[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Sam Protsenko]

In case of error in dfu_config_entities(), it frees "dfu" array, which
leads to "data abort" in dfu_free_entities(), which tries to free the
same array (and even tries to access it from linked list first). The
issue occurs e.g. when partition table on device does not match
$dfu_alt_info layout:

    => dfu 0 mmc 1 list
    Couldn't find part #2 on mmc device #1
    DFU entities configuration failed!
    data abort

To fix this issue, do not free "dfu" array in dfu_config_entities(). It
will be freed later in dfu_free_entities().

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
---
 drivers/dfu/dfu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
index e7c91193b9..a3c09334b7 100644
--- a/drivers/dfu/dfu.c
+++ b/drivers/dfu/dfu.c
@@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char *interface, char *devstr)
 		ret = dfu_fill_entity(&dfu[i], s, alt_num_cnt, interface,
 				      devstr);
 		if (ret) {
-			free(dfu);
+			/* We will free "dfu" in dfu_free_entities() */
 			return -1;
 		}
 
-- 
2.18.0

[U-Boot] [PATCH 2/3] dfu: Fix memory leak in dfu_init_env_entities()

[Sam Protsenko]

In case of error in dfu_init_env_entities(), env_bkp will leak. Fix it
by providing single return path.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
---
 drivers/dfu/dfu.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
index a3c09334b7..5b9abd685d 100644
--- a/drivers/dfu/dfu.c
+++ b/drivers/dfu/dfu.c
@@ -56,7 +56,7 @@ int dfu_init_env_entities(char *interface, char *devstr)
 {
 	const char *str_env;
 	char *env_bkp;
-	int ret;
+	int ret = 0;
 
 #ifdef CONFIG_SET_DFU_ALT_INFO
 	set_dfu_alt_info(interface, devstr);
@@ -71,11 +71,12 @@ int dfu_init_env_entities(char *interface, char *devstr)
 	ret = dfu_config_entities(env_bkp, interface, devstr);
 	if (ret) {
 		pr_err("DFU entities configuration failed!\n");
-		return ret;
+		goto done;
 	}
 
+done:
 	free(env_bkp);
-	return 0;
+	return ret;
 }
 
 static unsigned char *dfu_buf;
-- 
2.18.0

[U-Boot] [PATCH 3/3] dfu: Provide more verbose error message

[Sam Protsenko]

It might be useful for user to see some human-readable root cause
message in addition to "configuration failed" message, so that the issue
can be fixed quickly.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
---
 drivers/dfu/dfu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
index 5b9abd685d..318949529b 100644
--- a/drivers/dfu/dfu.c
+++ b/drivers/dfu/dfu.c
@@ -71,6 +71,7 @@ int dfu_init_env_entities(char *interface, char *devstr)
 	ret = dfu_config_entities(env_bkp, interface, devstr);
 	if (ret) {
 		pr_err("DFU entities configuration failed!\n");
+		pr_err("(partition table does not match dfu_alt_info?)\n");
 		goto done;
 	}
 
-- 
2.18.0

[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Sam Protsenko]

The story of this change goes further... Just checked the reason, the
bug was introduced here [1]. So we can either use my patch (which adds
corresponding comment to ensure we won't "fix" it later), or the whole
design of dfu_config_entities() vs dfu_free_entities() should be
revised.

Lukasz, what do you think about this?

[1] http://git.denx.de/?p=u-boot.git;a=commit;h=5d8fae79163e94671956c99654abf48cf49757ba

On Fri, Jul 13, 2018 at 12:52 AM, Sam Protsenko
<semen.protsenko@linaro.org> wrote:
> In case of error in dfu_config_entities(), it frees "dfu" array, which
> leads to "data abort" in dfu_free_entities(), which tries to free the
> same array (and even tries to access it from linked list first). The
> issue occurs e.g. when partition table on device does not match
> $dfu_alt_info layout:
>
>     => dfu 0 mmc 1 list
>     Couldn't find part #2 on mmc device #1
>     DFU entities configuration failed!
>     data abort
>
> To fix this issue, do not free "dfu" array in dfu_config_entities(). It
> will be freed later in dfu_free_entities().
>
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  drivers/dfu/dfu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
> index e7c91193b9..a3c09334b7 100644
> --- a/drivers/dfu/dfu.c
> +++ b/drivers/dfu/dfu.c
> @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char *interface, char *devstr)
>                 ret = dfu_fill_entity(&dfu[i], s, alt_num_cnt, interface,
>                                       devstr);
>                 if (ret) {
> -                       free(dfu);
> +                       /* We will free "dfu" in dfu_free_entities() */
>                         return -1;
>                 }
>
> --
> 2.18.0
>

[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Andy Shevchenko]

On Fri, Jul 13, 2018 at 1:10 AM, Sam Protsenko
<semen.protsenko@linaro.org> wrote:
> The story of this change goes further... Just checked the reason, the
> bug was introduced here [1]. So we can either use my patch (which adds
> corresponding comment to ensure we won't "fix" it later), or the whole
> design of dfu_config_entities() vs dfu_free_entities() should be
> revised.

