[PATCH 4.1 001/159] NFC: st21nfca: fix use of uninitialized variables in error path

Greg Kroah-Hartman
2015-09-26T21:54:10Z

From: Christophe Ricard <christophe.ricard@gmail.com>

commit 5a3570061a131309143a49e4bbdbce7e23f261e7 upstream.

st21nfca_hci_load_session() calls kfree_skb() on unitialized
variables skb_pipe_info and skb_pipe_list if the call to
nfc_hci_connect_gate() failed. Reword the error path to not use
these variables when they are not initialized. While at it, there
seemed to be a memory leak because skb_pipe_info was only freed
once, after the for-loop, even though several ones were created
by nfc_hci_send_cmd.

Fixes: ec03ff1a8f9a
("NFC: st21nfca: Remove skb_pipe_list and skb_pipe_info
useless allocation")

Acked-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/nfc/st21nfca/st21nfca.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/nfc/st21nfca/st21nfca.c
+++ b/drivers/nfc/st21nfca/st21nfca.c
@@ -148,14 +148,14 @@ static int st21nfca_hci_load_session(str
ST21NFCA_DEVICE_MGNT_GATE,
ST21NFCA_DEVICE_MGNT_PIPE);
if (r < 0)
- goto free_info;
+ return r;

/* Get pipe list */
r = nfc_hci_send_cmd(hdev, ST21NFCA_DEVICE_MGNT_GATE,
ST21NFCA_DM_GETINFO, pipe_list, sizeof(pipe_list),
&skb_pipe_list);
if (r < 0)
- goto free_info;
+ return r;

/* Complete the existing gate_pipe table */
for (i = 0; i < skb_pipe_list->len; i++) {
@@ -181,6 +181,7 @@ static int st21nfca_hci_load_session(str
info->src_host_id != ST21NFCA_ESE_HOST_ID) {
pr_err("Unexpected apdu_reader pipe on host %x\n",
info->src_host_id);
+ kfree_skb(skb_pipe_info);
continue;
}

@@ -200,6 +201,7 @@ static int st21nfca_hci_load_session(str
hdev->pipes[st21nfca_gates[j].pipe].dest_host =
info->src_host_id;
}
+ kfree_skb(skb_pipe_info);
}

/*
@@ -214,13 +216,12 @@ static int st21nfca_hci_load_session(str
st21nfca_gates[i].gate,
st21nfca_gates[i].pipe);
if (r < 0)
- goto free_info;
+ goto free_list;
}
}

memcpy(hdev->init_data.gates, st21nfca_gates, sizeof(st21nfca_gates));
-free_info:
- kfree_skb(skb_pipe_info);
+free_list:
kfree_skb(skb_pipe_list);
return r;
}