RAVENPLAT 2381:OSS vulnerability found in [boot.img]:[linux_kernel] (CVE-2018-6555...

PD#OTT-5671

[Problem]
The irda_setsockopt function in net/irda/af_irda.c and later in
drivers/staging/irda/net/af_irda.c in the Linux kernel before 4.17
allows local users to cause a denial of service (ias_object
		use-after-free and system crash) or possibly have unspecified other
impact via an AF_IRDA socket.

[Solution]
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.

[Test]

Change-Id: Idbdc870be0064e331969b39a7b6e447c16a9073a
Signed-off-by: Hanjie Lin <hanjie.lin@amlogic.com>

diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index 101ed6c..4497d78 100644 (file)
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -2016,7 +2016,11 @@ 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: