| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
mm, slub: avoid zeroing kmalloc redzone
Since commit 946fa0dbf2d8 ("mm/slub: extend redzone check to extra
allocated kmalloc space than requested"), setting orig_size treats
the wasted space (object_size - orig_size) as a redzone. However with
init_on_free=1 we clear the full object->size, including the redzone.
Additionally we clear the object metadata, including the stored orig_size,
making it zero, which makes check_object() treat the whole object as a
redzone.
These issues lead to the following BUG report with "slub_debug=FUZ
init_on_free=1":
[ 0.000000] =============================================================================
[ 0.000000] BUG kmalloc-8 (Not tainted): kmalloc Redzone overwritten
[ 0.000000] -----------------------------------------------------------------------------
[ 0.000000]
[ 0.000000] 0xffff000010032858-0xffff00001003285f @offset=2136. First byte 0x0 instead of 0xcc
[ 0.000000] FIX kmalloc-8: Restoring kmalloc Redzone 0xffff000010032858-0xffff00001003285f=0xcc
[ 0.000000] Slab 0xfffffdffc0400c80 objects=36 used=23 fp=0xffff000010032a18 flags=0x3fffe0000000200(workingset|node=0|zone=0|lastcpupid=0x1ffff)
[ 0.000000] Object 0xffff000010032858 @offset=2136 fp=0xffff0000100328c8
[ 0.000000]
[ 0.000000] Redzone ffff000010032850: cc cc cc cc cc cc cc cc ........
[ 0.000000] Object ffff000010032858: cc cc cc cc cc cc cc cc ........
[ 0.000000] Redzone ffff000010032860: cc cc cc cc cc cc cc cc ........
[ 0.000000] Padding ffff0000100328b4: 00 00 00 00 00 00 00 00 00 00 00 00 ............
[ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.11.0-rc3-next-20240814-00004-g61844c55c3f4 #144
[ 0.000000] Hardware name: NXP i.MX95 19X19 board (DT)
[ 0.000000] Call trace:
[ 0.000000] dump_backtrace+0x90/0xe8
[ 0.000000] show_stack+0x18/0x24
[ 0.000000] dump_stack_lvl+0x74/0x8c
[ 0.000000] dump_stack+0x18/0x24
[ 0.000000] print_trailer+0x150/0x218
[ 0.000000] check_object+0xe4/0x454
[ 0.000000] free_to_partial_list+0x2f8/0x5ec
To address the issue, use orig_size to clear the used area. And restore
the value of orig_size after clear the remaining area.
When CONFIG_SLUB_DEBUG not defined, (get_orig_size()' directly returns
s->object_size. So when using memset to init the area, the size can simply
be orig_size, as orig_size returns object_size when CONFIG_SLUB_DEBUG not
enabled. And orig_size can never be bigger than object_size. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: lpfc: Handle mailbox timeouts in lpfc_get_sfp_info
The MBX_TIMEOUT return code is not handled in lpfc_get_sfp_info and the
routine unconditionally frees submitted mailbox commands regardless of
return status. The issue is that for MBX_TIMEOUT cases, when firmware
returns SFP information at a later time, that same mailbox memory region
references previously freed memory in its cmpl routine.
Fix by adding checks for the MBX_TIMEOUT return code. During mailbox
resource cleanup, check the mbox flag to make sure that the wait did not
timeout. If the MBOX_WAKE flag is not set, then do not free the resources
because it will be freed when firmware completes the mailbox at a later
time in its cmpl routine.
Also, increase the timeout from 30 to 60 seconds to accommodate boot
scripts requiring longer timeouts. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: avoid PMD-size page cache if needed
xarray can't support arbitrary page cache size. the largest and supported
page cache size is defined as MAX_PAGECACHE_ORDER by commit 099d90642a71
("mm/filemap: make MAX_PAGECACHE_ORDER acceptable to xarray"). However,
it's possible to have 512MB page cache in the huge memory's collapsing
path on ARM64 system whose base page size is 64KB. 512MB page cache is
breaking the limitation and a warning is raised when the xarray entry is
split as shown in the following example.
