isdn: prevent NULL ptr Oops in capi_cmsg2str()
The dereferencing of the private pointer cmsg->m in capi_cmsg2str() may
cause an Oops in case of an error, which is particularly inconvenient
as that function is typically used to format an error message. Add a
NULL pointer check to avoid this.
Impact: error handling improvement
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/capi/capiutil.c b/drivers/isdn/capi/capiutil.c
index c7c2902..16f2e46 100644
--- a/drivers/isdn/capi/capiutil.c
+++ b/drivers/isdn/capi/capiutil.c
@@ -989,6 +989,8 @@
{
_cdebbuf *cdb;
+ if (!cmsg->m)
+ return NULL; /* no message */
cdb = cdebbuf_alloc();
if (!cdb)
return NULL;