| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT
lppaca_shared_proc() takes a pointer to the lppaca which is typically
accessed through get_lppaca(). With DEBUG_PREEMPT enabled, this leads
to checking if preemption is enabled, for example:
BUG: using smp_processor_id() in preemptible [00000000] code: grep/10693
caller is lparcfg_data+0x408/0x19a0
CPU: 4 PID: 10693 Comm: grep Not tainted 6.5.0-rc3 #2
Call Trace:
dump_stack_lvl+0x154/0x200 (unreliable)
check_preemption_disabled+0x214/0x220
lparcfg_data+0x408/0x19a0
...
This isn't actually a problem however, as it does not matter which
lppaca is accessed, the shared proc state will be the same.
vcpudispatch_stats_procfs_init() already works around this by disabling
preemption, but the lparcfg code does not, erroring any time
/proc/powerpc/lparcfg is accessed with DEBUG_PREEMPT enabled.
Instead of disabling preemption on the caller side, rework
lppaca_shared_proc() to not take a pointer and instead directly access
the lppaca, bypassing any potential preemption checks.
[mpe: Rework to avoid needing a definition in paca.h and lppaca.h] |
| In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Fix a possible null-pointer dereference in ni_clear()
In a previous commit c1006bd13146, ni->mi.mrec in ni_write_inode()
could be NULL, and thus a NULL check is added for this variable.
However, in the same call stack, ni->mi.mrec can be also dereferenced
in ni_clear():
ntfs_evict_inode(inode)
ni_write_inode(inode, ...)
ni = ntfs_i(inode);
is_rec_inuse(ni->mi.mrec) -> Add a NULL check by previous commit
ni_clear(ntfs_i(inode))
is_rec_inuse(ni->mi.mrec) -> No check
Thus, a possible null-pointer dereference may exist in ni_clear().
To fix it, a NULL check is added in this function. |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/srpt: Add a check for valid 'mad_agent' pointer
When unregistering MAD agent, srpt module has a non-null check
for 'mad_agent' pointer before invoking ib_unregister_mad_agent().
This check can pass if 'mad_agent' variable holds an error value.
The 'mad_agent' can have an error value for a short window when
srpt_add_one() and srpt_remove_one() is executed simultaneously.
In srpt module, added a valid pointer check for 'sport->mad_agent'
before unregistering MAD agent.
This issue can hit when RoCE driver unregisters ib_device
Stack Trace:
------------
BUG: kernel NULL pointer dereference, address: 000000000000004d
PGD 145003067 P4D 145003067 PUD 2324fe067 PMD 0
Oops: 0002 [#1] PREEMPT SMP NOPTI
CPU: 10 PID: 4459 Comm: kworker/u80:0 Kdump: loaded Tainted: P
Hardware name: Dell Inc. PowerEdge R640/06NR82, BIOS 2.5.4 01/13/2020
Workqueue: bnxt_re bnxt_re_task [bnxt_re]
RIP: 0010:_raw_spin_lock_irqsave+0x19/0x40
Call Trace:
ib_unregister_mad_agent+0x46/0x2f0 [ib_core]
IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready
? __schedule+0x20b/0x560
srpt_unregister_mad_agent+0x93/0xd0 [ib_srpt]
srpt_remove_one+0x20/0x150 [ib_srpt]
remove_client_context+0x88/0xd0 [ib_core]
bond0: (slave p2p1): link status definitely up, 100000 Mbps full duplex
disable_device+0x8a/0x160 [ib_core]
bond0: active interface up!
? kernfs_name_hash+0x12/0x80
(NULL device *): Bonding Info Received: rdev: 000000006c0b8247
__ib_unregister_device+0x42/0xb0 [ib_core]
(NULL device *): Master: mode: 4 num_slaves:2
ib_unregister_device+0x22/0x30 [ib_core]
(NULL device *): Slave: id: 105069936 name:p2p1 link:0 state:0
bnxt_re_stopqps_and_ib_uninit+0x83/0x90 [bnxt_re]
bnxt_re_alloc_lag+0x12e/0x4e0 [bnxt_re] |
| In the Linux kernel, the following vulnerability has been resolved:
media: af9005: Fix null-ptr-deref in af9005_i2c_xfer
In af9005_i2c_xfer, msg is controlled by user. When msg[i].buf
is null and msg[i].len is zero, former checks on msg[i].buf would be
passed. Malicious data finally reach af9005_i2c_xfer. If accessing
msg[i].buf[0] without sanity check, null ptr deref would happen.
