Re: [PATCH] tpm2: fix off-by-one comparison and out-of-bounds read error

[Colin Ian King]

On 22/03/17 11:42, Jarkko Sakkinen wrote:
> On Mon, Mar 20, 2017 at 02:23:36PM +0000, Colin King wrote:
>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>
>> The comparison of an out of range index into space->context_tbl is
>> off-by-one and should be using >= rather than > in the comparison.
>>
>> Detected by CoverityScan, CID#1419694 ("Out-of-bounds read")
>>
>> Fixes: 849246e7ce9ce ("tpm2: add session handle context saving and restoring to the space code")
>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>> ---
>>  drivers/char/tpm/tpm2-space.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
>> index d36d81e07076..009934269514 100644
>> --- a/drivers/char/tpm/tpm2-space.c
>> +++ b/drivers/char/tpm/tpm2-space.c
>> @@ -229,7 +229,7 @@ static bool tpm2_map_to_phandle(struct tpm_space *space, void *handle)
>>  	int i;
>>  
>>  	i = 0xFFFFFF - (vhandle & 0xFFFFFF);
>> -	if (i > ARRAY_SIZE(space->context_tbl) || !space->context_tbl[i])
>> +	if (i >= ARRAY_SIZE(space->context_tbl) || !space->context_tbl[i])
>>  		return false;
>>  
>>  	phandle = space->context_tbl[i];
>> -- 
>> 2.11.0
> 
> Thanks. If you don't mind, I would squash this to that patch?
> 
> /Jarkko
> 
Sure squash it, and maybe add a Reported-by: Colin Ian King
<colin.king@xxxxxxxxxxxxx> if that's OK with you.

Colin