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SubjectRe: [PATCH][next] mailbox: PCC: check for negative count for parse failure checking
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On 05/30/2018 12:24 PM, Colin Ian King wrote:
> On 30/05/18 18:59, Al Stone wrote:
>> On 05/30/2018 11:14 AM, Colin King wrote:
>>> From: Colin Ian King <colin.king@canonical.com>
>>>
>>> The function acpi_table_parse_enties_array can potentially return a
>>> negative value if parsing fails. Currently the check on the return
>>> is not checking for errors, so fix this by adding a -ve check too.
>>>
>>> Detected by CoverityScan, CID#1469477 ("Improper use of negative value")
>>>
>>> Fixes: 8f8027c5f935 ("mailbox: PCC: erroneous error message when parsing ACPI PCCT")
>>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>>> ---
>>> drivers/mailbox/pcc.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
>>> index fc3c237daef2..87d67922020d 100644
>>> --- a/drivers/mailbox/pcc.c
>>> +++ b/drivers/mailbox/pcc.c
>>> @@ -461,7 +461,7 @@ static int __init acpi_pcc_probe(void)
>>> count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
>>> sizeof(struct acpi_table_pcct), proc,
>>> ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
>>> - if (count == 0 || count > MAX_PCC_SUBSPACES) {
>>> + if (count <= 0 || count > MAX_PCC_SUBSPACES) {
>>> pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
>>> return -EINVAL;
>>> }
>>>
>>
>> Yup, nice catch. A little paranoid, but we like that in a kernel :). Thanks.
>
> If it can go wrong, it will go wrong, especially with firmware :-)

Amen to that! You are preachin' to the choir, brother ...

>>
>> Reviewed-by: Al Stone <ahs3@redhat.com>
>>
>


--
ciao,
al
-----------------------------------
Al Stone
Software Engineer
Red Hat, Inc.
ahs3@redhat.com
-----------------------------------

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