[root@dhcp-10-26-1-207 ~]# cat /proc/1/smaps | grep KernelPageSize
KernelPageSize: 64 kB
[root@dhcp-10-26-1-207 ~]# cat /tmp/test.c
:
int main(int argc, char **argv)
{
const char *filename = TEST_XFS_FILENAME;
int fd = 0;
void *buf = (void *)-1, *p;
int pgsize = getpagesize();
int ret = 0;
if (pgsize != 0x10000) {
fprintf(stdout, "System with 64KB base page size is required!\n");
return -EPERM;
}
system("echo 0 > /sys/devices/virtual/bdi/253:0/read_ahead_kb");
system("echo 1 > /proc/sys/vm/drop_caches");
/* Open the xfs file */
fd = open(filename, O_RDONLY);
assert(fd > 0);
/* Create VMA */
buf = mmap(NULL, TEST_MEM_SIZE, PROT_READ, MAP_SHARED, fd, 0);
assert(buf != (void *)-1);
fprintf(stdout, "mapped buffer at 0x%p\n", buf);
/* Populate VMA */
ret = madvise(buf, TEST_MEM_SIZE, MADV_NOHUGEPAGE);
assert(ret == 0);
ret = madvise(buf, TEST_MEM_SIZE, MADV_POPULATE_READ);
assert(ret == 0);
/* Collapse VMA */
ret = madvise(buf, TEST_MEM_SIZE, MADV_HUGEPAGE);
assert(ret == 0);
ret = madvise(buf, TEST_MEM_SIZE, MADV_COLLAPSE);
if (ret) {
fprintf(stdout, "Error %d to madvise(MADV_COLLAPSE)\n", errno);
goto out;
}
/* Split xarray entry. Write permission is needed */
munmap(buf, TEST_MEM_SIZE);
buf = (void *)-1;
close(fd);
fd = open(filename, O_RDWR);
assert(fd > 0);
fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
TEST_MEM_SIZE - pgsize, pgsize);
out:
if (buf != (void *)-1)
munmap(buf, TEST_MEM_SIZE);
if (fd > 0)
close(fd);
return ret;
}
[root@dhcp-10-26-1-207 ~]# gcc /tmp/test.c -o /tmp/test
[root@dhcp-10-26-1-207 ~]# /tmp/test
------------[ cut here ]------------
WARNING: CPU: 25 PID: 7560 at lib/xarray.c:1025 xas_split_alloc+0xf8/0x128
Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib \
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct \
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 \
ip_set rfkill nf_tables nfnetlink vfat fat virtio_balloon drm fuse \
xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 virtio_net \
sha1_ce net_failover virtio_blk virtio_console failover dimlib virtio_mmio
CPU: 25 PID: 7560 Comm: test Kdump: loaded Not tainted 6.10.0-rc7-gavin+ #9
Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-1.el9 05/24/2024
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : xas_split_alloc+0xf8/0x128
lr : split_huge_page_to_list_to_order+0x1c4/0x780
sp : ffff8000ac32f660
x29: ffff8000ac32f660 x28: ffff0000e0969eb0 x27: ffff8000ac32f6c0
x26: 0000000000000c40 x25: ffff0000e0969eb0 x24: 000000000000000d
x23: ffff8000ac32f6c0 x22: ffffffdfc0700000 x21: 0000000000000000
x20: 0000000000000000 x19: ffffffdfc0700000 x18: 0000000000000000
x17: 0000000000000000 x16: ffffd5f3708ffc70 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: ffffffffffffffc0 x10: 0000000000000040 x9 : ffffd5f3708e692c
x8 : 0000000000000003 x7 : 0000000000000000 x6 : ffff0000e0969eb8
x5 : ffffd5f37289e378 x4 : 0000000000000000 x3 : 0000000000000c40
x2 : 000000000000000d x1 : 000000000000000c x0 : 0000000000000000
Call trace:
xas_split_alloc+0xf8/0x128
split_huge_page_to_list_to_order+0x1c4/0x780
truncate_inode_partial_folio+0xdc/0x160
truncate_inode_pages_range+0x1b4/0x4a8
truncate_pagecache_range+0x84/0xa
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
gve: Account for stopped queues when reading NIC stats
We now account for the fact that the NIC might send us stats for a
subset of queues. Without this change, gve_get_ethtool_stats might make
an invalid access on the priv->stats_report->stats array. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()
set_memory_ro() can fail, leaving memory unprotected.
Check its return and take it into account as an error. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro()
set_memory_rox() can fail, leaving memory unprotected.
