diff options
Diffstat (limited to 'drivers/android/binder.c')
| -rw-r--r-- | drivers/android/binder.c | 299 |
1 files changed, 274 insertions, 25 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 608ff978564b..5497797ab258 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2233,7 +2233,246 @@ err_fd_not_accepted: return ret; } -static int binder_translate_fd_array(struct binder_fd_array_object *fda, +/** + * struct binder_ptr_fixup - data to be fixed-up in target buffer + * @offset offset in target buffer to fixup + * @skip_size bytes to skip in copy (fixup will be written later) + * @fixup_data data to write at fixup offset + * @node list node + * + * This is used for the pointer fixup list (pf) which is created and consumed + * during binder_transaction() and is only accessed locally. No + * locking is necessary. + * + * The list is ordered by @offset. + */ +struct binder_ptr_fixup { + binder_size_t offset; + size_t skip_size; + binder_uintptr_t fixup_data; + struct list_head node; +}; + +/** + * struct binder_sg_copy - scatter-gather data to be copied + * @offset offset in target buffer + * @sender_uaddr user address in source buffer + * @length bytes to copy + * @node list node + * + * This is used for the sg copy list (sgc) which is created and consumed + * during binder_transaction() and is only accessed locally. No + * locking is necessary. + * + * The list is ordered by @offset. + */ +struct binder_sg_copy { + binder_size_t offset; + const void __user *sender_uaddr; + size_t length; + struct list_head node; +}; + +/** + * binder_do_deferred_txn_copies() - copy and fixup scatter-gather data + * @alloc: binder_alloc associated with @buffer + * @buffer: binder buffer in target process + * @sgc_head: list_head of scatter-gather copy list + * @pf_head: list_head of pointer fixup list + * + * Processes all elements of @sgc_head, applying fixups from @pf_head + * and copying the scatter-gather data from the source process' user + * buffer to the target's buffer. It is expected that the list creation + * and processing all occurs during binder_transaction() so these lists + * are only accessed in local context. + * + * Return: 0=success, else -errno + */ +static int binder_do_deferred_txn_copies(struct binder_alloc *alloc, + struct binder_buffer *buffer, + struct list_head *sgc_head, + struct list_head *pf_head) +{ + int ret = 0; + struct binder_sg_copy *sgc, *tmpsgc; + struct binder_ptr_fixup *pf = + list_first_entry_or_null(pf_head, struct binder_ptr_fixup, + node); + + list_for_each_entry_safe(sgc, tmpsgc, sgc_head, node) { + size_t bytes_copied = 0; + + while (bytes_copied < sgc->length) { + size_t copy_size; + size_t bytes_left = sgc->length - bytes_copied; + size_t offset = sgc->offset + bytes_copied; + + /* + * We copy up to the fixup (pointed to by pf) + */ + copy_size = pf ? min(bytes_left, (size_t)pf->offset - offset) + : bytes_left; + if (!ret && copy_size) + ret = binder_alloc_copy_user_to_buffer( + alloc, buffer, + offset, + sgc->sender_uaddr + bytes_copied, + copy_size); + bytes_copied += copy_size; + if (copy_size != bytes_left) { + BUG_ON(!pf); + /* we stopped at a fixup offset */ + if (pf->skip_size) { + /* + * we are just skipping. This is for + * BINDER_TYPE_FDA where the translated + * fds will be fixed up when we get + * to target context. + */ + bytes_copied += pf->skip_size; + } else { + /* apply the fixup indicated by pf */ + if (!ret) + ret = binder_alloc_copy_to_buffer( + alloc, buffer, + pf->offset, + &pf->fixup_data, + sizeof(pf->fixup_data)); + bytes_copied += sizeof(pf->fixup_data); + } + list_del(&pf->node); + kfree(pf); + pf = list_first_entry_or_null(pf_head, + struct binder_ptr_fixup, node); + } + } + list_del(&sgc->node); + kfree(sgc); + } + BUG_ON(!list_empty(pf_head)); + BUG_ON(!list_empty(sgc_head)); + + return ret > 0 ? -EINVAL : ret; +} + +/** + * binder_cleanup_deferred_txn_lists() - free specified lists + * @sgc_head: list_head of scatter-gather