[PATCH 5.1 300/405] misc: fastrpc: Fix a possible double free

From: Greg Kroah-Hartman
Date: Thu May 30 2019 - 00:48:42 EST


[ Upstream commit b49f6d83e290f17e20f4e5cf31288d3bb4955ea6 ]

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.escande@xxxxxxxxxx>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 a10937652ca73..35be1cc11dd85 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -856,12 +856,12 @@ 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;
@@ -875,17 +875,15 @@ 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;
@@ -921,13 +919,24 @@ 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;
--
2.20.1