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-rw-r--r--drivers/android/binder.c244
-rw-r--r--include/uapi/linux/android/binder.h45
2 files changed, 276 insertions, 13 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 25aa452d2738..3d241fbab533 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -152,6 +152,9 @@ module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
#define to_binder_fd_object(hdr) container_of(hdr, struct binder_fd_object, hdr)
+#define to_binder_buffer_object(hdr) \
+ container_of(hdr, struct binder_buffer_object, hdr)
+
enum binder_stat_types {
BINDER_STAT_PROC,
BINDER_STAT_THREAD,
@@ -165,7 +168,7 @@ enum binder_stat_types {
struct binder_stats {
int br[_IOC_NR(BR_FAILED_REPLY) + 1];
- int bc[_IOC_NR(BC_DEAD_BINDER_DONE) + 1];
+ int bc[_IOC_NR(BC_REPLY_SG) + 1];
int obj_created[BINDER_STAT_COUNT];
int obj_deleted[BINDER_STAT_COUNT];
};
@@ -1304,6 +1307,9 @@ static size_t binder_validate_object(struct binder_buffer *buffer, u64 offset)
case BINDER_TYPE_FD:
object_size = sizeof(struct binder_fd_object);
break;
+ case BINDER_TYPE_PTR:
+ object_size = sizeof(struct binder_buffer_object);
+ break;
default:
return 0;
}
@@ -1314,11 +1320,111 @@ static size_t binder_validate_object(struct binder_buffer *buffer, u64 offset)
return 0;
}
+/**
+ * binder_validate_ptr() - validates binder_buffer_object in a binder_buffer.
+ * @b: binder_buffer containing the object
+ * @index: index in offset array at which the binder_buffer_object is
+ * located
+ * @start: points to the start of the offset array
+ * @num_valid: the number of valid offsets in the offset array
+ *
+ * Return: If @index is within the valid range of the offset array
+ * described by @start and @num_valid, and if there's a valid
+ * binder_buffer_object at the offset found in index @index
+ * of the offset array, that object is returned. Otherwise,
+ * %NULL is returned.
+ * Note that the offset found in index @index itself is not
+ * verified; this function assumes that @num_valid elements
+ * from @start were previously verified to have valid offsets.
+ */
+static struct binder_buffer_object *binder_validate_ptr(struct binder_buffer *b,
+ binder_size_t index,
+ binder_size_t *start,
+ binder_size_t num_valid)
+{
+ struct binder_buffer_object *buffer_obj;
+ binder_size_t *offp;
+
+ if (index >= num_valid)
+ return NULL;
+
+ offp = start + index;
+ buffer_obj = (struct binder_buffer_object *)(b->data + *offp);
+ if (buffer_obj->hdr.type != BINDER_TYPE_PTR)
+ return NULL;
+
+ return buffer_obj;
+}
+
+/**
+ * binder_validate_fixup() - validates pointer/fd fixups happen in order.
+ * @b: transaction buffer
+ * @objects_start start of objects buffer
+ * @buffer: binder_buffer_object in which to fix up
+ * @offset: start offset in @buffer to fix up
+ * @last_obj: last binder_buffer_object that we fixed up in
+ * @last_min_offset: minimum fixup offset in @last_obj
+ *
+ * Return: %true if a fixup in buffer @buffer at offset @offset is
+ * allowed.
+ *
+ * For safety reasons, we only allow fixups inside a buffer to happen
+ * at increasing offsets; additionally, we only allow fixup on the last
+ * buffer object that was verified, or one of its parents.
+ *
+ * Example of what is allowed:
+ *
+ * A
+ * B (parent = A, offset = 0)
+ * C (parent = A, offset = 16)
+ * D (parent = C, offset = 0)
+ * E (parent = A, offset = 32) // min_offset is 16 (C.parent_offset)
+ *
+ * Examples of what is not allowed:
+ *
+ * Decreasing offsets within the same parent:
+ * A
+ * C (parent = A, offset = 16)
+ * B (parent = A, offset = 0) // decreasing offset within A
+ *
+ * Referring to a parent that wasn't the last object or any of its parents:
+ * A
+ * B (parent = A, offset = 0)
+ * C (parent = A, offset = 0)
+ * C (parent = A, offset = 16)
+ * D (parent = B, offset = 0) // B is not A or any of A's parents
+ */
+static bool binder_validate_fixup(struct binder_buffer *b,
+ binder_size_t *objects_start,
+ struct binder_buffer_object *buffer,
+ binder_size_t fixup_offset,
+ struct binder_buffer_object *last_obj,
+ binder_size_t last_min_offset)
+{
+ if (!last_obj) {
+ /* Nothing to fix up in */
+ return false;
+ }
+
+ while (last_obj != buffer) {
+ /*
+ * Safe to retrieve the parent of last_obj, since it
+ * was already previously verified by the driver.