copy list + * @pf_head: list_head of pointer fixup list + * + * Called to clean up @sgc_head and @pf_head if there is an + * error. + */ +static void binder_cleanup_deferred_txn_lists(struct list_head *sgc_head, + struct list_head *pf_head) +{ + struct binder_sg_copy *sgc, *tmpsgc; + struct binder_ptr_fixup *pf, *tmppf; + + list_for_each_entry_safe(sgc, tmpsgc, sgc_head, node) { + list_del(&sgc->node); + kfree(sgc); + } + list_for_each_entry_safe(pf, tmppf, pf_head, node) { + list_del(&pf->node); + kfree(pf); + } +} + +/** + * binder_defer_copy() - queue a scatter-gather buffer for copy + * @sgc_head: list_head of scatter-gather copy list + * @offset: binder buffer offset in target process + * @sender_uaddr: user address in source process + * @length: bytes to copy + * + * Specify a scatter-gather block to be copied. The actual copy must + * be deferred until all the needed fixups are identified and queued. + * Then the copy and fixups are done together so un-translated values + * from the source are never visible in the target buffer. + * + * We are guaranteed that repeated calls to this function will have + * monotonically increasing @offset values so the list will naturally + * be ordered. + * + * Return: 0=success, else -errno + */ +static int binder_defer_copy(struct list_head *sgc_head, binder_size_t offset, + const void __user *sender_uaddr, size_t length) +{ + struct binder_sg_copy *bc = kzalloc(sizeof(*bc), GFP_KERNEL); + + if (!bc) + return -ENOMEM; + + bc->offset = offset; + bc->sender_uaddr = sender_uaddr; + bc->length = length; + INIT_LIST_HEAD(&bc->node); + + /* + * We are guaranteed that the deferred copies are in-order + * so just add to the tail. + */ + list_add_tail(&bc->node, sgc_head); + + return 0; +} + +/** + * binder_add_fixup() - queue a fixup to be applied to sg copy + * @pf_head: list_head of binder ptr fixup list + * @offset: binder buffer offset in target process + * @fixup: bytes to be copied for fixup + * @skip_size: bytes to skip when copying (fixup will be applied later) + * + * Add the specified fixup to a list ordered by @offset. When copying + * the scatter-gather buffers, the fixup will be copied instead of + * data from the source buffer. For BINDER_TYPE_FDA fixups, the fixup + * will be applied later (in target process context), so we just skip + * the bytes specified by @skip_size. If @skip_size is 0, we copy the + * value in @fixup. + * + * This function is called *mostly* in @offset order, but there are + * exceptions. Since out-of-order inserts are relatively uncommon, + * we insert the new element by searching backward from the tail of + * the list. + * + * Return: 0=success, else -errno + */ +static int binder_add_fixup(struct list_head *pf_head, binder_size_t offset, + binder_uintptr_t fixup, size_t skip_size) +{ + struct binder_ptr_fixup *pf = kzalloc(sizeof(*pf), GFP_KERNEL); + struct binder_ptr_fixup *tmppf; + + if (!pf) + return -ENOMEM; + + pf->offset = offset; + pf->fixup_data = fixup; + pf->skip_size = skip_size; + INIT_LIST_HEAD(&pf->node); + + /* Fixups are *mostly* added in-order, but there are some + * exceptions. Look backwards through list for insertion point. + */ + list_for_each_entry_reverse(tmppf, pf_head, node) { + if (tmppf->offset < pf->offset) { + list_add(&pf->node, &tmppf->node); + return 0; + } + } + /* + * if we get here, then the new offset is the lowest so + * insert at the head + */ + list_add(&pf->node, pf_head); + return 0; +} + +static int binder_translate_fd_array(struct list_head *pf_head, + struct binder_fd_array_object *fda, const void __user *sender_ubuffer, struct binder_buffer_object *parent, struct binder_buffer_object *sender_uparent, @@ -2245,6 +2484,7 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda, binder_size_t fda_offset; const void __user *sender_ufda_base; struct binder_proc *proc = thread->proc; + int ret; fd_buf_size = sizeof(u32) * fda->num_fds; if (fda->num_fds >= SIZE_MAX / sizeof(u32)) { @@ -2276,9 +2516,12 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda, proc->pid, thread->pid); return -EINVAL; } + ret = binder_add_fixup(pf_head, fda_offset, 0, fda->num_fds * sizeof(u32)); + if (ret) + return ret; + for (fdi = 0; fdi < fda->num_fds; fdi++) { u32 fd; - int ret; binder_size_t offset = fda_offset + fdi * sizeof(fd); binder_size_t sender_uoffset = fdi * sizeof(fd); @@ -2292,7 +2535,8 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda, return 0; } -static int binder_fixup_parent(struct binder_transaction *t, +static int binder_fixup_parent(struct list_head *pf_head, + struct binder_transaction *t, struct binder_thread *thread, struct binder_buffer_object *bp, binder_size_t off_start_offset, @@ -2338,14 +2582,7 @@ static int binder_fixup_parent(struct binder_transaction *t, } buffer_offset = bp->parent_offset + (uintptr_t)parent->buffer - (uintptr_t)b->user_data; - if (binder_alloc_copy_to_buffer(&target_proc->alloc, b, buffer_offset, - &bp->buffer, sizeof(bp->buffer))) { - binder_user_error("%d:%d got transaction with invalid parent offset\n", - proc->pid, thread->pid); - return -EINVAL; - } - - return 0; + return binder_add_fixup(pf_head, buffer_offset, bp->buffer, 0); } /** @@ -2487,8 +2724,12 @@ static void binder_transaction(struct binder_proc *proc, int t_debug_id = atomic_inc_return(&binder_last_id); char *secctx = NULL; u32 secctx_sz = 0; + struct list_head sgc_head; + struct list_head pf_head; const void __user *user_buffer = (const void __user *) (uintptr_t)tr->data.ptr.buffer; + INIT_LIST_HEAD(&sgc_head); + INIT_LIST_HEAD(&pf_head); e = binder_transaction_log_add(&binder_transaction_log); e->debug_id = t_debug_id; @@ -3005,8 +3246,8 @@ static void binder_transaction(struct binder_proc *proc, return_error_line = __LINE__; goto err_bad_parent; } - ret = binder_translate_fd_array(fda, user_buffer, - parent, + ret = binder_translate_fd_array(&pf_head, fda, + user_buffer, parent, &user_object.bbo, t, thread, in_reply_to); if (!ret) @@ -3038,19 +3279,14 @@ static void binder_transaction(struct binder_proc *proc, return_error_line = __LINE__; goto err_bad_offset; } - if (binder_alloc_copy_user_to_buffer( - &target_proc->alloc, - t->buffer, - sg_buf_offset, - (const void __user *) - (uintptr_t)bp->buffer, - bp->length)) { - binder_user_error("%d:%d got transaction with invalid offsets ptr\n", - proc->pid, thread->pid); - return_error_param = -EFAULT; + ret = binder_defer_copy(&sgc_head, sg_buf_offset, + (const void __user *)(uintptr_t)bp->buffer, + bp->length); + if (ret) { return_error = BR_FAILED_REPLY; + return_error_param = ret; return_error_line = __LINE__; - goto err_copy_data_failed; + goto err_translate_failed; } /* Fixup buffer pointer to target proc address space */ bp->buffer = (uintptr_t) @@ -3059,7 +3295,8 @@ static void binder_transaction(struct binder_proc *proc, num_valid = (buffer_offset - off_start_offset) / sizeof(binder_size_t); - ret = binder_fixup_parent(t, thread, bp, + ret = binder_fixup_parent(&pf_head, t, + thread, bp, off_start_offset, num_valid, last_fixup_obj_off, @@ -3099,6 +3336,17 @@ static void binder_transaction(struct binder_proc *proc, return_error_line = __LINE__; goto err_copy_data_failed; } + + ret = binder_do_deferred_txn_copies(&target_proc->alloc, t->buffer, + &sgc_head, &pf_head); + if (ret) { + binder_user_error("%d:%d got transaction with invalid offsets ptr\n", + proc->pid, thread->pid); + return_error = BR_FAILED_REPLY; + return_error_param = ret; + return_error_line = __LINE__; + goto err_copy_data_failed; + } if (t->buffer->oneway_spam_suspect) tcomplete->type = BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT; else @@ -3172,6 +3420,7 @@ err_bad_object_type: err_bad_offset: err_bad_parent: err_copy_data_failed: + binder_cleanup_deferred_txn_lists(&sgc_head, &pf_head); binder_free_txn_fixups(t); trace_binder_transaction_failed_buffer_release(t->buffer); binder_transaction_buffer_release(target_proc, NULL, t->buffer, |