On 02/06/2023 12:36, Sukrut Bellary wrote:
smatch warning:
drivers/misc/fastrpc.c:1926 fastrpc_req_mmap() error: double free of 'buf'
In fastrpc_req_mmap() error path, the fastrpc buffer is freed in
fastrpc_req_munmap_impl() if unmap is successful.
But in the end, there is an unconditional call to fastrpc_buf_free().
So the above case triggers the double free of fastrpc buf.
Fixes: 72fa6f7820c4 ("misc: fastrpc: Rework fastrpc_req_munmap")
Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Not sure how was this reviewed-by picked up on this patch.
Suggested-by will be a right choice here.
Will manually edit before applying it.
--srini
Signed-off-by: Sukrut Bellary <sukrut.bellary@xxxxxxxxx>
---
This is based on static analysis. Compilation tested.
---
Changes in v2:
- Fixed the commit message.
- Addressed the review comment about deleting buf from the list
before freeing.
- Link to v1: https://lore.kernel.org/all/20230518100829.515143-1-sukrut.bellary@xxxxxxxxx/
---
drivers/misc/fastrpc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index f48466960f1b..b3b520fcfb75 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1882,7 +1882,8 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
&args[0]);
if (err) {
dev_err(dev, "mmap error (len 0x%08llx)\n", buf->size);
- goto err_invoke;
+ fastrpc_buf_free(buf);
+ return err;
}
/* update the buffer to be able to deallocate the memory on the DSP */
@@ -1922,8 +1923,6 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
err_assign:
fastrpc_req_munmap_impl(fl, buf);
-err_invoke:
- fastrpc_buf_free(buf);
return err;
}
