4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
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 <tyhicks@xxxxxxxxxxxxx>
Reviewed-by: Seth Arnold <seth.arnold@xxxxxxxxxxxxx>
Reviewed-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/irda/af_irda.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -2027,7 +2027,11 @@ static int irda_setsockopt(struct socket
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:
