Revert "Fix an OOB write bug in attp_build_value_cmd"
This reverts commit a0d4425c3964f99f589d449deed2f1bbe520218c.
Reason for revert: LE Device name is incorrect after the change. See b/315127634
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:6dbe94fe556ef67f3bbb7d7bb2da3320d68619df)
Merged-In: I93906e7ab768b4015fe3491e171fdb0ec8cf3077
Change-Id: I93906e7ab768b4015fe3491e171fdb0ec8cf3077
diff --git a/system/stack/gatt/att_protocol.cc b/system/stack/gatt/att_protocol.cc
index f055fb8..29ceec2 100644
--- a/system/stack/gatt/att_protocol.cc
+++ b/system/stack/gatt/att_protocol.cc
@@ -286,79 +286,46 @@
static BT_HDR* attp_build_value_cmd(uint16_t payload_size, uint8_t op_code,
uint16_t handle, uint16_t offset,
uint16_t len, uint8_t* p_data) {
- uint8_t *p, *pp, *p_pair_len;
- size_t pair_len;
- size_t size_now = 1;
-
- #define CHECK_SIZE() do { \
- if (size_now > payload_size) { \
- LOG(ERROR) << "payload size too small"; \
- osi_free(p_buf); \
- return nullptr; \
- } \
- } while (false)
-
+ uint8_t *p, *pp, pair_len, *p_pair_len;
BT_HDR* p_buf =
(BT_HDR*)osi_malloc(sizeof(BT_HDR) + payload_size + L2CAP_MIN_OFFSET);
p = pp = (uint8_t*)(p_buf + 1) + L2CAP_MIN_OFFSET;
-
- CHECK_SIZE();
UINT8_TO_STREAM(p, op_code);
p_buf->offset = L2CAP_MIN_OFFSET;
+ p_buf->len = 1;
if (op_code == GATT_RSP_READ_BY_TYPE) {
p_pair_len = p;
pair_len = len + 2;
- size_now += 1;
- CHECK_SIZE();
- // this field will be backfilled in the end of this function
+ UINT8_TO_STREAM(p, pair_len);
+ p_buf->len += 1;
}
-
if (op_code != GATT_RSP_READ_BLOB && op_code != GATT_RSP_READ) {
- size_now += 2;
- CHECK_SIZE();
UINT16_TO_STREAM(p, handle);
+ p_buf->len += 2;
}
if (op_code == GATT_REQ_PREPARE_WRITE || op_code == GATT_RSP_PREPARE_WRITE) {
- size_now += 2;
- CHECK_SIZE();
UINT16_TO_STREAM(p, offset);
+ p_buf->len += 2;
}
- if (len > 0 && p_data != NULL && payload_size > size_now) {
+ if (len > 0 && p_data != NULL) {
/* ensure data not exceed MTU size */
- if (payload_size - size_now < len) {
- len = payload_size - size_now;
+ if (payload_size - p_buf->len < len) {
+ len = payload_size - p_buf->len;
/* update handle value pair length */
- if (op_code == GATT_RSP_READ_BY_TYPE) {
- pair_len = (len + 2);
- }
+ if (op_code == GATT_RSP_READ_BY_TYPE) *p_pair_len = (len + 2);
LOG(WARNING) << StringPrintf(
"attribute value too long, to be truncated to %d", len);
}
- size_now += len;
- CHECK_SIZE();
ARRAY_TO_STREAM(p, p_data, len);
+ p_buf->len += len;
}
- // backfill pair len field
- if (op_code == GATT_RSP_READ_BY_TYPE) {
- if (pair_len > UINT8_MAX) {
- LOG(ERROR) << "pair_len greater than" << UINT8_MAX;
- osi_free(p_buf);
- return nullptr;
- }
-
- *p_pair_len = (uint8_t) pair_len;
- }
-
- #undef CHECK_SIZE
-
- p_buf->len = (uint16_t) size_now;
return p_buf;
}