[SLOF] [PATCH 1/2] tcgbios: Fix endianess of NumberOfPartitions

[Alexey Kardashevskiy]

On Tue, 25 Mar 2025, at 04:29, Stefan Berger wrote:
> From: Stefan Berger <stefanb at linux.ibm.com>
> 
> Write the 64bit integer 'NumberOfPartitions' in little endian format into
> the uefi_gpt_data so that they end up in little endian format in the
> measurement log.
> 
> Fixes: 16a1867425ee ("tcgbios: Measure the GPT table")
> Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
> ---
> lib/libtpm/tcgbios.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/libtpm/tcgbios.c b/lib/libtpm/tcgbios.c
> index 03443f9..9a10dbe 100644
> --- a/lib/libtpm/tcgbios.c
> +++ b/lib/libtpm/tcgbios.c
> @@ -1092,7 +1092,7 @@ void tpm_gpt_set_lba1(const uint8_t *addr, uint32_t length)
>  
> memcpy(&uefi_gpt_data->EfiPartitionHeader,
>        addr, MIN(sizeof(uefi_gpt_data->EfiPartitionHeader), length));
> - uefi_gpt_data->NumberOfPartitions = 0;
> + uefi_gpt_data->NumberOfPartitions = cpu_to_le64(0);
> }
>  
> /*
> @@ -1104,6 +1104,7 @@ void tpm_gpt_add_entry(const uint8_t *addr, uint32_t length)
> size_t sz;
> UEFI_PARTITION_ENTRY *upe = (void *)addr;
> void *tmp;
> + uint64_t numberOfPartitions;
>  
> if (!tpm_is_working() ||
>     !uefi_gpt_data ||
> @@ -1111,8 +1112,9 @@ void tpm_gpt_add_entry(const uint8_t *addr, uint32_t length)
>     !memcmp(upe->partTypeGuid, ZeroGuid, sizeof(ZeroGuid)))
> return;
>  
> + numberOfPartitions = le64_to_cpu(uefi_gpt_data->NumberOfPartitions);
> sz = offset_of(UEFI_GPT_DATA, Partitions) +
> -        (uefi_gpt_data->NumberOfPartitions + 1)
> +        (numberOfPartitions + 1)
>        * sizeof(UEFI_PARTITION_ENTRY);
> if (sz > uefi_gpt_data_size) {
> tmp = SLOF_alloc_mem(sz);
> @@ -1125,10 +1127,11 @@ void tpm_gpt_add_entry(const uint8_t *addr, uint32_t length)
> uefi_gpt_data_size = sz;
> }
>  
> - memcpy(&uefi_gpt_data->Partitions[uefi_gpt_data->NumberOfPartitions],
> + memcpy(&uefi_gpt_data->Partitions[numberOfPartitions],
>        addr,
>        sizeof(UEFI_PARTITION_ENTRY));
> - uefi_gpt_data->NumberOfPartitions++;
> +
> + uefi_gpt_data->NumberOfPartitions = cpu_to_le64(++numberOfPartitions);

nit: s/++numberOfPartitions/numberOfPartitions + 1/  or  have "++numberOfPartitions" in a separate line.
I would not probably bother commenting but since I am going to comment on 2/2... Thanks,

>  
> return;
>  
> @@ -1150,7 +1153,8 @@ uint32_t tpm_measure_gpt(void)
> return TCGBIOS_GENERAL_ERROR;
>  
> sz = offset_of(UEFI_GPT_DATA, Partitions) +
> -      uefi_gpt_data->NumberOfPartitions * sizeof(UEFI_PARTITION_ENTRY);
> +        le64_to_cpu(uefi_gpt_data->NumberOfPartitions)
> +        * sizeof(UEFI_PARTITION_ENTRY);
>  
> return tpm_add_measurement_to_log(5, EV_EFI_GPT_EVENT,
>   (const char *)uefi_gpt_data, sz,
> -- 
> 2.25.1
> 
>