linux-kernel - Re: [PATCH] efi: fix memory leak in krealloc failure handling

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Date:   Fri, 13 Oct 2023 12:32:53 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Kuan-Wei Chiu <visitorckw@...il.com>
Cc:     linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] efi: fix memory leak in krealloc failure handling

On Sun, 24 Sept 2023 at 16:26, Kuan-Wei Chiu <visitorckw@...il.com> wrote:
>
> In the previous code, there was a memory leak issue where the
> previously allocated memory was not freed upon a failed krealloc
> operation. This patch addresses the problem by releasing the old memory
> before setting the pointer to NULL in case of a krealloc failure. This
> ensures that memory is properly managed and avoids potential memory
> leaks.
>
> Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
> ---
>  drivers/firmware/efi/efi.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>

Queued as a fix

Thanks,

> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index ce20a60676f0..1974f0ad32ba 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -273,9 +273,13 @@ static __init int efivar_ssdt_load(void)
>                 if (status == EFI_NOT_FOUND) {
>                         break;
>                 } else if (status == EFI_BUFFER_TOO_SMALL) {
> -                       name = krealloc(name, name_size, GFP_KERNEL);
> -                       if (!name)
> +                       efi_char16_t *name_tmp =
> +                               krealloc(name, name_size, GFP_KERNEL);
> +                       if (!name_tmp) {
> +                               kfree(name);
>                                 return -ENOMEM;
> +                       }
> +                       name = name_tmp;
>                         continue;
>                 }
>
> --
> 2.25.1
>