In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: cortina: Make RX SKB per-port
The SKB used to assemble packets from fragments in gmac_rx()
is static local, but the Gemini has two ethernet ports, meaning
there can be races between the ports on a bad day if a device
is using both.
Make the RX SKB a per-port variable and carry it over between
invocations in the port struct instead.
Zero the pointer once we call napi_gro_frags(), on error (after
calling napi_free_frags()) or if the port is stopped.
Zero it in some place where not strictly necessary just to
emphasize what is going on.
This was found by Sashiko during normal patch review.
In the Linux kernel, the following vulnerability has been resolved:
afs: Fix the locking used by afs_get_link()
The afs filesystem in the kernel doesn't do locking correctly for symbolic
links. There are a number of problems:
(1) It doesn't do any locking around afs_read_single() to prevent races
between multiple ->get_link() calls, thereby allowing the possibility
of leaks.
(2) It doesn't use RCU barriering when accessing the buffer pointers
during RCU pathwalk.
(3) It can race with another thread updating the contents of the symlink
if a third party updated it on the server.
Fix this by the following means:
(0) Move symlink handling into its own file as this makes it more
complicated.
(1) Take the validate_lock around afs_read_single() to prevent races
between multiple ->get_link() calls.
(2) Keep a separate copy of the symlink contents with an rcu_head. This
is always going to be a lot smaller than a page, so it can be
kmalloc'd and save quite a bit of memory. It also needs a refcount
for non-RCU pathwalk.
(3) Split the symlink read and write-to-cache routines in afs from those
for directories.
(4) Discard the I/O buffer as soon as the write-to-cache completes as this
is a full page (plus a folio_queue).
(5) If there's no cache, discard the I/O buffer immediately after reading
and copying if there is no cache.
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix netfs_read_folio() to wait on writeback
Fix netfs_read_folio() to wait for an ongoing writeback to complete so that
it can trust the dirty flag and whatever is attached to folio->private
(folio->private may get cleaned up by the collector before it clears the
writeback flag).
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix folio->private handling in netfs_perform_write()
Under some circumstances, netfs_perform_write() doesn't correctly
manipulate folio->private between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing
to a group and pointing to a netfs_folio struct, leading to potential
multiple attachments of private data with associated folio ref leaks and
also leaks of netfs_folio structs or netfs_group refs.
Fix this by consolidating the place at which a folio is marked uptodate in
one place and having that look at what's attached to folio->private and
decide how to clean it up and then set the new group. Also, the content
shouldn't be flushed if group is NULL, even if a group is specified in the
netfs_group parameter, as that would be the case for a new folio. A
filesystem should always specify netfs_group or never specify netfs_group.
The Sashiko auto-review tool noted that it was theoretically possible that
the fpos >= ctx->zero_point section might leak if it modified a streaming
write folio. This is unlikely, but with a network filesystem, third party
changes can happen. It also pointed out that __netfs_set_group() would
leak if called multiple times on the same folio from the "whole folio
modify section".
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix leak of request in netfs_write_begin() error handling
Fix netfs_write_begin() to not leak our ref on the request in the event
that we get an error from netfs_wait_for_read().
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix early put of sink folio in netfs_read_gaps()
Fix netfs_read_gaps() to release the sink page it uses after waiting for
the request to complete. The way the sink page is used is that an
ITER_BVEC-class iterator is created that has the gaps from the target folio
at either end, but has the sink page tiled over the middle so that a single
read op can fill in both gaps.
The bug was found by KASAN detecting a UAF on the generic/075 xfstest in
the cifsd kernel thread that handles reception of data from the TCP socket:
BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20
Write of size 885 at addr ffff888107f92000 by task cifsd/1285
CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)
Call Trace:
dump_stack_lvl+0x5d/0x80
print_report+0x17f/0x4f1
kasan_report+0x100/0x1e0
kasan_check_range+0x10f/0x1e0
__asan_memcpy+0x3c/0x60
_copy_to_iter+0x48a/0xa20
__skb_datagram_iter+0x2c9/0x430
skb_copy_datagram_iter+0x6e/0x160
tcp_recvmsg_locked+0xce0/0x1130
tcp_recvmsg+0xeb/0x300
inet_recvmsg+0xcf/0x3a0
sock_recvmsg+0xea/0x100
cifs_readv_from_socket+0x3a6/0x4d0 [cifs]
cifs_read_iter_from_socket+0xdd/0x130 [cifs]
cifs_readv_receive+0xaad/0xb10 [cifs]
cifs_demultiplex_thread+0x1148/0x1740 [cifs]
kthread+0x1cf/0x210
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix potential deadlock in write-through mode
Fix netfs_advance_writethrough() to always unlock the supplied folio and to
mark it dirty if it isn't yet written to the end. Unfortunately, it can't
be marked for writeback until the folio is done with as that may cause a
deadlock against mmapped reads and writes.
Even though it has been marked dirty, premature writeback can't occur as
the caller is holding both inode->i_rwsem (which will prevent concurrent
truncation, fallocation, DIO and other writes) and ictx->wb_lock (which
will cause flushing to wait and writeback to skip or wait).
Note that this may be easier to deal with once the queuing of folios is
split from the generation of subrequests.
