| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode
- ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink
- f2fs_gc
- gc_data_segment
- ra_data_block(cow_inode)
- mapping = F2FS_I(inode)->atomic_inode->i_mapping
: f2fs_is_cow_file(cow_inode) is true
- f2fs_evict_inode(atomic_inode)
- clear_inode_flag(fi->cow_inode, FI_COW_FILE)
- F2FS_I(fi->cow_inode)->atomic_inode = NULL
...
- truncate_inode_pages_final(atomic_inode)
- f2fs_grab_cache_folio(mapping)
: create folio in atomic_inode->mapping
- clear_inode(atomic_inode)
- BUG_ON(atomic_inode->i_data.nrpages)
We need to add a reference on fi->atomic_inode before using its mapping
field during garbage collection, otherwise, it will cause UAF issue. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: bound i_inline_xattr_size for non-inline-xattr inodes
When the flexible_inline_xattr feature is enabled, do_read_inode() loads
the on-disk i_inline_xattr_size unconditionally:
if (f2fs_sb_has_flexible_inline_xattr(sbi))
fi->i_inline_xattr_size = le16_to_cpu(ri->i_inline_xattr_size);
but sanity_check_inode() only range-checks it when the inode also has the
FI_INLINE_XATTR flag set. An inode that carries an inline dentry or inline
data but not FI_INLINE_XATTR -- the normal layout for an inline
directory -- therefore keeps a fully attacker-controlled
i_inline_xattr_size from a crafted image.
get_inline_xattr_addrs() returns that value with no flag gating, so it
feeds the inode geometry:
MAX_INLINE_DATA() = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1)
NR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...)
addrs_per_page() = CUR_ADDRS_PER_INODE - i_inline_xattr_size
A large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY()
negative, so make_dentry_ptr_inline() sets d->max (int) to a negative
value. The inline directory walk then compares an unsigned long bit_pos
against that negative d->max, which is promoted to a huge unsigned bound,
and reads far past the inline area:
while (bit_pos < d->max) /* fs/f2fs/dir.c */
... test_bit_le(bit_pos, d->bitmap) / d->dentry[bit_pos] ...
Mounting a crafted image and reading such a directory triggers an
out-of-bounds read in f2fs_fill_dentries(); the same underflow also
corrupts ADDRS_PER_INODE for regular files.
Validate i_inline_xattr_size against MAX_INLINE_XATTR_SIZE whenever the
flexible_inline_xattr feature is enabled -- i.e. whenever the value is
loaded from disk and consumed -- and keep the lower MIN_INLINE_XATTR_SIZE
bound gated on inodes that actually carry an inline xattr, so legitimate
inodes with i_inline_xattr_size == 0 are still accepted. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: validate ACL entry sizes in f2fs_acl_from_disk()
f2fs_acl_count() only validates the aggregate ACL xattr length. A
malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only
contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk()
then reads entry->e_id before verifying that a full entry fits.
Require a short entry before reading e_tag and e_perm, and require a
full entry before reading e_id for ACL_USER and ACL_GROUP. Return
-EFSCORRUPTED from these new truncated-entry checks, while keeping the
pre-existing -EINVAL paths unchanged.
Validation reproduced this kernel report:
KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0
RIP: 0033:0x7f4b835ea7aa
The buggy address belongs to the object at ffff888114589960 which belongs
to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of allocated 8-byte
region [ffff888114589960, ffff888114589968)
Read of size 4
Call trace:
dump_stack_lvl+0x66/0xa0 (?:?)
print_report+0xce/0x630 (?:?)
__f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169)
srso_alias_return_thunk+0x5/0xfbef5 (?:?)
__virt_addr_valid+0x224/0x430 (?:?)
kasan_report+0xe0/0x110 (?:?)
__f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169)
__get_acl+0x281/0x380 (?:?)
vfs_get_acl+0x10b/0x190 (?:?)
do_get_acl+0x2a/0x410 (?:?)
do_get_acl+0x9/0x410 (?:?)
do_getxattr+0xe8/0x260 (?:?)
filename_getxattr+0xd1/0x140 (?:?)
do_getname+0x2d/0x2d0 (?:?)
path_getxattrat+0x16c/0x200 (?:?)
lock_release+0xc8/0x290 (?:?)
cgroup_update_frozen+0x9d/0x320 (?:?)
lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?)
trace_hardirqs_on+0x1a/0x170 (?:?)
_raw_spin_unlock_irq+0x28/0x50 (?:?)
do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)
entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?) |
| In the Linux kernel, the following vulnerability has been resolved:
Revert "f2fs: remove non-uptodate folio from the page cache in move_data_block"
This reverts commit 9609dd704725a40cd63d915f2ab6c44248a44598.
