[PATCH 51/81] isdn/gigaset: fix zero size border case in debug dump

From: Herton Ronaldo Krzesinski
Date: Tue Feb 19 2013 - 13:53:25 EST -stable review patch. If anyone has any objections, please let me know.


From: Tilman Schmidt <tilman@xxxxxxx>

commit d721a1752ba544df8d7d36959038b26bc92bdf80 upstream.

If subtracting 12 from l leaves zero we'd do a zero size allocation,
leading to an oops later when we try to set the NUL terminator.

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Tilman Schmidt <tilman@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
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 27e4a3e..f45b5b0 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -248,6 +248,8 @@ static inline void dump_rawmsg(enum debuglevel level, const char *tag,
l -= 12;
+ if (l <= 0)
+ return;
dbgline = kmalloc(3 * l, GFP_ATOMIC);
if (!dbgline)

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