2023-07-12 13:23:24

by Chris Lu

Subject: [PATCH v4] Bluetooth: btmtk: Fix null pointer when processing coredump

There may be a potential null pointer risk if offset value is
less than 0 when doing memcmp in btmtk_process_coredump().
Check offset is valid before doing memcmp.

Signed-off-by: Chris Lu <[email protected]>
Co-developed-by: Sean Wang <[email protected]>
Signed-off-by: Sean Wang <[email protected]>
---
v2: fix typo
v3: fix bot checking error
v4: reduce variable 'offset' declaration in v3
---
drivers/bluetooth/btmtk.c | 12 ++++++------
drivers/bluetooth/btmtk.h | 1 +
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 786f775196ae..9cc789272ab7 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -395,12 +395,12 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)

/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
- skb->len > sizeof(MTK_COREDUMP_END) &&
- !memcmp((char *)&skb->data[skb->len - sizeof(MTK_COREDUMP_END)],
- MTK_COREDUMP_END, sizeof(MTK_COREDUMP_END) - 1)) {
- bt_dev_info(hdev, "Mediatek coredump end");
- hci_devcd_complete(hdev);
- }
+ skb->len > MTK_COREDUMP_END_LEN)
+ if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
+ MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) {
+ bt_dev_info(hdev, "Mediatek coredump end");
+ hci_devcd_complete(hdev);
+ }

break;
}
diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
index 68309dfe076a..56f5502baadf 100644
--- a/drivers/bluetooth/btmtk.h
+++ b/drivers/bluetooth/btmtk.h
@@ -24,6 +24,7 @@

#define MTK_COREDUMP_SIZE (1024 * 1000)
#define MTK_COREDUMP_END "coredump end"
+#define MTK_COREDUMP_END_LEN (sizeof(MTK_COREDUMP_END))
#define MTK_COREDUMP_NUM 255

enum {
--
2.18.0

2023-07-12 13:57:17

by bluez.test.bot

Subject: RE: [v4] Bluetooth: btmtk: Fix null pointer when processing coredump

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=764864

---Test result---

Test Summary:
CheckPatch PASS 0.76 seconds
GitLint PASS 0.28 seconds
SubjectPrefix PASS 0.10 seconds
BuildKernel PASS 32.72 seconds
CheckAllWarning PASS 35.67 seconds
CheckSparse PASS 40.50 seconds
CheckSmatch PASS 113.44 seconds
BuildKernel32 PASS 31.76 seconds
TestRunnerSetup PASS 477.48 seconds
TestRunner_l2cap-tester PASS 22.23 seconds
TestRunner_iso-tester PASS 39.87 seconds
TestRunner_bnep-tester PASS 10.26 seconds
TestRunner_mgmt-tester PASS 212.08 seconds
TestRunner_rfcomm-tester PASS 15.16 seconds
TestRunner_sco-tester PASS 15.95 seconds
TestRunner_ioctl-tester PASS 17.20 seconds
TestRunner_mesh-tester PASS 12.71 seconds
TestRunner_smp-tester PASS 13.75 seconds
TestRunner_userchan-tester PASS 10.54 seconds
IncrementalBuild PASS 29.52 seconds



---
Regards,
Linux Bluetooth

2023-07-12 21:11:16

by Luiz Augusto von Dentz

Subject: Re: [PATCH v4] Bluetooth: btmtk: Fix null pointer when processing coredump

Hi Chris,

On Wed, Jul 12, 2023 at 6:03 AM Chris Lu <[email protected]> wrote:
>
> There may be a potential null pointer risk if offset value is
> less than 0 when doing memcmp in btmtk_process_coredump().
> Check offset is valid before doing memcmp.
>
> Signed-off-by: Chris Lu <[email protected]>
> Co-developed-by: Sean Wang <[email protected]>
> Signed-off-by: Sean Wang <[email protected]>

You should probably include the Fixes tag of the patch that introduced
the problem.

