{"id":"CVE-2022-48689","state":"PUBLISHED","title":"tcp: TX zerocopy should not sense pfmemalloc status","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: TX zerocopy should not sense pfmemalloc status\n\nWe got a recent syzbot report [1] showing a possible misuse\nof pfmemalloc page status in TCP zerocopy paths.\n\nIndeed, for pages coming from user space or other layers,\nusing page_is_pfmemalloc() is moot, and possibly could give\nfalse positives.\n\nThere has been attempts to make page_is_pfmemalloc() more robust,\nbut not using it in the first place in this context is probably better,\nremoving cpu cycles.\n\nNote to stable teams :\n\nYou need to backport 84ce071e38a6 (\"net: introduce\n__skb_fill_page_desc_noacc\") as a prereq.\n\nRace is more probable after commit c07aea3ef4d4\n(\"mm: add a signature in struct page\") because page_is_pfmemalloc()\nis now using low order bit from page->lru.next, which can change\nmore often than page->index.\n\nLow order bit should never be set for lru.next (when used as an anchor\nin LRU list), so KCSAN report is mostly a false positive.\n\nBackporting to older kernel versions seems not necessary.\n\n[1]\nBUG: KCSAN: data-race in lru_add_fn / tcp_build_frag\n\nwrite to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:\n__list_add include/linux/list.h:73 [inline]\nlist_add include/linux/list.h:88 [inline]\nlruvec_add_folio include/linux/mm_inline.h:105 [inline]\nlru_add_fn+0x440/0x520 mm/swap.c:228\nfolio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246\nfolio_batch_add_and_move mm/swap.c:263 [inline]\nfolio_add_lru+0xf1/0x140 mm/swap.c:490\nfilemap_add_folio+0xf8/0x150 mm/filemap.c:948\n__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981\npagecache_get_page+0x26/0x190 mm/folio-compat.c:104\ngrab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116\next4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988\ngeneric_perform_write+0x1d4/0x3f0 mm/filemap.c:3738\next4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270\next4_file_write_iter+0x2e3/0x1210\ncall_write_iter include/linux/fs.h:2187 [inline]\nnew_sync_write fs/read_write.c:491 [inline]\nvfs_write+0x468/0x760 fs/read_write.c:578\nksys_write+0xe8/0x1a0 fs/read_write.c:631\n__do_sys_write fs/read_write.c:643 [inline]\n__se_sys_write fs/read_write.c:640 [inline]\n__x64_sys_write+0x3e/0x50 fs/read_write.c:640\ndo_syscall_x64 arch/x86/entry/common.c:50 [inline]\ndo_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nread to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:\npage_is_pfmemalloc include/linux/mm.h:1740 [inline]\n__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]\nskb_fill_page_desc include/linux/skbuff.h:2443 [inline]\ntcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018\ndo_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075\ntcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]\ntcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150\ninet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833\nkernel_sendpage+0x184/0x300 net/socket.c:3561\nsock_sendpage+0x5a/0x70 net/socket.c:1054\npipe_to_sendpage+0x128/0x160 fs/splice.c:361\nsplice_from_pipe_feed fs/splice.c:415 [inline]\n__splice_from_pipe+0x222/0x4d0 fs/splice.c:559\nsplice_from_pipe fs/splice.c:594 [inline]\ngeneric_splice_sendpage+0x89/0xc0 fs/splice.c:743\ndo_splice_from fs/splice.c:764 [inline]\ndirect_splice_actor+0x80/0xa0 fs/splice.c:931\nsplice_direct_to_actor+0x305/0x620 fs/splice.c:886\ndo_splice_direct+0xfb/0x180 fs/splice.c:974\ndo_sendfile+0x3bf/0x910 fs/read_write.c:1249\n__do_sys_sendfile64 fs/read_write.c:1317 [inline]\n__se_sys_sendfile64 fs/read_write.c:1303 [inline]\n__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303\ndo_syscall_x64 arch/x86/entry/common.c:50 [inline]\ndo_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nvalue changed: 0x0000000000000000 -> 0xffffea0004a1d288\n\nReported by Kernel Concurrency Sanitizer