Check return and bail out when bpf_jit_binary_lock_ro() returns
an error. |
| In the Linux kernel, the following vulnerability has been resolved:
sched: fix warning in sched_setaffinity
Commit 8f9ea86fdf99b added some logic to sched_setaffinity that included
a WARN when a per-task affinity assignment races with a cpuset update.
Specifically, we can have a race where a cpuset update results in the
task affinity no longer being a subset of the cpuset. That's fine; we
have a fallback to instead use the cpuset mask. However, we have a WARN
set up that will trigger if the cpuset mask has no overlap at all with
the requested task affinity. This shouldn't be a warning condition; its
trivial to create this condition.
Reproduced the warning by the following setup:
- $PID inside a cpuset cgroup
- another thread repeatedly switching the cpuset cpus from 1-2 to just 1
- another thread repeatedly setting the $PID affinity (via taskset) to 2 |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix UAF on lgr list traversal in smcr_port_err()
smcr_port_err() traverses smc_lgr_list.list without holding
smc_lgr_list.lock, allowing a concurrent smc_lgr_terminate_sched()
to free an lgr while it is still being dereferenced.
Hold smc_lgr_list.lock across the traversal. Update
smc_ib_gid_check() to call smcr_port_err() after releasing the lock. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: use d_instantiate_new() in ntfs_create_inode() and murder syzbot's "WARNING in do_new_mount" saga
ntfs_create_inode() creates a new inode via ntfs_new_inode(). It hashes
it with insert_inode_locked() and so it's marked as I_NEW until
unlock_new_inode().
ntfs 3 calls d_instantiate() in between though... Since the dentry was
already hashed by the lookup before the create any path walk finds it
without touching the parent's i_rwsem and so can lock the inode.
If the inode is a directory unlock_new_inode() calls
lockdep_annotate_inode_mutex_key() and marks i_rwsem with the
i_mutex_dir_key class.
That resets the count and the owner of a lock somebody else may already
hold by now...
syzbot has been spamming us with the same godforsaken bug
"WARNING in do_new_mount"
since 2023. I can't take it anymore so I went looking. Afaict, syzbot's
executor chdirs into a freshly mounted ntfs3 image, creates a
directory and then mounts some pseudofs on it. Everytime the mkdir()
takes longer than syzbot waits mount() runs concurrently:
mkdir("./sys") mount(NULL, "./sys", "sysfs")
ntfs_create_inode()
d_instantiate()
user_path_at() finds the dentry
do_lock_mount()
inode_lock(inode)
namespace_lock()
unlock_new_inode()
lockdep_annotate_inode_mutex_key()
init_rwsem(&inode->i_rwsem)
unlock_mount()
inode_unlock(inode)
The mount side then releases a lock that according to the rwsem nobody
holds:
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && ...):
count = 0x0, magic = 0xffff888043a854e8, owner = 0x0,
curr 0xffff888000244880, list empty
WARNING: CPU: 0 PID: 5346 at kernel/locking/rwsem.c:1368 __up_write
Call Trace:
inode_unlock include/linux/fs.h:877 [inline]
unlock_mount fs/namespace.c:2892 [inline]
do_new_mount_fc fs/namespace.c:3828 [inline]
do_new_mount+0x777/0xa40 fs/namespace.c:3887
On PREEMPT_RT the same thing shows up as
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current)
WARNING: kernel/locking/rtmutex_common.h:193 at rt_mutex_slowunlock
The up_write() underflows the reset count. A following inode_lock() on
that directory then never returns. A path walk into the new directory
racing with the mkdir() corrupts the lock the same way via
inode_lock_shared() in lookup_slow().
Switch to d_instantiate_new() and drop the trailing unlock_new_inode().
All error paths bail out before that point with I_NEW still set and
keep using discard_new_inode().
May we never see this fscking bug report again. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: reject invalid and unexpected GRP_ACK_MSG to prevent bc_ackers underflow
Commit 48a5fe38772b ("tipc: fix bc_ackers underflow on duplicate
GRP_ACK_MSG") rejected duplicate/stale ACKs in tipc_group_proto_rcv()
by returning early when less_eq(acked, m->bc_acked).
However, that check remains incomplete in two ways:
1. When grp->bc_ackers is zero (e.g. on a quiet group, when replicast
ACKs were not requested, or after all expected members have already
acknowledged), an unexpected GRP_ACK_MSG with acked > m->bc_acked
passes less_eq() and unconditionally decrements grp->bc_ackers.
