CVE-2023-54155: In the Linux kernel, the following vulnerability has been resolved: net: core: remove unnecessary frame_sz check in bpf_xdp_adjust_tail() Syzkaller reported…

PriorityP420medium4.4

EPSS

0.17%

7.1th percentile

In the Linux kernel, the following vulnerability has been resolved: net: core: remove unnecessary frame_sz check in bpf_xdp_adjust_tail() Syzkaller reported the following issue: Too BIG xdp->frame_sz = 131072 WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121 ____bpf_xdp_adjust_tail net/core/filter.c:4121 [inline] WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121 bpf_xdp_adjust_tail+0x466/0xa10 net/core/filter.c:4103 ... Call Trace: bpf_prog_4add87e5301a4105+0x1a/0x1c __bpf_prog_run include/linux/filter.h:600 [inline] bpf_prog_run_xdp include/linux/filter.h:775 [inline] bpf_prog_run_generic_xdp+0x57e/0x11e0 net/core/dev.c:4721 netif_receive_generic_xdp net/core/dev.c:4807 [inline] do_xdp_generic+0x35c/0x770 net/core/dev.c:4866 tun_get_user+0x2340/0x3ca0 drivers/net/tun.c:1919 tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2043 call_write_iter include/linux/fs.h:1871 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x650/0xe40 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd xdp->frame_sz > PAGE_SIZE check was introduced in commit c8741e2bfe87 ("xdp: Allow bpf_xdp_adjust_tail() to grow packet size"). But Jesper Dangaard Brouer noted that after introducing the xdp_init_buff() which all XDP driver use - it's safe to remove this check. The original intend was to catch cases where XDP drivers have not been updated to use xdp.frame_sz, but that is not longer a concern (since xdp_init_buff). Running the initial syzkaller repro it was discovered that the contiguous physical memory allocation is used for both xdp paths in tun_get_user(), e.g. tun_build_skb() and tun_alloc_skb(). It was also stated by Jesper Dangaard Brouer that XDP can work on higher order pages, as long as this is contiguous physical memory (e.g. a page).

Affected

12 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.1.52-1 (bookworm)	linux 6.1.52-1 (bookworm)
linux	linux	—	—
linux	linux	>= 43b5169d8355ccf26d726fbc75f083b2429113e4 < a09c258cfa77d3ba0a7acc555c73eb6b005c4bd8	a09c258cfa77d3ba0a7acc555c73eb6b005c4bd8
linux	linux	>= 43b5169d8355ccf26d726fbc75f083b2429113e4 < 20acffcdc2b74fb7dcc4e299f7aca173df89d911	20acffcdc2b74fb7dcc4e299f7aca173df89d911
linux	linux	>= 43b5169d8355ccf26d726fbc75f083b2429113e4 < d9252d67ed2f921c230bba449ee051b5c32e4841	d9252d67ed2f921c230bba449ee051b5c32e4841
linux	linux	>= 43b5169d8355ccf26d726fbc75f083b2429113e4 < d14eea09edf427fa36bd446f4a3271f99164202f	d14eea09edf427fa36bd446f4a3271f99164202f
linux	linux_kernel	>= 0 < 6.1.52-1	6.1.52-1
linux	linux_kernel	>= 0 < 6.4.11-1	6.4.11-1
linux	linux_kernel	>= 0 < 6.4.11-1	6.4.11-1
linux	linux_kernel	>= 5.12.0 < 5.15.127	5.15.127
linux	linux_kernel	>= 5.16.0 < 6.1.46	6.1.46
linux	linux_kernel	>= 6.2.0 < 6.4.11	6.4.11

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