We add check on msg[i].len to prevent crash.
Similar commit:
commit 0ed554fd769a
("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()") |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: udlfb: Fix endpoint check
The syzbot fuzzer detected a problem in the udlfb driver, caused by an
endpoint not having the expected type:
usb 1-1: Read EDID byte 0 failed: -71
usb 1-1: Unable to get valid EDID from device/display
------------[ cut here ]------------
usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 9 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880
drivers/usb/core/urb.c:504
Modules linked in:
CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted
6.4.0-rc1-syzkaller-00016-ga4422ff22142 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
04/28/2023
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
...
Call Trace:
<TASK>
dlfb_submit_urb+0x92/0x180 drivers/video/fbdev/udlfb.c:1980
dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315
dlfb_ops_set_par+0x2a7/0x8d0 drivers/video/fbdev/udlfb.c:1111
dlfb_usb_probe+0x149a/0x2710 drivers/video/fbdev/udlfb.c:1743
The current approach for this issue failed to catch the problem
because it only checks for the existence of a bulk-OUT endpoint; it
doesn't check whether this endpoint is the one that the driver will
actually use.
We can fix the problem by instead checking that the endpoint used by
the driver does exist and is bulk-OUT. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Address KCSAN report on bpf_lru_list
KCSAN reported a data-race when accessing node->ref.
Although node->ref does not have to be accurate,
take this chance to use a more common READ_ONCE() and WRITE_ONCE()
pattern instead of data_race().
There is an existing bpf_lru_node_is_ref() and bpf_lru_node_set_ref().
This patch also adds bpf_lru_node_clear_ref() to do the
WRITE_ONCE(node->ref, 0) also.
==================================================================
BUG: KCSAN: data-race in __bpf_lru_list_rotate / __htab_lru_percpu_map_update_elem
write to 0xffff888137038deb of 1 bytes by task 11240 on cpu 1:
__bpf_lru_node_move kernel/bpf/bpf_lru_list.c:113 [inline]
__bpf_lru_list_rotate_active kernel/bpf/bpf_lru_list.c:149 [inline]
__bpf_lru_list_rotate+0x1bf/0x750 kernel/bpf/bpf_lru_list.c:240
bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:329 [inline]
bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline]
bpf_lru_pop_free+0x638/0xe20 kernel/bpf/bpf_lru_list.c:499
prealloc_lru_pop kernel/bpf/hashtab.c:290 [inline]
__htab_lru_percpu_map_update_elem+0xe7/0x820 kernel/bpf/hashtab.c:1316
bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313
bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200
generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687
bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534
__sys_bpf+0x338/0x810
__do_sys_bpf kernel/bpf/syscall.c:5096 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5094 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read to 0xffff888137038deb of 1 bytes by task 11241 on cpu 0:
bpf_lru_node_set_ref kernel/bpf/bpf_lru_list.h:70 [inline]
__htab_lru_percpu_map_update_elem+0x2f1/0x820 kernel/bpf/hashtab.c:1332
bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313
bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200
generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687
bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534
__sys_bpf+0x338/0x810
__do_sys_bpf kernel/bpf/syscall.c:5096 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5094 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x01 -> 0x00
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11241 Comm: syz-executor.3 Not tainted 6.3.0-rc7-syzkaller-00136-g6a66fdd29ea1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
================================================================== |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qedf: Fix NULL dereference in error handling
Smatch reported:
drivers/scsi/qedf/qedf_main.c:3056 qedf_alloc_global_queues()
warn: missing unwind goto?
At this point in the function, nothing has been allocated so we can return
directly. In particular the "qedf->global_queues" have not been allocated
so calling qedf_free_global_queues() will lead to a NULL dereference when
we check if (!gl[i]) and "gl" is NULL. |
| In the Linux kernel, the following vulnerability has been resolved:
mtd: spi-nor: Fix shift-out-of-bounds in spi_nor_set_erase_type
spi_nor_set_erase_type() was used either to set or to mask out an erase
type. When we used it to mask out an erase type a shift-out-of-bounds
was hit:
UBSAN: shift-out-of-bounds in drivers/mtd/spi-nor/core.c:2237:24
shift exponent 4294967295 is too large for 32-bit type 'int'
The setting of the size_{shift, mask} and of the opcode are unnecessary
when the erase size is zero, as throughout the code just the erase size
is considered to determine whether an erase type is supported or not.
Setting the opcode to 0xFF was wrong too as nobody guarantees that 0xFF
is an unused opcode. Thus when masking out an erase type, just set the
erase size to zero. This will fix the shift-out-of-bounds.
