[PATCH 03/12] isdn/gigaset: limit raw CAPI message dump length

Tilman Schmidt <[email protected]> Sat, 11 Oct 2014 13:46:29 +0200 (CEST)
Newsgroups gmane.linux.network,gmane.linux.isdn.i4l.user
Message-ID <36d3e64c941166c19c80987fcd692fece72ced17.1413021630.git.tilman@imap.cc>
In dump_rawmsg, the length field from a received data package was
used unscrutinized, allowing an attacker to control the size of the
allocated buffer and the number of times the output loop iterates.
Fix by limiting to a reasonable value.

Spotted with Coverity.

Signed-off-by: Tilman Schmidt <[email protected]>
---
 drivers/isdn/gigaset/capi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index 044392c..47e2a91 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -250,6 +250,8 @@ static inline void dump_rawmsg(enum debuglevel level, const char *tag,
 	l -= 12;
 	if (l <= 0)
 		return;
+	if (l > 64)
+		l = 64; /* arbitrary limit */
 	dbgline = kmalloc(3 * l, GFP_ATOMIC);
 	if (!dbgline)
 		return;
-- 
1.9.2.459.g68773ac