> ---
> v2: fix typo
> v3: fix bot checking error
> v4: reduce variable 'offset' declaration in v3
> ---
> drivers/bluetooth/btmtk.c | 12 ++++++------
> drivers/bluetooth/btmtk.h | 1 +
> 2 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> index 786f775196ae..9cc789272ab7 100644
> --- a/drivers/bluetooth/btmtk.c
> +++ b/drivers/bluetooth/btmtk.c
> @@ -395,12 +395,12 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
>
> /* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
> if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
> - skb->len > sizeof(MTK_COREDUMP_END) &&
> - !memcmp((char *)&skb->data[skb->len - sizeof(MTK_COREDUMP_END)],
> - MTK_COREDUMP_END, sizeof(MTK_COREDUMP_END) - 1)) {
> - bt_dev_info(hdev, "Mediatek coredump end");
> - hci_devcd_complete(hdev);
> - }
> + skb->len > MTK_COREDUMP_END_LEN)
> + if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
> + MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) {
> + bt_dev_info(hdev, "Mediatek coredump end");
> + hci_devcd_complete(hdev);
> + }
>
> break;
> }
> diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
> index 68309dfe076a..56f5502baadf 100644
> --- a/drivers/bluetooth/btmtk.h
> +++ b/drivers/bluetooth/btmtk.h
> @@ -24,6 +24,7 @@
>
> #define MTK_COREDUMP_SIZE (1024 * 1000)
> #define MTK_COREDUMP_END "coredump end"
> +#define MTK_COREDUMP_END_LEN (sizeof(MTK_COREDUMP_END))
> #define MTK_COREDUMP_NUM 255
>
> enum {
> --
> 2.18.0
>


--
Luiz Augusto von Dentz

2023-07-13 06:41:47

by Chris Lu

Subject: Re: [PATCH v4] Bluetooth: btmtk: Fix null pointer when processing coredump

On Wed, 2023-07-12 at 13:29 -0700, Luiz Augusto von Dentz wrote:
>
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> Hi Chris,
>
> On Wed, Jul 12, 2023 at 6:03 AM Chris Lu <[email protected]>
> wrote:
> >
> > There may be a potential null pointer risk if offset value is
> > less than 0 when doing memcmp in btmtk_process_coredump().
> > Check offset is valid before doing memcmp.
> >
> > Signed-off-by: Chris Lu <[email protected]>
> > Co-developed-by: Sean Wang <[email protected]>
> > Signed-off-by: Sean Wang <[email protected]>
>
> You should probably include the Fixes tag of the patch that
> introduced
> the problem.
>
Hi Luiz,

Thanks for reminding, I'll update Bug ad fixs info in commit message
and send the v5 patch.

BRs,
Chris

> > ---
> > v2: fix typo
> > v3: fix bot checking error
> > v4: reduce variable 'offset' declaration in v3
> > ---
> > drivers/bluetooth/btmtk.c | 12 ++++++------
> > drivers/bluetooth/btmtk.h | 1 +
> > 2 files changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> > index 786f775196ae..9cc789272ab7 100644
> > --- a/drivers/bluetooth/btmtk.c
> > +++ b/drivers/bluetooth/btmtk.c
> > @@ -395,12 +395,12 @@ int btmtk_process_coredump(struct hci_dev
> *hdev, struct sk_buff *skb)
> >
> > /* Mediatek coredump data would be more than
> MTK_COREDUMP_NUM */
> > if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
> > - skb->len > sizeof(MTK_COREDUMP_END) &&
> > - !memcmp((char *)&skb->data[skb->len -
> sizeof(MTK_COREDUMP_END)],
> > - MTK_COREDUMP_END,
> sizeof(MTK_COREDUMP_END) - 1)) {
> > - bt_dev_info(hdev, "Mediatek coredump end");
> > - hci_devcd_complete(hdev);
> > - }
> > + skb->len > MTK_COREDUMP_END_LEN)
> > + if (!memcmp((char *)&skb->data[skb->len -
> MTK_COREDUMP_END_LEN],
> > + MTK_COREDUMP_END, MTK_COREDUMP_END_LEN
> - 1)) {
> > + bt_dev_info(hdev, "Mediatek
> coredump end");
> > + hci_devcd_complete(hdev);
> > + }
> >
> > break;
> > }
> > diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
> > index 68309dfe076a..56f5502baadf 100644
> > --- a/drivers/bluetooth/btmtk.h
> > +++ b/drivers/bluetooth/btmtk.h
> > @@ -24,6 +24,7 @@
> >
> > #define MTK_COREDUMP_SIZE (1024 * 1000)
> > #define MTK_COREDUMP_END "coredump end"
> > +#define MTK_COREDUMP_END_LEN (sizeof(MTK_COREDUMP_END))
> > #define MTK_COREDUMP_NUM 255
> >
> > enum {
> > --
> > 2.18.0
> >
>
>
> --
> Luiz Augusto von Dentz