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 <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
Reviewed-by: Srinivas Kandagatla <[email protected]>
Signed-off-by: Sukrut Bellary <[email protected]>
---
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/[email protected]/
---
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;
}
--
2.34.1
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 <[email protected]>
> Reviewed-by: Dan Carpenter <[email protected]>
> Reviewed-by: Srinivas Kandagatla <[email protected]>
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 <[email protected]>
> ---
> 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/[email protected]/
> ---
> 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;
> }
On Fri, 02 Jun 2023 04:36:02 -0700, 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.
>
> [...]
Applied, thanks!
[1/1] misc: fastrpc: Fix double free of 'buf' in error path
commit: 5b3006fffce89706a12741d7f657869ca2be1640
Best regards,
--
Srinivas Kandagatla <[email protected]>