In the Linux kernel, the following vulnerability has been resolved:
sctp: linearize cloned gso packets in sctp_rcv
A cloned head skb still shares these frag skbs in fraglist with the
original head skb. It's not safe to access these frag skbs.
syzbot reported two use-of-uninitialized-memory bugs caused by this:
BUG: KMSAN: uninit-value in sctp_inq_pop+0x15b7/0x1920 net/sctp/inqueue.c:211
sctp_inq_pop+0x15b7/0x1920 net/sctp/inqueue.c:211
sctp_assoc_bh_rcv+0x1a7/0xc50 net/sctp/associola.c:998
sctp_inq_push+0x2ef/0x380 net/sctp/inqueue.c:88
sctp_backlog_rcv+0x397/0xdb0 net/sctp/input.c:331
sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1122
__release_sock+0x1da/0x330 net/core/sock.c:3106
release_sock+0x6b/0x250 net/core/sock.c:3660
sctp_wait_for_connect+0x487/0x820 net/sctp/socket.c:9360
sctp_sendmsg_to_asoc+0x1ec1/0x1f00 net/sctp/socket.c:1885
sctp_sendmsg+0x32b9/0x4a80 net/sctp/socket.c:2031
inet_sendmsg+0x25a/0x280 net/ipv4/af_inet.c:851
sock_sendmsg_nosec net/socket.c:718 [inline]
and
BUG: KMSAN: uninit-value in sctp_assoc_bh_rcv+0x34e/0xbc0 net/sctp/associola.c:987
sctp_assoc_bh_rcv+0x34e/0xbc0 net/sctp/associola.c:987
sctp_inq_push+0x2a3/0x350 net/sctp/inqueue.c:88
sctp_backlog_rcv+0x3c7/0xda0 net/sctp/input.c:331
sk_backlog_rcv+0x142/0x420 include/net/sock.h:1148
__release_sock+0x1d3/0x330 net/core/sock.c:3213
release_sock+0x6b/0x270 net/core/sock.c:3767
sctp_wait_for_connect+0x458/0x820 net/sctp/socket.c:9367
sctp_sendmsg_to_asoc+0x223a/0x2260 net/sctp/socket.c:1886
sctp_sendmsg+0x3910/0x49f0 net/sctp/socket.c:2032
inet_sendmsg+0x269/0x2a0 net/ipv4/af_inet.c:851
sock_sendmsg_nosec net/socket.c:712 [inline]
This patch fixes it by linearizing cloned gso packets in sctp_rcv().
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: fix refcount leak on table dump
There is a reference count leak in ctnetlink_dump_table():
if (res < 0) {
nf_conntrack_get(&ct->ct_general); // HERE
cb->args[1] = (unsigned long)ct;
...
While its very unlikely, its possible that ct == last.
If this happens, then the refcount of ct was already incremented.
This 2nd increment is never undone.
This prevents the conntrack object from being released, which in turn
keeps prevents cnet->count from dropping back to 0.
This will then block the netns dismantle (or conntrack rmmod) as
nf_conntrack_cleanup_net_list() will wait forever.
This can be reproduced by running conntrack_resize.sh selftest in a loop.
It takes ~20 minutes for me on a preemptible kernel on average before
I see a runaway kworker spinning in nf_conntrack_cleanup_net_list.
One fix would to change this to:
if (res < 0) {
if (ct != last)
nf_conntrack_get(&ct->ct_general);
But this reference counting isn't needed in the first place.
We can just store a cookie value instead.
A followup patch will do the same for ctnetlink_exp_dump_table,
it looks to me as if this has the same problem and like
ctnetlink_dump_table, we only need a 'skip hint', not the actual
object so we can apply the same cookie strategy there as well.
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Validate i_depth for exhash directories
A fuzzer test introduced corruption that ends up with a depth of 0 in
dir_e_read(), causing an undefined shift by 32 at:
index = hash >> (32 - dip->i_depth);
As calculated in an open-coded way in dir_make_exhash(), the minimum
depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is
invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time.
So we can avoid the undefined behaviour by checking for depth values
lower than the minimum in gfs2_dinode_in(). Values greater than the
maximum are already being checked for there.
Also switch the calculation in dir_make_exhash() to use ilog2() to
clarify how the depth is calculated.
Tested with the syzkaller repro.c and xfstests '-g quick'.
In the Linux kernel, the following vulnerability has been resolved:
hfsplus: don't use BUG_ON() in hfsplus_create_attributes_file()
When the volume header contains erroneous values that do not reflect
the actual state of the filesystem, hfsplus_fill_super() assumes that
the attributes file is not yet created, which later results in hitting
BUG_ON() when hfsplus_create_attributes_file() is called. Replace this
BUG_ON() with -EIO error with a message to suggest running fsck tool.
In the Linux kernel, the following vulnerability has been resolved:
hfs: fix slab-out-of-bounds in hfs_bnode_read()
This patch introduces is_bnode_offset_valid() method that checks
the requested offset value. Also, it introduces
check_and_correct_requested_length() method that checks and
correct the requested length (if it is necessary). These methods
are used in hfs_bnode_read(), hfs_bnode_write(), hfs_bnode_clear(),
hfs_bnode_copy(), and hfs_bnode_move() with the goal to prevent
the access out of allocated memory and triggering the crash.
In the Linux kernel, the following vulnerability has been resolved:
rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: fix null pointer access
Writing a string without delimiters (' ', '\n', '\0') to the under
gpu_od/fan_ctrl sysfs or pp_power_profile_mode for the CUSTOM profile
will result in a null pointer dereference.
In the Linux kernel, the following vulnerability has been resolved:
drbd: add missing kref_get in handle_write_conflicts
With `two-primaries` enabled, DRBD tries to detect "concurrent" writes
and handle write conflicts, so that even if you write to the same sector
simultaneously on both nodes, they end up with the identical data once
the writes are completed.
In handling "superseeded" writes, we forgot a kref_get,
resulting in a premature drbd_destroy_device and use after free,
and further to kernel crashes with symptoms.
Relevance: No one should use DRBD as a random data generator, and apparently
all users of "two-primaries" handle concurrent writes correctly on layer up.
That is cluster file systems use some distributed lock manager,
and live migration in virtualization environments stops writes on one node
before starting writes on the other node.
Which means that other than for "test cases",
this code path is never taken in real life.
FYI, in DRBD 9, things are handled differently nowadays. We still detect
"write conflicts", but no longer try to be smart about them.
We decided to disconnect hard instead: upper layers must not submit concurrent
writes. If they do, that's their fault.