linux-kernel - Re: [PATCH] tools/bootconfig: fix resource leak in apply

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Date:   Thu, 7 May 2020 22:30:11 +0200
From:   Markus Elfring <Markus.Elfring@....de>
To:     Yunfeng Ye <yeyunfeng@...wei.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
        Hewenliang <hewenliang4@...wei.com>,
        Shiyuan Hu <hushiyuan@...wei.com>
Subject: Re: [PATCH] tools/bootconfig: fix resource leak in apply_xbc()

> The @data and @fd is leak in the error path of apply_xbc(), so this
> patch fix it.

I suggest to improve this change description.

* Please use an imperative wording.

* Would you like to add the tag “Fixes”?


> +++ b/tools/bootconfig/main.c
> @@ -314,6 +314,7 @@  int apply_xbc(const char *path, const char *xbc_path)
>  	ret = delete_xbc(path);
>  	if (ret < 0) {
>  		pr_err("Failed to delete previous boot config: %d\n", ret);
> +		free(data);
>  		return ret;
>  	}

I propose to adjust the exception handling.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?id=6e7f2eacf09811d092c1b41263108ac7fe0d089d#n450

-		return ret;
+		goto free_data;


> @@ -321,24 +322,26 @@ int apply_xbc(const char *path, const char *xbc_path)
>  	fd = open(path, O_RDWR | O_APPEND);
>  	if (fd < 0) {
>  		pr_err("Failed to open %s: %d\n", path, fd);
> +		free(data);
>  		return fd;

-		return fd;
+		ret = fd;
+		goto free_data;


>  	}
>  	/* TODO: Ensure the @path is initramfs/initrd image */
>  	ret = write(fd, data, size + 8);
>  	if (ret < 0) {
>  		pr_err("Failed to apply a boot config: %d\n", ret);
> -		return ret;
> +		goto out;

+		goto free_data;


>  	}
>  	/* Write a magic word of the bootconfig */
>  	ret = write(fd, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);
>  	if (ret < 0) {

-	if (ret < 0) {
+	if (ret < 0)


>  		pr_err("Failed to apply a boot config magic: %d\n", ret);
> -		return ret;
> +		goto out;

I suggest to avoid an extra jump at such a place.


>  	}

-	}
+


> +out:

+close_fd:
>  	close(fd);

+free_data:
>  	free(data);


How do you think about to complete the error handling also at other
source code places?

Regards,
Markus