|
From: | Liam Merwick |
Subject: | Re: [Qemu-devel] [PATCH 2/8] job: Fix off-by-one accesses to JobSTT and JobVerbTable |
Date: | Fri, 31 Aug 2018 14:22:04 +0100 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
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 <address@hidden> Reviewed-by: Darren Kenny <address@hidden> Reviewed-by: Mark Kanda <address@hidden> --- job.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)Reviewed-by: Eric Blake <address@hidden>
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]) {
[Prev in Thread] | Current Thread | [Next in Thread] |