on:\nCPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022","publishedAt":"2024-05-03T15:00:02.083Z","updatedAt":"2026-05-11T18:45:03.597Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c07aea3ef4d4076f18f567b98ed01e082e02ed51","status":"affected","lessThan":"8527c9a6bf8e54fef0a8d3d7d8874a48c725c915","versionType":"git"},{"version":"c07aea3ef4d4076f18f567b98ed01e082e02ed51","status":"affected","lessThan":"6730c48ed6b0cd939fc9b30b2d621ce0b89bea83","versionType":"git"},{"version":"c07aea3ef4d4076f18f567b98ed01e082e02ed51","status":"affected","lessThan":"3261400639463a853ba2b3be8bd009c2a8089775","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/skbuff.h","net/core/datagram.c","net/ipv4/tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.14","versionType":"semver"},{"version":"5.15.68","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"5.19.9","status":"unaffected","lessThanOrEqual":"5.19.*","versionType":"semver"},{"version":"6.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/skbuff.h","net/core/datagram.c","net/ipv4/tcp.c"]}],"references":["https://git.kernel.org/stable/c/8527c9a6bf8e54fef0a8d3d7d8874a48c725c915","https://git.kernel.org/stable/c/6730c48ed6b0cd939fc9b30b2d621ce0b89bea83","https://git.kernel.org/stable/c/3261400639463a853ba2b3be8bd009c2a8089775"],"weaknesses":[],"ingestedAt":"2026-10-29T20:05:26.763Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2022/48xxx/CVE-2022-48689.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2022-48689","state":"PUBLISHED","datePublished":"2024-05-03T15:00:02.083Z","dateUpdated":"2026-05-11T18:45:03.597Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-05-03T14:55:07.144Z"},"containers":{"cna":{"title":"tcp: TX zerocopy should not sense pfmemalloc status","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: TX zerocopy should not sense pfmemalloc status\n\nWe got a recent syzbot report [1] showing a possible misuse\nof pfmemalloc page status in TCP zerocopy paths.\n\nIndeed, for pages coming from user space or other layers,\nusing page_is_pfmemalloc() is moot, and possibly could give\nfalse positives.\n\nThere has been attempts to make page_is_pfmemalloc() more robust,\nbut not using it in the first place in this context is probably better,\nremoving cpu cycles.\n\nNote to stable teams :\n\nYou need to backport 84ce071e38a6 (\"net: introduce\n__skb_fill_page_desc_noacc\") as a prereq.\n\nRace is more probable after commit c07aea3ef4d4\n(\"mm: add a signature in struct page\") because page_is_pfmemalloc()\nis now using low order bit from page->lru.next, which can change\nmore often than page->index.\n\nLow order bit should never be set for lru.next (when used as an anchor\nin LRU list), so KCSAN report is mostly a false positive.\n\nBackporting to older kernel versions seems not necessary.\n\n[1]\nBUG: KCSAN: data-race in lru_add_fn / tcp_build_frag\n\nwrite to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:\n__list_add include/linux/list.h:73 [inline]\nlist_add include/linux/list.h:88 [inline]\nlruvec_add_folio include/linux/mm_inline.h:105 [inline]\nlru_add_fn+0x440/0x520 mm/swap.c:228\nfolio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246\nfolio_batch_add_and_move mm/swap.c:263 [inline]\nfolio_add_lru+0xf1/0x140 mm/swap.c:490\nfilemap_add_folio+0xf8/0x150 mm/filemap.c:948\n__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981\npagecache_get_page+0x26/0x190 mm/folio-compat.c:104\ngrab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116\next4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988\ngeneric_perform_write+0x1d4/0x3f0 mm/filemap.c:3738\next4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270\next4_file_write_iter+0x2e3/0x1210\ncall_write_iter include/linux/fs.h:2187 [inline]\nnew_sync_write fs/read_write.c:491 [inline]\nvfs_write+0x468/0x760 fs/read_write.c:578\nksys_write+0xe8/0x1a0 fs/read_write.c:631\n__do_sys_write fs/read_write.c:643 [inline]\n__se_sys_write fs/read_write.c:640 [inline]\n__x64_sys_write+0x3e/0x50 fs/read_write.c:640\ndo_syscall_x64 arch/x86/entry/common.c:50 [inline]\ndo_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nread to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:\npage_is_pfmemalloc include/linux/mm.h:1740 [inline]\n__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]\nskb_fill_page_desc include/linux/skbuff.h:2443 [inline]\ntcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018\ndo_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075\ntcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]\ntcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150\ninet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833\nkernel_sendpage+0x184/0x300 net/socket.c:3561\nsock_sendpage+0x5a/0x70 net/socket.c:1054\npipe_to_sendpage+0x128/0x160 fs/splice.c:361\nsplice_from_pipe_feed fs/splice.c:415 [inline]\n__splice_from_pipe+0x222/0x4d0 fs/splice.c:559\nsplice_from_pipe fs/splice.c:594 [inline]\ngeneric_splice_sendpage+0x89/0xc0 fs/splice.c:743\ndo_splice_from fs/splice.c:764 [inline]\ndirect_splice_actor+0x80/0xa0 fs/splice.c:931\nsplice_direct_to_actor+0x305/0x620 fs/splice.c:886\ndo_splice_direct+0xfb/0x180 fs/splice.c:974\ndo_sendfile+0x3bf/0x910 fs/read_write.c:1249\n__do_sys_sendfile64 fs/read_write.c:1317 [inline]\n__se_sys_sendfile64 fs/read_write.c:1303 [inline]\n__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303\ndo_syscall_x64 arch/x86/entry/common.c:50 [inline]\ndo_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nvalue changed: 0x0000000000000000 -> 0xffffea0004a1d288\n\nReported by Kernel Concurrency Sanitizer on:\nCPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c07aea3ef4d4076f18f567b98ed01e082e02ed51","status":"affected","lessThan":"8527c9a6bf8e54fef0a8d3d7d8874a48c725c915","versionType":"git"},{"version":"c07aea3ef4d4076f18f567b98ed01e082e02ed51","status":"affected","lessThan":"6730c48ed6b0cd939fc9b30b2d621ce0b89bea83","versionType":"git"},{"version":"c07aea3ef4d4076f18f567b98ed01e082e02ed51","status":"affected","lessThan":"3261400639463a853ba2b3be8bd009c2a8089775","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/skbuff.h","net/core/datagram.c","net/ipv4/tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.14","versionType":"semver"},{"version":"5.15.68","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"5.19.9","status":"unaffected","lessThanOrEqual":"5.19.*","versionType":"semver"},{"version":"6.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/skbuff.h","net/core/datagram.c","net/ipv4/tcp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8527c9a6bf8e54fef0a8d3d7d8874a48c725c915"},{"url":"https://git.kernel.org/stable/c/6730c48ed6b0cd939fc9b30b2d621ce0b89bea83"},{"url":"https://git.kernel.org/stable/c/3261400639463a853ba2b3be8bd009c2a8089775"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T18:45:03.597Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"5.15.68"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"5.19.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.3,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L","integrityImpact":"LOW","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"LOW","privilegesRequired":"LOW","confidentialityImpact":"LOW"}},{"other":{"type":"ssvc","content":{"timestamp":"2024-06-12T20:38:37.630720Z","id":"CVE-2022-48689","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"type":"CWE","lang":"en","description":"CWE-noinfo Not enough information"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-10-30T15:49:47.193Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/8527c9a6bf8e54fef0a8d3d7d8874a48c725c915","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/6730c48ed6b0cd939fc9b30b2d621ce0b89bea83","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/3261400639463a853ba2b3be8bd009c2a8089775","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-03T15:17:55.728Z"}}]}}}