The kernel panics are keeping to be reported especially when the f2fs
partition get almost full. By investigation, we find that the reason is
one f2fs page got freed to buddy without being deleted from LRU and the
root cause is the race happened in [2] which is enrolled by this commit.
There are 3 race processes in this scenario, please find below for their
main activities.
The changed code in move_data_block() lets the GC path evict the tail-end
folio from the page cache through folio_end_dropbehind(). Once
folio_unmap_invalidate() removes the folio from mapping->i_pages, the
page-cache references for all pages in the folio are dropped. The folio
is then kept alive only by temporary external references, which allows a
later split to operate on a folio whose subpages are no longer protected
by page-cache references.
After the page-cache references are gone, split_folio_to_order() can
split the big folio into individual pages and put the resulting subpages
back on the LRU. For tail pages beyond EOF, split removes them from the
page cache and drops their page-cache references. A tail page can then
remain on the LRU with PG_lru set while holding only the split caller's
temporary reference. When free_folio_and_swap_cache() drops that final
reference, the page enters the final folio_put() release path.
In parallel, folio_isolate_lru() can observe the same tail page with a
non-zero refcount and PG_lru set. It clears PG_lru before taking its own
reference. If this races with the final folio_put() from the split path,
__folio_put() sees PG_lru already cleared and skips lruvec_del_folio().
The page is then freed back to the allocator while its lru links are
still present in the LRU list. A later LRU operation on a neighboring
page detects the stale link and reports list corruption.
[1]
[ 22.486082] list_del corruption. next->prev should be fffffffec10e0ac8, but was dead000000000122. (next=fffffffec10e0a88)
[ 22.486130] ------------[ cut here ]------------
[ 22.486134] kernel BUG at lib/list_debug.c:67!
[ 22.486141] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
[ 22.488502] Tainted: [W]=WARN, [O]=OOT_MODULE
[ 22.488506] Hardware name: Spreadtrum UMS9230 1H10 SoC (DT)
[ 22.488511] pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 22.488517] pc : __list_del_entry_valid_or_report+0x14c/0x154
[ 22.488531] lr : __list_del_entry_valid_or_report+0x14c/0x154
[ 22.488539] sp : ffffffc08006b830
[ 22.488542] x29: ffffffc08006b868 x28: 0000000000003020 x27: 0000000000000000
[ 22.488553] x26: 0000000000000000 x25: 0000000000000004 x24: fffffffec10e0ac0
[ 22.488564] x23: 00000000000000e8 x22: 0000000000000024 x21: dead000000000122
[ 22.488574] x20: fffffffec10e0a88 x19: fffffffec10e0ac8 x18: ffffffc080061060
[ 22.488585] x17: 20747562202c3863 x16: 6130653031636566 x15: 0000000000000058
[ 22.488595] x14: 0000000000000004 x13: ffffff80f91e0000 x12: 0000000000000003
[ 22.488605] x11: 0000000000000003 x10: 0000000000000001 x9 : ffe85721f0e25f00
[ 22.488615] x8 : ffe85721f0e25f00 x7 : 0000000000000000 x6 : 6c65645f7473696c
[ 22.488625] x5 : ffffffed39b23026 x4 : 0000000000000000 x3 : 0000000000000010
[ 22.488636] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 000000000000006d
[ 22.488647] Call trace:
[ 22.488651] __list_del_entry_valid_or_report+0x14c/0x154 (P)
[ 22.488661] __folio_put+0x2bc/0x434
[ 22.488670] folio_put+0x28/0x58
[ 22.488678] do_garbage_collect+0x1a34/0x2584
[ 22.488689] f2fs_gc+0x230/0x9b4
[ 22.488697] f2fs_fallocate+0xb90/0xdf4
[ 22.488706] vfs_fallocate+0x1b4/0x2bc
[ 22.488716] __arm64_sys_fallocate+0x44/0x78
[ 22.488725] invoke_syscall+0x58/0xe4
[ 22.488732] do_el0_svc+0x48/0xdc
[ 22.488739] el0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()
When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does
not reset the length of the largest extent to 0 and update the inode
folio. Since modifications to the extent tree are disallowed afterward,
the cached largest extent may become stale. This can trigger the
following error in xfstests generic/388:
F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix
In the f2fs_drop_inode path, __destroy_extent_node() does not need to
guarantee that et->node_cnt is 0, because concurrency with writeback
is expected in this path, and writeback may update the extent cache.
This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between
extent node destroy and writeback"), and remove the unnecessary zero
check of et->node_cnt. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: read COW data with the original inode during atomic write
When updating an atomic-write file, f2fs_write_begin() may read the
previously written data back from the COW inode:
prepare_atomic_write_begin() locates the block in the COW inode and sets
use_cow, and the read bio is then built with the COW inode:
f2fs_submit_page_read(use_cow ? F2FS_I(inode)->cow_inode : inode,
...);
and f2fs_grab_read_bio() decides whether to schedule fs-layer decryption
(STEP_DECRYPT) for the bio based on that inode via
fscrypt_inode_uses_fs_layer_crypto().
However, the folio being filled belongs to the original inode
(folio->mapping->host == inode), and the data stored in the COW block was
encrypted (or left as plaintext) using the original inode's context, not
the COW inode's -- see f2fs_encrypt_one_page(), which keys off
fio->page->mapping->host. fscrypt_decrypt_pagecache_blocks() likewise
operates on folio->mapping->host.
The COW inode is created as a tmpfile in the parent directory and inherits
its encryption policy from there. With test_dummy_encryption the newly
created COW inode gets the dummy policy and becomes encrypted, while a
pre-existing regular file -- created before the policy applied, e.g.
already present in the on-disk image -- stays unencrypted. The read
path then sets STEP_DECRYPT based on the encrypted COW inode and calls
fscrypt_decrypt_pagecache_blocks() on a folio whose host (the unencrypted
original inode) has a NULL ->i_crypt_info, dereferencing it:
Oops: general protection fault, probably for non-canonical address ...
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
RIP: 0010:fscrypt_decrypt_pagecache_blocks+0xa0/0x310
Workqueue: f2fs_post_read_wq f2fs_post_read_work
Call Trace:
fscrypt_decrypt_bio+0x1eb/0x340
f2fs_post_read_work+0xba/0x140
process_one_work+0x91c/0x1a40
worker_thread+0x677/0xe90
kthread+0x2bc/0x3a0
The COW inode is only needed to locate the on-disk block, and that block
address is already resolved into @blkaddr by prepare_atomic_write_begin()
via __find_data_block(cow_inode, ...); f2fs_submit_page_read() then reads
from that physical @blkaddr directly, so the inode argument only selects
the post-read crypto context, not which block is fetched. Reading with
@inode therefore returns the same (latest, not-yet-committed) COW data,
while making both the fs-layer decryption decision and the inline crypto
path use the correct (original inode's) key.
With the COW inode no longer used at the read site, the use_cow flag has no
remaining consumer; drop it from f2fs_write_begin() and
prepare_atomic_write_begin(). |
| In the Linux kernel, the following vulnerability has been resolved:
block: Avoid mounting the bdev pseudo-filesystem in userspace
The bdev pseudo-filesystem is an internal kernel filesystem with which
userspace should not interfere. Unregister it so that userspace cannot
even attempt to mount it.
This fixes a bug [1] that occurs when attempting to access files,
because the system call move_mount() uses pointers declared in the
inode_operations structure, which for the bdev pseudo-filesystem
are always equal to 0. `inode->i_op = &empty_iops;`
[1]
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 23380067 P4D 23380067 PUD 23381067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI
CPU: 2 PID: 17125 Comm: syz-executor.0 Not tainted 6.1.155-syzkaller-00350-g84221fde2681 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:0x0
Call Trace:
<TASK>
lookup_open.isra.0+0x700/0x1180 fs/namei.c:3460
open_last_lookups fs/namei.c:3550 [inline]
path_openat+0x953/0x2700 fs/namei.c:3780
do_filp_open+0x1c5/0x410 fs/namei.c:3810
do_sys_openat2+0x171/0x4d0 fs/open.c:1318
do_sys_open fs/open.c:1334 [inline]
__do_sys_openat fs/open.c:1350 [inline]
__se_sys_openat fs/open.c:1345 [inline]
__x64_sys_openat+0x13c/0x1f0 fs/open.c:1345
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Found by Linux Verification Center (linuxtesting.org) with Syzkaller. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: use kvfree() for replaced sysctl write buffer
proc_sys_call_handler() allocates its temporary sysctl buffer with
kvzalloc() and passes it to __cgroup_bpf_run_filter_sysctl(). Since
kvzalloc() may fall back to vmalloc() for large allocations, freeing
that buffer with kfree() is wrong and can corrupt memory.
Use kvfree() to safely handle both kmalloc and kvzalloc()/vmalloc
allocations.
The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1-rc5.
