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CVE fix for chromium kernel v5.4.76 - #45

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CVE fix for chromium kernel v5.4.76#45
muhammadaksar wants to merge 3 commits into
projectceladon:masterfrom
projectceladon-ci:cve_fix_v5.4.76

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a13xp0p0v and others added 3 commits February 19, 2021 14:22
There are multiple similar bugs implicitly introduced by the
commit c0cfa2d8a788fcf4 ("vsock: add multi-transports support") and
commit 6a2c0962105ae8ce ("vsock: prevent transport modules unloading").

The bug pattern:
 [1] vsock_sock.transport pointer is copied to a local variable,
 [2] lock_sock() is called,
 [3] the local variable is used.
VSOCK multi-transport support introduced the race condition:
vsock_sock.transport value may change between [1] and [2].

Let's copy vsock_sock.transport pointer to local variables after
the lock_sock() call.

Fixes: c0cfa2d8a788fcf4 ("vsock: add multi-transports support")
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Link: https://lore.kernel.org/r/20210201084719.2257066-1-alex.popov@linux.com
Tracked-On: OAM-96000
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Muhammad Aksar <muhammad.aksar@intel.com>
Updating pi_state::owner is done at several places with the same
code. Provide a function for it and use that at the obvious places.

This is also a preparation for a bug fix to avoid yet another copy of the
same code or alternatively introducing a completely unpenetratable mess of
gotos.

Originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Aksar <muhammad.aksar@intel.com>
This commit add the invalid check for connected socket, without it will
causes the following crash due to sco_pi(sk)->conn being NULL:

KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057]
CPU: 3 PID: 4284 Comm: test_sco Not tainted 5.10.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1 04/01/2014
RIP: 0010:sco_sock_getsockopt+0x45d/0x8e0
Code: 48 c1 ea 03 80 3c 02 00 0f 85 ca 03 00 00 49 8b 9d f8 04 00 00 48
b8 00
      00 00 00 00 fc ff df 48 8d 7b 50 48 89 fa 48 c1 ea 03 <0f> b6 04
02 84
      c0 74 08 3c 03 0f 8e b5 03 00 00 8b 43 50 48 8b 0c
RSP: 0018:ffff88801bb17d88 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff83a4ecdf
RDX: 000000000000000a RSI: ffffc90002fce000 RDI: 0000000000000050
RBP: 1ffff11003762fb4 R08: 0000000000000001 R09: ffff88810e1008c0
R10: ffffffffbd695dcf R11: fffffbfff7ad2bb9 R12: 0000000000000000
R13: ffff888018ff1000 R14: dffffc0000000000 R15: 000000000000000d
FS:  00007fb4f76c1700(0000) GS:ffff88811af80000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555e3b7a938 CR3: 00000001117be001 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 ? sco_skb_put_cmsg+0x80/0x80
 ? sco_skb_put_cmsg+0x80/0x80
 __sys_getsockopt+0x12a/0x220
 ? __ia32_sys_setsockopt+0x150/0x150
 ? syscall_enter_from_user_mode+0x18/0x50
 ? rcu_read_lock_bh_held+0xb0/0xb0
 __x64_sys_getsockopt+0xba/0x150
 ? syscall_enter_from_user_mode+0x1d/0x50
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 0fc1a726f897 ("Bluetooth: sco: new getsockopt options
BT_SNDMTU/BT_RCVMTU")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Luiz Augusto Von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Muhammad Aksar <muhammad.aksar@intel.com>
sysopenci pushed a commit that referenced this pull request May 28, 2021
[ Upstream commit d5027ca63e0e778b641cf23e3f5c6d6212cf412b ]

Ritesh reported a bug [1] against UML, noting that it crashed on
startup. The backtrace shows the following (heavily redacted):

(gdb) bt
...
 #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2
 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72
...
 #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359
...
 #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486
 #45 0x00007f8990968b85 in __getgrnam_r [...]
 #46 0x00007f89909d6b77 in grantpt [...]
 #47 0x00007f8990a9394e in __GI_openpty [...]
 #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407
 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598
 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45
 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334
 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144

indicating that the UML function openpty_cb() calls openpty(),
which internally calls __getgrnam_r(), which causes the nsswitch
machinery to get started.

This loads, through lots of indirection that I snipped, the
libcom_err.so.2 library, which (in an unknown function, "??")
calls sem_init().

Now, of course it wants to get libpthread's sem_init(), since
it's linked against libpthread. However, the dynamic linker
looks up that symbol against the binary first, and gets the
kernel's sem_init().

Hajime Tazaki noted that "objcopy -L" can localize a symbol,
so the dynamic linker wouldn't do the lookup this way. I tried,
but for some reason that didn't seem to work.

Doing the same thing in the linker script instead does seem to
work, though I cannot entirely explain - it *also* works if I
just add "VERSION { { global: *; }; }" instead, indicating that
something else is happening that I don't really understand. It
may be that explicitly doing that marks them with some kind of
empty version, and that's different from the default.

Explicitly marking them with a version breaks kallsyms, so that
doesn't seem to be possible.

Marking all the symbols as local seems correct, and does seem
to address the issue, so do that. Also do it for static link,
nsswitch libraries could still be loaded there.

[1] https://bugs.debian.org/983379

Reported-by: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-By: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
@sysopenci sysopenci added the Stale Stale label for inactive open prs label Sep 5, 2024
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4 participants