Effectively you are reverting that commit, perhaps make it clear in
commit message that this is a revert.

>
> Lukasz, what do you think about this?
>
> [1] http://git.denx.de/?p=u-boot.git;a=commit;h=5d8fae79163e94671956c99654abf48cf49757ba
>
> On Fri, Jul 13, 2018 at 12:52 AM, Sam Protsenko
> <semen.protsenko@linaro.org> wrote:
>> In case of error in dfu_config_entities(), it frees "dfu" array, which
>> leads to "data abort" in dfu_free_entities(), which tries to free the
>> same array (and even tries to access it from linked list first). The
>> issue occurs e.g. when partition table on device does not match
>> $dfu_alt_info layout:
>>
>>     => dfu 0 mmc 1 list
>>     Couldn't find part #2 on mmc device #1
>>     DFU entities configuration failed!
>>     data abort
>>
>> To fix this issue, do not free "dfu" array in dfu_config_entities(). It
>> will be freed later in dfu_free_entities().
>>
>> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
>> ---
>>  drivers/dfu/dfu.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
>> index e7c91193b9..a3c09334b7 100644
>> --- a/drivers/dfu/dfu.c
>> +++ b/drivers/dfu/dfu.c
>> @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char *interface, char *devstr)
>>                 ret = dfu_fill_entity(&dfu[i], s, alt_num_cnt, interface,
>>                                       devstr);
>>                 if (ret) {
>> -                       free(dfu);
>> +                       /* We will free "dfu" in dfu_free_entities() */
>>                         return -1;
>>                 }
>>
>> --
>> 2.18.0
>>
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot



-- 
With Best Regards,
Andy Shevchenko

[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Lukasz Majewski]

Hi Sam,

> In case of error in dfu_config_entities(), it frees "dfu" array, which
> leads to "data abort" in dfu_free_entities(), which tries to free the
> same array (and even tries to access it from linked list first). The
> issue occurs e.g. when partition table on device does not match
> $dfu_alt_info layout:
> 
>     => dfu 0 mmc 1 list  
>     Couldn't find part #2 on mmc device #1
>     DFU entities configuration failed!
>     data abort
> 
> To fix this issue, do not free "dfu" array in dfu_config_entities().
> It will be freed later in dfu_free_entities().
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  drivers/dfu/dfu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
> index e7c91193b9..a3c09334b7 100644
> --- a/drivers/dfu/dfu.c
> +++ b/drivers/dfu/dfu.c
> @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char
> *interface, char *devstr) ret = dfu_fill_entity(&dfu[i], s,
> alt_num_cnt, interface, devstr);
>  		if (ret) {
> -			free(dfu);
> +			/* We will free "dfu" in dfu_free_entities()
> */ return -1;
>  		}
>  

Thanks for catching it.

Acked-by: Lukasz Majewski <lukma@denx.de>

Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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[U-Boot] [PATCH 2/3] dfu: Fix memory leak in dfu_init_env_entities()

[Lukasz Majewski]

Hi Sam,

> In case of error in dfu_init_env_entities(), env_bkp will leak. Fix it
> by providing single return path.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  drivers/dfu/dfu.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
> index a3c09334b7..5b9abd685d 100644
> --- a/drivers/dfu/dfu.c
> +++ b/drivers/dfu/dfu.c
> @@ -56,7 +56,7 @@ int dfu_init_env_entities(char *interface, char
> *devstr) {
>  	const char *str_env;
>  	char *env_bkp;
> -	int ret;
> +	int ret = 0;
>  
>  #ifdef CONFIG_SET_DFU_ALT_INFO
>  	set_dfu_alt_info(interface, devstr);
> @@ -71,11 +71,12 @@ int dfu_init_env_entities(char *interface, char
> *devstr) ret = dfu_config_entities(env_bkp, interface, devstr);
>  	if (ret) {
>  		pr_err("DFU entities configuration failed!\n");
> -		return ret;
> +		goto done;
>  	}
>  
> +done:
>  	free(env_bkp);
> -	return 0;
> +	return ret;
>  }
>  
>  static unsigned char *dfu_buf;

