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Commit af452e35 authored Feb 25, 2023 by Fedor Pchelkin Committed by Greg Kroah-Hartman Mar 11, 2023

nfc: fix memory leak of se_io context in nfc_genl_se_io



[ Upstream commit 25ff6f8a5a3b8dc48e8abda6f013e8cc4b14ffea ]

The callback context for sending/receiving APDUs to/from the selected
secure element is allocated inside nfc_genl_se_io and supposed to be
eventually freed in se_io_cb callback function. However, there are several
error paths where the bwi_timer is not charged to call se_io_cb later, and
the cb_context is leaked.

The patch proposes to free the cb_context explicitly on those error paths.

At the moment we can't simply check 'dev->ops->se_io()' return value as it
may be negative in both cases: when the timer was charged and was not.

Fixes: 5ce3f32b ("NFC: netlink: SE API implementation")
Reported-by:  <syzbot+df64c0a2e8d68e78a4fa@syzkaller.appspotmail.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent d6d35998

drivers/nfc/st-nci/se.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -676,6 +676,12 @@ int st_nci_se_io(struct nci_dev *ndev, u32 se_idx,
	ST_NCI_EVT_TRANSMIT_DATA, apdu,		ST_NCI_EVT_TRANSMIT_DATA, apdu,
	apdu_length);		apdu_length);
	default:		default:
			/* Need to free cb_context here as at the moment we can't
			* clearly indicate to the caller if the callback function
			* would be called (and free it) or not. In both cases a
			* negative value may be returned to the caller.
			*/
			kfree(cb_context);
	return -ENODEV;		return -ENODEV;
	}		}
	}		}

drivers/nfc/st21nfca/se.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -247,6 +247,12 @@ int st21nfca_hci_se_io(struct nfc_hci_dev *hdev, u32 se_idx,
	ST21NFCA_EVT_TRANSMIT_DATA,		ST21NFCA_EVT_TRANSMIT_DATA,
	apdu, apdu_length);		apdu, apdu_length);
	default:		default:
			/* Need to free cb_context here as at the moment we can't
			* clearly indicate to the caller if the callback function
			* would be called (and free it) or not. In both cases a
			* negative value may be returned to the caller.
			*/
			kfree(cb_context);
	return -ENODEV;		return -ENODEV;
	}		}
	}		}

net/nfc/netlink.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1460,7 +1460,11 @@ static int nfc_se_io(struct nfc_dev *dev, u32 se_idx,
	rc = dev->ops->se_io(dev, se_idx, apdu,		rc = dev->ops->se_io(dev, se_idx, apdu,
	apdu_length, cb, cb_context);		apdu_length, cb, cb_context);

			device_unlock(&dev->dev);
			return rc;

	error:		error:
			kfree(cb_context);
	device_unlock(&dev->dev);		device_unlock(&dev->dev);
	return rc;		return rc;
	}		}