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tun: add missing verification for short frame - #206
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jallisonciq merged 1 commit intoApr 14, 2025
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jira VULN-9005 cve CVE-2024-41091 commit-author Dongli Zhang <dongli.zhang@oracle.com> commit 0495848 The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less than ETH_HLEN. Once transmitted, this could either cause out-of-bound access beyond the actual length, or confuse the underlayer with incorrect or inconsistent header length in the skb metadata. In the alternative path, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP. This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does. CVE: CVE-2024-41091 Inspired-by: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/ Fixes: 043d222 ("tuntap: accept an array of XDP buffs through sendmsg()") Cc: stable@vger.kernel.org Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Jason Wang <jasowang@redhat.com> Link: https://patch.msgid.link/20240724170452.16837-3-dongli.zhang@oracle.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> (cherry picked from commit 0495848) Signed-off-by: Jeremy Allison <jallison@ciq.com>
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JIRA: https://issues.redhat.com/browse/RHEL-140878 [ Upstream commit 6aecd91 ] [BUG] Syzbot reported a crash with the following call trace: BTRFS info (device loop0): scrub: started on devid 1 BUG: kernel NULL pointer dereference, address: 0000000000000208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 106e70067 P4D 106e70067 PUD 107143067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 UID: 0 PID: 689 Comm: repro Kdump: loaded Tainted: G O 6.13.0-rc4-custom+ #206 Tainted: [O]=OOT_MODULE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:find_first_extent_item+0x26/0x1f0 [btrfs] Call Trace: <TASK> scrub_find_fill_first_stripe+0x13d/0x3b0 [btrfs] scrub_simple_mirror+0x175/0x260 [btrfs] scrub_stripe+0x5d4/0x6c0 [btrfs] scrub_chunk+0xbb/0x170 [btrfs] scrub_enumerate_chunks+0x2f4/0x5f0 [btrfs] btrfs_scrub_dev+0x240/0x600 [btrfs] btrfs_ioctl+0x1dc8/0x2fa0 [btrfs] ? do_sys_openat2+0xa5/0xf0 __x64_sys_ioctl+0x97/0xc0 do_syscall_64+0x4f/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> [CAUSE] The reproducer is using a corrupted image where extent tree root is corrupted, thus forcing to use "rescue=all,ro" mount option to mount the image. Then it triggered a scrub, but since scrub relies on extent tree to find where the data/metadata extents are, scrub_find_fill_first_stripe() relies on an non-empty extent root. But unfortunately scrub_find_fill_first_stripe() doesn't really expect an NULL pointer for extent root, it use extent_root to grab fs_info and triggered a NULL pointer dereference. [FIX] Add an extra check for a valid extent root at the beginning of scrub_find_fill_first_stripe(). The new error path is introduced by 42437a6 ("btrfs: introduce mount option rescue=ignorebadroots"), but that's pretty old, and later commit b979547 ("btrfs: scrub: introduce helper to find and fill sector info for a scrub_stripe") changed how we do scrub. So for kernels older than 6.6, the fix will need manual backport. Reported-by: syzbot+339e9dbe3a2ca419b85d@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/67756935.050a0220.25abdd.0a12.GAE@google.com/ Fixes: 42437a6 ("btrfs: introduce mount option rescue=ignorebadroots") Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org> (cherry picked from commit aee5f69) Signed-off-by: Ravi Singh <ravising@redhat.com>
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baseline_selftest.txt
patched_selftest.txt
uname -a
"Linux r8_6_lts_fips 4.18.0+ #1 SMP Wed Apr 9 00:27:11 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux"
jira VULN-9005
cve CVE-2024-41091
commit-author Dongli Zhang dongli.zhang@oracle.com commit 0495848
The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less than ETH_HLEN. Once transmitted, this could either cause out-of-bound access beyond the actual length, or confuse the underlayer with incorrect or inconsistent header length in the skb metadata.
In the alternative path, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP.
This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does.
CVE: CVE-2024-41091
Inspired-by: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/ Fixes: 043d222 ("tuntap: accept an array of XDP buffs through sendmsg()")
Cc: stable@vger.kernel.org
Signed-off-by: Dongli Zhang dongli.zhang@oracle.com
Reviewed-by: Si-Wei Liu si-wei.liu@oracle.com
Reviewed-by: Willem de Bruijn willemb@google.com
Reviewed-by: Paolo Abeni pabeni@redhat.com
Reviewed-by: Jason Wang jasowang@redhat.com
Link: https://patch.msgid.link/20240724170452.16837-3-dongli.zhang@oracle.com
Signed-off-by: Jakub Kicinski kuba@kernel.org
(cherry picked from commit 0495848)