On 2021/7/1 11:23, Zhiqiang Liu wrote:
>
> On 2021/7/1 1:41, Alison Schofield wrote:
>> On Tue, Jun 15, 2021 at 08:38:33PM +0800, Zhiqiang Liu wrote:
>>> ndctl_pfn_get_namespace() may return NULL, so callers
>>> should check return value of it. Otherwise, it may
>>> cause access NULL pointer problem.
>>>
>> Hi Zhiqiang,
>>
>> I see you mentioned this was found by Coverity in the cover letter.
>> Please repeat that in the commit log here.
>>
>> What about the call path:
>> ndctl_dax_get_namespace() --> ndctl_pfn_get_namespace()
>>
>> Seems like another place where ndctl_pfn_get_namespace() could
>> eventually lead to a NULL ptr dereference.
>>
>> Alison
>
> Thanks for your reply.
>
> Call path:
>
> namespace_clear_bb
>
> -> if (dax) dax_clear_badblocks(dax)
>
> ->ndctl_dax_get_namespace(dax)
>
> ->ndctl_pfn_get_namespace(&dax->pfn)
>
> ->ndctl_pfn_get_ctx(pfn)
>
>
> struct ndctl_dax {
> struct ndctl_pfn pfn;
> struct daxctl_region *region;
> };
>
> Here, we have checked that dax is not NULL before calling
> ndctl_dax_get_namespace(dax).
>
> If dax is not a NULL pointer, the dax->pfn will not be a NULL pointer.
>
> As for ndctl_pfn_get_ctx(pfn), it will access pfn->region->bus without
> NULL-checking, which
>
> may lead to a NULL ptr dereference as you said. I will correct it in the v2
> patch.
>
Null_check in ndctl_pfn_get_**(pfn) is a common problem. I will try to solve
this kind
problem in new patches.
Regards
Zhiqiang Liu
>
> Regards,
>
> Zhiqiang Liu
>
>>> Signed-off-by: Zhiqiang Liu <[email protected]>
>>> ---
>>> ndctl/namespace.c | 18 ++++++++++++++----
>>> test/libndctl.c | 4 ++--
>>> util/json.c | 2 ++
>>> 3 files changed, 18 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/ndctl/namespace.c b/ndctl/namespace.c
>>> index 0c8df9f..21089d7 100644
>>> --- a/ndctl/namespace.c
>>> +++ b/ndctl/namespace.c
>>> @@ -1417,11 +1417,16 @@ static int nstype_clear_badblocks(struct
>>> ndctl_namespace *ndns,
>>>
>>> static int dax_clear_badblocks(struct ndctl_dax *dax)
>>> {
>>> - struct ndctl_namespace *ndns = ndctl_dax_get_namespace(dax);
>>> - const char *devname = ndctl_dax_get_devname(dax);
>>> + struct ndctl_namespace *ndns;
>>> + const char *devname;
>>> unsigned long long begin, size;
>>> int rc;
>>>
>>> + ndns = ndctl_dax_get_namespace(dax);
>>> + if (!ndns)
>>> + return -ENXIO;
>>> +
>>> + devname = ndctl_dax_get_devname(dax);
>>> begin = ndctl_dax_get_resource(dax);
>>> if (begin == ULLONG_MAX)
>>> return -ENXIO;
>>> @@ -1441,11 +1446,16 @@ static int dax_clear_badblocks(struct ndctl_dax
>>> *dax)
>>>
>>> static int pfn_clear_badblocks(struct ndctl_pfn *pfn)
>>> {
>>> - struct ndctl_namespace *ndns = ndctl_pfn_get_namespace(pfn);
>>> - const char *devname = ndctl_pfn_get_devname(pfn);
>>> + struct ndctl_namespace *ndns;
>>> + const char *devname;
>>> unsigned long long begin, size;
>>> int rc;
>>>
>>> + ndns = ndctl_pfn_get_namespace(pfn);
>>> + if (!ndns)
>>> + return -ENXIO;
>>> +
>>> + devname = ndctl_pfn_get_devname(pfn);
>>> begin = ndctl_pfn_get_resource(pfn);
>>> if (begin == ULLONG_MAX)
>>> return -ENXIO;
>>> diff --git a/test/libndctl.c b/test/libndctl.c
>>> index 24d72b3..05e5ff2 100644
>>> --- a/test/libndctl.c
>>> +++ b/test/libndctl.c
>>> @@ -1275,7 +1275,7 @@ static int check_pfn_autodetect(struct ndctl_bus *bus,
>>> if (!ndctl_pfn_is_enabled(pfn))
>>> continue;
>>> pfn_ndns = ndctl_pfn_get_namespace(pfn);
>>> - if (strcmp(ndctl_namespace_get_devname(pfn_ndns), devname) != 0)
>>> + if (!pfn_ndns || strcmp(ndctl_namespace_get_devname(pfn_ndns),
>>> devname) != 0)
>>> continue;
>>> fprintf(stderr, "%s: pfn_ndns: %p ndns: %p\n", __func__,
>>> pfn_ndns, ndns);
>>> @@ -1372,7 +1372,7 @@ static int check_dax_autodetect(struct ndctl_bus *bus,
>>> if (!ndctl_dax_is_enabled(dax))
>>> continue;
>>> dax_ndns = ndctl_dax_get_namespace(dax);
>>> - if (strcmp(ndctl_namespace_get_devname(dax_ndns), devname) != 0)
>>> + if (!dax_ndns || strcmp(ndctl_namespace_get_devname(dax_ndns),
>>> devname) != 0)
>>> continue;
>>> fprintf(stderr, "%s: dax_ndns: %p ndns: %p\n", __func__,
>>> dax_ndns, ndns);
>>> diff --git a/util/json.c b/util/json.c
>>> index ca0167b..249f021 100644
>>> --- a/util/json.c
>>> +++ b/util/json.c
>>> @@ -1002,6 +1002,8 @@ static struct json_object
>>> *util_pfn_badblocks_to_json(struct ndctl_pfn *pfn,
>>> pfn_begin = ndctl_pfn_get_resource(pfn);
>>> if (pfn_begin == ULLONG_MAX) {
>>> struct ndctl_namespace *ndns = ndctl_pfn_get_namespace(pfn);
>>> + if (!ndns)
>>> + return NULL;
>>>
>>> return util_namespace_badblocks_to_json(ndns, bb_count, flags);
>>> }
>>> --
>>> 2.23.0
>>>
>>>
>>>
>>>
>>> .
>>>
>>>
>>>
>> .
