2022-05-28 20:00:03

by Luiz Augusto von Dentz

Subject: [PATCH-stable v2] Bluetooth: eir: Fix using strlen with hdev->{dev_name,short_name}

From: Luiz Augusto von Dentz <[email protected]>

Both dev_name and short_name are not guaranteed to be NULL terminated so
this instead use strnlen and then attempt to determine if the resulting
string needs to be truncated or not.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216018
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
---
net/bluetooth/eir.c | 41 ++++++++++++++++++++++++++---------------
net/bluetooth/mgmt.c | 4 ++--
2 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/net/bluetooth/eir.c b/net/bluetooth/eir.c
index 7d77fb00c2bf..776d27f7e18d 100644
--- a/net/bluetooth/eir.c
+++ b/net/bluetooth/eir.c
@@ -13,6 +13,20 @@

#define PNP_INFO_SVCLASS_ID 0x1200

+static u8 eir_append_name(u8 *eir, u16 eir_len, u8 type, u8 *data, u8 data_len)
+{
+ u8 name[HCI_MAX_SHORT_NAME_LENGTH + 1];
+
+ /* If data is already NULL terminated just pass it directly */
+ if (data[data_len - 1] == '\0')
+ return eir_append_data(eir, eir_len, type, data, data_len);
+
+ memcpy(name, data, HCI_MAX_SHORT_NAME_LENGTH);
+ name[HCI_MAX_SHORT_NAME_LENGTH] = '\0';
+
+ return eir_append_data(eir, eir_len, type, name, sizeof(name));
+}
+
u8 eir_append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
{
size_t short_len;
@@ -23,29 +37,26 @@ u8 eir_append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
return ad_len;

/* use complete name if present and fits */
- complete_len = strlen(hdev->dev_name);
+ complete_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
if (complete_len && complete_len <= HCI_MAX_SHORT_NAME_LENGTH)
- return eir_append_data(ptr, ad_len, EIR_NAME_COMPLETE,
+ return eir_append_name(ptr, ad_len, EIR_NAME_COMPLETE,
hdev->dev_name, complete_len + 1);

/* use short name if present */
- short_len = strlen(hdev->short_name);
+ short_len = strnlen(hdev->short_name, sizeof(hdev->short_name));
if (short_len)
- return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
- hdev->short_name, short_len + 1);
+ return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,
+ hdev->short_name,
+ short_len == HCI_MAX_SHORT_NAME_LENGTH ?
+ short_len : short_len + 1);

/* use shortened full name if present, we already know that name
* is longer then HCI_MAX_SHORT_NAME_LENGTH
*/
- if (complete_len) {
- u8 name[HCI_MAX_SHORT_NAME_LENGTH + 1];
-
- memcpy(name, hdev->dev_name, HCI_MAX_SHORT_NAME_LENGTH);
- name[HCI_MAX_SHORT_NAME_LENGTH] = '\0';
-
- return eir_append_data(ptr, ad_len, EIR_NAME_SHORT, name,
- sizeof(name));
- }
+ if (complete_len)
+ return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,
+ hdev->dev_name,
+ HCI_MAX_SHORT_NAME_LENGTH);

return ad_len;
}
@@ -181,7 +192,7 @@ void eir_create(struct hci_dev *hdev, u8 *data)
u8 *ptr = data;
size_t name_len;

- name_len = strlen(hdev->dev_name);
+ name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));

if (name_len > 0) {
/* EIR Data type */
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index cd1b300b9be7..82cc645193f2 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -1082,11 +1082,11 @@ static u16 append_eir_data_to_buf(struct hci_dev *hdev, u8 *eir)
eir_len = eir_append_le16(eir, eir_len, EIR_APPEARANCE,
hdev->appearance);

- name_len = strlen(hdev->dev_name);
+ name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
eir_len = eir_append_data(eir, eir_len, EIR_NAME_COMPLETE,
hdev->dev_name, name_len);

- name_len = strlen(hdev->short_name);
+ name_len = strnlen(hdev->short_name, sizeof(hdev->short_name));
eir_len = eir_append_data(eir, eir_len, EIR_NAME_SHORT,
hdev->short_name, name_len);

--
2.35.1

2022-06-21 19:14:44

by patchwork-bot+bluetooth

Subject: Re: [PATCH-stable v2] Bluetooth: eir: Fix using strlen with hdev->{dev_name,short_name}

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <[email protected]>:

On Fri, 27 May 2022 17:35:28 -0700 you wrote:
> From: Luiz Augusto von Dentz <[email protected]>
>
> Both dev_name and short_name are not guaranteed to be NULL terminated so
> this instead use strnlen and then attempt to determine if the resulting
> string needs to be truncated or not.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216018
> Signed-off-by: Luiz Augusto von Dentz <[email protected]>
>
> [...]

Here is the summary with links:
- [PATCH-stable,v2] Bluetooth: eir: Fix using strlen with hdev->{dev_name,short_name}
https://git.kernel.org/bluetooth/bluetooth-next/c/c8490f375393

You are awesome, thank you!
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