[ta: refine changes, new commit message, fix compilation error] |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: fix memory leak after finding block group with super blocks
At exclude_super_stripes(), if we happen to find a block group that has
super blocks mapped to it and we are on a zoned filesystem, we error out
as this is not supposed to happen, indicating either a bug or maybe some
memory corruption for example. However we are exiting the function without
freeing the memory allocated for the logical address of the super blocks.
Fix this by freeing the logical address. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: typec: bus: verify partner exists in typec_altmode_attention
Some usb hubs will negotiate DisplayPort Alt mode with the device
but will then negotiate a data role swap after entering the alt
mode. The data role swap causes the device to unregister all alt
modes, however the usb hub will still send Attention messages
even after failing to reregister the Alt Mode. type_altmode_attention
currently does not verify whether or not a device's altmode partner
exists, which results in a NULL pointer error when dereferencing
the typec_altmode and typec_altmode_ops belonging to the altmode
partner.
Verify the presence of a device's altmode partner before sending
the Attention message to the Alt Mode driver. |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/irdma: Fix data race on CQP completion stats
CQP completion statistics is read lockesly in irdma_wait_event and
irdma_check_cqp_progress while it can be updated in the completion
thread irdma_sc_ccq_get_cqe_info on another CPU as KCSAN reports.
Make completion statistics an atomic variable to reflect coherent updates
to it. This will also avoid load/store tearing logic bug potentially
possible by compiler optimizations.
[77346.170861] BUG: KCSAN: data-race in irdma_handle_cqp_op [irdma] / irdma_sc_ccq_get_cqe_info [irdma]
[77346.171383] write to 0xffff8a3250b108e0 of 8 bytes by task 9544 on cpu 4:
[77346.171483] irdma_sc_ccq_get_cqe_info+0x27a/0x370 [irdma]
[77346.171658] irdma_cqp_ce_handler+0x164/0x270 [irdma]
[77346.171835] cqp_compl_worker+0x1b/0x20 [irdma]
[77346.172009] process_one_work+0x4d1/0xa40
[77346.172024] worker_thread+0x319/0x700
[77346.172037] kthread+0x180/0x1b0
[77346.172054] ret_from_fork+0x22/0x30
[77346.172136] read to 0xffff8a3250b108e0 of 8 bytes by task 9838 on cpu 2:
[77346.172234] irdma_handle_cqp_op+0xf4/0x4b0 [irdma]
[77346.172413] irdma_cqp_aeq_cmd+0x75/0xa0 [irdma]
[77346.172592] irdma_create_aeq+0x390/0x45a [irdma]
[77346.172769] irdma_rt_init_hw.cold+0x212/0x85d [irdma]
[77346.172944] irdma_probe+0x54f/0x620 [irdma]
[77346.173122] auxiliary_bus_probe+0x66/0xa0
[77346.173137] really_probe+0x140/0x540
[77346.173154] __driver_probe_device+0xc7/0x220
[77346.173173] driver_probe_device+0x5f/0x140
[77346.173190] __driver_attach+0xf0/0x2c0
[77346.173208] bus_for_each_dev+0xa8/0xf0
[77346.173225] driver_attach+0x29/0x30
[77346.173240] bus_add_driver+0x29c/0x2f0
[77346.173255] driver_register+0x10f/0x1a0
[77346.173272] __auxiliary_driver_register+0xbc/0x140
[77346.173287] irdma_init_module+0x55/0x1000 [irdma]
[77346.173460] do_one_initcall+0x7d/0x410
[77346.173475] do_init_module+0x81/0x2c0
[77346.173491] load_module+0x1232/0x12c0
[77346.173506] __do_sys_finit_module+0x101/0x180
[77346.173522] __x64_sys_finit_module+0x3c/0x50
[77346.173538] do_syscall_64+0x39/0x90
[77346.173553] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[77346.173634] value changed: 0x0000000000000094 -> 0x0000000000000095 |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix deadlock when converting an inline directory in nojournal mode
In no journal mode, ext4_finish_convert_inline_dir() can self-deadlock
by calling ext4_handle_dirty_dirblock() when it already has taken the
directory lock. There is a similar self-deadlock in
ext4_incvert_inline_data_nolock() for data files which we'll fix at
the same time.
