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VMCI: Fix integer overflow in VMCI handle arrays 

The VMCI handle array has an integer overflow in
vmci_handle_arr_append_entry when it tries to expand the array. This can be
triggered from a guest, since the doorbell link hypercall doesn't impose a
limit on the number of doorbell handles that a VM can create in the
hypervisor, and these handles are stored in a handle array.

In this change, we introduce a mandatory max capacity for handle
arrays/lists to avoid excessive memory usage.

Signed-off-by: Vishnu Dasa <vdasa@vmware.com>
Reviewed-by: Adit Ranadive <aditr@vmware.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vishnu DASA 2019-05-24 15:13:10 +00:00 committed by Greg Kroah-Hartman
parent 84705f9f8c
commit 1c2eb5b285
4 changed files with 99 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
drivers/misc/vmw_vmci/vmci_context.c
View File

@ -21,6 +21,9 @@
#include "vmci_driver.h"
#include "vmci_event.h"
/* Use a wide upper bound for the maximum contexts. */
#define VMCI_MAX_CONTEXTS 2000
/*
* List of current VMCI contexts. Contexts can be added by
* vmci_ctx_create() and removed via vmci_ctx_destroy().
@ -117,19 +120,22 @@ struct vmci_ctx *vmci_ctx_create(u32 cid, u32 priv_flags,
/* Initialize host-specific VMCI context. */
init_waitqueue_head(&context->host_context.wait_queue);
context->queue_pair_array = vmci_handle_arr_create(0);
context->queue_pair_array =
vmci_handle_arr_create(0, VMCI_MAX_GUEST_QP_COUNT);
if (!context->queue_pair_array) {
error = -ENOMEM;
goto err_free_ctx;
}
context->doorbell_array = vmci_handle_arr_create(0);
context->doorbell_array =
vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT);
if (!context->doorbell_array) {
error = -ENOMEM;
goto err_free_qp_array;
}
context->pending_doorbell_array = vmci_handle_arr_create(0);
context->pending_doorbell_array =
vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT);
if (!context->pending_doorbell_array) {
error = -ENOMEM;
goto err_free_db_array;
@ -204,7 +210,7 @@ static int ctx_fire_notification(u32 context_id, u32 priv_flags)
* We create an array to hold the subscribers we find when
* scanning through all contexts.
*/
subscriber_array = vmci_handle_arr_create(0);
subscriber_array = vmci_handle_arr_create(0, VMCI_MAX_CONTEXTS);
if (subscriber_array == NULL)
return VMCI_ERROR_NO_MEM;
@ -623,20 +629,26 @@ int vmci_ctx_add_notification(u32 context_id, u32 remote_cid)
spin_lock(&context->lock);
list_for_each_entry(n, &context->notifier_list, node) {
if (vmci_handle_is_equal(n->handle, notifier->handle)) {
exists = true;
break;
if (context->n_notifiers < VMCI_MAX_CONTEXTS) {
list_for_each_entry(n, &context->notifier_list, node) {
if (vmci_handle_is_equal(n->handle, notifier->handle)) {
exists = true;
break;
}
}
}
if (exists) {
kfree(notifier);
result = VMCI_ERROR_ALREADY_EXISTS;
if (exists) {
kfree(notifier);
result = VMCI_ERROR_ALREADY_EXISTS;
} else {
list_add_tail_rcu(&notifier->node,
&context->notifier_list);
context->n_notifiers++;
result = VMCI_SUCCESS;
}
} else {
list_add_tail_rcu(&notifier->node, &context->notifier_list);
context->n_notifiers++;
result = VMCI_SUCCESS;
kfree(notifier);
result = VMCI_ERROR_NO_MEM;
}
spin_unlock(&context->lock);
@ -721,8 +733,7 @@ static int vmci_ctx_get_chkpt_doorbells(struct vmci_ctx *context,
u32 *buf_size, void **pbuf)
{
struct dbell_cpt_state *dbells;
size_t n_doorbells;
int i;
u32 i, n_doorbells;
n_doorbells = vmci_handle_arr_get_size(context->doorbell_array);
if (n_doorbells > 0) {
@ -860,7 +871,8 @@ int vmci_ctx_rcv_notifications_get(u32 context_id,
spin_lock(&context->lock);
*db_handle_array = context->pending_doorbell_array;
context->pending_doorbell_array = vmci_handle_arr_create(0);
context->pending_doorbell_array =
vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT);
if (!context->pending_doorbell_array) {
context->pending_doorbell_array = *db_handle_array;
*db_handle_array = NULL;
@ -942,12 +954,11 @@ int vmci_ctx_dbell_create(u32 context_id, struct vmci_handle handle)
return VMCI_ERROR_NOT_FOUND;
spin_lock(&context->lock);
if (!vmci_handle_arr_has_entry(context->doorbell_array, handle)) {
vmci_handle_arr_append_entry(&context->doorbell_array, handle);
result = VMCI_SUCCESS;
} else {
if (!vmci_handle_arr_has_entry(context->doorbell_array, handle))
result = vmci_handle_arr_append_entry(&context->doorbell_array,
handle);
else
result = VMCI_ERROR_DUPLICATE_ENTRY;
}
spin_unlock(&context->lock);
vmci_ctx_put(context);
@ -1083,15 +1094,16 @@ int vmci_ctx_notify_dbell(u32 src_cid,
if (!vmci_handle_arr_has_entry(
dst_context->pending_doorbell_array,
handle)) {
vmci_handle_arr_append_entry(
result = vmci_handle_arr_append_entry(
&dst_context->pending_doorbell_array,
handle);
ctx_signal_notify(dst_context);
wake_up(&dst_context->host_context.wait_queue);
if (result == VMCI_SUCCESS) {
ctx_signal_notify(dst_context);
wake_up(&dst_context->host_context.wait_queue);
}
} else {
result = VMCI_SUCCESS;
}
result = VMCI_SUCCESS;
}
spin_unlock(&dst_context->lock);
}
@ -1118,13 +1130,11 @@ int vmci_ctx_qp_create(struct vmci_ctx *context, struct vmci_handle handle)
if (context == NULL || vmci_handle_is_invalid(handle))
return VMCI_ERROR_INVALID_ARGS;
if (!vmci_handle_arr_has_entry(context->queue_pair_array, handle)) {
vmci_handle_arr_append_entry(&context->queue_pair_array,
handle);
result = VMCI_SUCCESS;
} else {
if (!vmci_handle_arr_has_entry(context->queue_pair_array, handle))
result = vmci_handle_arr_append_entry(
&context->queue_pair_array, handle);
else
result = VMCI_ERROR_DUPLICATE_ENTRY;
}
return result;
}

