From 8b36e8c70a9e0d71d015448fefdf3e3bc5eb85e8 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 17 Aug 2017 16:30:47 -0700 Subject: [PATCH] ANDROID: nfc: fdp: Fix possible buffer overflow in WCS4000 NFC driver Possible buffer overflow when reading next_read_size bytes into tmp buffer after next_read_size was extracted from a previous packet. Bug: 62678828 Signed-off-by: Suren Baghdasaryan --- drivers/nfc/fdp/i2c.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c index a5d7332dfce5..2d043415f326 100644 --- a/drivers/nfc/fdp/i2c.c +++ b/drivers/nfc/fdp/i2c.c @@ -177,6 +177,16 @@ static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb) /* Packet that contains a length */ if (tmp[0] == 0 && tmp[1] == 0) { phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3; + /* + * Ensure next_read_size does not exceed sizeof(tmp) + * for reading that many bytes during next iteration + */ + if (phy->next_read_size > FDP_NCI_I2C_MAX_PAYLOAD) { + dev_dbg(&client->dev, "%s: corrupted packet\n", + __func__); + phy->next_read_size = 5; + goto flush; + } } else { phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;