| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
tpm: Use auth only after NULL check in tpm_buf_check_hmac_response()
Dereference auth after NULL check in tpm_buf_check_hmac_response().
Otherwise, unless tpm2_sessions_init() was called, a call can cause NULL
dereference, when TCG_TPM2_HMAC is enabled.
[jarkko: adjusted the commit message.] |
| In the Linux kernel, the following vulnerability has been resolved:
io_uring: fix error pbuf checking
Syz reports a problem, which boils down to NULL vs IS_ERR inconsistent
error handling in io_alloc_pbuf_ring().
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:__io_remove_buffers+0xac/0x700 io_uring/kbuf.c:341
Call Trace:
<TASK>
io_put_bl io_uring/kbuf.c:378 [inline]
io_destroy_buffers+0x14e/0x490 io_uring/kbuf.c:392
io_ring_ctx_free+0xa00/0x1070 io_uring/io_uring.c:2613
io_ring_exit_work+0x80f/0x8a0 io_uring/io_uring.c:2844
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 |
| In the Linux kernel, the following vulnerability has been resolved:
gpio: pca953x: fix pca953x_irq_bus_sync_unlock race
Ensure that `i2c_lock' is held when setting interrupt latch and mask in
pca953x_irq_bus_sync_unlock() in order to avoid races.
The other (non-probe) call site pca953x_gpio_set_multiple() ensures the
lock is held before calling pca953x_write_regs().
The problem occurred when a request raced against irq_bus_sync_unlock()
approximately once per thousand reboots on an i.MX8MP based system.
* Normal case
0-0022: write register AI|3a {03,02,00,00,01} Input latch P0
0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0
0-0022: write register AI|08 {ff,00,00,00,00} Output P3
0-0022: write register AI|12 {fc,00,00,00,00} Config P3
* Race case
0-0022: write register AI|08 {ff,00,00,00,00} Output P3
0-0022: write register AI|08 {03,02,00,00,01} *** Wrong register ***
0-0022: write register AI|12 {fc,00,00,00,00} Config P3
0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0 |
| In the Linux kernel, the following vulnerability has been resolved:
closures: Change BUG_ON() to WARN_ON()
If a BUG_ON() can be hit in the wild, it shouldn't be a BUG_ON()
For reference, this has popped up once in the CI, and we'll need more
info to debug it:
03240 ------------[ cut here ]------------
03240 kernel BUG at lib/closure.c:21!
03240 kernel BUG at lib/closure.c:21!
03240 Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
03240 Modules linked in:
03240 CPU: 15 PID: 40534 Comm: kworker/u80:1 Not tainted 6.10.0-rc4-ktest-ga56da69799bd #25570
03240 Hardware name: linux,dummy-virt (DT)
03240 Workqueue: btree_update btree_interior_update_work
03240 pstate: 00001005 (nzcv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=--)
03240 pc : closure_put+0x224/0x2a0
03240 lr : closure_put+0x24/0x2a0
03240 sp : ffff0000d12071c0
03240 x29: ffff0000d12071c0 x28: dfff800000000000 x27: ffff0000d1207360
03240 x26: 0000000000000040 x25: 0000000000000040 x24: 0000000000000040
03240 x23: ffff0000c1f20180 x22: 0000000000000000 x21: ffff0000c1f20168
03240 x20: 0000000040000000 x19: ffff0000c1f20140 x18: 0000000000000001
03240 x17: 0000000000003aa0 x16: 0000000000003ad0 x15: 1fffe0001c326974
03240 x14: 0000000000000a1e x13: 0000000000000000 x12: 1fffe000183e402d
03240 x11: ffff6000183e402d x10: dfff800000000000 x9 : ffff6000183e402e
03240 x8 : 0000000000000001 x7 : 00009fffe7c1bfd3 x6 : ffff0000c1f2016b
03240 x5 : ffff0000c1f20168 x4 : ffff6000183e402e x3 : ffff800081391954
03240 x2 : 0000000000000001 x1 : 0000000000000000 x0 : 00000000a8000000
03240 Call trace:
03240 closure_put+0x224/0x2a0
03240 bch2_check_for_deadlock+0x910/0x1028
03240 bch2_six_check_for_deadlock+0x1c/0x30
03240 six_lock_slowpath.isra.0+0x29c/0xed0
03240 six_lock_ip_waiter+0xa8/0xf8
03240 __bch2_btree_node_lock_write+0x14c/0x298
03240 bch2_trans_lock_write+0x6d4/0xb10
03240 __bch2_trans_commit+0x135c/0x5520
03240 btree_interior_update_work+0x1248/0x1c10
03240 process_scheduled_works+0x53c/0xd90
03240 worker_thread+0x370/0x8c8
03240 kthread+0x258/0x2e8
03240 ret_from_fork+0x10/0x20
03240 Code: aa1303e0 d63f0020 a94363f7 17ffff8c (d4210000)
03240 ---[ end trace 0000000000000000 ]---
03240 Kernel panic - not syncing: Oops - BUG: Fatal exception
03240 SMP: stopping secondary CPUs
03241 SMP: failed to stop secondary CPUs 13,15
03241 Kernel Offset: disabled
03241 CPU features: 0x00,00000003,80000008,4240500b
03241 Memory Limit: none
03241 ---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]---
03246 ========= FAILED TIMEOUT copygc_torture_no_checksum in 7200s |
| In the Linux kernel, the following vulnerability has been resolved:
mm: page_ref: remove folio_try_get_rcu()
The below bug was reported on a non-SMP kernel:
[ 275.267158][ T4335] ------------[ cut here ]------------
[ 275.267949][ T4335] kernel BUG at include/linux/page_ref.h:275!
