In the Linux kernel, the following vulnerability has been resolved:
tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp.
syzkaller reported [0] memory leaks of an UDP socket and ZEROCOPY
skbs. We can reproduce the problem with these sequences:
sk = socket(AF_INET, SOCK_DGRAM, 0)
sk.setsockopt(SOL_SOCKET, SO_TIMESTAMPING, SOF_TIMESTAMPING_TX_SOFTWARE)
sk.setsockopt(SOL_SOCKET, SO_ZEROCOPY, 1)
sk.sendto(b'', MSG_ZEROCOPY, ('127.0.0.1', 53))
sk.close()
sendmsg() calls msg_zerocopy_alloc(), which allocates a skb, sets
skb->cb->ubuf.refcnt to 1, and calls sock_hold(). Here, struct
ubuf_info_msgzc indirectly holds a refcnt of the socket. When the
skb is sent, __skb_tstamp_tx() clones it and puts the clone into
the socket's error queue with the TX timestamp.
When the original skb is received locally, skb_copy_ubufs() calls
skb_unclone(), and pskb_expand_head() increments skb->cb->ubuf.refcnt.
This additional count is decremented while freeing the skb, but struct
ubuf_info_msgzc still has a refcnt, so __msg_zerocopy_callback() is
not called.
The last refcnt is not released unless we retrieve the TX timestamped
skb by recvmsg(). Since we clear the error queue in inet_sock_destruct()
after the socket's refcnt reaches 0, there is a circular dependency.
If we close() the socket holding such skbs, we never call sock_put()
and leak the count, sk, and skb.
TCP has the same problem, and commit e0c8bccd40fc ("net: stream:
purge sk_error_queue in sk_stream_kill_queues()") tried to fix it
by calling skb_queue_purge() during close(). However, there is a
small chance that skb queued in a qdisc or device could be put
into the error queue after the skb_queue_purge() call.
In __skb_tstamp_tx(), the cloned skb should not have a reference
to the ubuf to remove the circular dependency, but skb_clone() does
not call skb_copy_ubufs() for zerocopy skb. So, we need to call
skb_orphan_frags_rx() for the cloned skb to call skb_copy_ubufs().
[0]:
BUG: memory leak
unreferenced object 0xffff88800c6d2d00 (size 1152):
comm "syz-executor392", pid 264, jiffies 4294785440 (age 13.044s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 cd af e8 81 00 00 00 00 ................
02 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............
backtrace:
[<0000000055636812>] sk_prot_alloc+0x64/0x2a0 net/core/sock.c:2024
[<0000000054d77b7a>] sk_alloc+0x3b/0x800 net/core/sock.c:2083
[<0000000066f3c7e0>] inet_create net/ipv4/af_inet.c:319 [inline]
[<0000000066f3c7e0>] inet_create+0x31e/0xe40 net/ipv4/af_inet.c:245
[<000000009b83af97>] __sock_create+0x2ab/0x550 net/socket.c:1515
[<00000000b9b11231>] sock_create net/socket.c:1566 [inline]
[<00000000b9b11231>] __sys_socket_create net/socket.c:1603 [inline]
[<00000000b9b11231>] __sys_socket_create net/socket.c:1588 [inline]
[<00000000b9b11231>] __sys_socket+0x138/0x250 net/socket.c:1636
[<000000004fb45142>] __do_sys_socket net/socket.c:1649 [inline]
[<000000004fb45142>] __se_sys_socket net/socket.c:1647 [inline]
[<000000004fb45142>] __x64_sys_socket+0x73/0xb0 net/socket.c:1647
[<0000000066999e0e>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<0000000066999e0e>] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
[<0000000017f238c1>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
BUG: memory leak
unreferenced object 0xffff888017633a00 (size 240):
comm "syz-executor392", pid 264, jiffies 4294785440 (age 13.044s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 2d 6d 0c 80 88 ff ff .........-m.....
backtrace:
[<000000002b1c4368>] __alloc_skb+0x229/0x320 net/core/skbuff.c:497
[<00000000143579a6>] alloc_skb include/linux/skbuff.h:1265 [inline]
[<00000000143579a6>] sock_omalloc+0xaa/0x190 net/core/sock.c:2596
[<00000000be626478>] msg_zerocopy_alloc net/core/skbuff.c:1294 [inline]
[<00000000be626478>]
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Add lwtunnel encap size of all siblings in nexthop calculation
In function rt6_nlmsg_size(), the length of nexthop is calculated
by multipling the nexthop length of fib6_info and the number of
siblings. However if the fib6_info has no lwtunnel but the siblings
have lwtunnels, the nexthop length is less than it should be, and
it will trigger a warning in inet6_rt_notify() as follows:
WARNING: CPU: 0 PID: 6082 at net/ipv6/route.c:6180 inet6_rt_notify+0x120/0x130
......
