Bluetooth: SCO: Fix not validating setsockopt user input

syzbot reported sco_sock_setsockopt() is copying data without
checking user input length.

BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset
include/linux/sockptr.h:49 [inline]
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr
include/linux/sockptr.h:55 [inline]
BUG: KASAN: slab-out-of-bounds in sco_sock_setsockopt+0xc0b/0xf90
net/bluetooth/sco.c:893
Read of size 4 at addr ffff88805f7b15a3 by task syz-executor.5/12578

Fixes: ad10b1a48754 ("Bluetooth: Add Bluetooth socket voice option")
Fixes: b96e9c671b05 ("Bluetooth: Add BT_DEFER_SETUP option to sco socket")
Fixes: 00398e1d5183 ("Bluetooth: Add support for BT_PKT_STATUS CMSG data for SCO connections")
Fixes: f6873401a608 ("Bluetooth: Allow setting of codec for HFP offload use case")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 9fe95a22abeb7e2fb12d7384a974e5689db61211..eaec5d6caa29d293902f86666c91cceebd6f388c 100644 (file)
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -585,6 +585,15 @@ static inline struct sk_buff *bt_skb_sendmmsg(struct sock *sk,
        return skb;
 }
 
+static inline int bt_copy_from_sockptr(void *dst, size_t dst_size,
+                                      sockptr_t src, size_t src_size)
+{
+       if (dst_size > src_size)
+               return -EINVAL;
+
+       return copy_from_sockptr(dst, src, dst_size);
+}
+
 int bt_to_errno(u16 code);
 __u8 bt_status(int err);
 

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 43daf965a01e4ac5c9329150080b00dcd63c7e1c..368e026f4d15ca4711737af941ad30c7b48b827f 100644 (file)
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -824,7 +824,7 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
                               sockptr_t optval, unsigned int optlen)
 {
        struct sock *sk = sock->sk;
-       int len, err = 0;
+       int err = 0;
        struct bt_voice voice;
        u32 opt;
        struct bt_codecs *codecs;
@@ -843,10 +843,9 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
                        break;
                }
 
-               if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
-                       err = -EFAULT;
+               err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+               if (err)
                        break;
-               }
 
                if (opt)
                        set_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
@@ -863,11 +862,10 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
 
                voice.setting = sco_pi(sk)->setting;
 
-               len = min_t(unsigned int, sizeof(voice), optlen);
-               if (copy_from_sockptr(&voice, optval, len)) {
-                       err = -EFAULT;
+               err = bt_copy_from_sockptr(&voice, sizeof(voice), optval,
+                                          optlen);
+               if (err)
                        break;
-               }
 
                /* Explicitly check for these values */
                if (voice.setting != BT_VOICE_TRANSPARENT &&
@@ -890,10 +888,9 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
                break;
 
        case BT_PKT_STATUS:
-               if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
-                       err = -EFAULT;
+               err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+               if (err)
                        break;
-               }
 
                if (opt)
                        set_bit(BT_SK_PKT_STATUS, &bt_sk(sk)->flags);
@@ -934,9 +931,9 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
                        break;
                }
 
-               if (copy_from_sockptr(buffer, optval, optlen)) {
+               err = bt_copy_from_sockptr(buffer, optlen, optval, optlen);
+               if (err) {
                        hci_dev_put(hdev);
-                       err = -EFAULT;
                        break;
                }