[ 275.268526][ T4335] invalid opcode: 0000 [#1] KASAN PTI
[ 275.269001][ T4335] CPU: 0 PID: 4335 Comm: trinity-c3 Not tainted 6.7.0-rc4-00061-gefa7df3e3bb5 #1
[ 275.269787][ T4335] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 275.270679][ T4335] RIP: 0010:try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.272813][ T4335] RSP: 0018:ffffc90005dcf650 EFLAGS: 00010202
[ 275.273346][ T4335] RAX: 0000000000000246 RBX: ffffea00066e0000 RCX: 0000000000000000
[ 275.274032][ T4335] RDX: fffff94000cdc007 RSI: 0000000000000004 RDI: ffffea00066e0034
[ 275.274719][ T4335] RBP: ffffea00066e0000 R08: 0000000000000000 R09: fffff94000cdc006
[ 275.275404][ T4335] R10: ffffea00066e0037 R11: 0000000000000000 R12: 0000000000000136
[ 275.276106][ T4335] R13: ffffea00066e0034 R14: dffffc0000000000 R15: ffffea00066e0008
[ 275.276790][ T4335] FS: 00007fa2f9b61740(0000) GS:ffffffff89d0d000(0000) knlGS:0000000000000000
[ 275.277570][ T4335] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 275.278143][ T4335] CR2: 00007fa2f6c00000 CR3: 0000000134b04000 CR4: 00000000000406f0
[ 275.278833][ T4335] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 275.279521][ T4335] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 275.280201][ T4335] Call Trace:
[ 275.280499][ T4335] <TASK>
[ 275.280751][ T4335] ? die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434 arch/x86/kernel/dumpstack.c:447)
[ 275.281087][ T4335] ? do_trap (arch/x86/kernel/traps.c:112 arch/x86/kernel/traps.c:153)
[ 275.281463][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.281884][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.282300][ T4335] ? do_error_trap (arch/x86/kernel/traps.c:174)
[ 275.282711][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.283129][ T4335] ? handle_invalid_op (arch/x86/kernel/traps.c:212)
[ 275.283561][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.283990][ T4335] ? exc_invalid_op (arch/x86/kernel/traps.c:264)
[ 275.284415][ T4335] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:568)
[ 275.284859][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.285278][ T4335] try_grab_folio (mm/gup.c:148)
[ 275.285684][ T4335] __get_user_pages (mm/gup.c:1297 (discriminator 1))
[ 275.286111][ T4335] ? __pfx___get_user_pages (mm/gup.c:1188)
[ 275.286579][ T4335] ? __pfx_validate_chain (kernel/locking/lockdep.c:3825)
[ 275.287034][ T4335] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 1))
[ 275.287416][ T4335] __gup_longterm_locked (mm/gup.c:1509 mm/gup.c:2209)
[ 275.288192][ T4335] ? __pfx___gup_longterm_locked (mm/gup.c:2204)
[ 275.288697][ T4335] ? __pfx_lock_acquire (kernel/locking/lockdep.c:5722)
[ 275.289135][ T4335] ? __pfx___might_resched (kernel/sched/core.c:10106)
[ 275.289595][ T4335] pin_user_pages_remote (mm/gup.c:3350)
[ 275.290041][ T4335] ? __pfx_pin_user_pages_remote (mm/gup.c:3350)
[ 275.290545][ T4335] ? find_held_lock (kernel/locking/lockdep.c:5244 (discriminator 1))
[ 275.290961][ T4335] ? mm_access (kernel/fork.c:1573)
[ 275.291353][ T4335] process_vm_rw_single_vec+0x142/0x360
[ 275.291900][ T4335] ? __pfx_process_vm_rw_single_vec+0x10/0x10
[ 275.292471][ T4335] ? mm_access (kernel/fork.c:1573)
[ 275.292859][ T4335] process_vm_rw_core+0x272/0x4e0
[ 275.293384][ T4335] ? hlock_class (a
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: add missing lock protection when polling
Add missing lock protection in poll routine when iterating xarray,
otherwise:
Even with RCU read lock held, only the slot of the radix tree is
ensured to be pinned there, while the data structure (e.g. struct
cachefiles_req) stored in the slot has no such guarantee. The poll
routine will iterate the radix tree and dereference cachefiles_req
accordingly. Thus RCU read lock is not adequate in this case and
spinlock is needed here. |
| In the Linux kernel, the following vulnerability has been resolved:
spi: don't unoptimize message in spi_async()
Calling spi_maybe_unoptimize_message() in spi_async() is wrong because
the message is likely to be in the queue and not transferred yet. This
can corrupt the message while it is being used by the controller driver.
