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authorBen Seri <ben@armis.com>2017-12-08 15:14:47 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-17 09:38:56 +0100
commit6aebc2670ebfdda0762a6b471fbf8ca18dcf44f2 (patch)
treeaa62de2369bcf8070e1fa9fa12126e70109545ac
parentc51d23dffc2e9ca05d611c86c440f9055541c62d (diff)
Bluetooth: Prevent stack info leak from the EFS element.
commit 06e7e776ca4d36547e503279aeff996cbb292c16 upstream. In the function l2cap_parse_conf_rsp and in the function l2cap_parse_conf_req the following variable is declared without initialization: struct l2cap_conf_efs efs; In addition, when parsing input configuration parameters in both of these functions, the switch case for handling EFS elements may skip the memcpy call that will write to the efs variable: ... case L2CAP_CONF_EFS: if (olen == sizeof(efs)) memcpy(&efs, (void *)val, olen); ... The olen in the above if is attacker controlled, and regardless of that if, in both of these functions the efs variable would eventually be added to the outgoing configuration request that is being built: l2cap_add_conf_opt(&ptr, L2CAP_CONF_EFS, sizeof(efs), (unsigned long) &efs); So by sending a configuration request, or response, that contains an L2CAP_CONF_EFS element, but with an element length that is not sizeof(efs) - the memcpy to the uninitialized efs variable can be avoided, and the uninitialized variable would be returned to the attacker (16 bytes). This issue has been assigned CVE-2017-1000410 Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Signed-off-by: Ben Seri <ben@armis.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/bluetooth/l2cap_core.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ffd09c1675d4..2bbca23a9d05 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3353,9 +3353,10 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data
break;
case L2CAP_CONF_EFS:
- remote_efs = 1;
- if (olen == sizeof(efs))
+ if (olen == sizeof(efs)) {
+ remote_efs = 1;
memcpy(&efs, (void *) val, olen);
+ }
break;
case L2CAP_CONF_EWS:
@@ -3574,16 +3575,17 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
break;
case L2CAP_CONF_EFS:
- if (olen == sizeof(efs))
+ if (olen == sizeof(efs)) {
memcpy(&efs, (void *)val, olen);
- if (chan->local_stype != L2CAP_SERV_NOTRAFIC &&
- efs.stype != L2CAP_SERV_NOTRAFIC &&
- efs.stype != chan->local_stype)
- return -ECONNREFUSED;
+ if (chan->local_stype != L2CAP_SERV_NOTRAFIC &&
+ efs.stype != L2CAP_SERV_NOTRAFIC &&
+ efs.stype != chan->local_stype)
+ return -ECONNREFUSED;
- l2cap_add_conf_opt(&ptr, L2CAP_CONF_EFS, sizeof(efs),
- (unsigned long) &efs, endptr - ptr);
+ l2cap_add_conf_opt(&ptr, L2CAP_CONF_EFS, sizeof(efs),
+ (unsigned long) &efs, endptr - ptr);
+ }
break;
case L2CAP_CONF_FCS: