Security Vulnerabilities - CVEs Published In May 2024
In the Linux kernel, the following vulnerability has been resolved:
idpf: fix kernel panic on unknown packet types
In the very rare case where a packet type is unknown to the driver,
idpf_rx_process_skb_fields would return early without calling
eth_type_trans to set the skb protocol / the network layer handler.
This is especially problematic if tcpdump is running when such a
packet is received, i.e. it would cause a kernel panic.
Instead, call eth_type_trans for every single packet, even when
the packet type is unknown.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in smb2_is_valid_oplock_break()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in cifs_dump_full_key()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in cifs_stats_proc_show()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in cifs_stats_proc_write()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
smb: client: guarantee refcounted children from parent session
Avoid potential use-after-free bugs when walking DFS referrals,
mounting and performing DFS failover by ensuring that all children
from parent @tcon->ses are also refcounted. They're all needed across
the entire DFS mount. Get rid of @tcon->dfs_ses_list while we're at
it, too.
CVSS Score
8.4
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix UAF in smb2_reconnect_server()
The UAF bug is due to smb2_reconnect_server() accessing a session that
is already being teared down by another thread that is executing
__cifs_put_smb_ses(). This can happen when (a) the client has
connection to the server but no session or (b) another thread ends up
setting @ses->ses_status again to something different than
SES_EXITING.
To fix this, we need to make sure to unconditionally set
@ses->ses_status to SES_EXITING and prevent any other threads from
setting a new status while we're still tearing it down.
The following can be reproduced by adding some delay to right after
the ipc is freed in __cifs_put_smb_ses() - which will give
smb2_reconnect_server() worker a chance to run and then accessing
@ses->ipc:
kinit ...
mount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10
[disconnect srv]
ls /mnt/1 &>/dev/null
sleep 30
kdestroy
[reconnect srv]
sleep 10
umount /mnt/1
...
CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed
CIFS: VFS: \\srv Send error in SessSetup = -126
CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed
CIFS: VFS: \\srv Send error in SessSetup = -126
general protection fault, probably for non-canonical address
0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI
CPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39
04/01/2014
Workqueue: cifsiod smb2_reconnect_server [cifs]
RIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0
Code: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad
de 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 <48> 8b 01 48 39 f8 75
7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8
RSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83
RAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b
RDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800
RBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000
R13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000
FS: 0000000000000000(0000) GS:ffff888157c00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
<TASK>
? die_addr+0x36/0x90
? exc_general_protection+0x1c1/0x3f0
? asm_exc_general_protection+0x26/0x30
? __list_del_entry_valid_or_report+0x33/0xf0
__cifs_put_smb_ses+0x1ae/0x500 [cifs]
smb2_reconnect_server+0x4ed/0x710 [cifs]
process_one_work+0x205/0x6b0
worker_thread+0x191/0x360
? __pfx_worker_thread+0x10/0x10
kthread+0xe2/0x110
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
CVSS Score
4.4
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
riscv: process: Fix kernel gp leakage
childregs represents the registers which are active for the new thread
in user context. For a kernel thread, childregs->gp is never used since
the kernel gp is not touched by switch_to. For a user mode helper, the
gp value can be observed in user space after execve or possibly by other
means.
[From the email thread]
The /* Kernel thread */ comment is somewhat inaccurate in that it is also used
for user_mode_helper threads, which exec a user process, e.g. /sbin/init or
when /proc/sys/kernel/core_pattern is a pipe. Such threads do not have
PF_KTHREAD set and are valid targets for ptrace etc. even before they exec.
childregs is the *user* context during syscall execution and it is observable
from userspace in at least five ways:
1. kernel_execve does not currently clear integer registers, so the starting
register state for PID 1 and other user processes started by the kernel has
sp = user stack, gp = kernel __global_pointer$, all other integer registers
zeroed by the memset in the patch comment.
This is a bug in its own right, but I'm unwilling to bet that it is the only
way to exploit the issue addressed by this patch.
2. ptrace(PTRACE_GETREGSET): you can PTRACE_ATTACH to a user_mode_helper thread
before it execs, but ptrace requires SIGSTOP to be delivered which can only
happen at user/kernel boundaries.
3. /proc/*/task/*/syscall: this is perfectly happy to read pt_regs for
user_mode_helpers before the exec completes, but gp is not one of the
registers it returns.
4. PERF_SAMPLE_REGS_USER: LOCKDOWN_PERF normally prevents access to kernel
addresses via PERF_SAMPLE_REGS_INTR, but due to this bug kernel addresses
are also exposed via PERF_SAMPLE_REGS_USER which is permitted under
LOCKDOWN_PERF. I have not attempted to write exploit code.
5. Much of the tracing infrastructure allows access to user registers. I have
not attempted to determine which forms of tracing allow access to user
registers without already allowing access to kernel registers.
CVSS Score
7.1
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
mm/secretmem: fix GUP-fast succeeding on secretmem folios
folio_is_secretmem() currently relies on secretmem folios being LRU
folios, to save some cycles.
However, folios might reside in a folio batch without the LRU flag set, or
temporarily have their LRU flag cleared. Consequently, the LRU flag is
unreliable for this purpose.
In particular, this is the case when secretmem_fault() allocates a fresh
page and calls filemap_add_folio()->folio_add_lru(). The folio might be
added to the per-cpu folio batch and won't get the LRU flag set until the
batch was drained using e.g., lru_add_drain().
Consequently, folio_is_secretmem() might not detect secretmem folios and
GUP-fast can succeed in grabbing a secretmem folio, crashing the kernel
when we would later try reading/writing to the folio, because the folio
has been unmapped from the directmap.
Fix it by removing that unreliable check.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-19
In the Linux kernel, the following vulnerability has been resolved:
riscv: Fix vector state restore in rt_sigreturn()
The RISC-V Vector specification states in "Appendix D: Calling
Convention for Vector State" [1] that "Executing a system call causes
all caller-saved vector registers (v0-v31, vl, vtype) and vstart to
become unspecified.". In the RISC-V kernel this is called "discarding
the vstate".
Returning from a signal handler via the rt_sigreturn() syscall, vector
discard is also performed. However, this is not an issue since the
vector state should be restored from the sigcontext, and therefore not
care about the vector discard.
The "live state" is the actual vector register in the running context,
and the "vstate" is the vector state of the task. A dirty live state,
means that the vstate and live state are not in synch.
When vectorized user_from_copy() was introduced, an bug sneaked in at
the restoration code, related to the discard of the live state.
An example when this go wrong:
1. A userland application is executing vector code
2. The application receives a signal, and the signal handler is
entered.
3. The application returns from the signal handler, using the
rt_sigreturn() syscall.
4. The live vector state is discarded upon entering the
rt_sigreturn(), and the live state is marked as "dirty", indicating
that the live state need to be synchronized with the current
vstate.
5. rt_sigreturn() restores the vstate, except the Vector registers,
from the sigcontext
6. rt_sigreturn() restores the Vector registers, from the sigcontext,
and now the vectorized user_from_copy() is used. The dirty live
state from the discard is saved to the vstate, making the vstate
corrupt.
7. rt_sigreturn() returns to the application, which crashes due to
corrupted vstate.
Note that the vectorized user_from_copy() is invoked depending on the
value of CONFIG_RISCV_ISA_V_UCOPY_THRESHOLD. Default is 768, which
means that vlen has to be larger than 128b for this bug to trigger.
The fix is simply to mark the live state as non-dirty/clean prior
performing the vstate restore.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-19