| Message ID | 20180712215253.4290-1-semen.protsenko@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/3] dfu: Fix data abort in dfu_free_entities() | expand |
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 >
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@lists.denx.de > https://lists.denx.de/listinfo/u-boot
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@denx.de
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@denx.de
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@lists.denx.de >> https://lists.denx.de/listinfo/u-boot > > > > -- > With Best Regards, > Andy Shevchenko
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@denx.de
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; }
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(-)