diff options
Diffstat (limited to 'drivers/android')
| -rw-r--r-- | drivers/android/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/android/binder.c | 112 | ||||
| -rw-r--r-- | drivers/android/binder_alloc.c | 42 | ||||
| -rw-r--r-- | drivers/android/binder_alloc.h | 1 |
4 files changed, 94 insertions, 62 deletions
diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig index 9801d852bd56..7dce3795b887 100644 --- a/drivers/android/Kconfig +++ b/drivers/android/Kconfig @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 menu "Android" config ANDROID diff --git a/drivers/android/binder.c b/drivers/android/binder.c index d055b3f2a207..fddf76ef5bd6 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2217,7 +2217,7 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, debug_id, (u64)fda->num_fds); continue; } - fd_array = (u32 *)(parent_buffer + fda->parent_offset); + fd_array = (u32 *)(parent_buffer + (uintptr_t)fda->parent_offset); for (fd_index = 0; fd_index < fda->num_fds; fd_index++) task_close_fd(proc, fd_array[fd_index]); } break; @@ -2326,7 +2326,6 @@ static int binder_translate_handle(struct flat_binder_object *fp, (u64)node->ptr); binder_node_unlock(node); } else { - int ret; struct binder_ref_data dest_rdata; binder_node_unlock(node); @@ -2442,7 +2441,7 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda, */ parent_buffer = parent->buffer - binder_alloc_get_user_buffer_offset(&target_proc->alloc); - fd_array = (u32 *)(parent_buffer + fda->parent_offset); + fd_array = (u32 *)(parent_buffer + (uintptr_t)fda->parent_offset); if (!IS_ALIGNED((unsigned long)fd_array, sizeof(u32))) { binder_user_error("%d:%d parent offset not aligned correctly.\n", proc->pid, thread->pid); @@ -2508,7 +2507,7 @@ static int binder_fixup_parent(struct binder_transaction *t, proc->pid, thread->pid); return -EINVAL; } - parent_buffer = (u8 *)(parent->buffer - + parent_buffer = (u8 *)((uintptr_t)parent->buffer - binder_alloc_get_user_buffer_offset( &target_proc->alloc)); *(binder_uintptr_t *)(parent_buffer + bp->parent_offset) = bp->buffer; @@ -2583,6 +2582,48 @@ static bool binder_proc_transaction(struct binder_transaction *t, return true; } +/** + * binder_get_node_refs_for_txn() - Get required refs on node for txn + * @node: struct binder_node for which to get refs + * @proc: returns @node->proc if valid + * @error: if no @proc then returns BR_DEAD_REPLY + * + * User-space normally keeps the node alive when creating a transaction + * since it has a reference to the target. The local strong ref keeps it + * alive if the sending process dies before the target process processes + * the transaction. If the source process is malicious or has a reference + * counting bug, relying on the local strong ref can fail. + * + * Since user-space can cause the local strong ref to go away, we also take + * a tmpref on the node to ensure it survives while we are constructing + * the transaction. We also need a tmpref on the proc while we are + * constructing the transaction, so we take that here as well. + * + * Return: The target_node with refs taken or NULL if no @node->proc is NULL. + * Also sets @proc if valid. If the @node->proc is NULL indicating that the + * target proc has died, @error is set to BR_DEAD_REPLY + */ +static struct binder_node *binder_get_node_refs_for_txn( + struct binder_node *node, + struct binder_proc **procp, + uint32_t *error) +{ + struct binder_node *target_node = NULL; + + binder_node_inner_lock(node); + if (node->proc) { + target_node = node; + binder_inc_node_nilocked(node, 1, 0, NULL); + binder_inc_node_tmpref_ilocked(node); + node->proc->tmp_ref++; + *procp = node->proc; + } else + *error = BR_DEAD_REPLY; + binder_node_inner_unlock(node); + + return target_node; +} + static void binder_transaction(struct