[PATCH] Fix buffer overflow and races in capi debug functions

The CAPI trace debug functions were using a fixed size buffer, which can be
overflowed if wrong formatted CAPI messages were sent to the kernel capi
layer.  The code was also not protected against multiple callers.  This fix
bug 8028.

Additionally the patch make the CAPI trace functions optional.

Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 19 insertions, 2 deletions

diff --git a/include/linux/isdn/capiutil.h b/include/linux/isdn/capiutil.h
index 2e79f816703b..63bd9cf821a7 100644
--- a/include/linux/isdn/capiutil.h
+++ b/include/linux/isdn/capiutil.h
@@ -174,9 +174,26 @@ char *capi_info2str(__u16 reason);
 /*
  * Debugging / Tracing functions
  */
+
 char *capi_cmd2str(__u8 cmd, __u8 subcmd);
-char *capi_cmsg2str(_cmsg * cmsg);
-char *capi_message2str(__u8 * msg);
+
+typedef struct {
+        u_char  *buf;
+        u_char  *p;
+        size_t  size;
+        size_t  pos;
+} _cdebbuf;
+
+#define CDEBUG_SIZE     1024
+#define CDEBUG_GSIZE    4096
+
+_cdebbuf *cdebbuf_alloc(void);
+void cdebbuf_free(_cdebbuf *cdb);
+int cdebug_init(void);
+void cdebug_exit(void);
+
+_cdebbuf *capi_cmsg2str(_cmsg *cmsg);
+_cdebbuf *capi_message2str(__u8 *msg);
 
 /*-----------------------------------------------------------------------*/