Acked-by: Lukasz Majewski <lukma@denx.de>


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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[U-Boot] [PATCH 3/3] dfu: Provide more verbose error message

[Lukasz Majewski]

Hi Sam,

> It might be useful for user to see some human-readable root cause
> message in addition to "configuration failed" message, so that the
> issue can be fixed quickly.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  drivers/dfu/dfu.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
> index 5b9abd685d..318949529b 100644
> --- a/drivers/dfu/dfu.c
> +++ b/drivers/dfu/dfu.c
> @@ -71,6 +71,7 @@ int dfu_init_env_entities(char *interface, char
> *devstr) ret = dfu_config_entities(env_bkp, interface, devstr);
>  	if (ret) {
>  		pr_err("DFU entities configuration failed!\n");
> +		pr_err("(partition table does not match
> dfu_alt_info?)\n"); goto done;
>  	}
>  

Acked-by: Lukasz Majewski <lukma@denx.de>

Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Lukasz Majewski]

Hi Sam,

> The story of this change goes further... Just checked the reason, the
> bug was introduced here [1]. So we can either use my patch (which adds
> corresponding comment to ensure we won't "fix" it later), or the whole
> design of dfu_config_entities() vs dfu_free_entities() should be
> revised.
> 
> Lukasz, what do you think about this?

Your patch seems OK to me. I've checked all use cases and in the error
path the dfu_free_entities() is called.


(Or have I misunderstood something) ?

> 
> [1]
> http://git.denx.de/?p=u-boot.git;a=commit;h=5d8fae79163e94671956c99654abf48cf49757ba
> 
> On Fri, Jul 13, 2018 at 12:52 AM, Sam Protsenko
> <semen.protsenko@linaro.org> wrote:
> > In case of error in dfu_config_entities(), it frees "dfu" array,
> > which leads to "data abort" in dfu_free_entities(), which tries to
> > free the same array (and even tries to access it from linked list
> > first). The issue occurs e.g. when partition table on device does
> > not match $dfu_alt_info layout:
> >  
> >     => dfu 0 mmc 1 list  
> >     Couldn't find part #2 on mmc device #1
> >     DFU entities configuration failed!
> >     data abort
> >
> > To fix this issue, do not free "dfu" array in
> > dfu_config_entities(). It will be freed later in
> > dfu_free_entities().
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> > ---
> >  drivers/dfu/dfu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
> > index e7c91193b9..a3c09334b7 100644
> > --- a/drivers/dfu/dfu.c
> > +++ b/drivers/dfu/dfu.c
> > @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char
> > *interface, char *devstr) ret = dfu_fill_entity(&dfu[i], s,
> > alt_num_cnt, interface, devstr);
> >                 if (ret) {
> > -                       free(dfu);
> > +                       /* We will free "dfu" in
> > dfu_free_entities() */ return -1;
> >                 }
> >
> > --
> > 2.18.0
> >  




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Sam Protsenko]

On Fri, Jul 13, 2018 at 5:32 AM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Fri, Jul 13, 2018 at 1:10 AM, Sam Protsenko
> <semen.protsenko@linaro.org> wrote:
>> The story of this change goes further... Just checked the reason, the
>> bug was introduced here [1]. So we can either use my patch (which adds
>> corresponding comment to ensure we won't "fix" it later), or the whole
>> design of dfu_config_entities() vs dfu_free_entities() should be
>> revised.
>
> Effectively you are reverting that commit, perhaps make it clear in
> commit message that this is a revert.
>

Yeah, I just found that commit after sending my patch. Will add that
info in v2, thanks.