Reproduced the bug based on v7.1-rc4 in a QEMU x86_64 guest booted with
KASAN and CONFIG_FAILSLAB enabled. To exercise the replacement path, the
test tree also included the accompanying fix for the stale ret == 1
check in __cgroup_bpf_run_filter_sysctl(). The reproducer confines
failslab injections to the proc_sys_call_handler() range, uses
stacktrace-depth=32, and injects fail-nth=1 while writing 8191 bytes to
/proc/sys/kernel/domainname from a task in the target cgroup. Under
that setup, fail-nth=1 triggered the fault:
BUG: unable to handle page fault for address: ffffeb0200024d48
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 SMP KASAN NOPTI
CPU: 2 UID: 0 PID: 209 Comm: repro_proc_sys_ Not tainted 7.1.0-rc4-00686-g97625979a5d4 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:kfree+0x6e/0x510
...
Call Trace:
<TASK>
? __cgroup_bpf_run_filter_sysctl+0x626/0xc30
__cgroup_bpf_run_filter_sysctl+0x74d/0xc30
? __pfx___cgroup_bpf_run_filter_sysctl+0x10/0x10
? srso_return_thunk+0x5/0x5f
? __kvmalloc_node_noprof+0x345/0x870
? proc_sys_call_handler+0x250/0x480
? srso_return_thunk+0x5/0x5f
proc_sys_call_handler+0x3a2/0x480
? __pfx_proc_sys_call_handler+0x10/0x10
? srso_return_thunk+0x5/0x5f
? selinux_file_permission+0x39f/0x500
? srso_return_thunk+0x5/0x5f
? lock_is_held_type+0x9e/0x120
vfs_write+0x98e/0x1000
...
</TASK>
With this fix applied on top of the same test setup, rerunning the
reproducer with fail-nth=1 yields no corresponding Oops reports. |
| In the Linux kernel, the following vulnerability has been resolved:
exfat: fix potential use-after-free in exfat_find_dir_entry()
In exfat_find_dir_entry(), the buffer_head obtained from
exfat_get_dentry() is released with brelse(bh) before the fall-through
TYPE_EXTEND branch reads the directory entry through ep (which points
into bh->b_data):
brelse(bh);
if (entry_type == TYPE_EXTEND) {
...
len = exfat_extract_uni_name(ep, entry_uniname);
...
}
After brelse() drops our reference, nothing guarantees that the
underlying page backing bh->b_data remains valid for the subsequent
exfat_extract_uni_name() read. This is the same pattern fixed in
commit fc961522ddbd ("exfat: Fix potential use after free in
exfat_load_upcase_table()").
Move brelse(bh) so it runs after ep is no longer dereferenced on
each branch.
Confirmed on QEMU x86_64 with CONFIG_KASAN=y + CONFIG_DEBUG_PAGEALLOC=y
+ CONFIG_PAGE_POISONING=y on linux-next, using a crafted exFAT image
(long filename with same-hash collisions forcing the TYPE_EXTEND path).
With a debug-only invalidate_bdev() inserted between brelse(bh) and
the ep read to make the stale-deref window deterministic, the
unpatched kernel faults:
BUG: KASAN: use-after-free in exfat_find_dir_entry+0x133b/0x15a0
BUG: unable to handle page fault for address: ffff88801a5fa0c2
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
RIP: 0010:exfat_find_dir_entry+0x1188/0x15a0
With this patch applied, the same instrumented harness completes
cleanly under the same sanitizer stack. I have not reproduced a
crash on an uninstrumented kernel under ordinary reclaim; the
instrumented A/B establishes the lifetime violation and that the
patch closes it, not an unaided triggerability claim. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level
When recovering hugepages in the shadow MMU, verify that the base gfn of
the shadow page is actually contained within the target memslot, *before*
querying the max mapping level given the shadow page's gfn. Failure to
pre-check the validity of the gfn can lead to an out-of-bounds access to
the slot's lpage_info (which typically manifests as a host #PF because the
lpage_info is vmalloc'd) if the guest creates a hugepage mapping (in its
PTEs) that extends "below" the bounds of a memslot.
When faulting in memory for a guest, and the size of the guest mapping is
greater than KVM's (current) max mapping, then KVM will create a "direct"
shadow page (direct in that there are no gPTEs to shadow, and so the target
gfn is a direct calculation given the base gfn of the shadow page). The
hugepage recovery flow looks for such direct shadow pages, as forcing 4KiB
mappings when dirty logging generates the guest > host mapping size case.
When the 4KiB restriction is lifted, then KVM can replace the shadow page
with a hugepage.
