In the Linux kernel, the following vulnerability has been resolved:
mxser: fix xmit_buf leak in activate when LSR == 0xff
When LSR is 0xff in ->activate() (rather unlike), we return an error.
Provided ->shutdown() is not called when ->activate() fails, nothing
actually frees the buffer in this case.
Fix this by properly freeing the buffer in a designated label. We jump
there also from the "!info->type" if now too.
In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries: Fix use after free in remove_phb_dynamic()
In remove_phb_dynamic() we use &phb->io_resource, after we've called
device_unregister(&host_bridge->dev). But the unregister may have freed
phb, because pcibios_free_controller_deferred() is the release function
for the host_bridge.
If there are no outstanding references when we call device_unregister()
then phb will be freed out from under us.
This has gone mainly unnoticed, but with slub_debug and page_poison
enabled it can lead to a crash:
PID: 7574 TASK: c0000000d492cb80 CPU: 13 COMMAND: "drmgr"
#0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc
#1 [c0000000e4f075d0] oops_end at c000000000029608
#2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4
#3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8
#4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30
Data SLB Access [380] exception frame:
R0: c000000000167250 R1: c0000000e4f07a00 R2: c000000002a46100
R3: c000000002b39ce8 R4: 00000000000000c0 R5: 00000000000000a9
R6: 3894674d000000c0 R7: 0000000000000000 R8: 00000000000000ff
R9: 0000000000000100 R10: 6b6b6b6b6b6b6b6b R11: 0000000000008000
R12: c00000000023da80 R13: c0000009ffd38b00 R14: 0000000000000000
R15: 000000011c87f0f0 R16: 0000000000000006 R17: 0000000000000003
R18: 0000000000000002 R19: 0000000000000004 R20: 0000000000000005
R21: 000000011c87ede8 R22: 000000011c87c5a8 R23: 000000011c87d3a0
R24: 0000000000000000 R25: 0000000000000001 R26: c0000000e4f07cc8
R27: c00000004d1cc400 R28: c0080000031d00e8 R29: c00000004d23d800
R30: c00000004d1d2400 R31: c00000004d1d2540
NIP: c000000000167258 MSR: 8000000000009033 OR3: c000000000e9f474
CTR: 0000000000000000 LR: c000000000167250 XER: 0000000020040003
CCR: 0000000024088420 MQ: 0000000000000000 DAR: 6b6b6b6b6b6b6ba3
DSISR: c0000000e4f07920 Syscall Result: fffffffffffffff2
[NIP : release_resource+56]
[LR : release_resource+48]
#5 [c0000000e4f07a00] release_resource at c000000000167258 (unreliable)
#6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648
#7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io]
#8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io]
#9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c
#10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504
#11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868
#12 [c0000000e4f07c70] new_sync_write at c00000000054339c
#13 [c0000000e4f07d10] vfs_write at c000000000546624
#14 [c0000000e4f07d60] ksys_write at c0000000005469f4
#15 [c0000000e4f07db0] system_call_exception at c000000000030840
#16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168
To avoid it, we can take a reference to the host_bridge->dev until we're
done using phb. Then when we drop the reference the phb will be freed.
In the Linux kernel, the following vulnerability has been resolved:
af_netlink: Fix shift out of bounds in group mask calculation
When a netlink message is received, netlink_recvmsg() fills in the address
of the sender. One of the fields is the 32-bit bitfield nl_groups, which
carries the multicast group on which the message was received. The least
significant bit corresponds to group 1, and therefore the highest group
that the field can represent is 32. Above that, the UB sanitizer flags the
out-of-bounds shift attempts.
Which bits end up being set in such case is implementation defined, but
it's either going to be a wrong non-zero value, or zero, which is at least
not misleading. Make the latter choice deterministic by always setting to 0
for higher-numbered multicast groups.
To get information about membership in groups >= 32, userspace is expected
to use nl_pktinfo control messages[0], which are enabled by NETLINK_PKTINFO
socket option.
