[PATCH 2/8] misc: fastrpc: Fix a possible double free

[Srinivas Kandagatla]

From: Thierry Escande <thierry.esca...@linaro.org>

This patch fixes the error exit path of fastrpc_init_create_process().
If the DMA allocation or the DSP invoke fails the fastrpc_map was freed
but not removed from the mapping list leading to a double free once the
mapping list is emptied in fastrpc_device_release().

[srinivas kandagatla]: Cleaned up error path labels and reset init mem
to NULL after free
Fixes: d73f71c7c6ee("misc: fastrpc: Add support for create remote init process")
Signed-off-by: Thierry Escande <thierry.esca...@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandaga...@linaro.org>
---
 drivers/misc/fastrpc.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 82e7217ae87a..8fbcc607a77e 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -853,12 +853,12 @@ static int fastrpc_init_create_process(struct 
fastrpc_user *fl,
 
        if (copy_from_user(&init, argp, sizeof(init))) {
                err = -EFAULT;
-               goto bail;
+               goto err;
        }
 
        if (init.filelen > INIT_FILELEN_MAX) {
                err = -EINVAL;
-               goto bail;
+               goto err;
        }
 
        inbuf.pgid = fl->tgid;
@@ -872,17 +872,15 @@ static int fastrpc_init_create_process(struct 
fastrpc_user *fl,
        if (init.filelen && init.filefd) {
                err = fastrpc_map_create(fl, init.filefd, init.filelen, &map);
                if (err)
-                       goto bail;
+                       goto err;
        }
 
        memlen = ALIGN(max(INIT_FILELEN_MAX, (int)init.filelen * 4),
                       1024 * 1024);
        err = fastrpc_buf_alloc(fl, fl->sctx->dev, memlen,
                                &imem);
-       if (err) {
-               fastrpc_map_put(map);
-               goto bail;
-       }
+       if (err)
+               goto err_alloc;
 
        fl->init_mem = imem;
        args[0].ptr = (u64)(uintptr_t)&inbuf;
@@ -918,13 +916,24 @@ static int fastrpc_init_create_process(struct 
fastrpc_user *fl,
 
        err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE,
                                      sc, args);
+       if (err)
+               goto err_invoke;
 
-       if (err) {
+       kfree(args);
+
+       return 0;
+
+err_invoke:
+       fl->init_mem = NULL;
+       fastrpc_buf_free(imem);
+err_alloc:
+       if (map) {
+               spin_lock(&fl->lock);
+               list_del(&map->node);
+               spin_unlock(&fl->lock);
                fastrpc_map_put(map);
-               fastrpc_buf_free(imem);
        }
-
-bail:
+err:
        kfree(args);
 
        return err;
-- 
2.21.0