Syzkaller reports a memory leak as follows:
====================================
BUG: memory leak
unreferenced object 0xffff88810d81ac00 (size 240):
[...]
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418
[<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline]
[<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]
[<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline]
[<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511
[<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline]
[<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline]
[<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578
[<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631
[<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
====================================
HCI core will uses hci_rx_work() to process frame, which is queued to
the hdev->rx_q tail in hci_recv_frame() by HCI driver.
Yet the problem is that, HCI core does not free the skb after handling
ACL data packets. To be more specific, when start fragment does not
contain the L2CAP length, HCI core just reads possible bytes and
finishes frame process in l2cap_recv_acldata(), without freeing the skb,
which triggers the above memory leak.
This patch solves it by releasing the relative skb, after processing the
above case in l2cap_recv_acldata()
Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length")
Link: https://lore.kernel.org/all/[email protected]/
Reported-and-tested-by: [email protected]
Signed-off-by: Hawkins Jiawei <[email protected]>
---
net/bluetooth/l2cap_core.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 1f34b82ca0ec..e0a00854c02e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -8426,9 +8426,8 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
* expected length.
*/
if (skb->len < L2CAP_LEN_SIZE) {
- if (l2cap_recv_frag(conn, skb, conn->mtu) < 0)
- goto drop;
- return;
+ l2cap_recv_frag(conn, skb, conn->mtu);
+ goto drop;
}
len = get_unaligned_le16(skb->data) + L2CAP_HDR_SIZE;
@@ -8472,7 +8471,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
/* Header still could not be read just continue */
if (conn->rx_skb->len < L2CAP_LEN_SIZE)
- return;
+ goto drop;
}
if (skb->len > conn->rx_len) {
--
2.25.1
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=685727
---Test result---
Test Summary:
CheckPatch FAIL 0.99 seconds
GitLint FAIL 0.49 seconds
SubjectPrefix PASS 0.31 seconds
BuildKernel PASS 44.65 seconds
BuildKernel32 PASS 40.74 seconds
Incremental Build with patchesPASS 58.75 seconds
TestRunner: Setup PASS 661.99 seconds
TestRunner: l2cap-tester PASS 21.06 seconds
TestRunner: iso-tester PASS 21.23 seconds
TestRunner: bnep-tester PASS 8.15 seconds
TestRunner: mgmt-tester PASS 133.51 seconds
TestRunner: rfcomm-tester PASS 12.73 seconds
TestRunner: sco-tester PASS 11.87 seconds
TestRunner: ioctl-tester PASS 13.82 seconds
TestRunner: mesh-tester PASS 10.06 seconds
TestRunner: smp-tester PASS 11.82 seconds
TestRunner: userchan-tester PASS 8.53 seconds
Details
##############################
Test: CheckPatch - FAIL - 0.99 seconds
Run checkpatch.pl script with rule in .checkpatch.conf
Bluetooth: L2CAP: Fix memory leak in vhci_write\WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#124:
Reported-and-tested-by: [email protected]
total: 0 errors, 1 warnings, 0 checks, 19 lines checked
NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.
/github/workspace/src/13008275.patch has style problems, please review.
NOTE: Ignored message types: UNKNOWN_COMMIT_ID
NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
##############################
Test: GitLint - FAIL - 0.49 seconds
Run gitlint with rule in .gitlint
Bluetooth: L2CAP: Fix memory leak in vhci_write
14: B1 Line exceeds max length (84>80): " [<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]"
---
Regards,
Linux Bluetooth
Hi Hawkins,
On Mon, Oct 17, 2022 at 12:47 AM Hawkins Jiawei <[email protected]> wrote:
>
> Syzkaller reports a memory leak as follows:
> ====================================
> BUG: memory leak
> unreferenced object 0xffff88810d81ac00 (size 240):
> [...]
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418
> [<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline]
> [<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]
> [<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline]
> [<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511
> [<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline]
> [<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline]
> [<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578
> [<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631
> [<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> ====================================
>
> HCI core will uses hci_rx_work() to process frame, which is queued to
> the hdev->rx_q tail in hci_recv_frame() by HCI driver.
