From 131a3b82c853483b1809cad06f8997421dd49500 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 4 Sep 2018 15:24:05 +0000 Subject: irda: Only insert new objects into the global database via setsockopt The irda_setsockopt() function conditionally allocates memory for a new self->ias_object or, in some cases, reuses the existing self->ias_object. Existing objects were incorrectly reinserted into the LM_IAS database which corrupted the doubly linked list used for the hashbin implementation of the LM_IAS database. When combined with a memory leak in irda_bind(), this issue could be leveraged to create a use-after-free vulnerability in the hashbin list. This patch fixes the issue by only inserting newly allocated objects into the database. CVE-2018-6555 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Tyler Hicks Reviewed-by: Seth Arnold Reviewed-by: Stefan Bader Signed-off-by: Greg Kroah-Hartman --- net/irda/af_irda.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c index 82e632b2c5a1..7cc9db38e1b6 100644 --- a/net/irda/af_irda.c +++ b/net/irda/af_irda.c @@ -2027,7 +2027,11 @@ static int irda_setsockopt(struct socket *sock, int level, int optname, err = -EINVAL; goto out; } - irias_insert_object(ias_obj); + + /* Only insert newly allocated objects */ + if (free_ias) + irias_insert_object(ias_obj); + kfree(ias_opt); break; case IRLMP_IAS_DEL: -- cgit v1.2.3