[PATCH 6.1 308/312] Bluetooth: eir: Fix possible crashes on eir_create_adv_data

Greg Kroah-Hartman
2026-04-08T18:20:06Z

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit 47c03902269aff377f959dc3fd94a9733aa31d6e ]

eir_create_adv_data may attempt to add EIR_FLAGS and EIR_TX_POWER
without checking if that would fit.

Link: https://github.com/bluez/bluez/issues/1117#issuecomment-2958244066
Fixes: 01ce70b0a274 ("Bluetooth: eir: Move EIR/Adv Data functions to its own file")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
[ Use pdu.data instead of pdu->data in hci_set_ext_adv_data_sync()
to keep context consistency. ]
Signed-off-by: Robert Garcia <rob_garcia@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/bluetooth/eir.c | 7 ++++---
net/bluetooth/eir.h | 2 +-
net/bluetooth/hci_sync.c | 5 +++--
3 files changed, 8 insertions(+), 6 deletions(-)

--- a/net/bluetooth/eir.c
+++ b/net/bluetooth/eir.c
@@ -242,7 +242,7 @@ u8 eir_create_per_adv_data(struct hci_de
return ad_len;
}

-u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
+u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr, u8 size)
{
struct adv_info *adv = NULL;
u8 ad_len = 0, flags = 0;
@@ -286,7 +286,7 @@ u8 eir_create_adv_data(struct hci_dev *h
/* If flags would still be empty, then there is no need to
* include the "Flags" AD field".
*/
- if (flags) {
+ if (flags && (ad_len + eir_precalc_len(1) <= size)) {
ptr[0] = 0x02;
ptr[1] = EIR_FLAGS;
ptr[2] = flags;
@@ -316,7 +316,8 @@ skip_flags:
}

/* Provide Tx Power only if we can provide a valid value for it */
- if (adv_tx_power != HCI_TX_POWER_INVALID) {
+ if (adv_tx_power != HCI_TX_POWER_INVALID &&
+ (ad_len + eir_precalc_len(1) <= size)) {
ptr[0] = 0x02;
ptr[1] = EIR_TX_POWER;
ptr[2] = (u8)adv_tx_power;
--- a/net/bluetooth/eir.h
+++ b/net/bluetooth/eir.h
@@ -9,7 +9,7 @@

void eir_create(struct hci_dev *hdev, u8 *data);

-u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr);
+u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr, u8 size);
u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr);
u8 eir_create_per_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr);

--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -1248,7 +1248,8 @@ static int hci_set_ext_adv_data_sync(str
return 0;
}

- len = eir_create_adv_data(hdev, instance, pdu.data);
+ len = eir_create_adv_data(hdev, instance, pdu.data,
+ HCI_MAX_EXT_AD_LENGTH);

pdu.cp.length = len;
pdu.cp.handle = instance;
@@ -1279,7 +1280,7 @@ static int hci_set_adv_data_sync(struct

memset(&cp, 0, sizeof(cp));

- len = eir_create_adv_data(hdev, instance, cp.data);
+ len = eir_create_adv_data(hdev, instance, cp.data, sizeof(cp.data));

/* There's nothing to do if the data hasn't changed */
if (hdev->adv_data_len == len &&