But if KVM originally used a smaller mapping than the guest because the
range of memory covered by the guest hugepage exceeds the bounds of a
memslot, then KVM will link a direct shadow page with a gfn that is outside
the bounds of the memslot being used to fault in memory. The rmap entry
added for the leaf mapping is correct and within bounds, but the gfn of the
leaf SPTE's parent shadow page will be out of bounds.
BUG: unable to handle page fault for address: ffffc90000806ffc
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 100000067 P4D 100000067 PUD 1002a7067 PMD 10612f067 PTE 0
Oops: Oops: 0000 [#1] SMP
CPU: 13 UID: 1000 PID: 757 Comm: mmu_stress_test Not tainted 7.1.0-rc1-48ce1e26eace-x86_pir_to_irr_comments-vm #341 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:kvm_mmu_max_mapping_level+0x79/0x2b0 [kvm]
Call Trace:
<TASK>
kvm_mmu_recover_huge_pages+0x21b/0x320 [kvm]
kvm_set_memslot+0x1ee/0x590 [kvm]
kvm_set_memory_region.part.0+0x3a1/0x4d0 [kvm]
kvm_vm_ioctl+0x9bf/0x15d0 [kvm]
__x64_sys_ioctl+0x8a/0xd0
do_syscall_64+0xb7/0xbb0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f21c0f1a9bf
</TASK>
Don't bother pre-checking the bounds of the potential hugepage, i.e. don't
check that e.g. sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level + 1) is also
within the memslot, as the checks performed by kvm_mmu_max_mapping_level()
are a superset of the basic bounds checks. I.e. pre-checking the full
range would be a dubious micro-optimization. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: Replace guest-triggerable BUG_ON() in ioeventfd datamatch with get_unaligned()
Drop a BUG_ON() that has been reachable since it was first added, way back
in 2009, and instead use get_unaligned() to perform potentially-unaligned
accesses.
For a given store, KVM x86's emulator tracks the entire value in the
destination operand, x86_emulate_ctxt.dst. If the destination is memory,
and the target splits multiple pages and/or is emulated MMIO, then KVM
handles each fragment independently. E.g. on a page split starting at page
offset 0xffc, KVM writes 4 bytes to the first page, then the remaining
bytes to the second page, using ctxt->dst as the source for both (with
appropriate offsets).
If the destination splits a page *and* hits emulated MMIO on the second
page, then KVM will complete the write to the first page, then emulate the
MMIO access to the second page. If there is a datamatch-enabled ioeventfd
at offset 0 of the second page, then KVM will process the remainder of the
store as a potential ioeventfd signal.
Putting it all together, if the guest emits a store that splits a page
starting at page offset N, and the second page has a datamatch-enabled
ioeventfd at offset 0, then KVM will check for datamatch using
&dst.valptr[N] as the source. Due to dst (and thus dst.valptr) being
32-byte aligned, if N is not aligned to @len, the BUG_ON() fires.
E.g. with a 16-byte store at page offset 0xffc, to an ioeventfd of len 8,
all initial checks in ioeventfd_in_range() will succeed, and the BUG_ON()
fires due to @val being 4-byte aligned, but not 8-byte aligned.
------------[ cut here ]------------
kernel BUG at arch/x86/kvm/../../../virt/kvm/eventfd.c:783!
Oops: invalid opcode: 0000 [#1] SMP
CPU: 0 UID: 1000 PID: 615 Comm: repro Not tainted 7.1.0-rc2-ff238429d1ea #365 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:ioeventfd_write+0x6c/0x70 [kvm]
Call Trace:
<TASK>
__kvm_io_bus_write+0x85/0xb0 [kvm]
kvm_io_bus_write+0x53/0x80 [kvm]
vcpu_mmio_write+0x66/0xf0 [kvm]
emulator_read_write_onepage+0x12a/0x540 [kvm]
emulator_read_write+0x109/0x2b0 [kvm]
x86_emulate_insn+0x4f8/0xfb0 [kvm]
x86_emulate_instruction+0x181/0x790 [kvm]
kvm_mmu_page_fault+0x313/0x630 [kvm]
vmx_handle_exit+0x18a/0x590 [kvm_intel]
kvm_arch_vcpu_ioctl_run+0xc81/0x1c90 [kvm]
kvm_vcpu_ioctl+0x2d5/0x970 [kvm]
__x64_sys_ioctl+0x8a/0xd0
do_syscall_64+0xb7/0x890
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f19c931a9bf
</TASK>
Modules linked in: kvm_intel kvm irqbypass
---[ end trace 0000000000000000 ]---
In a perfect world, the fix would be to simply delete the BUG_ON(), as KVM
x86 doesn't perform alignment checks on "normal" memory accesses at CPL0.
