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From: Petr Lautrbach <plautrba@redhat.com>
To: selinux@vger.kernel.org
Cc: Nicolas Iooss <nicolas.iooss@m4x.org>, jwcart2 <jwcart2@tycho.nsa.gov>
Subject: Re: [Non-DoD Source] [PATCH 1/1] libsepol: do not use uninitialized value for low_value
Date: Wed, 06 Feb 2019 09:12:44 +0100	[thread overview]
Message-ID: <pjdimxxz66b.fsf@redhat.com> (raw)
In-Reply-To: <0e0c3fc1-e6db-d59f-5f8c-5cc1b58705d1@tycho.nsa.gov> (jwcart2's message of "Mon, 4 Feb 2019 11:54:09 -0500")

jwcart2 <jwcart2@tycho.nsa.gov> writes:

> On 2/3/19 6:01 AM, Nicolas Iooss wrote:
>> clang's static analyzer reports a warning when low_bit is used without
>> having been initialized in statements such as:
>>
>>      low_value = low_bit << 8;
>>
>> The warning is: "Result of operation is garbage or undefined".
>>
>> This is caused by low_bit being only initialized when in_range is true.
>> This issue is not critical because low_value is only used in an
>> "if (in_range)" block. Silence this warning by moving low_value's
>> assignment inside this block.
>>
>> Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
>
> Acked-by: James Carter <jwcart2@tycho.nsa.gov>

Merged.

>
>> ---
>>   libsepol/src/kernel_to_cil.c | 4 ++--
>>   libsepol/src/module_to_cil.c | 4 ++--
>>   libsepol/src/util.c          | 4 ++--
>>   3 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/libsepol/src/kernel_to_cil.c b/libsepol/src/kernel_to_cil.c
>> index 63e4d4899758..cd3554e8dfd9 100644
>> --- a/libsepol/src/kernel_to_cil.c
>> +++ b/libsepol/src/kernel_to_cil.c
>> @@ -1614,8 +1614,8 @@ static char *xperms_to_str(avtab_extended_perms_t *xperms)
>>     		if (xperms->specified & AVTAB_XPERMS_IOCTLFUNCTION) {
>>   			value = xperms->driver<<8 | bit;
>> -			low_value = xperms->driver<<8 | low_bit;
>>   			if (in_range) {
>> +				low_value = xperms->driver<<8 | low_bit;
>>   				len = snprintf(p, remaining, " (range 0x%hx 0x%hx)", low_value, value);
>>   				in_range = 0;
>>   			} else {
>> @@ -1623,8 +1623,8 @@ static char *xperms_to_str(avtab_extended_perms_t *xperms)
>>   			}
>>   		} else if (xperms->specified & AVTAB_XPERMS_IOCTLDRIVER) {
>>   			value = bit << 8;
>> -			low_value = low_bit << 8;
>>   			if (in_range) {
>> +				low_value = low_bit << 8;
>>   				len = snprintf(p, remaining, " (range 0x%hx 0x%hx)", low_value, (uint16_t) (value|0xff));
>>   				in_range = 0;
>>   			} else {
>> diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
>> index 4cb44e0ee657..f04589edaeff 100644
>> --- a/libsepol/src/module_to_cil.c
>> +++ b/libsepol/src/module_to_cil.c
>> @@ -655,8 +655,8 @@ static int xperms_to_cil(const av_extended_perms_t *xperms)
>>     		if (xperms->specified & AVTAB_XPERMS_IOCTLFUNCTION) {
>>   			value = xperms->driver<<8 | bit;
>> -			low_value = xperms->driver<<8 | low_bit;
>>   			if (in_range) {
>> +				low_value = xperms->driver<<8 | low_bit;
>>   				cil_printf("(range 0x%hx 0x%hx)", low_value, value);
>>   				in_range = 0;
>>   			} else {
>> @@ -664,8 +664,8 @@ static int xperms_to_cil(const av_extended_perms_t *xperms)
>>   			}
>>   		} else if (xperms->specified & AVTAB_XPERMS_IOCTLDRIVER) {
>>   			value = bit << 8;
>> -			low_value = low_bit << 8;
>>   			if (in_range) {
>> +				low_value = low_bit << 8;
>>   				cil_printf("(range 0x%hx 0x%hx)", low_value, (uint16_t) (value|0xff));
>>   				in_range = 0;
>>   			} else {
>> diff --git a/libsepol/src/util.c b/libsepol/src/util.c
>> index b00251c69aa5..a4008882b94b 100644
>> --- a/libsepol/src/util.c
>> +++ b/libsepol/src/util.c
>> @@ -159,16 +159,16 @@ char *sepol_extended_perms_to_string(avtab_extended_perms_t *xperms)
>>     		if (xperms->specified & AVTAB_XPERMS_IOCTLFUNCTION) {
>>   			value = xperms->driver<<8 | bit;
>> -			low_value = xperms->driver<<8 | low_bit;
>>   			if (in_range) {
>> +				low_value = xperms->driver<<8 | low_bit;
>>   				len = snprintf(p, sizeof(xpermsbuf) - xpermslen, "0x%hx-0x%hx ", low_value, value);
>>   			} else {
>>   				len = snprintf(p, sizeof(xpermsbuf) - xpermslen, "0x%hx ", value);
>>   			}
>>   		} else if (xperms->specified & AVTAB_XPERMS_IOCTLDRIVER) {
>>   			value = bit << 8;
>> -			low_value = low_bit << 8;
>>   			if (in_range) {
>> +				low_value = low_bit << 8;
>>   				len = snprintf(p, sizeof(xpermsbuf) - xpermslen, "0x%hx-0x%hx ", low_value, (uint16_t) (value|0xff));
>>   			} else {
>>   				len = snprintf(p, sizeof(xpermsbuf) - xpermslen, "0x%hx-0x%hx ", value, (uint16_t) (value|0xff));
>>

      reply	other threads:[~2019-02-06  8:12 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-03 11:01 [PATCH 1/1] libsepol: do not use uninitialized value for low_value Nicolas Iooss
2019-02-04 16:54 ` [Non-DoD Source] " jwcart2
2019-02-06  8:12   ` Petr Lautrbach [this message]

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