The hci_conn_unlink function is being called by hci_conn_del, which means
it should not call hci_conn_del with the input parameter conn again. If it
does, conn may have already been released when hci_conn_unlink returns,
leading to potential UAF and double-free issues.
This patch resolves the problem by modifying hci_conn_unlink to release
only conn's child links when necessary, but never release conn itself.
Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon")
Signed-off-by: Ruihan Li <[email protected]>
---
Changes since v1:
* CI complains that there are some merge conflicts. This is because
void hci_conn_del(struct hci_conn *conn)
this completely unrelated line makes the patch dependent on another fix:
https://lore.kernel.org/linux-bluetooth/[email protected]/
But actually, deleting that line makes the two patches independent of
each other, and everything still works.
net/bluetooth/hci_conn.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 85c34c837..5f388202f 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1083,8 +1083,18 @@ static void hci_conn_unlink(struct hci_conn *conn)
if (!conn->parent) {
struct hci_link *link, *t;
- list_for_each_entry_safe(link, t, &conn->link_list, list)
- hci_conn_unlink(link->conn);
+ list_for_each_entry_safe(link, t, &conn->link_list, list) {
+ struct hci_conn *child = link->conn;
+
+ hci_conn_unlink(child);
+
+ /* Due to race, SCO connection might be not established
+ * yet at this point. Delete it now, otherwise it is
+ * possible for it to be stuck and can't be deleted.
+ */
+ if (child->handle == HCI_CONN_HANDLE_UNSET)
+ hci_conn_del(child);
+ }
return;
}
@@ -1100,12 +1110,5 @@ static void hci_conn_unlink(struct hci_conn *conn)
kfree(conn->link);
conn->link = NULL;
-
- /* Due to race, SCO connection might be not established
- * yet at this point. Delete it now, otherwise it is
- * possible for it to be stuck and can't be deleted.
- */
- if (conn->handle == HCI_CONN_HANDLE_UNSET)
- hci_conn_del(conn);
}
--
2.40.0
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=744077
---Test result---
Test Summary:
CheckPatch PASS 0.70 seconds
GitLint FAIL 0.56 seconds
SubjectPrefix PASS 0.13 seconds
BuildKernel PASS 31.08 seconds
CheckAllWarning PASS 34.53 seconds
CheckSparse PASS 39.20 seconds
CheckSmatch PASS 109.45 seconds
BuildKernel32 PASS 30.18 seconds
TestRunnerSetup PASS 441.36 seconds
TestRunner_l2cap-tester PASS 16.54 seconds
TestRunner_iso-tester PASS 20.36 seconds
TestRunner_bnep-tester PASS 5.30 seconds
TestRunner_mgmt-tester PASS 111.39 seconds
TestRunner_rfcomm-tester PASS 8.46 seconds
TestRunner_sco-tester PASS 7.88 seconds
TestRunner_ioctl-tester PASS 9.17 seconds
TestRunner_mesh-tester PASS 6.77 seconds
TestRunner_smp-tester PASS 7.77 seconds
TestRunner_userchan-tester PASS 5.56 seconds
IncrementalBuild PASS 28.59 seconds
Details
##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
[v2] Bluetooth: Fix potential double free caused by hci_conn_unlink
WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
15: B3 Line contains hard tab characters (\t): " void hci_conn_del(struct hci_conn *conn)"
17: B1 Line exceeds max length (84>80): " https://lore.kernel.org/linux-bluetooth/[email protected]/"
17: B3 Line contains hard tab characters (\t): " https://lore.kernel.org/linux-bluetooth/[email protected]/"
---
Regards,
Linux Bluetooth
On Mon, May 01, 2023 at 02:05:35AM +0800, Ruihan Li wrote:
> The hci_conn_unlink function is being called by hci_conn_del, which means
> it should not call hci_conn_del with the input parameter conn again. If it
> does, conn may have already been released when hci_conn_unlink returns,
> leading to potential UAF and double-free issues.
>
> This patch resolves the problem by modifying hci_conn_unlink to release
> only conn's child links when necessary, but never release conn itself.
Syzbot also found this bug several days ago (but it does not email
linux-bluetooth until today).
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=690b90b14f14f43f4688
> Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon")
> Signed-off-by: Ruihan Li <[email protected]>
> ---
> Changes since v1:
> * CI complains that there are some merge conflicts. This is because
> void hci_conn_del(struct hci_conn *conn)
> this completely unrelated line makes the patch dependent on another fix:
> https://lore.kernel.org/linux-bluetooth/[email protected]/
> But actually, deleting that line makes the two patches independent of
> each other, and everything still works.
>
> net/bluetooth/hci_conn.c | 21 ++++++++++++---------
> 1 file changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
> index 85c34c837..5f388202f 100644
> --- a/net/bluetooth/hci_conn.c
> +++ b/net/bluetooth/hci_conn.c
> @@ -1083,8 +1083,18 @@ static void hci_conn_unlink(struct hci_conn *conn)
> if (!conn->parent) {
> struct hci_link *link, *t;
>
> - list_for_each_entry_safe(link, t, &conn->link_list, list)
> - hci_conn_unlink(link->conn);
> + list_for_each_entry_safe(link, t, &conn->link_list, list) {
> + struct hci_conn *child = link->conn;
> +
> + hci_conn_unlink(child);
> +
> + /* Due to race, SCO connection might be not established
> + * yet at this point. Delete it now, otherwise it is
> + * possible for it to be stuck and can't be deleted.
> + */
> + if (child->handle == HCI_CONN_HANDLE_UNSET)
> + hci_conn_del(child);
> + }
>
> return;
> }
> @@ -1100,12 +1110,5 @@ static void hci_conn_unlink(struct hci_conn *conn)
>
> kfree(conn->link);
> conn->link = NULL;
> -
> - /* Due to race, SCO connection might be not established
> - * yet at this point. Delete it now, otherwise it is
> - * possible for it to be stuck and can't be deleted.
> - */
> - if (conn->handle == HCI_CONN_HANDLE_UNSET)
> - hci_conn_del(conn);
> }
>
> --
> 2.40.0
Thanks,
Ruihan Li