Re: [U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
Hi Lukasz,
On Fri, Jul 13, 2018 at 12:49 PM, Lukasz Majewski 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
>> 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
>> > ---
>> > 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([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: w...@denx.de
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Re: [U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
On Fri, Jul 13, 2018 at 5:32 AM, Andy Shevchenko
wrote:
> On Fri, Jul 13, 2018 at 1:10 AM, Sam Protsenko
> 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
>> 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
>>> ---
>>> 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([i], s, alt_num_cnt, interface,
>>> devstr);
>>> if (ret) {
>>> - free(dfu);
>>> + /* We will free "dfu" in dfu_free_entities() */
>>> return -1;
>>> }
>>>
>>> --
>>> 2.18.0
>>>
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>
>
>
> --
> With Best Regards,
> Andy Shevchenko
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Re: [U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
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
> 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
> > ---
> > 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([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: w...@denx.de
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Re: [U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
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
> ---
> 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([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
Best regards,
Lukasz Majewski
--
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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
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Re: [U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
On Fri, Jul 13, 2018 at 1:10 AM, Sam Protsenko
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
> 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
>> ---
>> 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([i], s, alt_num_cnt, interface,
>> devstr);
>> if (ret) {
>> - free(dfu);
>> + /* We will free "dfu" in dfu_free_entities() */
>> return -1;
>> }
>>
>> --
>> 2.18.0
>>
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Andy Shevchenko
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Re: [U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
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
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
> ---
> 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([i], s, alt_num_cnt, interface,
> devstr);
> if (ret) {
> - free(dfu);
> + /* We will free "dfu" in dfu_free_entities() */
> return -1;
> }
>
> --
> 2.18.0
>
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[U-Boot] [PATCH 1/3] dfu: Fix data abort in dfu_free_entities()
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
---
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([i], s, alt_num_cnt, interface,
devstr);
if (ret) {
- free(dfu);
+ /* We will free "dfu" in dfu_free_entities() */
return -1;
}
--
2.18.0
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