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CVE-2024-35877— x86/mm/pat: fix VM_PAT handling in COW mappings

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 x86/mm/pat 模块存在漏洞。

AI Predicted 5.5 Difficulty: Easy EPSS 0.25% · P16

Possible ATT&CK Techniques 1 AI

T1057 · Process Discovery

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 5899329b19100c0b82dc78e9b21ed8b920c9ffb3< f18681daaec9665a15c5e7e0f591aad5d0ac622b affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< 09e6bb53217bf388a0d2fd7fb21e74ab9dffc173 affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4 affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< 7cfee26d1950250b14c5cb0a37b142f3fcc6396a affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< 97e93367e82752e475a33839a80b33bdbef1209f affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< 51b7841f3fe84606ec0bd8da859d22e05e5419ec affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< 1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6 affected
5899329b19100c0b82dc78e9b21ed8b920c9ffb3< 04c35ab3bdae7fefbd7c7a7355f29fa03a035221 affected
… +10 more rows
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I. Basic Information for CVE-2024-35877

Vulnerability Information
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Vulnerability Title
x86/mm/pat: fix VM_PAT handling in COW mappings
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: x86/mm/pat: fix VM_PAT handling in COW mappings PAT handling won't do the right thing in COW mappings: the first PTE (or, in fact, all PTEs) can be replaced during write faults to point at anon folios. Reliably recovering the correct PFN and cachemode using follow_phys() from PTEs will not work in COW mappings. Using follow_phys(), we might just get the address+protection of the anon folio (which is very wrong), or fail on swap/nonswap entries, failing follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and track_pfn_copy(), not properly calling free_pfn_range(). In free_pfn_range(), we either wouldn't call memtype_free() or would call it with the wrong range, possibly leaking memory. To fix that, let's update follow_phys() to refuse returning anon folios, and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings if we run into that. We will now properly handle untrack_pfn() with COW mappings, where we don't need the cachemode. We'll have to fail fork()->track_pfn_copy() if the first page was replaced by an anon folio, though: we'd have to store the cachemode in the VMA to make this work, likely growing the VMA size. For now, lets keep it simple and let track_pfn_copy() just fail in that case: it would have failed in the past with swap/nonswap entries already, and it would have done the wrong thing with anon folios. Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn(): <--- C reproducer ---> #include <stdio.h> #include <sys/mman.h> #include <unistd.h> #include <liburing.h> int main(void) { struct io_uring_params p = {}; int ring_fd; size_t size; char *map; ring_fd = io_uring_setup(1, &p); if (ring_fd < 0) { perror("io_uring_setup"); return 1; } size = p.sq_off.array + p.sq_entries * sizeof(unsigned); /* Map the submission queue ring MAP_PRIVATE */ map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, ring_fd, IORING_OFF_SQ_RING); if (map == MAP_FAILED) { perror("mmap"); return 1; } /* We have at least one page. Let's COW it. */ *map = 0; pause(); return 0; } <--- C reproducer ---> On a system with 16 GiB RAM and swap configured: # ./iouring & # memhog 16G # killall iouring [ 301.552930] ------------[ cut here ]------------ [ 301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100 [ 301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g [ 301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1 [ 301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4 [ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100 [ 301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000 [ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282 [ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047 [ 301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200 [ 301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000 [ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000 [ 301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000 [ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000 [ 301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0 [ 301.565725] PKRU: 55555554 [ 301.565944] Call Trace: [ 301.566148] <TASK> [ 301.566325] ? untrack_pfn+0xf4/0x100 [ 301.566618] ? __warn+0x81/0x130 [ 301.566876] ? untrack_pfn+0xf4/0x100 [ 3 ---truncated---
Source: CVE Program / CVE List V5
CVSS Information
N/A
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 x86/mm/pat 模块存在漏洞。
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 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 ~ f18681daaec9665a15c5e7e0f591aad5d0ac622b -
Linux Linux 2.6.29 -

II. Public POCs for CVE-2024-35877

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III. Intelligence Information for CVE-2024-35877

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Mailing List Discussions for CVE-2024-35877 (2)

Other References for CVE-2024-35877 (6)

Same Patch Batch · Linux · 2024-05-19 · 82 CVEs total

CVE-2024-35861 9.8 CRITICAL smb: client: fix potential UAF in cifs_signal_cifsd_for_reconnect()
CVE-2024-35862 9.8 CRITICAL smb: client: fix potential UAF in smb2_is_network_name_deleted()
CVE-2024-35863 9.8 CRITICAL smb: client: fix potential UAF in is_valid_oplock_break()
CVE-2024-35864 9.8 CRITICAL smb: client: fix potential UAF in smb2_is_valid_lease_break()
CVE-2024-35865 9.8 CRITICAL smb: client: fix potential UAF in smb2_is_valid_oplock_break()
CVE-2024-35884 9.8 CRITICAL udp: do not accept non-tunnel GSO skbs landing in a tunnel
CVE-2024-35870 9.8 CRITICAL smb: client: fix UAF in smb2_reconnect_server()
CVE-2024-35869 9.8 CRITICAL smb: client: guarantee refcounted children from parent session
CVE-2024-35939 9.3 CRITICAL dma-direct: Leak pages on dma_set_decrypted() failure
CVE-2024-35887 8.8 HIGH ax25: fix use-after-free bugs caused by ax25_ds_del_timer
CVE-2024-35915 8.8 HIGH nfc: nci: Fix uninit-value in nci_dev_up and nci_ntf_packet
CVE-2024-35889 8.6 HIGH idpf: fix kernel panic on unknown packet types
CVE-2024-35875 8.4 HIGH x86/coco: Require seeding RNG with RDRAND on CoCo systems
CVE-2024-35937 8.1 HIGH wifi: cfg80211: check A-MSDU format more carefully
CVE-2024-35919 7.8 HIGH media: mediatek: vcodec: adding lock to protect encoder context list
CVE-2024-35931 7.8 HIGH drm/amdgpu: Skip do PCI error slot reset during RAS recovery
CVE-2024-35890 7.8 HIGH gro: fix ownership transfer
CVE-2024-35920 7.8 HIGH media: mediatek: vcodec: adding lock to protect decoder context list
CVE-2024-35921 7.8 HIGH media: mediatek: vcodec: Fix oops when HEVC init fails
CVE-2024-35897 7.8 HIGH netfilter: nf_tables: discard table flag update with pending basechain deletion

Showing top 20 of 82 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2024-35877

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