In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Fix unremoved procfs host directory regression
Commit fc663711b944 ("scsi: core: Remove the /proc/scsi/${proc_name}
directory earlier") fixed a bug related to modules loading/unloading, by
adding a call to scsi_proc_hostdir_rm() on scsi_remove_host(). But that led
to a potential duplicate call to the hostdir_rm() routine, since it's also
called from scsi_host_dev_release(). That triggered a regression report,
which was then fixed by commit be03df3d4bfe ("scsi: core: Fix a procfs host
directory removal regression"). The fix just dropped the hostdir_rm() call
from dev_release().
But it happens that this proc directory is created on scsi_host_alloc(),
and that function "pairs" with scsi_host_dev_release(), while
scsi_remove_host() pairs with scsi_add_host(). In other words, it seems the
reason for removing the proc directory on dev_release() was meant to cover
cases in which a SCSI host structure was allocated, but the call to
scsi_add_host() didn't happen. And that pattern happens to exist in some
error paths, for example.
Syzkaller causes that by using USB raw gadget device, error'ing on
usb-storage driver, at usb_stor_probe2(). By checking that path, we can see
that the BadDevice label leads to a scsi_host_put() after a SCSI host
allocation, but there's no call to scsi_add_host() in such path. That leads
to messages like this in dmesg (and a leak of the SCSI host proc
structure):
usb-storage 4-1:87.51: USB Mass Storage device detected
proc_dir_entry 'scsi/usb-storage' already registered
WARNING: CPU: 1 PID: 3519 at fs/proc/generic.c:377 proc_register+0x347/0x4e0 fs/proc/generic.c:376
The proper fix seems to still call scsi_proc_hostdir_rm() on dev_release(),
but guard that with the state check for SHOST_CREATED; there is even a
comment in scsi_host_dev_release() detailing that: such conditional is
meant for cases where the SCSI host was allocated but there was no calls to
{add,remove}_host(), like the usb-storage case.
This is what we propose here and with that, the error path of usb-storage
does not trigger the warning anymore.
In PHP version 8.1.* before 8.1.28, 8.2.* before 8.2.18, 8.3.* before 8.3.5, if a password stored with password_hash() starts with a null byte (\x00), testing a blank string as the password via password_verify() will incorrectly return true.
In the Linux kernel, the following vulnerability has been resolved:
firmware: arm_scmi: Harden accesses to the reset domains
Accessing reset domains descriptors by the index upon the SCMI drivers
requests through the SCMI reset operations interface can potentially
lead to out-of-bound violations if the SCMI driver misbehave.
Add an internal consistency check before any such domains descriptors
accesses.
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in cifs_debug_files_proc_show()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.
In the Linux kernel, the following vulnerability has been resolved:
af_unix: Fix garbage collector racing against connect()
Garbage collector does not take into account the risk of embryo getting
enqueued during the garbage collection. If such embryo has a peer that
carries SCM_RIGHTS, two consecutive passes of scan_children() may see a
different set of children. Leading to an incorrectly elevated inflight
count, and then a dangling pointer within the gc_inflight_list.
sockets are AF_UNIX/SOCK_STREAM
S is an unconnected socket
L is a listening in-flight socket bound to addr, not in fdtable
V's fd will be passed via sendmsg(), gets inflight count bumped
connect(S, addr) sendmsg(S, [V]); close(V) __unix_gc()
---------------- ------------------------- -----------
NS = unix_create1()
skb1 = sock_wmalloc(NS)
L = unix_find_other(addr)
unix_state_lock(L)
unix_peer(S) = NS
// V count=1 inflight=0
NS = unix_peer(S)
skb2 = sock_alloc()
skb_queue_tail(NS, skb2[V])
// V became in-flight
// V count=2 inflight=1
close(V)
// V count=1 inflight=1
// GC candidate condition met
for u in gc_inflight_list:
if (total_refs == inflight_refs)
add u to gc_candidates
// gc_candidates={L, V}
for u in gc_candidates:
scan_children(u, dec_inflight)
// embryo (skb1) was not
// reachable from L yet, so V's
// inflight remains unchanged
__skb_queue_tail(L, skb1)
unix_state_unlock(L)
for u in gc_candidates:
if (u.inflight)
scan_children(u, inc_inflight_move_tail)
// V count=1 inflight=2 (!)
If there is a GC-candidate listening socket, lock/unlock its state. This
makes GC wait until the end of any ongoing connect() to that socket. After
flipping the lock, a possibly SCM-laden embryo is already enqueued. And if
there is another embryo coming, it can not possibly carry SCM_RIGHTS. At
this point, unix_inflight() can not happen because unix_gc_lock is already
taken. Inflight graph remains unaffected.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_set_pipapo: do not free live element
Pablo reports a crash with large batches of elements with a
back-to-back add/remove pattern. Quoting Pablo:
add_elem("00000000") timeout 100 ms
...
add_elem("0000000X") timeout 100 ms
del_elem("0000000X") <---------------- delete one that was just added
...
add_elem("00005000") timeout 100 ms
1) nft_pipapo_remove() removes element 0000000X
Then, KASAN shows a splat.
Looking at the remove function there is a chance that we will drop a
rule that maps to a non-deactivated element.
Removal happens in two steps, first we do a lookup for key k and return the
to-be-removed element and mark it as inactive in the next generation.
Then, in a second step, the element gets removed from the set/map.
The _remove function does not work correctly if we have more than one
element that share the same key.
This can happen if we insert an element into a set when the set already
holds an element with same key, but the element mapping to the existing
key has timed out or is not active in the next generation.
In such case its possible that removal will unmap the wrong element.
If this happens, we will leak the non-deactivated element, it becomes
unreachable.
The element that got deactivated (and will be freed later) will
remain reachable in the set data structure, this can result in
a crash when such an element is retrieved during lookup (stale
pointer).
Add a check that the fully matching key does in fact map to the element
that we have marked as inactive in the deactivation step.
If not, we need to continue searching.
Add a bug/warn trap at the end of the function as well, the remove
function must not ever be called with an invisible/unreachable/non-existent
element.
v2: avoid uneeded temporary variable (Stefano)
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: release mutex after nft_gc_seq_end from abort path
The commit mutex should not be released during the critical section
between nft_gc_seq_begin() and nft_gc_seq_end(), otherwise, async GC
worker could collect expired objects and get the released commit lock
within the same GC sequence.
nf_tables_module_autoload() temporarily releases the mutex to load
module dependencies, then it goes back to replay the transaction again.
Move it at the end of the abort phase after nft_gc_seq_end() is called.