Sadly, C99 ruins all the fun; while the x86 architecture plays nice,
dereferencing an unaligned pointer directly is undefined behavior in C,
e.g. triggers splats when running with CONFIG_UBSAN_ALIGNMENT=y. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: nx - fix nx_crypto_ctx_exit argument
nx_crypto_ctx_shash_exit calls nx_crypto_ctx_exit with crypto_shash_ctx(...)
but crypto_shash_ctx gives a nx_crypto_ctx *, not a crypto_tfm *.
Fix the type in nx_crypto_ctx_exit and drop the bogus crypto_tfm_ctx
call.
This fixes the following oops:
BUG: Unable to handle kernel data access at 0xc0403effffffffc8
Faulting instruction address: 0xc000000000396cb4
Oops: Kernel access of bad area, sig: 11 [#15]
Call Trace:
nx_crypto_ctx_shash_exit+0x24/0x60
crypto_shash_exit_tfm+0x28/0x40
crypto_destroy_tfm+0x98/0x140
crypto_exit_ahash_using_shash+0x20/0x40
crypto_destroy_tfm+0x98/0x140
hash_release+0x1c/0x30
alg_sock_destruct+0x38/0x60
__sk_destruct+0x48/0x2b0
af_alg_release+0x58/0xb0
__sock_release+0x68/0x150
sock_close+0x20/0x40
__fput+0x110/0x3a0
sys_close+0x48/0xa0
system_call_exception+0x140/0x2d0
system_call_common+0xf4/0x258
.. which came from hardlink(1) opportunistically using AF_ALG.
The same problem exists with nx_crypto_ctx_skcipher_exit getting a context
it wasn't expecting, but apparently nobody hit that for years. |
| In the Linux kernel, the following vulnerability has been resolved:
gfs2: fix use-after-free in gfs2_qd_dealloc
gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),
accesses the superblock object sdp through qd->qd_sbd after freeing qd.
It does so to decrement sd_quota_count and wake up sd_kill_wait.
However, by the time the RCU callback runs, gfs2_put_super() may have
already freed sdp via free_sbd(). This can happen when
gfs2_quota_cleanup() is called during unmount: it disposes of quota
objects via call_rcu() and then waits on sd_kill_wait with a 60-second
timeout. If the timeout expires, or if gfs2_gl_hash_clear() triggers
additional qd_put() calls that schedule more RCU callbacks after the
wait completes, gfs2_put_super() will proceed to free the superblock
while RCU callbacks referencing it are still pending.
Add an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure
all pending RCU callbacks (including gfs2_qd_dealloc) have completed
before the superblock is freed. |
| In the Linux kernel, the following vulnerability has been resolved:
hdlc_ppp: sync per-proto timers before freeing hdlc state
Each PPP control protocol (LCP/IPCP/IPV6CP) embedded in struct ppp
registers a timer via timer_setup(). That struct ppp is the
hdlc->state allocation, which detach_hdlc_protocol() frees with kfree()
in both teardown paths: unregister_hdlc_device() and the re-attach inside
attach_hdlc_protocol().
The ppp proto never registered a .detach callback, so
detach_hdlc_protocol() performs no timer synchronization before the
kfree(). The only cancel, timer_delete(&proto->timer) in ppp_cp_event(),
is partial (it does not wait for a running callback) and only runs on the
->CLOSED transition; ppp_stop()/ppp_close() do not sync either. A
ppp_timer callback already executing (blocked on ppp->lock) survives the
kfree and then dereferences proto->state / ppp->lock in freed memory,
leading to a use-after-free.
Fix this by adding a .detach helper that calls timer_shutdown_sync() on
every per-proto timer. detach_hdlc_protocol() invokes proto->detach(dev)
before kfree(hdlc->state), so timer_shutdown_sync()
now runs on both free paths.
timer_shutdown_sync() is used instead of timer_delete_sync() because the
keepalive path re-arms the timer through add_timer()/mod_timer() and
shutdown blocks any re-activation during teardown.
Initialize the per-protocol timers in ppp_ioctl() when the protocol is
attached, and remove the now-redundant timer_setup() from ppp_start(), so
that the timers are initialized exactly once at attach time and
ppp_timer_release() never operates on uninitialized timer_list
structures. attach_hdlc_protocol() uses kmalloc() (not kzalloc), so
struct ppp's protos[i].timer is uninitialized garbage until the first
timer_setup(); without this init-at-attach, attaching the PPP protocol
without ever bringing the device up would leave timer_shutdown_sync()
operating on uninitialized memory in .detach. Moving the init out of
ppp_start() (which only runs on NETDEV_UP) into the attach path makes the
initialization unconditional and avoids initializing the same timer_list
twice.