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix streaming write being overwritten
In order to avoid reading whilst writing, netfslib will allow "streaming
writes" in which dirty data is stored directly into folios without reading
them first. Such folios are marked dirty but may not be marked uptodate.
If a folio is entirely written by a streaming write, uptodate will be set,
otherwise it will have a netfs_folio struct attached to ->private recording
the dirty region.
In the event that a partially written streaming write page is to be
overwritten entirely by a single write(), netfs_perform_write() will try to
copy over it, but doesn't discard the netfs_folio if it succeeds; further,
it doesn't correctly handle a partial copy that overwrites some of the
dirty data.
Fix this by the following:
(1) If the folio is successfully overwritten, free the netfs_folio struct
before marking the page uptodate.
(2) If the copy to the folio partially fails, but short of the dirty data,
just ignore the copy.
(3) If the copy partially fails and overwrites some of the dirty data,
accept the copy, update the netfs_folio struct to record the new data.
If the folio is now filled, free the netfs_folio and set uptodate,
otherwise return a partial write.
Found with:
fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
/xfstest.test/junk --replay-ops=junk.fsxops
using the following as junk.fsxops:
truncate 0x0 0 0x927c0
write 0x63fb8 0x53c8 0
copy_range 0xb704 0x19b9 0x24429 0x79380
write 0x2402b 0x144a2 0x90660 *
write 0x204d5 0x140a0 0x927c0 *
copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 *
read 0x00000 0x20000 0x9157c
read 0x20000 0x20000 0x9157c
read 0x40000 0x20000 0x9157c
read 0x60000 0x20000 0x9157c
read 0x7e1a0 0xcfb9 0x9157c
on cifs with the default cache option.
It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in
netfs_perform_write():
if (//(file->f_mode & FMODE_READ) ||
netfs_is_cache_enabled(ctx)) {
and no fscache. This was initially found with the generic/522 xfstest.
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone
If a streaming write is made, this will leave the relevant modified folio
in a not-uptodate, but dirty state with a netfs_folio struct hung off of
folio->private indicating the dirty range. Subsequently truncating the
file such that the dirty data in the folio is removed, but the first part
of the folio theoretically remains will cause the netfs_folio struct to be
discarded... but will leave the dirty flag set.
If the folio is then read via mmap(), netfs_read_folio() will see that the
page is dirty and jump to netfs_read_gaps() to fill in the missing bits.
netfs_read_gaps(), however, expects there to be a netfs_folio struct
present and can oops because truncate removed it.
Fix this by calling folio_cancel_dirty() in netfs_invalidate_folio() in the
event that all the dirty data in the folio is erased (as nfs does).
Also add some tracepoints to log modifications to a dirty page.
This can be reproduced with something like:
dd if=/dev/zero of=/xfstest.test/foo bs=1M count=1
umount /xfstest.test
mount /xfstest.test
xfs_io -c "w 0xbbbf 0xf96c" \
-c "truncate 0xbbbf" \
-c "mmap -r 0xb000 0x11000" \
-c "mr 0xb000 0x11000" \
/xfstest.test/foo
with fscaching disabled (otherwise streaming writes are suppressed) and a
change to netfs_perform_write() to disallow streaming writes if the fd is
open O_RDWR:
if (//(file->f_mode & FMODE_READ) || <--- comment this out
netfs_is_cache_enabled(ctx)) {
It should be reproducible even without this change, but if prevents the
above trivial xfs_io command from reproducing it.
Note that the initial dd is important: the file must start out sufficiently
large that the zero-point logic doesn't just clear the gaps because it
knows there's nothing in the file to read yet. Unmounting and mounting is
needed to clear the pagecache (there are other ways to do that that may
also work).
This was initially reproduced with the generic/522 xfstest on some patches
that remove the FMODE_READ restriction.
In the Linux kernel, the following vulnerability has been resolved:
net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring
When an sk_msg scatterlist ring wraps (sg.end < sg.start),
tls_push_record() chains the tail portion of the ring to the head
using sg_chain(). An extra entry in the sg array is reserved for
this:
struct sk_msg_sg {
[...]
/* The extra two elements:
* 1) used for chaining the front and sections when the list becomes
* partitioned (e.g. end < start). The crypto APIs require the
* chaining;
* 2) to chain tailer SG entries after the message.
*/
struct scatterlist data[MAX_MSG_FRAGS + 2];
The current code uses MAX_SKB_FRAGS + 1 as the ring size:
sg_chain(&msg_pl->sg.data[msg_pl->sg.start],
MAX_SKB_FRAGS - msg_pl->sg.start + 1,
msg_pl->sg.data);
This places the chain pointer at
sg_chain(data[start], (MAX_SKB_FRAGS - msg_start + 1) .. =
&data[start] + (MAX_SKB_FRAGS - msg_start + 1) - 1 =
data[start + (MAX_SKB_FRAGS - start + 1) - 1] =
data[MAX_SKB_FRAGS]
instead of the true last entry. This is likely due to a "race" of
the commit under Fixes landing close to
commit 031097d9e079 ("bpf: sk_msg, zap ingress queue on psock down")
Convert to ARRAY_SIZE and drop the data[start] / - start (as suggested
by Sabrina).