spi_maybe_unoptimize_message() is already called in the correct place
in spi_finalize_current_message() to balance the call to
spi_maybe_optimize_message() in spi_async(). |
| In the Linux kernel, the following vulnerability has been resolved:
tty: serial: ma35d1: Add a NULL check for of_node
The pdev->dev.of_node can be NULL if the "serial" node is absent.
Add a NULL check to return an error in such cases. |
| In the Linux kernel, the following vulnerability has been resolved:
wireguard: allowedips: avoid unaligned 64-bit memory accesses
On the parisc platform, the kernel issues kernel warnings because
swap_endian() tries to load a 128-bit IPv6 address from an unaligned
memory location:
Kernel: unaligned access to 0x55f4688c in wg_allowedips_insert_v6+0x2c/0x80 [wireguard] (iir 0xf3010df)
Kernel: unaligned access to 0x55f46884 in wg_allowedips_insert_v6+0x38/0x80 [wireguard] (iir 0xf2010dc)
Avoid such unaligned memory accesses by instead using the
get_unaligned_be64() helper macro.
[Jason: replace src[8] in original patch with src+8] |
| In the Linux kernel, the following vulnerability has been resolved:
net, sunrpc: Remap EPERM in case of connection failure in xs_tcp_setup_socket
When using a BPF program on kernel_connect(), the call can return -EPERM. This
causes xs_tcp_setup_socket() to loop forever, filling up the syslog and causing
the kernel to potentially freeze up.
Neil suggested:
This will propagate -EPERM up into other layers which might not be ready
to handle it. It might be safer to map EPERM to an error we would be more
likely to expect from the network system - such as ECONNREFUSED or ENETDOWN.
ECONNREFUSED as error seems reasonable. For programs setting a different error
can be out of reach (see handling in 4fbac77d2d09) in particular on kernels
which do not have f10d05966196 ("bpf: Make BPF_PROG_RUN_ARRAY return -err
instead of allow boolean"), thus given that it is better to simply remap for
consistent behavior. UDP does handle EPERM in xs_udp_send_request(). |
| In the Linux kernel, the following vulnerability has been resolved:
Revert "sched/fair: Make sure to try to detach at least one movable task"
This reverts commit b0defa7ae03ecf91b8bfd10ede430cff12fcbd06.
b0defa7ae03ec changed the load balancing logic to ignore env.max_loop if
all tasks examined to that point were pinned. The goal of the patch was
to make it more likely to be able to detach a task buried in a long list
of pinned tasks. However, this has the unfortunate side effect of
creating an O(n) iteration in detach_tasks(), as we now must fully
iterate every task on a cpu if all or most are pinned. Since this load
balance code is done with rq lock held, and often in softirq context, it
is very easy to trigger hard lockups. We observed such hard lockups with
a user who affined O(10k) threads to a single cpu.
When I discussed this with Vincent he initially suggested that we keep
the limit on the number of tasks to detach, but increase the number of
tasks we can search. However, after some back and forth on the mailing
list, he recommended we instead revert the original patch, as it seems
likely no one was actually getting hit by the original issue. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/filemap: make MAX_PAGECACHE_ORDER acceptable to xarray
Patch series "mm/filemap: Limit page cache size to that supported by
xarray", v2.