This bug was found by static analysis. |
| In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: fix UAF in __blkcg_rstat_flush()
When multiple blkgs in the same blkcg are released concurrently,
a use-after-free can occur. The race happens when one blkg's
__blkcg_rstat_flush() removes another blkg's iostat entries via
llist_del_all(). The second blkg sees an empty list and proceeds
to free itself while the first is still iterating over its entries.
Move the flush from __blkg_release() (RCU callback) to blkg_release()
(before call_rcu). This ensures the RCU grace period waits for any
concurrent flush's rcu_read_lock() section to complete before freeing. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: fix slab-use-after-free Read in tipc_aead_decrypt_done
tipc_aead_decrypt() goes straight from tipc_bearer_hold(b) to
crypto_aead_decrypt(req) without taking a reference on the netns, unlike
the encrypt path. When crypto_aead_decrypt() is offloaded asynchronously
(e.g. the SIMD aead wrapper queuing to cryptd), the cryptd worker runs
tipc_aead_decrypt_done() later. If the bearer's netns is torn down in the
meantime, cleanup_net() -> tipc_exit_net() -> tipc_crypto_stop() frees the
per-netns tipc_crypto, and the completion then reads it:
tipc_aead_decrypt_done() dereferences aead->crypto->stats and
aead->crypto->net, and tipc_crypto_rcv_complete() dereferences
aead->crypto->aead[] and the node table -- reading freed memory.
Decoded KASAN splat (v7.1-rc7, CONFIG_KASAN_INLINE + TIPC + TIPC_CRYPTO):
BUG: KASAN: slab-use-after-free in tipc_aead_decrypt_done (net/tipc/crypto.c:999)
Read of size 8 at addr ffff8881056258a8 by task kworker/u16:2/51
Workqueue: events_unbound
Call Trace:
tipc_aead_decrypt_done (net/tipc/crypto.c:999)
process_one_work (kernel/workqueue.c:3314)
worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
Allocated by task 169:
__kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)
tipc_crypto_start (net/tipc/crypto.c:1502)
tipc_init_net (net/tipc/core.c:72)
ops_init (net/core/net_namespace.c:137)
setup_net (net/core/net_namespace.c:446)
copy_net_ns (net/core/net_namespace.c:579)
create_new_namespaces (kernel/nsproxy.c:132)
__x64_sys_unshare (kernel/fork.c:3316)
do_syscall_64 (arch/x86/entry/syscall_64.c:63)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Freed by task 8:
kfree (mm/slub.c:6566)
tipc_exit_net (net/tipc/core.c:119)
cleanup_net (net/core/net_namespace.c:704)
process_one_work (kernel/workqueue.c:3314)
kthread (kernel/kthread.c:436)
This is the same class of bug that commit e279024617134 ("net/tipc: fix
slab-use-after-free Read in tipc_aead_encrypt_done") fixed for the encrypt
side. The encrypt path takes maybe_get_net(aead->crypto->net) before
crypto_aead_encrypt() and drops it with put_net() on the synchronous
return paths and in tipc_aead_encrypt_done(); the -EINPROGRESS/-EBUSY
return keeps the reference for the async callback to release. The decrypt
path was left without the equivalent guard.
Mirror the encrypt-side fix on the decrypt path: take a net reference
before crypto_aead_decrypt() (failing with -ENODEV and the matching
bearer put if it cannot be acquired), keep it across the
-EINPROGRESS/-EBUSY async return, and drop it with put_net() on the
synchronous success/error return and at the end of
tipc_aead_decrypt_done().
Reproduced under KASAN on v7.1-rc7: a UDP bearer with a cluster key is
flooded with crafted encrypted frames from an unknown peer (driving the
cluster-key decrypt path) while the bearer's netns is repeatedly torn
down. The completion must run asynchronously to outlive
tipc_crypto_stop(); on x86 the stock aesni gcm(aes) now decrypts
synchronously, so the async path was exercised via cryptd offload. The
unguarded aead->crypto dereference in tipc_aead_decrypt_done() is the
unpatched upstream path; tipc_aead_decrypt() still lacks
maybe_get_net(aead->crypto->net), so the completion can outlive the free
on any config where crypto_aead_decrypt() goes async.
Found by 0sec automated security-research tooling (https://0sec.ai). |
| In the Linux kernel, the following vulnerability has been resolved:
pNFS: Fix use-after-free in pnfs_update_layout()
When hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(),
the code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds,
pnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(),
which still references 'lo'. This results in a use-after-free when the
tracepoint accesses lo's fields.
