve_ip(): ucma_close(): ctx = ucma_get_ctx(file, cmd.id); list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) { mutex_lock(&mut); idr_remove(&ctx_idr, ctx->id); mutex_unlock(&mut); ... mutex_lock(&mut); if (!ctx->closing) { mutex_unlock(&mut); rdma_destroy_id(ctx->cm_id); ... ucma_free_ctx(ctx); ret = rdma_resolve_addr(); ucma_put_ctx(ctx); Before idr_remove(), ucma_get_ctx() could still find the ctx and after rdma_destroy_id(), rdma_resolve_addr() may still access id_priv pointer. Also, ucma_put_ctx() may use ctx after ucma_free_ctx() too. ucma_close() should call ucma_put_ctx() too which tests the refcnt and waits for the last one releasing it. The similar pattern is already used by ucma_destroy_id(). Reported-and-tested-by: syzbot+da2591e115d57a9cbb8b@syzkaller.appspotmail.com Reported-by: syzbot+cfe3c1e8ef634ba8964b@syzkaller.appspotmail.com Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Leon Romanovsky <leon@kernel.org> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/core/ucma.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 5f437d1570fb..21863ddde63e 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1759,6 +1759,8 @@ static int ucma_close(struct inode *inode, struct file *filp)
mutex_lock(&mut);
if (!ctx->closing) {
mutex_unlock(&mut);
+ ucma_put_ctx(ctx);
+ wait_for_completion(&ctx->comp);
/* rdma_destroy_id ensures that no event handlers are
* inflight for that id before releasing it.
*/