+ */
+ if ((last_obj->flags & BINDER_BUFFER_FLAG_HAS_PARENT) == 0)
+ return false;
+ last_min_offset = last_obj->parent_offset + sizeof(uintptr_t);
+ last_obj = (struct binder_buffer_object *)
+ (b->data + *(objects_start + last_obj->parent));
+ }
+ return (fixup_offset >= last_min_offset);
+}
+
static void binder_transaction_buffer_release(struct binder_proc *proc,
struct binder_buffer *buffer,
binder_size_t *failed_at)
{
- binder_size_t *offp, *off_end;
+ binder_size_t *offp, *off_start, *off_end;
int debug_id = buffer->debug_id;
binder_debug(BINDER_DEBUG_TRANSACTION,
@@ -1329,13 +1435,13 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
if (buffer->target_node)
binder_dec_node(buffer->target_node, 1, 0);
- offp = (binder_size_t *)(buffer->data +
- ALIGN(buffer->data_size, sizeof(void *)));
+ off_start = (binder_size_t *)(buffer->data +
+ ALIGN(buffer->data_size, sizeof(void *)));
if (failed_at)
off_end = failed_at;
else
- off_end = (void *)offp + buffer->offsets_size;
- for (; offp < off_end; offp++) {
+ off_end = (void *)off_start + buffer->offsets_size;
+ for (offp = off_start; offp < off_end; offp++) {
struct binder_object_header *hdr;
size_t object_size = binder_validate_object(buffer, *offp);
@@ -1391,7 +1497,12 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
if (failed_at)
task_close_fd(proc, fp->fd);
} break;
-
+ case BINDER_TYPE_PTR:
+ /*
+ * Nothing to do here, this will get cleaned up when the
+ * transaction buffer gets freed
+ */
+ break;
default:
pr_err("transaction release %d bad object type %x\n",
debug_id, hdr->type);
@@ -1561,6 +1672,53 @@ err_fd_not_accepted:
return ret;
}
+static int binder_fixup_parent(struct binder_transaction *t,
+ struct binder_thread *thread,
+ struct binder_buffer_object *bp,
+ binder_size_t *off_start,
+ binder_size_t num_valid,
+ struct binder_buffer_object *last_fixup_obj,
+ binder_size_t last_fixup_min_off)
+{
+ struct binder_buffer_object *parent;
+ u8 *parent_buffer;
+ struct binder_buffer *b = t->buffer;
+ struct binder_proc *proc = thread->proc;
+ struct binder_proc *target_proc = t->to_proc;
+
+ if (!(bp->flags & BINDER_BUFFER_FLAG_HAS_PARENT))
+ return 0;
+
+ parent = binder_validate_ptr(b, bp->parent, off_start, num_valid);
+ if (!parent) {
+ binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
+ proc->pid, thread->pid);
+ return -EINVAL;
+ }
+
+ if (!binder_validate_fixup(b, off_start,
+ parent, bp->parent_offset,
+ last_fixup_obj,
+ last_fixup_min_off)) {
+ binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
+ proc->pid, thread->pid);
+ return -EINVAL;
+ }
+
+ if (parent->length < sizeof(binder_uintptr_t) ||
+ bp->parent_offset > parent->length - sizeof(binder_uintptr_t)) {
+ /* No space for a pointer here! */
+ binder_user_error("%d:%d got transaction with invalid parent offset\n",
+ proc->pid, thread->pid);
+ return -EINVAL;
+ }
+ parent_buffer = (u8 *)(parent->buffer -
+ target_proc->user_buffer_offset);
+ *(binder_uintptr_t *)(parent_buffer + bp->parent_offset) = bp->buffer;
+
+ return 0;
+}
+
static void binder_transaction(struct binder_proc *proc,
struct binder_thread *thread,
struct binder_transaction_data *tr, int reply,