>>
>> Lukasz, what do you think about this?
>>
>> [1] http://git.denx.de/?p=u-boot.git;a=commit;h=5d8fae79163e94671956c99654abf48cf49757ba
>>
>> On Fri, Jul 13, 2018 at 12:52 AM, Sam Protsenko
>> <semen.protsenko@linaro.org> wrote:
>>> In case of error in dfu_config_entities(), it frees "dfu" array, which
>>> leads to "data abort" in dfu_free_entities(), which tries to free the
>>> same array (and even tries to access it from linked list first). The
>>> issue occurs e.g. when partition table on device does not match
>>> $dfu_alt_info layout:
>>>
>>>     => dfu 0 mmc 1 list
>>>     Couldn't find part #2 on mmc device #1
>>>     DFU entities configuration failed!
>>>     data abort
>>>
>>> To fix this issue, do not free "dfu" array in dfu_config_entities(). It
>>> will be freed later in dfu_free_entities().
>>>
>>> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
>>> ---
>>>  drivers/dfu/dfu.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
>>> index e7c91193b9..a3c09334b7 100644
>>> --- a/drivers/dfu/dfu.c
>>> +++ b/drivers/dfu/dfu.c
>>> @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char *interface, char *devstr)
>>>                 ret = dfu_fill_entity(&dfu[i], s, alt_num_cnt, interface,
>>>                                       devstr);
>>>                 if (ret) {
>>> -                       free(dfu);
>>> +                       /* We will free "dfu" in dfu_free_entities() */
>>>                         return -1;
>>>                 }
>>>
>>> --
>>> 2.18.0
>>>
>> _______________________________________________
>> U-Boot mailing list
>> U-Boot at lists.denx.de
>> https://lists.denx.de/listinfo/u-boot
>
>
>
> --
> With Best Regards,
> Andy Shevchenko

[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()

[Sam Protsenko]

Hi Lukasz,

On Fri, Jul 13, 2018 at 12:49 PM, Lukasz Majewski <lukma@denx.de> wrote:
> Hi Sam,
>
>> The story of this change goes further... Just checked the reason, the
>> bug was introduced here [1]. So we can either use my patch (which adds
>> corresponding comment to ensure we won't "fix" it later), or the whole
>> design of dfu_config_entities() vs dfu_free_entities() should be
>> revised.
>>
>> Lukasz, what do you think about this?
>
> Your patch seems OK to me. I've checked all use cases and in the error
> path the dfu_free_entities() is called.
>

The patch itself is ok. What I'm trying to say, is that design of
dfu_config_entities() is not very good. It allocates memory for "dfu"
array, and on error it doesn't free it, relying on dfu_free_entities()
to free it later. That's why Coverity reported it as a memory leak in
a first place (though it was false positive of course). But such a
design is not what user of the function usually expects. Better design
(as for my taste) would be if dfu_config_entities() cleans up
everything on error, so that even if user doesn't call
dfu_free_entities() after calling dfu_config_entities() (with return
on error), there is no memory leak involved. This way it would be
easier to control code flow, and Coverity will be happy too.

I suggest next: let's merge this patch as is (at least it makes things
work as originally intended), and if my thoughts on design make sense
to you, dfu_config_entities() can be reworked in further commits.
Sounds ok?

I will send v2 with improved commit message soon.

>
> (Or have I misunderstood something) ?
>
>>
>> [1]
>> http://git.denx.de/?p=u-boot.git;a=commit;h=5d8fae79163e94671956c99654abf48cf49757ba
>>
>> On Fri, Jul 13, 2018 at 12:52 AM, Sam Protsenko
>> <semen.protsenko@linaro.org> wrote:
>> > In case of error in dfu_config_entities(), it frees "dfu" array,
>> > which leads to "data abort" in dfu_free_entities(), which tries to
>> > free the same array (and even tries to access it from linked list
>> > first). The issue occurs e.g. when partition table on device does
>> > not match $dfu_alt_info layout:
>> >
>> >     => dfu 0 mmc 1 list
>> >     Couldn't find part #2 on mmc device #1
>> >     DFU entities configuration failed!
>> >     data abort
>> >
>> > To fix this issue, do not free "dfu" array in
>> > dfu_config_entities(). It will be freed later in
>> > dfu_free_entities().
>> >
>> > Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
>> > ---
>> >  drivers/dfu/dfu.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
>> > index e7c91193b9..a3c09334b7 100644
>> > --- a/drivers/dfu/dfu.c
>> > +++ b/drivers/dfu/dfu.c
>> > @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char
>> > *interface, char *devstr) ret = dfu_fill_entity(&dfu[i], s,
>> > alt_num_cnt, interface, devstr);
>> >                 if (ret) {
>> > -                       free(dfu);
>> > +                       /* We will free "dfu" in
>> > dfu_free_entities() */ return -1;
>> >                 }
>> >
>> > --
>> > 2.18.0
>> >
>
>
>
>
> Best regards,
>
> Lukasz Majewski
>
> --
>
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de