In the Linux kernel, the following vulnerability has been resolved:
mptcp: Correctly set DATA_FIN timeout when number of retransmits is large
Syzkaller with UBSAN uncovered a scenario where a large number of DATAFIN retransmits caused a shift-out-of-bounds in the DATAFIN timeout calculation:
================================================================================ UBSAN: shift-out-of-bounds in net/mptcp/protocol.c:470:29 shift exponent 32 is too large for 32-bit type 'unsigned int' CPU: 1 PID: 13059 Comm: kworker/1:0 Not tainted 5.17.0-rc2-00630-g5fbf21c90c60 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: events mptcpworker Call Trace: <TASK> _dumpstack lib/dumpstack.c:88 [inline] dumpstacklvl+0xcd/0x134 lib/dumpstack.c:106 ubsanepilogue+0xb/0x5a lib/ubsan.c:151 _ubsanhandleshiftoutofbounds.cold+0xb2/0x20e lib/ubsan.c:330 mptcpsetdatafintimeout net/mptcp/protocol.c:470 [inline] _mptcpretrans.cold+0x72/0x77 net/mptcp/protocol.c:2445 mptcpworker+0x58a/0xa70 net/mptcp/protocol.c:2528 processonework+0x9df/0x16d0 kernel/workqueue.c:2307 workerthread+0x95/0xe10 kernel/workqueue.c:2454 kthread+0x2f4/0x3b0 kernel/kthread.c:377 retfromfork+0x1f/0x30 arch/x86/entry/entry64.S:295
This change limits the maximum timeout by limiting the size of the shift, which keeps all intermediate values in-bounds.
[
{
"signature_type": "Function",
"digest": {
"function_hash": "148448025580963437792049643993682410243",
"length": 187.0
},
"target": {
"file": "net/mptcp/protocol.c",
"function": "mptcp_set_datafin_timeout"
},
"signature_version": "v1",
"id": "CVE-2022-48906-047deaaf",
"deprecated": false,
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@877d11f0332cd2160e19e3313e262754c321fa36"
},
{
"signature_type": "Line",
"digest": {
"threshold": 0.9,
"line_hashes": [
"95120910647558400271911401659352442487",
"308110382085402981428575472284792295285",
"61869939738550163254979873516715809141",
"228116427398130106342025600519636718643",
"196487475706695012391460621067587355633",
"116224041995980112675558092039258022553"
]
},
"target": {
"file": "net/mptcp/protocol.c"
},
"signature_version": "v1",
"id": "CVE-2022-48906-2c6662a2",
"deprecated": false,
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@0c3f34beb459753f9f80d0cc14c1b50ab615c631"
},
{
"signature_type": "Line",
"digest": {
"threshold": 0.9,
"line_hashes": [
"95120910647558400271911401659352442487",
"308110382085402981428575472284792295285",
"61869939738550163254979873516715809141",
"228116427398130106342025600519636718643",
"196487475706695012391460621067587355633",
"116224041995980112675558092039258022553"
]
},
"target": {
"file": "net/mptcp/protocol.c"
},
"signature_version": "v1",
"id": "CVE-2022-48906-39345963",
"deprecated": false,
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@877d11f0332cd2160e19e3313e262754c321fa36"
},
{
"signature_type": "Function",
"digest": {
"function_hash": "148448025580963437792049643993682410243",
"length": 187.0
},
"target": {
"file": "net/mptcp/protocol.c",
"function": "mptcp_set_datafin_timeout"
},
"signature_version": "v1",
"id": "CVE-2022-48906-4aa29a3f",
"deprecated": false,
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@0c3f34beb459753f9f80d0cc14c1b50ab615c631"
},
{
"signature_type": "Line",
"digest": {
"threshold": 0.9,
"line_hashes": [
"95120910647558400271911401659352442487",
"308110382085402981428575472284792295285",
"61869939738550163254979873516715809141",
"228116427398130106342025600519636718643",
"196487475706695012391460621067587355633",
"116224041995980112675558092039258022553"
]
},
"target": {
"file": "net/mptcp/protocol.c"
},
"signature_version": "v1",
"id": "CVE-2022-48906-bc7986ee",
"deprecated": false,
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@03ae283bd71f761feae3f402668d698b393b0e79"
},
{
"signature_type": "Function",
"digest": {
"function_hash": "148448025580963437792049643993682410243",
"length": 187.0
},
"target": {
"file": "net/mptcp/protocol.c",
"function": "mptcp_set_datafin_timeout"
},
"signature_version": "v1",
"id": "CVE-2022-48906-e1f0f041",
"deprecated": false,
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@03ae283bd71f761feae3f402668d698b393b0e79"
}
]