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* [PATCH 1/1] libsepol: do not use uninitialized value for low_value
@ 2019-02-03 11:01 Nicolas Iooss
  2019-02-04 16:54 ` [Non-DoD Source] " jwcart2
  0 siblings, 1 reply; 3+ messages in thread
From: Nicolas Iooss @ 2019-02-03 11:01 UTC (permalink / raw)
  To: selinux

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>
---
 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));
-- 
2.20.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [Non-DoD Source] [PATCH 1/1] libsepol: do not use uninitialized value for low_value
  2019-02-03 11:01 [PATCH 1/1] libsepol: do not use uninitialized value for low_value Nicolas Iooss
@ 2019-02-04 16:54 ` " jwcart2
  2019-02-06  8:12   ` Petr Lautrbach
  0 siblings, 1 reply; 3+ messages in thread
From: jwcart2 @ 2019-02-04 16:54 UTC (permalink / raw)
  To: Nicolas Iooss, selinux

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>

> ---
>   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));
> 


-- 
James Carter <jwcart2@tycho.nsa.gov>
National Security Agency

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [Non-DoD Source] [PATCH 1/1] libsepol: do not use uninitialized value for low_value
  2019-02-04 16:54 ` [Non-DoD Source] " jwcart2
@ 2019-02-06  8:12   ` Petr Lautrbach
  0 siblings, 0 replies; 3+ messages in thread
From: Petr Lautrbach @ 2019-02-06  8:12 UTC (permalink / raw)
  To: selinux; +Cc: Nicolas Iooss, jwcart2

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));
>>

^ permalink raw reply	[flat|nested] 3+ messages in thread

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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

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