diff mbox series

[2/8] job: Fix off-by-one accesses to JobSTT and JobVerbTable

Message ID 1535644031-848-3-git-send-email-Liam.Merwick@oracle.com (mailing list archive)
State New, archived
Headers show
Series off-by-one and NULL pointer accesses detected by static analysis | expand

Commit Message

Liam Merwick Aug. 30, 2018, 3:47 p.m. UTC 
In the array dereference of JobVerbTable[verb] in job_apply_verb()
the check of the index, verb, allows an overrun because an index
equal to the array size is permitted.

Similarly, in the array dereference of JobSTT[s0][s1] with index s1
in job_state_transition(), an off-by-one overrun is possible.

Signed-off-by: Liam Merwick <Liam.Merwick@oracle.com>
Reviewed-by: Darren Kenny <Darren.Kenny@oracle.com>
Reviewed-by: Mark Kanda <Mark.Kanda@oracle.com>
---
 job.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Eric Blake Aug. 30, 2018, 6:34 p.m. UTC | #1 
On 08/30/2018 10:47 AM, Liam Merwick wrote:
> In the array dereference of JobVerbTable[verb] in job_apply_verb()
> the check of the index, verb, allows an overrun because an index
> equal to the array size is permitted.
> 
> Similarly, in the array dereference of JobSTT[s0][s1] with index s1
> in job_state_transition(), an off-by-one overrun is possible.

Fortunately, these are just assertions that are too weak; we don't have 
any actual callers passing the __MAX entry to cause an actual overrun.

> 
> Signed-off-by: Liam Merwick <Liam.Merwick@oracle.com>
> Reviewed-by: Darren Kenny <Darren.Kenny@oracle.com>
> Reviewed-by: Mark Kanda <Mark.Kanda@oracle.com>
> ---
>   job.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

> 
> diff --git a/job.c b/job.c
> index e36ebaafd81c..40320566f43b 100644
> --- a/job.c
> +++ b/job.c
> @@ -166,7 +166,7 @@ bool job_is_internal(Job *job)
>   static void job_state_transition(Job *job, JobStatus s1)
>   {
>       JobStatus s0 = job->status;
> -    assert(s1 >= 0 && s1 <= JOB_STATUS__MAX);
> +    assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
>       trace_job_state_transition(job, job->ret,
>                                  JobSTT[s0][s1] ? "allowed" : "disallowed",
>                                  JobStatus_str(s0), JobStatus_str(s1));
> @@ -181,7 +181,7 @@ static void job_state_transition(Job *job, JobStatus s1)
>   int job_apply_verb(Job *job, JobVerb verb, Error **errp)
>   {
>       JobStatus s0 = job->status;
> -    assert(verb >= 0 && verb <= JOB_VERB__MAX);
> +    assert(verb >= 0 && verb < JOB_VERB__MAX);
>       trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
>                            JobVerbTable[verb][s0] ? "allowed" : "prohibited");
>       if (JobVerbTable[verb][s0]) {
>
Liam Merwick Aug. 31, 2018, 1:22 p.m. UTC | #2 
On 30/08/18 19:34, Eric Blake wrote:
> On 08/30/2018 10:47 AM, Liam Merwick wrote:
>> In the array dereference of JobVerbTable[verb] in job_apply_verb()
>> the check of the index, verb, allows an overrun because an index
>> equal to the array size is permitted.
>>
>> Similarly, in the array dereference of JobSTT[s0][s1] with index s1
>> in job_state_transition(), an off-by-one overrun is possible.
> 
> Fortunately, these are just assertions that are too weak; we don't have 
> any actual callers passing the __MAX entry to cause an actual overrun.
> 

True. In v2 I'll clarify that in the commit message

>>
>> Signed-off-by: Liam Merwick <Liam.Merwick@oracle.com>
>> Reviewed-by: Darren Kenny <Darren.Kenny@oracle.com>
>> Reviewed-by: Mark Kanda <Mark.Kanda@oracle.com>
>> ---
>>   job.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Reviewed-by: Eric Blake <eblake@redhat.com>
> 

Thanks,
Liam


>>
>> diff --git a/job.c b/job.c
>> index e36ebaafd81c..40320566f43b 100644
>> --- a/job.c
>> +++ b/job.c
>> @@ -166,7 +166,7 @@ bool job_is_internal(Job *job)
>>   static void job_state_transition(Job *job, JobStatus s1)
>>   {
>>       JobStatus s0 = job->status;
>> -    assert(s1 >= 0 && s1 <= JOB_STATUS__MAX);
>> +    assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
>>       trace_job_state_transition(job, job->ret,
>>                                  JobSTT[s0][s1] ? "allowed" : 
>> "disallowed",
>>                                  JobStatus_str(s0), JobStatus_str(s1));
>> @@ -181,7 +181,7 @@ static void job_state_transition(Job *job, 
>> JobStatus s1)
>>   int job_apply_verb(Job *job, JobVerb verb, Error **errp)
>>   {
>>       JobStatus s0 = job->status;
>> -    assert(verb >= 0 && verb <= JOB_VERB__MAX);
>> +    assert(verb >= 0 && verb < JOB_VERB__MAX);
>>       trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
>>                            JobVerbTable[verb][s0] ? "allowed" : 
>> "prohibited");
>>       if (JobVerbTable[verb][s0]) {
>>
>
diff mbox series

Patch

diff --git a/job.c b/job.c
index e36ebaafd81c..40320566f43b 100644
--- a/job.c
+++ b/job.c
@@ -166,7 +166,7 @@  bool job_is_internal(Job *job)
 static void job_state_transition(Job *job, JobStatus s1)
 {
     JobStatus s0 = job->status;
-    assert(s1 >= 0 && s1 <= JOB_STATUS__MAX);
+    assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
     trace_job_state_transition(job, job->ret,
                                JobSTT[s0][s1] ? "allowed" : "disallowed",
                                JobStatus_str(s0), JobStatus_str(s1));
@@ -181,7 +181,7 @@  static void job_state_transition(Job *job, JobStatus s1)
 int job_apply_verb(Job *job, JobVerb verb, Error **errp)
 {
     JobStatus s0 = job->status;
-    assert(verb >= 0 && verb <= JOB_VERB__MAX);
+    assert(verb >= 0 && verb < JOB_VERB__MAX);
     trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
                          JobVerbTable[verb][s0] ? "allowed" : "prohibited");
     if (JobVerbTable[verb][s0]) {