Messages in this thread |  | | From | Zheng Hacker <> | Date | Thu, 22 Sep 2022 11:00:23 +0800 | Subject | Re: [PATCH] misc: sgi-gru: fix use-after-free error in gru_set_context_option, gru_fault and gru_handle_user_call_os |
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Hi,
I've sent the patch with anothe account. Could you please try this one?
Regards, Zheng Wang
Zheng Wang <zyytlz.wz@163.com> 于2022年9月19日周一 22:32写道: > > In grufile.c, gru_file_unlocked_ioctl function can be called by user. > > If the req is GRU_SET_CONTEXT_OPTION, it will call gru_set_context_option. > > In gru_set_context_option, as req can be controlled by user, > > We can reach gru_check_context_placement function call. > > In gru_check_context_placement function, if the error path was steped, > > say gru_check_chiplet_assignment return 0, > > Then it will fall into gru_unload_context function. > > And it will finnaly call kfree gts in gts_drop function. > > Then gru_unlock_gts will be called in gru_set_context_option function. > > This is a typical Use after free. > > The same problem exists in gru_handle_user_call_os and gru_fault. > > Fix it by introduce the return value to see if gts is in good case or not. > > Free the gts in caller when gru_check_chiplet_assignment check failed. > > Reported-by: Zheng Wang <hackerzheng666@gmail.com> Zhuorao Yang <alex000young@gmail.com> > > Signed-off-by: Zheng Wang <zyytlz.wz@163.com> > --- > drivers/misc/sgi-gru/grufault.c | 14 ++++++++++++-- > drivers/misc/sgi-gru/grumain.c | 17 +++++++++++++---- > drivers/misc/sgi-gru/grutables.h | 2 +- > 3 files changed, 26 insertions(+), 7 deletions(-) > > diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c > index d7ef61e602ed..2b5b049fbd38 100644 > --- a/drivers/misc/sgi-gru/grufault.c > +++ b/drivers/misc/sgi-gru/grufault.c > @@ -656,7 +656,9 @@ int gru_handle_user_call_os(unsigned long cb) > if (ucbnum >= gts->ts_cbr_au_count * GRU_CBR_AU_SIZE) > goto exit; > > - gru_check_context_placement(gts); > + ret = gru_check_context_placement(gts); > + if (ret) > + goto err; > > /* > * CCH may contain stale data if ts_force_cch_reload is set. > @@ -677,6 +679,10 @@ int gru_handle_user_call_os(unsigned long cb) > exit: > gru_unlock_gts(gts); > return ret; > +err: > + gru_unlock_gts(gts); > + gru_unload_context(gts, 1); > + return -EINVAL; > } > > /* > @@ -874,7 +880,7 @@ int gru_set_context_option(unsigned long arg) > } else { > gts->ts_user_blade_id = req.val1; > gts->ts_user_chiplet_id = req.val0; > - gru_check_context_placement(gts); > + ret = gru_check_context_placement(gts); > } > break; > case sco_gseg_owner: > @@ -889,6 +895,10 @@ int gru_set_context_option(unsigned long arg) > ret = -EINVAL; > } > gru_unlock_gts(gts); > + if (ret) { > + gru_unload_context(gts, 1); > + ret = -EINVAL; > + } > > return ret; > } > diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c > index 9afda47efbf2..79903cf7e706 100644 > --- a/drivers/misc/sgi-gru/grumain.c > +++ b/drivers/misc/sgi-gru/grumain.c > @@ -716,9 +716,10 @@ static int gru_check_chiplet_assignment(struct gru_state *gru, > * chiplet. Misassignment can occur if the process migrates to a different > * blade or if the user changes the selected blade/chiplet. > */ > -void gru_check_context_placement(struct gru_thread_state *gts) > +int gru_check_context_placement(struct gru_thread_state *gts) > { > struct gru_state *gru; > + int ret = 0; > > /* > * If the current task is the context owner, verify that the > @@ -727,14 +728,16 @@ void gru_check_context_placement(struct gru_thread_state *gts) > */ > gru = gts->ts_gru; > if (!gru || gts->ts_tgid_owner != current->tgid) > - return; > + return ret; > > if (!gru_check_chiplet_assignment(gru, gts)) { > STAT(check_context_unload); > - gru_unload_context(gts, 1); > + ret = -EINVAL; > } else if (gru_retarget_intr(gts)) { > STAT(check_context_retarget_intr); > } > + > + return ret; > } > > > @@ -919,6 +922,7 @@ vm_fault_t gru_fault(struct vm_fault *vmf) > struct gru_thread_state *gts; > unsigned long paddr, vaddr; > unsigned long expires; > + int ret; > > vaddr = vmf->address; > gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n", > @@ -934,7 +938,12 @@ vm_fault_t gru_fault(struct vm_fault *vmf) > mutex_lock(>s->ts_ctxlock); > preempt_disable(); > > - gru_check_context_placement(gts); > + ret = gru_check_context_placement(gts); > + if (ret) { > + mutex_unlock(>s->ts_ctxlock); > + gru_unload_context(gts, 1); > + return ret; > + } > > if (!gts->ts_gru) { > STAT(load_user_context); > diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h > index 5efc869fe59a..f4a5a787685f 100644 > --- a/drivers/misc/sgi-gru/grutables.h > +++ b/drivers/misc/sgi-gru/grutables.h > @@ -632,7 +632,7 @@ extern int gru_user_flush_tlb(unsigned long arg); > extern int gru_user_unload_context(unsigned long arg); > extern int gru_get_exception_detail(unsigned long arg); > extern int gru_set_context_option(unsigned long address); > -extern void gru_check_context_placement(struct gru_thread_state *gts); > +extern int gru_check_context_placement(struct gru_thread_state *gts); > extern int gru_cpu_fault_map_id(void); > extern struct vm_area_struct *gru_find_vma(unsigned long vaddr); > extern void gru_flush_all_tlb(struct gru_state *gru); > -- > 2.25.1 >
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