[patch] mISDN: array underflow in open_bchannel()

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

There are two channels here.  User space starts counting channels at one
but in the kernel we start at zero.  If the user passes in a zero
channel that's invalid and could lead to memory corruption.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
index d055ae7..e2c83a2 100644
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -1962,7 +1962,7 @@ open_bchannel(struct hfc_pci *hc, struct channel_req *rq)
 {
 	struct bchannel		*bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
diff --git a/drivers/isdn/hardware/mISDN/w6692.c b/drivers/isdn/hardware/mISDN/w6692.c
index 7f1e7ba..2183357 100644
--- a/drivers/isdn/hardware/mISDN/w6692.c
+++ b/drivers/isdn/hardware/mISDN/w6692.c
@@ -1015,7 +1015,7 @@ open_bchannel(struct w6692_hw *card, struct channel_req *rq)
 {
 	struct bchannel *bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
diff --git a/drivers/isdn/hardware/mISDN/mISDNisar.c b/drivers/isdn/hardware/mISDN/mISDNisar.c
index 10446ab..9a6da6e 100644
--- a/drivers/isdn/hardware/mISDN/mISDNisar.c
+++ b/drivers/isdn/hardware/mISDN/mISDNisar.c
@@ -1670,7 +1670,7 @@ isar_open(struct isar_hw *isar, struct channel_req *rq)
 {
 	struct bchannel		*bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
diff --git a/drivers/isdn/hardware/mISDN/netjet.c b/drivers/isdn/hardware/mISDN/netjet.c
index dd6de9f..c726e09 100644
--- a/drivers/isdn/hardware/mISDN/netjet.c
+++ b/drivers/isdn/hardware/mISDN/netjet.c
@@ -860,7 +860,7 @@ open_bchannel(struct tiger_hw *card, struct channel_req *rq)
 {
 	struct bchannel *bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
diff --git a/drivers/isdn/hardware/mISDN/avmfritz.c b/drivers/isdn/hardware/mISDN/avmfritz.c
index 05ed4d0c..c0b8c96 100644
--- a/drivers/isdn/hardware/mISDN/avmfritz.c
+++ b/drivers/isdn/hardware/mISDN/avmfritz.c
@@ -891,7 +891,7 @@ open_bchannel(struct fritzcard *fc, struct channel_req *rq)
 {
 	struct bchannel		*bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
index 6023387..8cde2a0 100644
--- a/drivers/isdn/hardware/mISDN/hfcsusb.c
+++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
@@ -486,7 +486,7 @@ open_bchannel(struct hfcsusb *hw, struct channel_req *rq)
 {
 	struct bchannel		*bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
diff --git a/drivers/isdn/hardware/mISDN/mISDNipac.c b/drivers/isdn/hardware/mISDN/mISDNipac.c
index b47e9be..884369f 100644
--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -1506,7 +1506,7 @@ open_bchannel(struct ipac_hw *ipac, struct channel_req *rq)
 {
 	struct bchannel		*bch;
 
-	if (rq->adr.channel > 2)
+	if (rq->adr.channel == 0 || rq->adr.channel > 2)
 		return -EINVAL;
 	if (rq->protocol == ISDN_P_NONE)
 		return -EINVAL;
--
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