Because bc_ackers is a u16, this wraps to 65535, causing
tipc_group_bc_cong() to permanently report congestion and blocking
all future group broadcasts on the socket.
2. During an active broadcast round (grp->bc_ackers > 0), the sender
transmits packet S and advances grp->bc_snd_nxt to S + 1. Receivers
increment their expected counter to S + 1 upon consuming packet S,
so the only valid ACK value for the current round is strictly
acked == grp->bc_snd_nxt.
However, tipc_group_update_bc_members() initializes each member's
m->bc_acked to prev = grp->bc_snd_nxt - 1 (S - 1 before increment).
This leaves a 2-sequence gap (S - 1 to S + 1) in sequence space.
An incoming ACK is therefore neither rejected as duplicate nor
prevented from decrementing grp->bc_ackers if an unexpected or stale
value (such as S) is received. A member sending acked = S followed
by acked = S + 1 could decrement grp->bc_ackers twice in the same
round, prematurely clearing bc_ackers or underflowing it.
Fix this by:
- Dropping GRP_ACK_MSG immediately if grp->bc_ackers is zero.
- Requiring acked == grp->bc_snd_nxt and rejecting duplicates where
m->bc_acked == acked. Because replicast broadcast rounds are strictly
sequential, only grp->bc_snd_nxt can be acknowledged, and each member
can acknowledge at most once per round.
Note that a related pre-existing issue in tipc_group_delete_member()
(where grp->bc_ackers decrementing to zero upon member departure does
not restore *grp->open or trigger a socket wakeup) will be addressed
in a separate patch. |
| In the Linux kernel, the following vulnerability has been resolved:
vlan: ensure sufficient headroom in vlan_dev_hard_header()
Callers that only reserve ETH_HLEN or less (such as llc_alloc_frame()),
or skbs allocated before dynamic device/headroom changes (e.g. toggling
VLAN_FLAG_REORDER_HDR or bonding/team switching slaves), can reach
vlan_dev_hard_header() with insufficient headroom and trigger
skb_under_panic().
Use skb_cow_head() in vlan_dev_hard_header() when VLAN_FLAG_REORDER_HDR
is not set to ensure sufficient headroom for the VLAN header(s) and the
underlying device hard header.
Use READ_ONCE() to read dev->hard_header_len and dev->needed_headroom as
they can be updated concurrently under RTNL (e.g. in
vlan_transfer_features()) while vlan_dev_hard_header() runs locklessly on
the transmit path. Also avoid LL_RESERVED_SPACE(dev) here so that the
extra HH_DATA_MOD alignment padding does not trigger unnecessary
pskb_expand_head() reallocations on inner stacked VLAN devices after the
outer VLAN header has been pushed. |
| In the Linux kernel, the following vulnerability has been resolved:
net: libwx: fix races in Tx timestamp handling
wx->ptp_tx_skb is shared between the Tx path, the PTP auxiliary
worker and the timestamp cleanup paths. The
WX_STATE_PTP_TX_IN_PROGRESS bit prevents multiple Tx paths from
submitting timestamp requests, but does not serialize the worker
against cleanup.
As a result, wx_ptp_clear_tx_timestamp() can free an skb after
wx_ptp_tx_hwtstamp_work() has obtained its pointer. The worker may
then pass the freed skb to skb_tstamp_tx() and release the same
reference again.
The cleanup path may also clear the in-progress bit while the worker
is still processing the old skb. This allows the Tx path to publish a
new skb which the worker can subsequently overwrite with NULL,
leaking its reference.
Add a dedicated spinlock to protect publication and consumption of
the Tx timestamp skb. Detach the skb and clear the in-progress bit
while holding the lock, then deliver the timestamp and release the skb
after dropping it. Use the same locked cleanup in the quiesce path,
but keep the detach there free of register accesses: quiesce runs
during PCIe error recovery, where MMIO is not reliable, and it
deliberately did not touch the device before. The lock is taken with
interrupts disabled, because netpoll can call ndo_start_xmit() with
hard interrupts already off.
When handling a Tx DMA mapping failure, keep the transmit path
reference until after comparing the skb under the lock. This prevents
skb address reuse from making the error path mistake a newer timestamp
request for the failed one. |
| In the Linux kernel, the following vulnerability has been resolved:
nfc: st21nfca: validate ISO15693 inventory length
The ISO15693 inventory helper removes a two-byte prefix without checking
that it exists, then accepts a one-byte remainder before reading data[1] as
the DSFID.
