CVE-2025-40243
15h31 +00:00
CVE 설명
hfs: fix KMSAN uninit-value issue in hfs_find_set_zero_bits()
In the Linux kernel, the following vulnerability has been resolved: hfs: fix KMSAN uninit-value issue in hfs_find_set_zero_bits() The syzbot reported issue in hfs_find_set_zero_bits(): ===================================================== BUG: KMSAN: uninit-value in hfs_find_set_zero_bits+0x74d/0xb60 fs/hfs/bitmap.c:45 hfs_find_set_zero_bits+0x74d/0xb60 fs/hfs/bitmap.c:45 hfs_vbm_search_free+0x13c/0x5b0 fs/hfs/bitmap.c:151 hfs_extend_file+0x6a5/0x1b00 fs/hfs/extent.c:408 hfs_get_block+0x435/0x1150 fs/hfs/extent.c:353 __block_write_begin_int+0xa76/0x3030 fs/buffer.c:2151 block_write_begin fs/buffer.c:2262 [inline] cont_write_begin+0x10e1/0x1bc0 fs/buffer.c:2601 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52 cont_expand_zero fs/buffer.c:2528 [inline] cont_write_begin+0x35a/0x1bc0 fs/buffer.c:2591 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52 hfs_file_truncate+0x1d6/0xe60 fs/hfs/extent.c:494 hfs_inode_setattr+0x964/0xaa0 fs/hfs/inode.c:654 notify_change+0x1993/0x1aa0 fs/attr.c:552 do_truncate+0x28f/0x310 fs/open.c:68 do_ftruncate+0x698/0x730 fs/open.c:195 do_sys_ftruncate fs/open.c:210 [inline] __do_sys_ftruncate fs/open.c:215 [inline] __se_sys_ftruncate fs/open.c:213 [inline] __x64_sys_ftruncate+0x11b/0x250 fs/open.c:213 x64_sys_call+0xfe3/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:78 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4154 [inline] slab_alloc_node mm/slub.c:4197 [inline] __kmalloc_cache_noprof+0x7f7/0xed0 mm/slub.c:4354 kmalloc_noprof include/linux/slab.h:905 [inline] hfs_mdb_get+0x1cc8/0x2a90 fs/hfs/mdb.c:175 hfs_fill_super+0x3d0/0xb80 fs/hfs/super.c:337 get_tree_bdev_flags+0x6e3/0x920 fs/super.c:1681 get_tree_bdev+0x38/0x50 fs/super.c:1704 hfs_get_tree+0x35/0x40 fs/hfs/super.c:388 vfs_get_tree+0xb0/0x5c0 fs/super.c:1804 do_new_mount+0x738/0x1610 fs/namespace.c:3902 path_mount+0x6db/0x1e90 fs/namespace.c:4226 do_mount fs/namespace.c:4239 [inline] __do_sys_mount fs/namespace.c:4450 [inline] __se_sys_mount+0x6eb/0x7d0 fs/namespace.c:4427 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4427 x64_sys_call+0xfa7/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:166 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 1 UID: 0 PID: 12609 Comm: syz.1.2692 Not tainted 6.16.0-syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 ===================================================== The HFS_SB(sb)->bitmap buffer is allocated in hfs_mdb_get(): HFS_SB(sb)->bitmap = kmalloc(8192, GFP_KERNEL); Finally, it can trigger the reported issue because kmalloc() doesn't clear the allocated memory. If allocated memory contains only zeros, then everything will work pretty fine. But if the allocated memory contains the "garbage", then it can affect the bitmap operations and it triggers the reported issue. This patch simply exchanges the kmalloc() on kzalloc() with the goal to guarantee the correctness of bitmap operations. Because, newly created allocation bitmap should have all available blocks free. Potentially, initialization bitmap's read operation could not fill the whole allocated memory and "garbage" in the not initialized memory will be the reason of volume coruptions and file system driver bugs.CVE 정보
메트릭
| 메트릭 | 점수 | 심각도 | CVSS 벡터 | 출처 |
|---|---|---|---|---|
| V3.1 | 7.8 | HIGH |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
추가 정보
Base: Exploitabilty MetricsThe Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack Vector This metric reflects the context by which vulnerability exploitation is possible. Local The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Attack Complexity This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Low Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component. Privileges Required This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. Low The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources. User Interaction This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component. None The vulnerable system can be exploited without interaction from any user. Base: Scope MetricsThe Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope. Scope Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs. Unchanged An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority. Base: Impact MetricsThe Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve. Confidentiality Impact This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. High There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server. Integrity Impact This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. High There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component. Availability Impact This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. High There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable). Temporal MetricsThe Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability. Environmental MetricsThese metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability. |