Currently, xarray can't support arbitrary page cache size. More details
can be found from the WARN_ON() statement in xas_split_alloc(). In our
test whose code is attached below, we hit the WARN_ON() on ARM64 system
where the base page size is 64KB and huge page size is 512MB. The issue
was reported long time ago and some discussions on it can be found here
[1].
[1] https://www.spinics.net/lists/linux-xfs/msg75404.html
In order to fix the issue, we need to adjust MAX_PAGECACHE_ORDER to one
supported by xarray and avoid PMD-sized page cache if needed. The code
changes are suggested by David Hildenbrand.
PATCH[1] adjusts MAX_PAGECACHE_ORDER to that supported by xarray
PATCH[2-3] avoids PMD-sized page cache in the synchronous readahead path
PATCH[4] avoids PMD-sized page cache for shmem files if needed
Test program
============
# cat test.c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#define TEST_XFS_FILENAME "/tmp/data"
#define TEST_SHMEM_FILENAME "/dev/shm/data"
#define TEST_MEM_SIZE 0x20000000
int main(int argc, char **argv)
{
const char *filename;
int fd = 0;
void *buf = (void *)-1, *p;
int pgsize = getpagesize();
int ret;
if (pgsize != 0x10000) {
fprintf(stderr, "64KB base page size is required\n");
return -EPERM;
}
system("echo force > /sys/kernel/mm/transparent_hugepage/shmem_enabled");
system("rm -fr /tmp/data");
system("rm -fr /dev/shm/data");
system("echo 1 > /proc/sys/vm/drop_caches");
/* Open xfs or shmem file */
filename = TEST_XFS_FILENAME;
if (argc > 1 && !strcmp(argv[1], "shmem"))
filename = TEST_SHMEM_FILENAME;
fd = open(filename, O_CREAT | O_RDWR | O_TRUNC);
if (fd < 0) {
fprintf(stderr, "Unable to open <%s>\n", filename);
return -EIO;
}
/* Extend file size */
ret = ftruncate(fd, TEST_MEM_SIZE);
if (ret) {
fprintf(stderr, "Error %d to ftruncate()\n", ret);
goto cleanup;
}
/* Create VMA */
buf = mmap(NULL, TEST_MEM_SIZE,
PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf == (void *)-1) {
fprintf(stderr, "Unable to mmap <%s>\n", filename);
goto cleanup;
}
fprintf(stdout, "mapped buffer at 0x%p\n", buf);
ret = madvise(buf, TEST_MEM_SIZE, MADV_HUGEPAGE);
if (ret) {
fprintf(stderr, "Unable to madvise(MADV_HUGEPAGE)\n");
goto cleanup;
}
/* Populate VMA */
ret = madvise(buf, TEST_MEM_SIZE, MADV_POPULATE_WRITE);
if (ret) {
fprintf(stderr, "Error %d to madvise(MADV_POPULATE_WRITE)\n", ret);
goto cleanup;
}
/* Punch the file to enforce xarray split */
ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
TEST_MEM_SIZE - pgsize, pgsize);
if (ret)
fprintf(stderr, "Error %d to fallocate()\n", ret);
cleanup:
if (buf != (void *)-1)
munmap(buf, TEST_MEM_SIZE);
if (fd > 0)
close(fd);
return 0;
}
# gcc test.c -o test
# cat /proc/1/smaps | grep KernelPageSize | head -n 1
KernelPageSize: 64 kB
# ./test shmem
:
------------[ cut here ]------------
WARNING: CPU: 17 PID: 5253 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 nf_tables rfkill nfnetlink vfat fat virtio_balloon \
drm fuse xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 \
virtio_net sha1_ce net_failover failover virtio_console virtio_blk \
dimlib virtio_mmio
CPU: 17 PID: 5253 Comm: test Kdump: loaded Tainted: G W 6.10.0-rc5-gavin+ #12
Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-1.el9 05/24/2024
pstate: 83400005 (Nzcv daif +PAN -UAO +TC
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: sdhci: Fix max_seg_size for 64KiB PAGE_SIZE
blk_queue_max_segment_size() ensured:
if (max_size < PAGE_SIZE)
max_size = PAGE_SIZE;
whereas:
blk_validate_limits() makes it an error:
if (WARN_ON_ONCE(lim->max_segment_size < PAGE_SIZE))
return -EINVAL;
The change from one to the other, exposed sdhci which was setting maximum
segment size too low in some circumstances.
