[U-Boot] [PATCH 1/4] disk: efi: Fix memory leak on 'gpt guid'

[Heinrich Schuchardt]

On 4/30/19 4:53 AM, Eugeniu Rosca wrote:
> Below is what happens on R-Car H3ULCB-KF using clean U-Boot
> v2019.04-00810-g6aebc0d11a10 and r8a7795_ulcb_defconfig:
>
>   => ### interrupt autoboot
>   => gpt guid mmc 1
>   21200400-0804-0146-9dcc-a8c51255994f
>   success!
>   => ### keep calling 'gpt guid mmc 1'
>   => ### on 59th call, we are out of memory:
>   => gpt guid mmc 1
>   alloc_read_gpt_entries: ERROR: Can't allocate 0X4000 bytes for GPT Entries
>   GPT: Failed to allocate memory for PTE
>   get_disk_guid: *** ERROR: Invalid GPT ***
>   alloc_read_gpt_entries: ERROR: Can't allocate 0X4000 bytes for GPT Entries
>   GPT: Failed to allocate memory for PTE
>   get_disk_guid: *** ERROR: Invalid Backup GPT ***
>   error!
>
> After some inspection, it looks like get_disk_guid(), added via v2017.09
> commit 73d6d18b7147c9 ("GPT: add accessor function for disk GUID"),
> unlike other callers of is_gpt_valid(), doesn't free the memory pointed
> out by 'gpt_entry *gpt_pte'. The latter is allocated by is_gpt_valid()
> via alloc_read_gpt_entries().
>
> With the fix applied, the reproduction scenario has been run hundreds
> of times ('while true; do gpt guid mmc 1; done') w/o running into OOM.
>
> Fixes: 73d6d18b7147c9 ("GPT: add accessor function for disk GUID")
> Signed-off-by: Eugeniu Rosca <erosca at de.adit-jv.com>

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

> ---
>   disk/part_efi.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/disk/part_efi.c b/disk/part_efi.c
> index 239455b8161e..812d14cdd871 100644
> --- a/disk/part_efi.c
> +++ b/disk/part_efi.c
> @@ -209,6 +209,8 @@ int get_disk_guid(struct blk_desc * dev_desc, char *guid)
>   	guid_bin = gpt_head->disk_guid.b;
>   	uuid_bin_to_str(guid_bin, guid, UUID_STR_FORMAT_GUID);
>
> +	/* Remember to free pte */
> +	free(gpt_pte);
>   	return 0;
>   }
>
>