A simple reproducer demonstrating the problem:
mke2fs -Fq -t ext2 -O inline_data -b 4k /dev/vdc 64
mount -t ext4 -o dirsync /dev/vdc /vdc
cd /vdc
mkdir file0
cd file0
touch file0
touch file1
attr -s BurnSpaceInEA -V abcde .
touch supercalifragilisticexpialidocious |
| In the Linux kernel, the following vulnerability has been resolved:
ovl: fix null pointer dereference in ovl_get_acl_rcu()
Following process:
P1 P2
path_openat
link_path_walk
may_lookup
inode_permission(rcu)
ovl_permission
acl_permission_check
check_acl
get_cached_acl_rcu
ovl_get_inode_acl
realinode = ovl_inode_real(ovl_inode)
drop_cache
__dentry_kill(ovl_dentry)
iput(ovl_inode)
ovl_destroy_inode(ovl_inode)
dput(oi->__upperdentry)
dentry_kill(upperdentry)
dentry_unlink_inode
upperdentry->d_inode = NULL
ovl_inode_upper
upperdentry = ovl_i_dentry_upper(ovl_inode)
d_inode(upperdentry) // returns NULL
IS_POSIXACL(realinode) // NULL pointer dereference
, will trigger an null pointer dereference at realinode:
[ 205.472797] BUG: kernel NULL pointer dereference, address:
0000000000000028
[ 205.476701] CPU: 2 PID: 2713 Comm: ls Not tainted
6.3.0-12064-g2edfa098e750-dirty #1216
[ 205.478754] RIP: 0010:do_ovl_get_acl+0x5d/0x300
[ 205.489584] Call Trace:
[ 205.489812] <TASK>
[ 205.490014] ovl_get_inode_acl+0x26/0x30
[ 205.490466] get_cached_acl_rcu+0x61/0xa0
[ 205.490908] generic_permission+0x1bf/0x4e0
[ 205.491447] ovl_permission+0x79/0x1b0
[ 205.491917] inode_permission+0x15e/0x2c0
[ 205.492425] link_path_walk+0x115/0x550
[ 205.493311] path_lookupat.isra.0+0xb2/0x200
[ 205.493803] filename_lookup+0xda/0x240
[ 205.495747] vfs_fstatat+0x7b/0xb0
Fetch a reproducer in [Link].
Use the helper ovl_i_path_realinode() to get realinode and then do
non-nullptr checking. |
| In the Linux kernel, the following vulnerability has been resolved:
powerpc/powernv/sriov: perform null check on iov before dereferencing iov
Currently pointer iov is being dereferenced before the null check of iov
which can lead to null pointer dereference errors. Fix this by moving the
iov null check before the dereferencing.
Detected using cppcheck static analysis:
linux/arch/powerpc/platforms/powernv/pci-sriov.c:597:12: warning: Either
the condition '!iov' is redundant or there is possible null pointer
dereference: iov. [nullPointerRedundantCheck]
num_vfs = iov->num_vfs;
^ |
| In the Linux kernel, the following vulnerability has been resolved:
refscale: Fix uninitalized use of wait_queue_head_t
Running the refscale test occasionally crashes the kernel with the
following error:
[ 8569.952896] BUG: unable to handle page fault for address: ffffffffffffffe8
[ 8569.952900] #PF: supervisor read access in kernel mode
[ 8569.952902] #PF: error_code(0x0000) - not-present page
[ 8569.952904] PGD c4b048067 P4D c4b049067 PUD c4b04b067 PMD 0
[ 8569.952910] Oops: 0000 [#1] PREEMPT_RT SMP NOPTI
[ 8569.952916] Hardware name: Dell Inc. PowerEdge R750/0WMWCR, BIOS 1.2.4 05/28/2021
[ 8569.952917] RIP: 0010:prepare_to_wait_event+0x101/0x190
:
[ 8569.952940] Call Trace:
[ 8569.952941] <TASK>
[ 8569.952944] ref_scale_reader+0x380/0x4a0 [refscale]
[ 8569.952959] kthread+0x10e/0x130
[ 8569.952966] ret_from_fork+0x1f/0x30
[ 8569.952973] </TASK>
The likely cause is that init_waitqueue_head() is called after the call to
the torture_create_kthread() function that creates the ref_scale_reader
kthread. Although this init_waitqueue_head() call will very likely
complete before this kthread is created and starts running, it is
possible that the calling kthread will be delayed between the calls to
torture_create_kthread() and init_waitqueue_head(). In this case, the
new kthread will use the waitqueue head before it is properly initialized,
which is not good for the kernel's health and well-being.
The above crash happened here:
static inline void __add_wait_queue(...)