@@ -1569,8 +1727,9 @@ static void binder_transaction(struct binder_proc *proc,
int ret;
struct binder_transaction *t;
struct binder_work *tcomplete;
- binder_size_t *offp, *off_end;
+ binder_size_t *offp, *off_end, *off_start;
binder_size_t off_min;
+ u8 *sg_bufp, *sg_buf_end;
struct binder_proc *target_proc;
struct binder_thread *target_thread = NULL;
struct binder_node *target_node = NULL;
@@ -1579,6 +1738,8 @@ static void binder_transaction(struct binder_proc *proc,
struct binder_transaction *in_reply_to = NULL;
struct binder_transaction_log_entry *e;
uint32_t return_error;
+ struct binder_buffer_object *last_fixup_obj = NULL;
+ binder_size_t last_fixup_min_off = 0;
struct binder_context *context = proc->context;
e = binder_transaction_log_add(&binder_transaction_log);
@@ -1753,8 +1914,9 @@ static void binder_transaction(struct binder_proc *proc,
if (target_node)
binder_inc_node(target_node, 1, 0, NULL);
- offp = (binder_size_t *)(t->buffer->data +
- ALIGN(tr->data_size, sizeof(void *)));
+ off_start = (binder_size_t *)(t->buffer->data +
+ ALIGN(tr->data_size, sizeof(void *)));
+ offp = off_start;
if (copy_from_user(t->buffer->data, (const void __user *)(uintptr_t)
tr->data.ptr.buffer, tr->data_size)) {
@@ -1776,7 +1938,16 @@ static void binder_transaction(struct binder_proc *proc,
return_error = BR_FAILED_REPLY;
goto err_bad_offset;
}
- off_end = (void *)offp + tr->offsets_size;
+ if (!IS_ALIGNED(extra_buffers_size, sizeof(u64))) {
+ binder_user_error("%d:%d got transaction with unaligned buffers size, %lld\n",
+ proc->pid, thread->pid,
+ (u64)extra_buffers_size);
+ return_error = BR_FAILED_REPLY;
+ goto err_bad_offset;
+ }
+ off_end = (void *)off_start + tr->offsets_size;
+ sg_bufp = (u8 *)(PTR_ALIGN(off_end, sizeof(void *)));
+ sg_buf_end = sg_bufp + extra_buffers_size;
off_min = 0;
for (; offp < off_end; offp++) {
struct binder_object_header *hdr;
@@ -1829,7 +2000,41 @@ static void binder_transaction(struct binder_proc *proc,
fp->pad_binder = 0;
fp->fd = target_fd;
} break;
-
+ case BINDER_TYPE_PTR: {
+ struct binder_buffer_object *bp =
+ to_binder_buffer_object(hdr);
+ size_t buf_left = sg_buf_end - sg_bufp;
+
+ if (bp->length > buf_left) {
+ binder_user_error("%d:%d got transaction with too large buffer\n",
+ proc->pid, thread->pid);
+ return_error = BR_FAILED_REPLY;
+ goto err_bad_offset;
+ }
+ if (copy_from_user(sg_bufp,
+ (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 = BR_FAILED_REPLY;
+ goto err_copy_data_failed;
+ }
+ /* Fixup buffer pointer to target proc address space */
+ bp->buffer = (uintptr_t)sg_bufp +
+ target_proc->user_buffer_offset;
+ sg_bufp += ALIGN(bp->length, sizeof(u64));
+
+ ret = binder_fixup_parent(t, thread, bp, off_start,
+ offp - off_start,
+ last_fixup_obj,
+ last_fixup_min_off);
+ if (ret < 0) {
+ return_error = BR_FAILED_REPLY;
+ goto err_translate_failed;
+ }
+ last_fixup_obj = bp;
+ last_fixup_min_off = 0;
+ } break;
default:
binder_user_error("%d:%d got transaction with invalid object type, %x\n",
proc->pid, thread->pid, hdr->type);
@@ -2083,6 +2288,17 @@ static int binder_thread_write(struct binder_proc *proc,
break;
}
+ case BC_TRANSACTION_SG:
+ case BC_REPLY_SG: {
