cbcvebase.
CVE-2022-48689
published 2024-05-03

CVE-2022-48689: In the Linux kernel, the following vulnerability has been resolved: tcp: TX zerocopy should not sense pfmemalloc status We got a recent syzbot report [1]…

PriorityP430high7CVSS 3.1
AVLACHPRLUINSUCHIHAH
EPSS
0.19%
9.2th percentile
In the Linux kernel, the following vulnerability has been resolved: tcp: TX zerocopy should not sense pfmemalloc status We got a recent syzbot report [1] showing a possible misuse of pfmemalloc page status in TCP zerocopy paths. Indeed, for pages coming from user space or other layers, using page_is_pfmemalloc() is moot, and possibly could give false positives. There has been attempts to make page_is_pfmemalloc() more robust, but not using it in the first place in this context is probably better, removing cpu cycles. Note to stable teams : You need to backport 84ce071e38a6 ("net: introduce __skb_fill_page_desc_noacc") as a prereq. Race is more probable after commit c07aea3ef4d4 ("mm: add a signature in struct page") because page_is_pfmemalloc() is now using low order bit from page->lru.next, which can change more often than page->index. Low order bit should never be set for lru.next (when used as an anchor in LRU list), so KCSAN report is mostly a false positive. Backporting to older kernel versions seems not necessary. [1] BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0: __list_add include/linux/list.h:73 [inline] list_add include/linux/list.h:88 [inline] lruvec_add_folio include/linux/mm_inline.h:105 [inline] lru_add_fn+0x440/0x520 mm/swap.c:228 folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246 folio_batch_add_and_move mm/swap.c:263 [inline] folio_add_lru+0xf1/0x140 mm/swap.c:490 filemap_add_folio+0xf8/0x150 mm/filemap.c:948 __filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981 pagecache_get_page+0x26/0x190 mm/folio-compat.c:104 grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116 ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988 generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270 ext4_file_write_iter+0x2e3/0x1210 call_write_iter include/linux/fs.h:2187 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x468/0x760 fs

Affected

10 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.19.11-1 (bookworm)linux 5.19.11-1 (bookworm)
linuxlinux
linuxlinux>= c07aea3ef4d4076f18f567b98ed01e082e02ed51 < 8527c9a6bf8e54fef0a8d3d7d8874a48c725c9158527c9a6bf8e54fef0a8d3d7d8874a48c725c915
linuxlinux>= c07aea3ef4d4076f18f567b98ed01e082e02ed51 < 6730c48ed6b0cd939fc9b30b2d621ce0b89bea836730c48ed6b0cd939fc9b30b2d621ce0b89bea83
linuxlinux>= c07aea3ef4d4076f18f567b98ed01e082e02ed51 < 3261400639463a853ba2b3be8bd009c2a80897753261400639463a853ba2b3be8bd009c2a8089775
linuxlinux_kernel>= 0 < 5.19.11-15.19.11-1
linuxlinux_kernel>= 0 < 5.19.11-15.19.11-1
linuxlinux_kernel>= 0 < 5.19.11-15.19.11-1
linuxlinux_kernel>= 5.14 < 5.15.685.15.68
linuxlinux_kernel>= 5.16 < 5.19.95.19.9

CVSS provenance

nvdv3.17.0HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.0HIGH
vendor_debian7.0HIGH
vendor_redhat7.0HIGH
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