{
:
if (!(wq->flags & WQ_FLAG_PRIORITY)) <=== Crash here
The offset of flags from list_head entry in wait_queue_entry is
-0x18. If reader_tasks[i].wq.head.next is NULL as allocated reader_task
structure is zero initialized, the instruction will try to access address
0xffffffffffffffe8, which is exactly the fault address listed above.
This commit therefore invokes init_waitqueue_head() before creating
the kthread. |
| In the Linux kernel, the following vulnerability has been resolved:
pinctrl: at91-pio4: check return value of devm_kasprintf()
devm_kasprintf() returns a pointer to dynamically allocated memory.
Pointer could be NULL in case allocation fails. Check pointer validity.
Identified with coccinelle (kmerr.cocci script).
Depends-on: 1c4e5c470a56 ("pinctrl: at91: use devm_kasprintf() to avoid potential leaks")
Depends-on: 5a8f9cf269e8 ("pinctrl: at91-pio4: use proper format specifier for unsigned int") |
| In the Linux kernel, the following vulnerability has been resolved:
dm: fix a race condition in retrieve_deps
There's a race condition in the multipath target when retrieve_deps
races with multipath_message calling dm_get_device and dm_put_device.
retrieve_deps walks the list of open devices without holding any lock
but multipath may add or remove devices to the list while it is
running. The end result may be memory corruption or use-after-free
memory access.
See this description of a UAF with multipath_message():
https://listman.redhat.com/archives/dm-devel/2022-October/052373.html
Fix this bug by introducing a new rw semaphore "devices_lock". We grab
devices_lock for read in retrieve_deps and we grab it for write in
dm_get_device and dm_put_device. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation
When btrfs_add_qgroup_relation() is called with invalid qgroup levels
(src >= dst), the function returns -EINVAL directly without freeing the
preallocated qgroup_list structure passed by the caller. This causes a
memory leak because the caller unconditionally sets the pointer to NULL
after the call, preventing any cleanup.
The issue occurs because the level validation check happens before the
mutex is acquired and before any error handling path that would free
the prealloc pointer. On this early return, the cleanup code at the
'out' label (which includes kfree(prealloc)) is never reached.
In btrfs_ioctl_qgroup_assign(), the code pattern is:
prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc);
prealloc = NULL; // Always set to NULL regardless of return value
...
kfree(prealloc); // This becomes kfree(NULL), does nothing
When the level check fails, 'prealloc' is never freed by either the
callee or the caller, resulting in a 64-byte memory leak per failed
operation. This can be triggered repeatedly by an unprivileged user
with access to a writable btrfs mount, potentially exhausting kernel
memory.
Fix this by freeing prealloc before the early return, ensuring prealloc
is always freed on all error paths. |
| In the Linux kernel, the following vulnerability has been resolved:
iommufd: Don't overflow during division for dirty tracking
If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow
to 0 and this triggers divide by 0.
In this case the index should just be 0, so reorganize things to divide
by shift and avoid hitting any overflows. |
| In the Linux kernel, the following vulnerability has been resolved:
futex: Don't leak robust_list pointer on exec race
sys_get_robust_list() and compat_get_robust_list() use ptrace_may_access()
to check if the calling task is allowed to access another task's
robust_list pointer. This check is racy against a concurrent exec() in the
target process.
During exec(), a task may transition from a non-privileged binary to a
privileged one (e.g., setuid binary) and its credentials/memory mappings
may change. If get_robust_list() performs ptrace_may_access() before
this transition, it may erroneously allow access to sensitive information
after the target becomes privileged.
A racy access allows an attacker to exploit a window during which
ptrace_may_access() passes before a target process transitions to a
privileged state via exec().
For example, consider a non-privileged task T that is about to execute a
setuid-root binary. An attacker task A calls get_robust_list(T) while T
is still unprivileged. Since ptrace_may_access() checks permissions
based on current credentials, it succeeds. However, if T begins exec
immediately afterwards, it becomes privileged and may change its memory
mappings. Because get_robust_list() proceeds to access T->robust_list
without synchronizing with exec() it may read user-space pointers from a
now-privileged process.
This violates the intended post-exec access restrictions and could
expose sensitive memory addresses or be used as a primitive in a larger
exploit chain. Consequently, the race can lead to unauthorized
disclosure of information across privilege boundaries and poses a
potential security risk.
Take a read lock on signal->exec_update_lock prior to invoking
ptrace_may_access() and accessing the robust_list/compat_robust_list.
This ensures that the target task's exec state remains stable during the
check, allowing for consistent and synchronized validation of
credentials. |