[0] https://lwn.net/Articles/147608/
The way to trigger this issue is e.g. through monitoring the BRVLAN group:
# bridge monitor vlan &
# ip link add name br type bridge
Which produces the following citation:
UBSAN: shift-out-of-bounds in net/netlink/af_netlink.c:162:19
shift exponent 32 is too large for 32-bit type 'int'
In the Linux kernel, the following vulnerability has been resolved:
LSM: general protection fault in legacy_parse_param
The usual LSM hook "bail on fail" scheme doesn't work for cases where
a security module may return an error code indicating that it does not
recognize an input. In this particular case Smack sees a mount option
that it recognizes, and returns 0. A call to a BPF hook follows, which
returns -ENOPARAM, which confuses the caller because Smack has processed
its data.
The SELinux hook incorrectly returns 1 on success. There was a time
when this was correct, however the current expectation is that it
return 0 on success. This is repaired.
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: nomadik: Add missing of_node_put() in nmk_pinctrl_probe
This node pointer is returned by of_parse_phandle() with refcount
incremented in this function. Calling of_node_put() to avoid
the refcount leak.
In the Linux kernel, the following vulnerability has been resolved:
clk: qcom: clk-rcg2: Update logic to calculate D value for RCG
The display pixel clock has a requirement on certain newer platforms to
support M/N as (2/3) and the final D value calculated results in
underflow errors.
As the current implementation does not check for D value is within
the accepted range for a given M & N value. Update the logic to
calculate the final D value based on the range.
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on curseg->alloc_type
As Wenqing Liu reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215657
- Overview
UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image
- Reproduce
tested on kernel 5.17-rc4, 5.17-rc6
1. mkdir test_crash
2. cd test_crash
3. unzip tmp2.zip
4. mkdir mnt
5. ./single_test.sh f2fs 2
- Kernel dump
[ 46.434454] loop0: detected capacity change from 0 to 131072
[ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9
[ 46.738319] ================================================================================
[ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2
[ 46.738475] index 231 is out of range for type 'unsigned int [2]'
[ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1
[ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 46.738551] Call Trace:
[ 46.738556] <TASK>
[ 46.738563] dump_stack_lvl+0x47/0x5c
[ 46.738581] ubsan_epilogue+0x5/0x50
[ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80
[ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs]
[ 46.738819] do_write_page+0xef/0x210 [f2fs]
[ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs]
[ 46.739038] __write_node_page+0x2b7/0x920 [f2fs]
[ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs]
[ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]
[ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs]
[ 46.739507] deactivate_locked_super+0x60/0xc0
[ 46.739517] deactivate_super+0x70/0xb0
[ 46.739524] cleanup_mnt+0x11a/0x200
[ 46.739532] __cleanup_mnt+0x16/0x20
[ 46.739538] task_work_run+0x67/0xa0
[ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0
[ 46.739559] syscall_exit_to_user_mode+0x26/0x40
[ 46.739568] do_syscall_64+0x46/0xb0
[ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is we missed to do sanity check on curseg->alloc_type,
result in out-of-bound accessing on sbi->block_count[] array, fix it.
In the Linux kernel, the following vulnerability has been resolved:
ext4: don't BUG if someone dirty pages without asking ext4 first
[un]pin_user_pages_remote is dirtying pages without properly warning
the file system in advance. A related race was noted by Jan Kara in
2018[1]; however, more recently instead of it being a very hard-to-hit
race, it could be reliably triggered by process_vm_writev(2) which was
discovered by Syzbot[2].
This is technically a bug in mm/gup.c, but arguably ext4 is fragile in
that if some other kernel subsystem dirty pages without properly
notifying the file system using page_mkwrite(), ext4 will BUG, while
other file systems will not BUG (although data will still be lost).
So instead of crashing with a BUG, issue a warning (since there may be
potential data loss) and just mark the page as clean to avoid
unprivileged denial of service attacks until the problem can be
properly fixed. More discussion and background can be found in the
thread starting at [2].
[1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
[2] https://lore.kernel.org/r/Yg0m6IjcNmfaSokM@google.com