Fix this by moving the tracepoint call before pnfs_put_layout_hdr(lo). |
| In the Linux kernel, the following vulnerability has been resolved:
sched/mmcid: Fix OOB clear_bit when CID is MM_CID_UNSET in fixup path
In mm_cid_fixup_cpus_to_tasks(), when rq->curr has the target mm and
mm_cid.active is set, the CID is checked with cid_in_transit() before
setting the transition bit. In per-CPU mode a newly forked or exec'd
task can be running with mm_cid.cid == MM_CID_UNSET because CIDs are
assigned lazily on schedule-in. With cid_in_transit() the guard passes
for MM_CID_UNSET (no transit bit), converts it to MM_CID_UNSET |
MM_CID_TRANSIT and stores it back; later mm_cid_schedout() feeds this
to clear_bit() with MM_CID_UNSET as the bit number, triggering an
out-of-bounds write.
Symptoms: this is genuine memory corruption, but a bounded out-of-bounds
write, not an arbitrary one. MM_CID_UNSET is the fixed sentinel BIT(31),
so once the bad value reaches mm_cid_schedout() the cid_from_transit_cid()
strip leaves MM_CID_UNSET, which fails the "cid < max_cids" convergence
test and falls into mm_drop_cid() -> clear_bit(MM_CID_UNSET,
mm_cidmask(mm)). The cid bitmap is embedded in the mm_struct slab object
(after cpu_bitmap and mm_cpus_allowed) and is only num_possible_cpus()
bits wide, so clearing bit 31 is a deterministic OOB bit-clear at a
fixed offset of 2^31 / 8 == 256 MiB past the bitmap base. The address is
not attacker-influenced (fixed sentinel -> fixed offset) and the op only
clears a single bit; what sits 256 MiB further along the direct map is
whatever kernel object happens to live there, so this corrupts one bit of
unpredictable kernel memory -- it is not an arbitrary-address or
arbitrary-value write.
It triggers only in per-CPU CID mode, when a CPU is running an active
task of the target mm whose cid is still MM_CID_UNSET -- the
fork()/execve() window before that task's next schedule-in assigns it a
real CID -- and a per-CPU -> per-task fixup walks over it (the mode
fallback driven by a thread exit, sched_mm_cid_exit(), or by the deferred
max_cids recompute in mm_cid_work_fn()).
In practice syzkaller surfaced it as a KASAN use-after-free reported in
__schedule -> mm_cid_switch_to, where the offending clear_bit() is inlined
via mm_cid_schedout() -> mm_drop_cid().
Guard the transition-bit assignment against MM_CID_UNSET, in addition to
the existing cid_in_transit() check, so the bit is only set on a genuine
task-owned CID. A CPU-owned (MM_CID_ONCPU) CID of a running active task
is handled by the cid_on_cpu(pcp->cid) branch above and never reaches
this path, so excluding MM_CID_UNSET (and the already-transitioning case)
is sufficient. |
| In the Linux kernel, the following vulnerability has been resolved:
irqchip/imgpdc: Fix resource leak, add missing chained handler cleanup on remove
The driver allocates domain generic chips using
irq_alloc_domain_generic_chips() during probe and sets up chained
handlers using irq_set_chained_handler_and_data(). However, on driver
removal, the generic chips are not freed and the chained handlers are
not removed.
The generic chips remain on the global gc_list and may later be accessed by
generic interrupt chip suspend, resume, or shutdown callbacks after the
driver has been removed, potentially resulting in a use-after-free and
kernel crash.
The chained handlers that were installed in probe for peripheral and
syswake interrupts are also left dangling, which can lead to spurious
interrupts accessing freed memory.
Fix these issues by:
- Setting IRQ_DOMAIN_FLAG_DESTROY_GC flag in domain->flags, so the
core code automatically removes generic chips when irq_domain_remove()
is called
- Clearing all chained handlers with NULL in pdc_intc_remove() |
| In the Linux kernel, the following vulnerability has been resolved:
rpmsg: char: Fix use-after-free on probe error path
rpmsg_chrdev_probe() stores the newly allocated eptdev in the default
endpoint's priv pointer before calling rpmsg_chrdev_eptdev_add(). If
rpmsg_chrdev_eptdev_add() then fails, its error path frees eptdev while
the default endpoint may still dispatch callbacks with the stale priv
pointer.
Avoid publishing eptdev through the default endpoint until
rpmsg_chrdev_eptdev_add() succeeds. Messages received before the priv
pointer is published should be ignored by rpmsg_ept_cb(). Flow-control
updates can hit rpmsg_ept_flow_cb() in the same window, so make both
callbacks return success when priv is NULL. |
