isdn: strcpy() => strlcpy()

setup.phone and setup.eazmsn are 32 character buffers.
rcvmsg.msg_data.byte_array is a 48 character buffer.
sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn is 50 chars.

The rcvmsg struct comes from the memcpy_fromio() in receivemessage().
I guess that means it's data off the wire.  I'm not very familiar with
this code but I don't see any reason to assume these strings are NULL
terminated.

Also it's weird that "dn" in a 50 character buffer but we only seem to
use 32 characters.  In drivers/isdn/sc/scioc.h, "dn" is only a 49
character buffer.  So potentially there is still an issue there.

The important thing for now is to prevent the memory corruption.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/isdn/sc/interrupt.c b/drivers/isdn/sc/interrupt.c
index 485be8b1e1b33bef2bd7e3af8fab2066d3687ec3..f0225bc0f2670ce2f0fde9b5d276f26151c6a046 100644 (file)
--- a/drivers/isdn/sc/interrupt.c
+++ b/drivers/isdn/sc/interrupt.c
@@ -112,11 +112,19 @@ irqreturn_t interrupt_handler(int dummy, void *card_inst)
                        }
                        else if(callid>=0x0000 && callid<=0x7FFF)
                        {
+                               int len;
+
                                pr_debug("%s: Got Incoming Call\n",
                                                sc_adapter[card]->devicename);
-                               strcpy(setup.phone,&(rcvmsg.msg_data.byte_array[4]));
-                               strcpy(setup.eazmsn,
-                                       sc_adapter[card]->channel[rcvmsg.phy_link_no-1].dn);
+                               len = strlcpy(setup.phone, &(rcvmsg.msg_data.byte_array[4]),
+                                               sizeof(setup.phone));
+                               if (len >= sizeof(setup.phone))
+                                       continue;
+                               len = strlcpy(setup.eazmsn,
+                                               sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn,
+                                               sizeof(setup.eazmsn));
+                               if (len >= sizeof(setup.eazmsn))
+                                       continue;
                                setup.si1 = 7;
                                setup.si2 = 0;
                                setup.plan = 0;
@@ -176,7 +184,9 @@ irqreturn_t interrupt_handler(int dummy, void *card_inst)
                 * Handle a GetMyNumber Rsp
                 */
                if (IS_CE_MESSAGE(rcvmsg,Call,0,GetMyNumber)){
-                       strcpy(sc_adapter[card]->channel[rcvmsg.phy_link_no-1].dn,rcvmsg.msg_data.byte_array);
+                       strlcpy(sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn,
+                               rcvmsg.msg_data.byte_array,
+                               sizeof(rcvmsg.msg_data.byte_array));
                        continue;
                }