Require the prefix and at least two remaining bytes before copying the UID
data and reading the DSFID. |
| In the Linux kernel, the following vulnerability has been resolved:
perf/core: Fix a refcount leak in attach_perf_ctx_data()
The attach_perf_ctx_data() can race on global and !global cases. The
global case is protected by global_ctx_data_rwsem and shares a single
reference count using perf_ctx_data.global field.
But when it races with !global case, it may miss to set the global field
and result in a reference count leak.
CPU1 CPU2
----------------------------------------------------------------
attach_task_ctx_data(.global=1) attach_task_ctx_data(.global=0)
cd1 = alloc_perf_ctx_data(); cd2 = alloc_perf_ctx_data();
// { .global = 0, .refcount = 1 };
try_cmpxchg(); // success,
// task->perf_ctx_data = cd2
try_cmpxhg(); // fail; old = cd2
refcount_inc_not_zero(&old->refcount); // success
// old.refcount = 2
free_perf_ctx_data(cd1);
Then later detach_global_ctx_data() will see the data but it's not
marked as global, so it won't call detach_task_ctx_data(). |
| In the Linux kernel, the following vulnerability has been resolved:
autofs: fix sbi->pipe file reference leak in autofs_kill_sb()
When autofs_fill_super() fails before clearing AUTOFS_SBI_CATATONIC (for
example, when find_get_pid() fails on an invalid pgrp mount option, or
when an fs_context is closed before mounting), deactivate_locked_super()
invokes autofs_kill_sb() -> autofs_catatonic_mode(sbi).
Because AUTOFS_SBI_CATATONIC is still set in sbi->flags,
autofs_catatonic_mode() returns early without calling fput(sbi->pipe),
permanently leaking the pipe struct file reference.
Explicitly release sbi->pipe in autofs_kill_sb() if it is still non-NULL
after autofs_catatonic_mode(). |
| In the Linux kernel, the following vulnerability has been resolved:
gve: DQO: reject TSO packets with an out of range MSS
gve_prep_tso() notes that the device requires the MSS to be <= 9728,
but does not enforce it, assuming the 9K MTU enforced by the hypervisor
and the 64KB limit on TSO sizes are enough.
This does not hold for packets that were not generated locally.
A guest behind a tap, or any packet socket user, can provide an
arbitrary gso_size in virtio_net_hdr. Layer 2 forwarding does not check
the MTU for GSO packets (is_skb_forwardable()), and gso_features_check()
only bounds skb->len and gso_segs, never gso_size.
Such a packet reaches gve_tx_fill_tso_ctx_desc(), which puts gso_size
into the mss field of the TSO context descriptor. This field is 14 bits
wide, so a gso_size of 16384 is silently turned into an MSS of zero.
Drop these packets from gve_prep_tso(), and make sure that
gve_features_check_dqo() leaves their GSO bits alone: skb_segment()
splits at gso_size regardless of the MTU, so falling back to software
segmentation would give the device non TSO packets bigger than the
9728 bytes it supports.
Note that the device can still be given oversized non TSO packets when
the stack segments in software for other reasons, for instance after
TSO has been disabled with ethtool. This is a generic issue, because
the MTU check is skipped for GSO packets in the forwarding path, and
is addressed separately. |
| In the Linux kernel, the following vulnerability has been resolved:
net: dsa: mt7530: leave the MDIO IRQ mappings to regmap-irq
mt7530_remove_common() disposes the per-PHY interrupt mappings from
.remove, but the regmap-irq chip that owns the domain is devm-registered,
so its parent interrupt is only freed once .remove has returned. The
switch's own regmap-irq thread can therefore still dispatch on a mapping
that is already gone: irq_find_mapping() returns 0, irq_to_desc() returns
NULL and handle_nested_irq() locks desc->lock without checking it. The
attached PHYs have not given those interrupts back yet either, which the
kernel warns about a moment before the fault.
regmap_del_irq_chip() disposes the same mappings itself, after freeing the
parent interrupt and before removing the domain, so there is nothing left
for the driver to do here. Until it runs the descriptors stay alive, and a
late dispatch on one of them is harmless: dsa_unregister_switch() has freed
the PHY handlers by then, so handle_nested_irq() finds no action and
returns. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject pkt arguments in mutating subprogs
The verifier tracks changes in how PTR_TO_PACKET registers'
bounds are modified across subprog boundaries. PTR_TO_PACKET
registers are actually passed as PTR_TO_MEM, which is assumed
valid for the entire call. This is not the case with packet memory,
where a pskb_* call may invalidate its memory region.