Fix the maximum segment size when it is too low. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/shmem: disable PMD-sized page cache if needed
For shmem files, it's possible that PMD-sized page cache can't be
supported by xarray. For example, 512MB page cache on ARM64 when the base
page size is 64KB can't be supported by xarray. It leads to errors as the
following messages indicate when this sort of xarray entry is split.
WARNING: CPU: 34 PID: 7578 at lib/xarray.c:1025 xas_split_alloc+0xf8/0x128
Modules linked in: binfmt_misc 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 sha1_ce virtio_net \
net_failover virtio_console virtio_blk failover dimlib virtio_mmio
CPU: 34 PID: 7578 Comm: test Kdump: loaded Tainted: G W 6.10.0-rc5-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+0x1c4/0x720
sp : ffff8000882af5f0
x29: ffff8000882af5f0 x28: ffff8000882af650 x27: ffff8000882af768
x26: 0000000000000cc0 x25: 000000000000000d x24: ffff00010625b858
x23: ffff8000882af650 x22: ffffffdfc0900000 x21: 0000000000000000
x20: 0000000000000000 x19: ffffffdfc0900000 x18: 0000000000000000
x17: 0000000000000000 x16: 0000018000000000 x15: 52f8004000000000
x14: 0000e00000000000 x13: 0000000000002000 x12: 0000000000000020
x11: 52f8000000000000 x10: 52f8e1c0ffff6000 x9 : ffffbeb9619a681c
x8 : 0000000000000003 x7 : 0000000000000000 x6 : ffff00010b02ddb0
x5 : ffffbeb96395e378 x4 : 0000000000000000 x3 : 0000000000000cc0
x2 : 000000000000000d x1 : 000000000000000c x0 : 0000000000000000
Call trace:
xas_split_alloc+0xf8/0x128
split_huge_page_to_list_to_order+0x1c4/0x720
truncate_inode_partial_folio+0xdc/0x160
shmem_undo_range+0x2bc/0x6a8
shmem_fallocate+0x134/0x430
vfs_fallocate+0x124/0x2e8
ksys_fallocate+0x4c/0xa0
__arm64_sys_fallocate+0x24/0x38
invoke_syscall.constprop.0+0x7c/0xd8
do_el0_svc+0xb4/0xd0
el0_svc+0x44/0x1d8
el0t_64_sync_handler+0x134/0x150
el0t_64_sync+0x17c/0x180
Fix it by disabling PMD-sized page cache when HPAGE_PMD_ORDER is larger
than MAX_PAGECACHE_ORDER. As Matthew Wilcox pointed, the page cache in a
shmem file isn't represented by a multi-index entry and doesn't have this
limitation when the xarry entry is split until commit 6b24ca4a1a8d ("mm:
Use multi-index entries in the page cache"). |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fail bpf_timer_cancel when callback is being cancelled
Given a schedule:
timer1 cb timer2 cb
bpf_timer_cancel(timer2); bpf_timer_cancel(timer1);
Both bpf_timer_cancel calls would wait for the other callback to finish
executing, introducing a lockup.
Add an atomic_t count named 'cancelling' in bpf_hrtimer. This keeps
track of all in-flight cancellation requests for a given BPF timer.
Whenever cancelling a BPF timer, we must check if we have outstanding
cancellation requests, and if so, we must fail the operation with an
error (-EDEADLK) since cancellation is synchronous and waits for the
callback to finish executing. This implies that we can enter a deadlock
situation involving two or more timer callbacks executing in parallel
and attempting to cancel one another.
Note that we avoid incrementing the cancelling counter for the target
timer (the one being cancelled) if bpf_timer_cancel is not invoked from
a callback, to avoid spurious errors. The whole point of detecting
cur->cancelling and returning -EDEADLK is to not enter a busy wait loop
(which may or may not lead to a lockup). This does not apply in case the
caller is in a non-callback context, the other side can continue to
cancel as it sees fit without running into errors.
Background on prior attempts:
Earlier versions of this patch used a bool 'cancelling' bit and used the
following pattern under timer->lock to publish cancellation status.
lock(t->lock);
t->cancelling = true;
mb();
if (cur->cancelling)
return -EDEADLK;
unlock(t->lock);
hrtimer_cancel(t->timer);
t->cancelling = false;
The store outside the critical section could overwrite a parallel
requests t->cancelling assignment to true, to ensure the parallely
executing callback observes its cancellation status.
