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CVE-2024-50250— fsdax: dax_unshare_iter needs to copy entire blocks

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于存在dax_unshare_iter中完整块复制问题。

CVSS 7.8 · High EPSS 0.23% · P13

Affected Version Matrix 11

VendorProduct Version RangeStatus
Linux Linux 1bec6782a25c9b92c203ea7a1b3e3dc6a468cbc4< bdbc96c23197d773a7d1bf03e4f11de593b0ff28 affected
d984648e428bf88cbd94ebe346c73632cb92fffb< 9bc18bb476e50e32e5d08f2734d63d63e0fa528c affected
d984648e428bf88cbd94ebe346c73632cb92fffb< 8e9c0f500b42216ef930f5c0d1703989a451913d affected
d984648e428bf88cbd94ebe346c73632cb92fffb< 50793801fc7f6d08def48754fb0f0706b0cfc394 affected
6.1.113< 6.1.116 affected
6.2 affected
< 6.2 unaffected
6.1.116≤ 6.1.* unaffected
… +3 more rows
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I. Basic Information for CVE-2024-50250

Vulnerability Information
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Vulnerability Title
fsdax: dax_unshare_iter needs to copy entire blocks
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: fsdax: dax_unshare_iter needs to copy entire blocks The code that copies data from srcmap to iomap in dax_unshare_iter is very very broken, which bfoster's recent fsx changes have exposed. If the pos and len passed to dax_file_unshare are not aligned to an fsblock boundary, the iter pos and length in the _iter function will reflect this unalignment. dax_iomap_direct_access always returns a pointer to the start of the kmapped fsdax page, even if its pos argument is in the middle of that page. This is catastrophic for data integrity when iter->pos is not aligned to a page, because daddr/saddr do not point to the same byte in the file as iter->pos. Hence we corrupt user data by copying it to the wrong place. If iter->pos + iomap_length() in the _iter function not aligned to a page, then we fail to copy a full block, and only partially populate the destination block. This is catastrophic for data confidentiality because we expose stale pmem contents. Fix both of these issues by aligning copy_pos/copy_len to a page boundary (remember, this is fsdax so 1 fsblock == 1 base page) so that we always copy full blocks. We're not done yet -- there's no call to invalidate_inode_pages2_range, so programs that have the file range mmap'd will continue accessing the old memory mapping after the file metadata updates have completed. Be careful with the return value -- if the unshare succeeds, we still need to return the number of bytes that the iomap iter thinks we're operating on.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于存在dax_unshare_iter中完整块复制问题。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 1bec6782a25c9b92c203ea7a1b3e3dc6a468cbc4 ~ bdbc96c23197d773a7d1bf03e4f11de593b0ff28 -
Linux Linux 6.2 -

II. Public POCs for CVE-2024-50250

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III. Intelligence Information for CVE-2024-50250

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Patches & Fixes for CVE-2024-50250 (4)

Same Patch Batch · Linux · 2024-11-09 · 49 CVEs total

CVE-2024-50215 8.1 HIGH nvmet-auth: assign dh_key to NULL after kfree_sensitive
CVE-2024-50262 7.8 HIGH bpf: Fix out-of-bounds write in trie_get_next_key()
CVE-2024-50246 7.8 HIGH fs/ntfs3: Add rough attr alloc_size check
CVE-2024-50253 7.8 HIGH bpf: Check the validity of nr_words in bpf_iter_bits_new()
CVE-2024-50225 7.8 HIGH btrfs: fix error propagation of split bios
CVE-2024-50230 7.8 HIGH nilfs2: fix kernel bug due to missing clearing of checked flag
CVE-2024-50237 7.8 HIGH wifi: mac80211: do not pass a stopped vif to the driver in .get_txpower
CVE-2024-50221 7.8 HIGH drm/amd/pm: Vangogh: Fix kernel memory out of bounds write
CVE-2024-50217 7.8 HIGH btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()
CVE-2024-50235 7.8 HIGH wifi: cfg80211: clear wdev->cqm_config pointer on free
CVE-2024-50261 7.8 HIGH macsec: Fix use-after-free while sending the offloading packet
CVE-2024-50241 7.5 HIGH NFSD: Initialize struct nfsd4_copy earlier
CVE-2024-50256 7.5 HIGH netfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6()
CVE-2024-50247 7.3 HIGH fs/ntfs3: Check if more than chunk-size bytes are written
CVE-2024-50248 7.1 HIGH ntfs3: Add bounds checking to mi_enum_attr()
CVE-2024-50257 7.0 HIGH netfilter: Fix use-after-free in get_info()
CVE-2024-50222 7.0 HIGH iov_iter: fix copy_page_from_iter_atomic() if KMAP_LOCAL_FORCE_MAP
CVE-2024-50243 fs/ntfs3: Fix general protection fault in run_is_mapped_full
CVE-2024-50244 fs/ntfs3: Additional check in ni_clear()
CVE-2024-50238 phy: qcom: qmp-usbc: fix NULL-deref on runtime suspend

Showing top 20 of 49 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2024-50250

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