Reject BPF code that passes PTR_TO_PACKET pointers to subprogs that
may mutate a packet. We cannot pass the pointer as a true PTR_TO_PACKET
because we would also need to somehow pass the PTR_TO_PACKET_META
or PTR_TO_PACKET_END to the subprog. Since we cannot avoid representing
the pointer in the subprog as PTR_TO_MEM, only permit it if the
subprog is guaranteed not to mutate the packet. |
| In the Linux kernel, the following vulnerability has been resolved:
tg3: clean up PHYLIB resources on probe failure
tg3_get_invariants() can register an MDIO bus and connect a PHY for
USE_PHYLIB devices. If tg3_init_one() later fails, its common error path
releases the mappings and netdev without undoing those PHYLIB resources.
Disconnect the PHY and unregister the MDIO bus before the remaining
teardown. Guard PHY cleanup with USE_PHYLIB to match tg3_phy_init(), and
call tg3_mdio_fini() unconditionally to match tg3_mdio_init(). The existing
IS_CONNECTED and MDIOBUS_INITED flags make both helpers safe when
initialization only completed partially.
This issue was identified during our ongoing static-analysis research while
reviewing kernel code. |
| In the Linux kernel, the following vulnerability has been resolved:
udp: remove a disconnected socket from the 4-tuple hash table
A UDP socket bound to a specific address and port keeps its entry in the
4-tuple hash table after it is disconnected:
sk binds to 127.0.0.1:21001
sk connects to 127.0.0.2:20001 // filed in the 4-tuple table
sk disconnects, connect(AF_UNSPEC) // still filed, peer now 0.0.0.0:0
__udp_disconnect() takes a socket out of that table only as a side effect
of ->rehash() or ->unhash(), and it skips ->rehash() when
SOCK_BINDADDR_LOCK is set and ->unhash() when SOCK_BINDPORT_LOCK is set.
commit 6996a2d2d0a6 ("udp: Unhash auto-bound connected sk from 4-tuple hash
table when disconnected.") fixed the same end state for a wildcard-bound
socket, by a path this one does not take.
The entry is counted whether or not anything hits it. hash4_cnt on the
hash2 slot stays raised for as long as the socket lives, so udp_has_hash4()
keeps sending every packet for that address and port through the 4-tuple
lookup first.
On IPv6 it can also be hit. __udp_disconnect() does not clear sk_v6_daddr,
so udp_v6_rehash() files the entry under the peer the socket was connected
to with a zero dport, and inet6_match() compares that same
field: a datagram from the former peer with a zero source port matches,
and source port zero is accepted on receive. On IPv4 the peer is cleared,
so a match would need a zero source address as well, which the routing
layer rejects as martian. The stale sk_v6_daddr is a separate defect, not
addressed here; removing the entry closes this path either way.
The entry can also be relocated. __udp_disconnect() clears sk_bound_dev_if,
so a subsequent SO_BINDTODEVICE calls ->rehash(), and because the receive
address is still specific udp_lib_rehash() moves the entry instead of
removing it, into the bucket that (rcv_saddr, num, 0, 0) hashes to -- a
pure function of the address and port, so every socket reaching this state
on one address and port collects in one bucket. The bucket cannot be chosen
from outside, as udp_ehashfn() is seeded with a per-boot secret. This last
one became reachable only with commit 644f9108f3a5 ("udp: Make rehash4
independent in udp_lib_rehash()"), which moved the hash4 handling out of a
branch a disconnected socket does not take; the stale entry itself dates
from the commit in Fixes.
Take the socket out of the table before __udp_disconnect() runs, while it
still matches how it was filed. This also reaches the wildcard case ahead
of udp_lib_rehash()'s udp_unhash4() branch, leaving that branch unreachable
from udp_disconnect(); removing it belongs in net-next. udp_disconnect()
and udp_abort() are the only UDP entries into __udp_disconnect(), which is
shared with raw, ping and l2tp sockets that are not struct udp_sock:
ping_prot.obj_size is sizeof(struct inet_sock), so udp_hashed4() on one
would read past the allocation. |