It would be necessary to clear this cancelling bit once hrtimer_cancel
is done, but lack of serialization introduced races. Another option was
explored where bpf_timer_start would clear the bit when (re)starting the
timer under timer->lock. This would ensure serialized access to the
cancelling bit, but may allow it to be cleared before in-flight
hrtimer_cancel has finished executing, such that lockups can occur
again.
Thus, we choose an atomic counter to keep track of all outstanding
cancellation requests and use it to prevent lockups in case callbacks
attempt to cancel each other while executing in parallel. |
| In the Linux kernel, the following vulnerability has been resolved:
s390/mm: Add NULL pointer check to crst_table_free() base_crst_free()
crst_table_free() used to work with NULL pointers before the conversion
to ptdescs. Since crst_table_free() can be called with a NULL pointer
(error handling in crst_table_upgrade() add an explicit check.
Also add the same check to base_crst_free() for consistency reasons.
In real life this should not happen, since order two GFP_KERNEL
allocations will not fail, unless FAIL_PAGE_ALLOC is enabled and used. |
| In the Linux kernel, the following vulnerability has been resolved:
mm: fix crashes from deferred split racing folio migration
Even on 6.10-rc6, I've been seeing elusive "Bad page state"s (often on
flags when freeing, yet the flags shown are not bad: PG_locked had been
set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from
deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN
symptoms implying double free by deferred split and large folio migration.
6.7 commit 9bcef5973e31 ("mm: memcg: fix split queue list crash when large
folio migration") was right to fix the memcg-dependent locking broken in
85ce2c517ade ("memcontrol: only transfer the memcg data for migration"),
but missed a subtlety of deferred_split_scan(): it moves folios to its own
local list to work on them without split_queue_lock, during which time
folio->_deferred_list is not empty, but even the "right" lock does nothing
to secure the folio and the list it is on.
Fortunately, deferred_split_scan() is careful to use folio_try_get(): so
folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()
while the old folio's reference count is temporarily frozen to 0 - adding
such a freeze in the !mapping case too (originally, folio lock and
unmapping and no swap cache left an anon folio unreachable, so no freezing
was needed there: but the deferred split queue offers a way to reach it). |
| In the Linux kernel, the following vulnerability has been resolved:
filemap: replace pte_offset_map() with pte_offset_map_nolock()
The vmf->ptl in filemap_fault_recheck_pte_none() is still set from
handle_pte_fault(). But at the same time, we did a pte_unmap(vmf->pte).
After a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table
may be racily changed and vmf->ptl maybe fails to protect the actual page
table. Fix this by replacing pte_offset_map() with
pte_offset_map_nolock().
As David said, the PTL pointer might be stale so if we continue to use
it infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, if
the PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoid
unnecessary major faults in filemap_fault()") might reappear. |
| In the Linux kernel, the following vulnerability has been resolved:
libceph: fix race between delayed_work() and ceph_monc_stop()
The way the delayed work is handled in ceph_monc_stop() is prone to
races with mon_fault() and possibly also finish_hunting(). Both of
these can requeue the delayed work which wouldn't be canceled by any of
the following code in case that happens after cancel_delayed_work_sync()
runs -- __close_session() doesn't mess with the delayed work in order
to avoid interfering with the hunting interval logic. This part was
missed in commit b5d91704f53e ("libceph: behave in mon_fault() if
cur_mon < 0") and use-after-free can still ensue on monc and objects
that hang off of it, with monc->auth and monc->monmap being
particularly susceptible to quickly being reused.
To fix this:
- clear monc->cur_mon and monc->hunting as part of closing the session
in ceph_monc_stop()
- bail from delayed_work() if monc->cur_mon is cleared, similar to how
it's done in mon_fault() and finish_hunting() (based on monc->hunting)
- call cancel_delayed_work_sync() after the session is closed |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: fix calc_available_free_space() for zoned mode
calc_available_free_space() returns the total size of metadata (or
system) block groups, which can be allocated from unallocated disk
space. The logic is wrong on zoned mode in two places.
First, the calculation of data_chunk_size is wrong. We always allocate
one zone as one chunk, and no partial allocation of a zone. So, we
should use zone_size (= data_sinfo->chunk_size) as it is.
Second, the result "avail" may not be zone aligned. Since we always
allocate one zone as one chunk on zoned mode, returning non-zone size
aligned bytes will result in less pressure on the async metadata reclaim
process.
This is serious for the nearly full state with a large zone size device.
Allowing over-commit too much will result in less async reclaim work and
end up in ENOSPC. We can align down to the zone size to avoid that. |