Call Trace:
<TASK>
fib6_add_rt2node+0x685/0xa30
fib6_add+0x96/0x1b0
ip6_route_add+0x50/0xd0
inet6_rtm_newroute+0x97/0xa0
rtnetlink_rcv_msg+0x156/0x3d0
netlink_rcv_skb+0x5a/0x110
netlink_unicast+0x246/0x350
netlink_sendmsg+0x250/0x4c0
sock_sendmsg+0x66/0x70
___sys_sendmsg+0x7c/0xd0
__sys_sendmsg+0x5d/0xb0
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
This bug can be reproduced by script:
ip -6 addr add 2002::2/64 dev ens2
ip -6 route add 100::/64 via 2002::1 dev ens2 metric 100
for i in 10 20 30 40 50 60 70;
do
ip link add link ens2 name ipv_$i type ipvlan
ip -6 addr add 2002::$i/64 dev ipv_$i
ifconfig ipv_$i up
done
for i in 10 20 30 40 50 60;
do
ip -6 route append 100::/64 encap ip6 dst 2002::$i via 2002::1
dev ipv_$i metric 100
done
ip -6 route append 100::/64 via 2002::1 dev ipv_70 metric 100
This patch fixes it by adding nexthop_len of every siblings using
rt6_nh_nlmsg_size().
In the Linux kernel, the following vulnerability has been resolved:
ubi: ubi_wl_put_peb: Fix infinite loop when wear-leveling work failed
Following process will trigger an infinite loop in ubi_wl_put_peb():
ubifs_bgt ubi_bgt
ubifs_leb_unmap
ubi_leb_unmap
ubi_eba_unmap_leb
ubi_wl_put_peb wear_leveling_worker
e1 = rb_entry(rb_first(&ubi->used)
e2 = get_peb_for_wl(ubi)
ubi_io_read_vid_hdr // return err (flash fault)
out_error:
ubi->move_from = ubi->move_to = NULL
wl_entry_destroy(ubi, e1)
ubi->lookuptbl[e->pnum] = NULL
retry:
e = ubi->lookuptbl[pnum]; // return NULL
if (e == ubi->move_from) { // NULL == NULL gets true
goto retry; // infinite loop !!!
$ top
PID USER PR NI VIRT RES SHR S %CPU %MEM COMMAND
7676 root 20 0 0 0 0 R 100.0 0.0 ubifs_bgt0_0
Fix it by:
1) Letting ubi_wl_put_peb() returns directly if wearl leveling entry has
been removed from 'ubi->lookuptbl'.
2) Using 'ubi->wl_lock' protecting wl entry deletion to preventing an
use-after-free problem for wl entry in ubi_wl_put_peb().
Fetch a reproducer in [Link].
In the Linux kernel, the following vulnerability has been resolved:
iommu: Fix error unwind in iommu_group_alloc()
If either iommu_group_grate_file() fails then the
iommu_group is leaked.
Destroy it on these error paths.
Found by kselftest/iommu/iommufd_fail_nth
In the Linux kernel, the following vulnerability has been resolved:
FS: JFS: Fix null-ptr-deref Read in txBegin
Syzkaller reported an issue where txBegin may be called
on a superblock in a read-only mounted filesystem which leads
to NULL pointer deref. This could be solved by checking if
the filesystem is read-only before calling txBegin, and returning
with appropiate error code.
In the Linux kernel, the following vulnerability has been resolved:
media: cx23885: Fix a null-ptr-deref bug in buffer_prepare() and buffer_finish()
When the driver calls cx23885_risc_buffer() to prepare the buffer, the
function call dma_alloc_coherent may fail, resulting in a empty buffer
risc->cpu. Later when we free the buffer or access the buffer, null ptr
deref is triggered.
This bug is similar to the following one:
https://git.linuxtv.org/media_stage.git/commit/?id=2b064d91440b33fba5b452f2d1b31f13ae911d71.
We believe the bug can be also dynamically triggered from user side.
Similarly, we fix this by checking the return value of cx23885_risc_buffer()
and the value of risc->cpu before buffer free.
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla4xxx: Add length check when parsing nlattrs
There are three places that qla4xxx parses nlattrs:
- qla4xxx_set_chap_entry()
- qla4xxx_iface_set_param()
- qla4xxx_sysfs_ddb_set_param()
and each of them directly converts the nlattr to specific pointer of
structure without length checking. This could be dangerous as those
attributes are not validated and a malformed nlattr (e.g., length 0) could
result in an OOB read that leaks heap dirty data.
Add the nla_len check before accessing the nlattr data and return EINVAL if
the length check fails.
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix potential NULL pointer dereference
Klocwork tool reported 'cur_dsd' may be dereferenced. Add fix to validate
pointer before dereferencing the pointer.