+ struct binder_transaction_data_sg tr;
+
+ if (copy_from_user(&tr, ptr, sizeof(tr)))
+ return -EFAULT;
+ ptr += sizeof(tr);
+ binder_transaction(proc, thread, &tr.transaction_data,
+ cmd == BC_REPLY_SG, tr.buffers_size);
+ break;
+ }
case BC_TRANSACTION:
case BC_REPLY: {
struct binder_transaction_data tr;
@@ -3609,7 +3825,9 @@ static const char * const binder_command_strings[] = {
"BC_EXIT_LOOPER",
"BC_REQUEST_DEATH_NOTIFICATION",
"BC_CLEAR_DEATH_NOTIFICATION",
- "BC_DEAD_BINDER_DONE"
+ "BC_DEAD_BINDER_DONE",
+ "BC_TRANSACTION_SG",
+ "BC_REPLY_SG",
};
static const char * const binder_objstat_strings[] = {
diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
index f67c2b1c0713..f3ef6e2634ba 100644
--- a/include/uapi/linux/android/binder.h
+++ b/include/uapi/linux/android/binder.h
@@ -33,6 +33,7 @@ enum {
BINDER_TYPE_HANDLE = B_PACK_CHARS('s', 'h', '*', B_TYPE_LARGE),
BINDER_TYPE_WEAK_HANDLE = B_PACK_CHARS('w', 'h', '*', B_TYPE_LARGE),
BINDER_TYPE_FD = B_PACK_CHARS('f', 'd', '*', B_TYPE_LARGE),
+ BINDER_TYPE_PTR = B_PACK_CHARS('p', 't', '*', B_TYPE_LARGE),
};
enum {
@@ -95,6 +96,39 @@ struct binder_fd_object {
binder_uintptr_t cookie;
};
+
+/* struct binder_buffer_object - object describing a userspace buffer
+ * @hdr: common header structure
+ * @flags: one or more BINDER_BUFFER_* flags
+ * @buffer: address of the buffer
+ * @length: length of the buffer
+ * @parent: index in offset array pointing to parent buffer
+ * @parent_offset: offset in @parent pointing to this buffer
+ *
+ * A binder_buffer object represents an object that the
+ * binder kernel driver can copy verbatim to the target
+ * address space. A buffer itself may be pointed to from
+ * within another buffer, meaning that the pointer inside
+ * that other buffer needs to be fixed up as well. This
+ * can be done by setting the BINDER_BUFFER_FLAG_HAS_PARENT
+ * flag in @flags, by setting @parent buffer to the index
+ * in the offset array pointing to the parent binder_buffer_object,
+ * and by setting @parent_offset to the offset in the parent buffer
+ * at which the pointer to this buffer is located.
+ */
+struct binder_buffer_object {
+ struct binder_object_header hdr;
+ __u32 flags;
+ binder_uintptr_t buffer;
+ binder_size_t length;
+ binder_size_t parent;
+ binder_size_t parent_offset;
+};
+
+enum {
+ BINDER_BUFFER_FLAG_HAS_PARENT = 0x01,
+};
+
/*
* On 64-bit platforms where user code may run in 32-bits the driver must
* translate the buffer (and local binder) addresses appropriately.
@@ -187,6 +221,11 @@ struct binder_transaction_data {
} data;
};
+struct binder_transaction_data_sg {
+ struct binder_transaction_data transaction_data;
+ binder_size_t buffers_size;
+};
+
struct binder_ptr_cookie {
binder_uintptr_t ptr;
binder_uintptr_t cookie;
@@ -371,6 +410,12 @@ enum binder_driver_command_protocol {
/*
* void *: cookie
*/
+
+ BC_TRANSACTION_SG = _IOW('c', 17, struct binder_transaction_data_sg),
+ BC_REPLY_SG = _IOW('c', 18, struct binder_transaction_data_sg),
+ /*
+ * binder_transaction_data_sg: the sent command.
+ */
};
#endif /* _UAPI_LINUX_BINDER_H */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-11 23:31:44 +0000