binder_proc *proc, struct binder_thread *thread, struct binder_transaction_data *tr, int reply, @@ -2686,43 +2727,35 @@ static void binder_transaction(struct binder_proc *proc, ref = binder_get_ref_olocked(proc, tr->target.handle, true); if (ref) { - binder_inc_node(ref->node, 1, 0, NULL); - target_node = ref->node; - } - binder_proc_unlock(proc); - if (target_node == NULL) { + target_node = binder_get_node_refs_for_txn( + ref->node, &target_proc, + &return_error); + } else { binder_user_error("%d:%d got transaction to invalid handle\n", - proc->pid, thread->pid); + proc->pid, thread->pid); return_error = BR_FAILED_REPLY; - return_error_param = -EINVAL; - return_error_line = __LINE__; - goto err_invalid_target_handle; } + binder_proc_unlock(proc); } else { mutex_lock(&context->context_mgr_node_lock); target_node = context->binder_context_mgr_node; - if (target_node == NULL) { + if (target_node) + target_node = binder_get_node_refs_for_txn( + target_node, &target_proc, + &return_error); + else return_error = BR_DEAD_REPLY; - mutex_unlock(&context->context_mgr_node_lock); - return_error_line = __LINE__; - goto err_no_context_mgr_node; - } - binder_inc_node(target_node, 1, 0, NULL); mutex_unlock(&context->context_mgr_node_lock); } - e->to_node = target_node->debug_id; - binder_node_lock(target_node); - target_proc = target_node->proc; - if (target_proc == NULL) { - binder_node_unlock(target_node); - return_error = BR_DEAD_REPLY; + if (!target_node) { + /* + * return_error is set above + */ + return_error_param = -EINVAL; return_error_line = __LINE__; goto err_dead_binder; } - binder_inner_proc_lock(target_proc); - target_proc->tmp_ref++; - binder_inner_proc_unlock(target_proc); - binder_node_unlock(target_node); + e->to_node = target_node->debug_id; if (security_binder_transaction(proc->tsk, target_proc->tsk) < 0) { return_error = BR_FAILED_REPLY; @@ -3072,6 +3105,8 @@ static void binder_transaction(struct binder_proc *proc, if (target_thread) binder_thread_dec_tmpref(target_thread); binder_proc_dec_tmpref(target_proc); + if (target_node) + binder_dec_node_tmpref(target_node); /* * write barrier to synchronize with initialization * of log entry @@ -3083,6 +3118,7 @@ static void binder_transaction(struct binder_proc *proc, err_dead_proc_or_thread: return_error = BR_DEAD_REPLY; return_error_line = __LINE__; + binder_dequeue_work(proc, tcomplete); err_translate_failed: err_bad_object_type: err_bad_offset: @@ -3090,6 +3126,8 @@ err_bad_parent: err_copy_data_failed: trace_binder_transaction_failed_buffer_release(t->buffer); binder_transaction_buffer_release(target_proc, t->buffer, offp); + if (target_node) + binder_dec_node_tmpref(target_node); target_node = NULL; t->buffer->transaction = NULL; binder_alloc_free_buf(&target_proc->alloc, t->buffer); @@ -3104,13 +3142,14 @@ err_bad_call_stack: err_empty_call_stack: err_dead_binder: err_invalid_target_handle: -err_no_context_mgr_node: if (target_thread) binder_thread_dec_tmpref(target_thread); if (target_proc) binder_proc_dec_tmpref(target_proc); - if (target_node) + if (target_node) { binder_dec_node(target_node, 1, 0); + binder_dec_node_tmpref(target_node); + } binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, "%d:%d transaction failed %d/%d, size %lld-%lld line %d\n", @@ -3623,12 +3662,6 @@ static void binder_stat_br(struct binder_proc *proc, } } -static int binder_has_thread_work(struct binder_thread *thread) -{ - return !binder_worklist_empty(thread->proc, &thread->todo) || - thread->looper_need_return; -} - static int binder_put_node_cmd(struct binder_proc *proc, struct binder_thread *thread, void __user **ptrp, @@ -4258,12 +4291,9 @@ static unsigned int binder_poll(struct file *filp, binder_inner_proc_unlock(thread->proc); - if (binder_has_work(thread, wait_for_proc_work)) - return POLLIN; - poll_wait(filp, &thread->wait, wait); - if (binder_has_thread_work(thread)) + if (binder_has_work(thread, wait_for_proc_work)) return POLLIN; return 0; diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 8fe165844e47..c2819a3d58a6 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -215,17 +215,12 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate, } } - if (!vma && need_mm) - mm = get_task_mm(alloc->tsk); + if (!vma && need_mm && mmget_not_zero(alloc->vma_vm_mm)) + mm = alloc->vma_vm_mm; if (mm) { down_write(&mm->mmap_sem); vma = alloc->vma; - if (vma && mm != alloc->vma_vm_mm) { - pr_err("%d: vma mm and task mm mismatch\n", - alloc->pid); - vma = NULL; - } } if (!vma && need_mm) { @@ -565,7 +560,7 @@ static void binder_delete_free_buffer(struct binder_alloc *alloc, binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, "%d: merge free, buffer %pK do not share page with %pK or %pK\n", alloc->pid, buffer->data, - prev->data, next->data); + prev->data, next ? next->data : NULL); binder_update_page_range(alloc, 0, buffer_start_page(buffer), buffer_start_page(buffer) + PAGE_SIZE, NULL); @@ -720,6 +715,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc, barrier(); alloc->vma = vma; alloc->vma_vm_mm = vma->vm_mm; + mmgrab(alloc->vma_vm_mm); return 0; @@ -795,6 +791,8 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc) vfree(alloc->buffer); } mutex_unlock(&alloc->mutex); + if (alloc->vma_vm_mm) + mmdrop(alloc->vma_vm_mm); binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE, "%s: %d buffers %d, pages %d\n", @@ -889,7 +887,6 @@ int binder_alloc_get_allocated_count(struct binder_alloc *alloc) void binder_alloc_vma_close(struct binder_alloc *alloc) { WRITE_ONCE(alloc->vma, NULL); - WRITE_ONCE(alloc->vma_vm_mm, NULL); } /** @@ -913,6 +910,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item, struct binder_alloc *alloc; uintptr_t page_addr; size_t index; + struct vm_area_struct *vma; alloc = page->alloc; if (!mutex_trylock(&alloc->mutex)) @@ -923,16 +921,22 @@ enum lru_status binder_alloc_free_page(struct list_head *item, index = page - alloc->pages; page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE; - if (alloc->vma) { - mm = get_task_mm(alloc->tsk); - if (!mm) - goto err_get_task_mm_failed; + vma = alloc->vma; + if (vma) { + if (!mmget_not_zero(alloc->vma_vm_mm)) + goto err_mmget; + mm = alloc->vma_vm_mm; if (!down_write_trylock(&mm->mmap_sem)) goto err_down_write_mmap_sem_failed; + } + + list_lru_isolate(lru, item); + spin_unlock(lock); + if (vma) { trace_binder_unmap_user_start(alloc, index); - zap_page_range(alloc->vma, + zap_page_range(vma, page_addr + alloc->user_buffer_offset, PAGE_SIZE); @@ -950,14 +954,13 @@ enum lru_status binder_alloc_free_page(struct list_head *item, trace_binder_unmap_kernel_end(alloc, index); - list_lru_isolate(lru, item); - + spin_lock(lock); mutex_unlock(&alloc->mutex); - return LRU_REMOVED; + return LRU_REMOVED_RETRY; err_down_write_mmap_sem_failed: - mmput(mm); -err_get_task_mm_failed: + mmput_async(mm); +err_mmget: err_page_already_freed: mutex_unlock(&alloc->mutex); err_get_alloc_mutex_failed: @@ -996,7 +999,6 @@ struct shrinker binder_shrinker = { */ void binder_alloc_init(struct binder_alloc *alloc) { - alloc->tsk = current->group_leader; alloc->pid = current->group_leader->pid; mutex_init(&alloc->mutex); INIT_LIST_HEAD(&alloc->buffers); diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h index a3a3602c689c..2dd33b6df104 100644 --- a/drivers/android/binder_alloc.h +++ b/drivers/android/binder_alloc.h @@ -100,7 +100,6 @@ struct binder_lru_page { */ struct binder_alloc { struct mutex mutex; - struct task_struct *tsk; struct vm_area_struct *vma; struct mm_struct *vma_vm_mm; void *buffer; |