>
> Yet the problem is that, HCI core does not free the skb after handling
> ACL data packets. To be more specific, when start fragment does not
> contain the L2CAP length, HCI core just reads possible bytes and
> finishes frame process in l2cap_recv_acldata(), without freeing the skb,
> which triggers the above memory leak.
>
> This patch solves it by releasing the relative skb, after processing the
> above case in l2cap_recv_acldata()
>
> Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length")
> Link: https://lore.kernel.org/all/[email protected]/
> Reported-and-tested-by: [email protected]
> Signed-off-by: Hawkins Jiawei <[email protected]>
> ---
> net/bluetooth/l2cap_core.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 1f34b82ca0ec..e0a00854c02e 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -8426,9 +8426,8 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
> * expected length.
> */
> if (skb->len < L2CAP_LEN_SIZE) {
> - if (l2cap_recv_frag(conn, skb, conn->mtu) < 0)
> - goto drop;
> - return;
> + l2cap_recv_frag(conn, skb, conn->mtu);
> + goto drop;
Let us use break; instead of goto drop since we have copied the skb into rx_sbk.
> }
>
> len = get_unaligned_le16(skb->data) + L2CAP_HDR_SIZE;
> @@ -8472,7 +8471,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
>
> /* Header still could not be read just continue */
> if (conn->rx_skb->len < L2CAP_LEN_SIZE)
> - return;
> + goto drop;
> }
>
> if (skb->len > conn->rx_len) {
> --
> 2.25.1
>
--
Luiz Augusto von Dentz
On Tue, 18 Oct 2022 at 04:01, Luiz Augusto von Dentz <[email protected]> wrote:
>
> Hi Hawkins,
>
> On Mon, Oct 17, 2022 at 12:47 AM Hawkins Jiawei <[email protected]> wrote:
> >
> > Syzkaller reports a memory leak as follows:
> > ====================================
> > BUG: memory leak
> > unreferenced object 0xffff88810d81ac00 (size 240):
> > [...]
> > hex dump (first 32 bytes):
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > backtrace:
> > [<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418
> > [<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline]
> > [<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]
> > [<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline]
> > [<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511
> > [<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline]
> > [<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline]
> > [<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578
> > [<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631
> > [<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > [<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > [<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > ====================================
> >
> > HCI core will uses hci_rx_work() to process frame, which is queued to
> > the hdev->rx_q tail in hci_recv_frame() by HCI driver.
> >
> > Yet the problem is that, HCI core does not free the skb after handling
> > ACL data packets. To be more specific, when start fragment does not
> > contain the L2CAP length, HCI core just reads possible bytes and
> > finishes frame process in l2cap_recv_acldata(), without freeing the skb,
> > which triggers the above memory leak.
> >
> > This patch solves it by releasing the relative skb, after processing the
> > above case in l2cap_recv_acldata()
> >
> > Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length")
> > Link: https://lore.kernel.org/all/[email protected]/
> > Reported-and-tested-by: [email protected]
> > Signed-off-by: Hawkins Jiawei <[email protected]>
> > ---
> > net/bluetooth/l2cap_core.c | 7 +++----
> > 1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> > index 1f34b82ca0ec..e0a00854c02e 100644
> > --- a/net/bluetooth/l2cap_core.c
> > +++ b/net/bluetooth/l2cap_core.c
> > @@ -8426,9 +8426,8 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
> > * expected length.
> > */
> > if (skb->len < L2CAP_LEN_SIZE) {
> > - if (l2cap_recv_frag(conn, skb, conn->mtu) < 0)
> > - goto drop;
> > - return;
> > + l2cap_recv_frag(conn, skb, conn->mtu);
> > + goto drop;
>
> Let us use break; instead of goto drop since we have copied the skb into rx_sbk.
Thanks for your suggestion. I will refactor this patch as you suggested.
>
> > }
> >
> > len = get_unaligned_le16(skb->data) + L2CAP_HDR_SIZE;
> > @@ -8472,7 +8471,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
> >
> > /* Header still could not be read just continue */
> > if (conn->rx_skb->len < L2CAP_LEN_SIZE)
> > - return;
> > + goto drop;
> > }
> >
> > if (skb->len > conn->rx_len) {
> > --
> > 2.25.1
> >
>
>
> --
> Luiz Augusto von Dentz