From: Zheng Wang zyytlz.wz@163.com
[ Upstream commit 643a16a0eb1d6ac23744bb6e90a00fc21148a9dc ]
In some bad situation, the gts may be freed gru_check_chiplet_assignment. The call chain can be gru_unload_context->gru_free_gru_context->gts_drop and kfree finally. However, the caller didn't know if the gts is freed or not and use it afterwards. This will trigger a Use after Free bug.
Fix it by introducing a return value to see if it's in error path or not. Free the gts in caller if gru_check_chiplet_assignment check failed.
Fixes: 55484c45dbec ("gru: allow users to specify gru chiplet 2") Signed-off-by: Zheng Wang zyytlz.wz@163.com Acked-by: Dimitri Sivanich sivanich@hpe.com Link: https://lore.kernel.org/r/20221110035033.19498-1-zyytlz.wz@163.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/misc/sgi-gru/grufault.c | 13 +++++++++++-- drivers/misc/sgi-gru/grumain.c | 22 ++++++++++++++++++---- drivers/misc/sgi-gru/grutables.h | 2 +- 3 files changed, 30 insertions(+), 7 deletions(-)
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index 4b713a80b572..7f26a78bb403 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -648,6 +648,7 @@ int gru_handle_user_call_os(unsigned long cb) if ((cb & (GRU_HANDLE_STRIDE - 1)) || ucbnum >= GRU_NUM_CB) return -EINVAL;
+again: gts = gru_find_lock_gts(cb); if (!gts) return -EINVAL; @@ -656,7 +657,11 @@ 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); + if (gru_check_context_placement(gts)) { + gru_unlock_gts(gts); + gru_unload_context(gts, 1); + goto again; + }
/* * CCH may contain stale data if ts_force_cch_reload is set. @@ -874,7 +879,11 @@ 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); + if (gru_check_context_placement(gts)) { + gru_unlock_gts(gts); + gru_unload_context(gts, 1); + return ret; + } } break; case sco_gseg_owner: diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c index 40ac59dd018c..e2325e3d077e 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 @@ -726,15 +727,23 @@ void gru_check_context_placement(struct gru_thread_state *gts) * references. Pthread apps use non-owner references to the CBRs. */ gru = gts->ts_gru; + /* + * If gru or gts->ts_tgid_owner isn't initialized properly, return + * success to indicate that the caller does not need to unload the + * gru context.The caller is responsible for their inspection and + * reinitialization if needed. + */ 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; }
@@ -934,7 +943,12 @@ vm_fault_t gru_fault(struct vm_fault *vmf) mutex_lock(>s->ts_ctxlock); preempt_disable();
- gru_check_context_placement(gts); + if (gru_check_context_placement(gts)) { + preempt_enable(); + mutex_unlock(>s->ts_ctxlock); + gru_unload_context(gts, 1); + return VM_FAULT_NOPAGE; + }
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 a7e44b2eb413..6cebec4dd316 100644 --- a/drivers/misc/sgi-gru/grutables.h +++ b/drivers/misc/sgi-gru/grutables.h @@ -637,7 +637,7 @@ 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);