From: Sukrut Bellary <sukrut.bellary@linux.com>
Date: Mon, 2 Sep 2024 14:14:09 +0000 (+0100)
Subject: misc: fastrpc: Fix double free of 'buf' in error path
X-Git-Tag: v6.11-rc7~3^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e8c276d4dc0e19ee48385f74426aebc855b49aaf;p=thirdparty%2Fkernel%2Flinux.git

misc: fastrpc: Fix double free of 'buf' in error path

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@linuxfoundation.org>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Sukrut Bellary <sukrut.bellary@linux.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20240902141409.70371-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 339d126414d4b..da87abe93daf2 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1910,7 +1910,8 @@ 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 */
@@ -1948,8 +1949,6 @@ 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;
 }