38
drivers/misc/vmw_vmci/vmci_handle_array.c
View File

@ -8,24 +8,29 @@
#include <linux/slab.h>
#include "vmci_handle_array.h"
static size_t handle_arr_calc_size(size_t capacity)
static size_t handle_arr_calc_size(u32 capacity)
{
return sizeof(struct vmci_handle_arr) +
return VMCI_HANDLE_ARRAY_HEADER_SIZE +
capacity * sizeof(struct vmci_handle);
}
struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity)
struct vmci_handle_arr *vmci_handle_arr_create(u32 capacity, u32 max_capacity)
{
struct vmci_handle_arr *array;
if (max_capacity == 0 || capacity > max_capacity)
return NULL;
if (capacity == 0)
capacity = VMCI_HANDLE_ARRAY_DEFAULT_SIZE;
capacity = min((u32)VMCI_HANDLE_ARRAY_DEFAULT_CAPACITY,
max_capacity);
array = kmalloc(handle_arr_calc_size(capacity), GFP_ATOMIC);
if (!array)
return NULL;
array->capacity = capacity;
array->max_capacity = max_capacity;
array->size = 0;
return array;
@ -36,27 +41,34 @@ void vmci_handle_arr_destroy(struct vmci_handle_arr *array)
kfree(array);
}
void vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
struct vmci_handle handle)
int vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
struct vmci_handle handle)
{
struct vmci_handle_arr *array = *array_ptr;
if (unlikely(array->size >= array->capacity)) {
/* reallocate. */
struct vmci_handle_arr *new_array;
size_t new_capacity = array->capacity * VMCI_ARR_CAP_MULT;
size_t new_size = handle_arr_calc_size(new_capacity);
u32 capacity_bump = min(array->max_capacity - array->capacity,
array->capacity);
size_t new_size = handle_arr_calc_size(array->capacity +
capacity_bump);
if (array->size >= array->max_capacity)
return VMCI_ERROR_NO_MEM;
new_array = krealloc(array, new_size, GFP_ATOMIC);
if (!new_array)
return;
return VMCI_ERROR_NO_MEM;
new_array->capacity = new_capacity;
new_array->capacity += capacity_bump;
*array_ptr = array = new_array;
}
array->entries[array->size] = handle;
array->size++;
return VMCI_SUCCESS;
}
/*
@ -66,7 +78,7 @@ struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
struct vmci_handle entry_handle)
{
struct vmci_handle handle = VMCI_INVALID_HANDLE;
size_t i;
u32 i;
for (i = 0; i < array->size; i++) {
if (vmci_handle_is_equal(array->entries[i], entry_handle)) {
@ -101,7 +113,7 @@ struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array)
* Handle at given index, VMCI_INVALID_HANDLE if invalid index.
*/
struct vmci_handle
vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index)
vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, u32 index)
{
if (unlikely(index >= array->size))
return VMCI_INVALID_HANDLE;
@ -112,7 +124,7 @@ vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index)
bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
struct vmci_handle entry_handle)
{
size_t i;
u32 i;
for (i = 0; i < array->size; i++)
if (vmci_handle_is_equal(array->entries[i], entry_handle))

29
drivers/misc/vmw_vmci/vmci_handle_array.h
View File

@ -9,32 +9,41 @@
#define _VMCI_HANDLE_ARRAY_H_
#include <linux/vmw_vmci_defs.h>
#include <linux/limits.h>
#include <linux/types.h>
#define VMCI_HANDLE_ARRAY_DEFAULT_SIZE 4
#define VMCI_ARR_CAP_MULT 2 /* Array capacity multiplier */
struct vmci_handle_arr {
size_t capacity;
size_t size;
u32 capacity;
u32 max_capacity;
u32 size;
u32 pad;
struct vmci_handle entries[];
};
struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity);
#define VMCI_HANDLE_ARRAY_HEADER_SIZE \
offsetof(struct vmci_handle_arr, entries)
/* Select a default capacity that results in a 64 byte sized array */
#define VMCI_HANDLE_ARRAY_DEFAULT_CAPACITY 6
/* Make sure that the max array size can be expressed by a u32 */
#define VMCI_HANDLE_ARRAY_MAX_CAPACITY \
((U32_MAX - VMCI_HANDLE_ARRAY_HEADER_SIZE - 1) / \
sizeof(struct vmci_handle))
struct vmci_handle_arr *vmci_handle_arr_create(u32 capacity, u32 max_capacity);
void vmci_handle_arr_destroy(struct vmci_handle_arr *array);
void vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
struct vmci_handle handle);
int vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
struct vmci_handle handle);
struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
struct vmci_handle
entry_handle);
struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array);
struct vmci_handle
vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index);
vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, u32 index);
bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
struct vmci_handle entry_handle);
struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array);
static inline size_t vmci_handle_arr_get_size(
static inline u32 vmci_handle_arr_get_size(
const struct vmci_handle_arr *array)
{
return array->size;

11
include/linux/vmw_vmci_defs.h
View File

@ -62,9 +62,18 @@ enum {
/*
* A single VMCI device has an upper limit of 128MB on the amount of
* memory that can be used for queue pairs.
* memory that can be used for queue pairs. Since each queue pair
* consists of at least two pages, the memory limit also dictates the
* number of queue pairs a guest can create.
*/
#define VMCI_MAX_GUEST_QP_MEMORY (128 * 1024 * 1024)
#define VMCI_MAX_GUEST_QP_COUNT (VMCI_MAX_GUEST_QP_MEMORY / PAGE_SIZE / 2)
/*
* There can be at most PAGE_SIZE doorbells since there is one doorbell
* per byte in the doorbell bitmap page.
*/
#define VMCI_MAX_GUEST_DOORBELL_COUNT PAGE_SIZE
/*
* Queues with pre-mapped data pages must be small, so that we don't pin