linux-kernel - Re: [PATCH v3] proc/vmcore: fix potential memory leak in vmcore

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Message-ID: <YsvWHwrltqqAb12h@MiWiFi-R3L-srv>
Date:   Mon, 11 Jul 2022 15:49:51 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Jianglei Nie <niejianglei2021@....com>
Cc:     vgoyal@...hat.com, dyoung@...hat.com, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v3] proc/vmcore: fix potential memory leak in
 vmcore_init()

On 07/11/22 at 03:34pm, Jianglei Nie wrote:
> elfcorehdr_alloc() allocates a memory chunk for elfcorehdr_addr with
> kzalloc(). If is_vmcore_usable() returns false, elfcorehdr_addr is a
> predefined value. If parse_crash_elf_headers() occurs some error and
> returns a negetive value, the elfcorehdr_addr should be released with
> elfcorehdr_free().
> 
> We can fix by calling elfcorehdr_free() when parse_crash_elf_headers()
> fails.
> 
> Signed-off-by: Jianglei Nie <niejianglei2021@....com>
> ---
>  fs/proc/vmcore.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index 4eaeb645e759..125efe63f281 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -1569,7 +1569,7 @@ static int __init vmcore_init(void)
>  	rc = parse_crash_elf_headers();
>  	if (rc) {
>  		pr_warn("Kdump: vmcore not initialized\n");
> -		return rc;
> +		goto fail;

Sigh. Why don't you copy my suggested code directly?

>  	}
>  	elfcorehdr_free(elfcorehdr_addr);

Remove above line.

>  	elfcorehdr_addr = ELFCORE_ADDR_ERR;
> @@ -1578,6 +1578,9 @@ static int __init vmcore_init(void)
>  	if (proc_vmcore)
>  		proc_vmcore->size = vmcore_size;
>  	return 0;

Remove above line too.

> +fail:
> +	elfcorehdr_free(elfcorehdr_addr);
> +	return rc;
>  }
>  fs_initcall(vmcore_init);
>  
> -- 
> 2.25.1
>