* CVE-2024-26805: netlink: Fix kernel-infoleak-after-free in __skb_datagram_iter
@ 2024-04-04 8:23 Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2024-04-04 8:23 UTC (permalink / raw)
To: linux-cve-announce; +Cc: Greg Kroah-Hartman
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
netlink: Fix kernel-infoleak-after-free in __skb_datagram_iter
syzbot reported the following uninit-value access issue [1]:
netlink_to_full_skb() creates a new `skb` and puts the `skb->data`
passed as a 1st arg of netlink_to_full_skb() onto new `skb`. The data
size is specified as `len` and passed to skb_put_data(). This `len`
is based on `skb->end` that is not data offset but buffer offset. The
`skb->end` contains data and tailroom. Since the tailroom is not
initialized when the new `skb` created, KMSAN detects uninitialized
memory area when copying the data.
This patch resolved this issue by correct the len from `skb->end` to
`skb->len`, which is the actual data offset.
BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak-after-free in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_ubuf include/linux/iov_iter.h:29 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance include/linux/iov_iter.h:271 [inline]
BUG: KMSAN: kernel-infoleak-after-free in _copy_to_iter+0x364/0x2520 lib/iov_iter.c:186
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
copy_to_user_iter lib/iov_iter.c:24 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x364/0x2520 lib/iov_iter.c:186
copy_to_iter include/linux/uio.h:197 [inline]
simple_copy_to_iter+0x68/0xa0 net/core/datagram.c:532
__skb_datagram_iter+0x123/0xdc0 net/core/datagram.c:420
skb_copy_datagram_iter+0x5c/0x200 net/core/datagram.c:546
skb_copy_datagram_msg include/linux/skbuff.h:3960 [inline]
packet_recvmsg+0xd9c/0x2000 net/packet/af_packet.c:3482
sock_recvmsg_nosec net/socket.c:1044 [inline]
sock_recvmsg net/socket.c:1066 [inline]
sock_read_iter+0x467/0x580 net/socket.c:1136
call_read_iter include/linux/fs.h:2014 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x8f6/0xe00 fs/read_write.c:470
ksys_read+0x20f/0x4c0 fs/read_write.c:613
__do_sys_read fs/read_write.c:623 [inline]
__se_sys_read fs/read_write.c:621 [inline]
__x64_sys_read+0x93/0xd0 fs/read_write.c:621
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was stored to memory at:
skb_put_data include/linux/skbuff.h:2622 [inline]
netlink_to_full_skb net/netlink/af_netlink.c:181 [inline]
__netlink_deliver_tap_skb net/netlink/af_netlink.c:298 [inline]
__netlink_deliver_tap+0x5be/0xc90 net/netlink/af_netlink.c:325
netlink_deliver_tap net/netlink/af_netlink.c:338 [inline]
netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline]
netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0x10f1/0x1250 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was created at:
free_pages_prepare mm/page_alloc.c:1087 [inline]
free_unref_page_prepare+0xb0/0xa40 mm/page_alloc.c:2347
free_unref_page_list+0xeb/0x1100 mm/page_alloc.c:2533
release_pages+0x23d3/0x2410 mm/swap.c:1042
free_pages_and_swap_cache+0xd9/0xf0 mm/swap_state.c:316
tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
tlb_flush_mmu+0x6f5/0x980 mm/mmu_gather.c:300
tlb_finish_mmu+0x101/0x260 mm/mmu_gather.c:392
exit_mmap+0x49e/0xd30 mm/mmap.c:3321
__mmput+0x13f/0x530 kernel/fork.c:1349
mmput+0x8a/0xa0 kernel/fork.c:1371
exit_mm+0x1b8/0x360 kernel/exit.c:567
do_exit+0xd57/0x4080 kernel/exit.c:858
do_group_exit+0x2fd/0x390 kernel/exit.c:1021
__do_sys_exit_group kernel/exit.c:1032 [inline]
__se_sys_exit_group kernel/exit.c:1030 [inline]
__x64_sys_exit_group+0x3c/0x50 kernel/exit.c:1030
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Bytes 3852-3903 of 3904 are uninitialized
Memory access of size 3904 starts at ffff88812ea1e000
Data copied to user address 0000000020003280
CPU: 1 PID: 5043 Comm: syz-executor297 Not tainted 6.7.0-rc5-syzkaller-00047-g5bd7ef53ffe5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
The Linux kernel CVE team has assigned CVE-2024-26805 to this issue.
Affected and fixed versions
===========================
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 4.19.309 with commit ec343a55b687
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 5.4.271 with commit 9ae51361da43
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 5.10.212 with commit f19d1f98e60e
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 5.15.151 with commit c71ed29d15b1
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 6.1.81 with commit 0b27bf4c494d
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 6.6.21 with commit d3ada42e534a
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 6.7.9 with commit 59fc3e3d049e
Issue introduced in 4.3 with commit 1853c9496460 and fixed in 6.8 with commit 661779e1fcaf
Issue introduced in 3.12.49 with commit 92994a5f49d0
Issue introduced in 3.14.54 with commit 85aec6328f33
Issue introduced in 3.18.23 with commit d38200098e32
Issue introduced in 4.1.10 with commit 65d48c630ff8
Issue introduced in 4.2.3 with commit 62f43b58d2b2
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2024-26805
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
net/netlink/af_netlink.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/ec343a55b687a452f5e87f3b52bf9f155864df65
https://git.kernel.org/stable/c/9ae51361da43270f4ba0eb924427a07e87e48777
https://git.kernel.org/stable/c/f19d1f98e60e68b11fc60839105dd02a30ec0d77
https://git.kernel.org/stable/c/c71ed29d15b1a1ed6c464f8c3536996963046285
https://git.kernel.org/stable/c/0b27bf4c494d61e5663baa34c3edd7ccebf0ea44
https://git.kernel.org/stable/c/d3ada42e534a83b618bbc1e490d23bf0fdae4736
https://git.kernel.org/stable/c/59fc3e3d049e39e7d0d271f20dd5fb47c57faf1d
https://git.kernel.org/stable/c/661779e1fcafe1b74b3f3fe8e980c1e207fea1fd
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