CVE-2024-26602: sched/membarrier: reduce the ability to hammer on sys_membarrier

CVE-2024-26602: sched/membarrier: reduce the ability to hammer on sys_membarrier

[Greg Kroah-Hartman]

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

sched/membarrier: reduce the ability to hammer on sys_membarrier

On some systems, sys_membarrier can be very expensive, causing overall
slowdowns for everything.  So put a lock on the path in order to
serialize the accesses to prevent the ability for this to be called at
too high of a frequency and saturate the machine.

The Linux kernel CVE team has assigned CVE-2024-26602 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 4.19.307 with commit 3cd139875e9a
	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.4.269 with commit 2441a64070b8
	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.10.210 with commit db896bbe4a9c
	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.15.149 with commit 50fb4e17df31
	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.1.79 with commit 24ec7504a08a
	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.6.18 with commit b6a2a9cbb675
	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.7.6 with commit c5b2063c65d0

Please see https://www.kernel.org or 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-2024-26602
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:
	kernel/sched/membarrier.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/3cd139875e9a7688b3fc715264032620812a5fa3
	https://git.kernel.org/stable/c/2441a64070b85c14eecc3728cc87e883f953f265
	https://git.kernel.org/stable/c/db896bbe4a9c67cee377e5f6a743350d3ae4acf6
	https://git.kernel.org/stable/c/50fb4e17df319bb33be6f14e2a856950c1577dee
	https://git.kernel.org/stable/c/24ec7504a08a67247fbe798d1de995208a8c128a
	https://git.kernel.org/stable/c/b6a2a9cbb67545c825ec95f06adb7ff300a2ad71
	https://git.kernel.org/stable/c/c5b2063c65d05e79fad8029324581d86cfba7eea

Re: CVE-2024-26602: sched/membarrier: reduce the ability to hammer on sys_membarrier

[Thorsten Leemhuis]

On 24.02.24 15:57, Greg Kroah-Hartman wrote:
> Description
> ===========
> 
> In the Linux kernel, the following vulnerability has been resolved:
> 
> sched/membarrier: reduce the ability to hammer on sys_membarrier
> 
> On some systems, sys_membarrier can be very expensive, causing overall
> slowdowns for everything.  So put a lock on the path in order to
> serialize the accesses to prevent the ability for this to be called at
> too high of a frequency and saturate the machine.
> 
> The Linux kernel CVE team has assigned CVE-2024-26602 to this issue.
> 
> 
> Affected and fixed versions
> ===========================
> 
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 4.19.307 with commit 3cd139875e9a
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.4.269 with commit 2441a64070b8
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.10.210 with commit db896bbe4a9c
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.15.149 with commit 50fb4e17df31
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.1.79 with commit 24ec7504a08a
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.6.18 with commit b6a2a9cbb675
> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.7.6 with commit c5b2063c65d0
>
> Please see [...]
Greg, JFYI, I noticed that this announcement did not refer to the fix in
mainline (944d5fe50f3f03 ("sched/membarrier: reduce the ability to
hammer on sys_membarrier")) while most of the others do that. I don't
care at all, just noticed this by chance and wanted to let you know in
case it's due to a bug in a script or something. I hope there is not a
good reason for that difference I just failed to spot... (if that's the
case: apologies in advance for the noise!).

Ciao, Thorsten

Re: CVE-2024-26602: sched/membarrier: reduce the ability to hammer on sys_membarrier

[Greg Kroah-Hartman]

On Sun, Feb 25, 2024 at 10:31:19AM +0100, Thorsten Leemhuis wrote:
> On 24.02.24 15:57, Greg Kroah-Hartman wrote:
> > Description
> > ===========
> > 
> > In the Linux kernel, the following vulnerability has been resolved:
> > 
> > sched/membarrier: reduce the ability to hammer on sys_membarrier
> > 
> > On some systems, sys_membarrier can be very expensive, causing overall
> > slowdowns for everything.  So put a lock on the path in order to
> > serialize the accesses to prevent the ability for this to be called at
> > too high of a frequency and saturate the machine.
> > 
> > The Linux kernel CVE team has assigned CVE-2024-26602 to this issue.
> > 
> > 
> > Affected and fixed versions
> > ===========================
> > 
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 4.19.307 with commit 3cd139875e9a
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.4.269 with commit 2441a64070b8
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.10.210 with commit db896bbe4a9c
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.15.149 with commit 50fb4e17df31
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.1.79 with commit 24ec7504a08a
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.6.18 with commit b6a2a9cbb675
> > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.7.6 with commit c5b2063c65d0
> >
> > Please see [...]
> Greg, JFYI, I noticed that this announcement did not refer to the fix in
> mainline (944d5fe50f3f03 ("sched/membarrier: reduce the ability to
> hammer on sys_membarrier")) while most of the others do that. I don't
> care at all, just noticed this by chance and wanted to let you know in
> case it's due to a bug in a script or something. I hope there is not a
> good reason for that difference I just failed to spot... (if that's the
> case: apologies in advance for the noise!).

The json entry will be updated when the commit shows up in a tagged
release (i.e. the next -rc release), and then when the real release
happens from Linus (i.e. 6.8), it will be updated then as well.

But for now, the mainline commit is not in any "real" release so we
can't reference it here in the message or in the json record as per the
rules from CVE.

hope this helps explain things better,

greg k-h

Re: CVE-2024-26602: sched/membarrier: reduce the ability to hammer on sys_membarrier

[Thorsten Leemhuis]

On 25.02.24 10:47, Greg Kroah-Hartman wrote:
> On Sun, Feb 25, 2024 at 10:31:19AM +0100, Thorsten Leemhuis wrote:
>> On 24.02.24 15:57, Greg Kroah-Hartman wrote:
> [...]
>>> Affected and fixed versions
>>> ===========================
>>>
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 4.19.307 with commit 3cd139875e9a
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.4.269 with commit 2441a64070b8
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.10.210 with commit db896bbe4a9c
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.15.149 with commit 50fb4e17df31
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.1.79 with commit 24ec7504a08a
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.6.18 with commit b6a2a9cbb675
>>> 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.7.6 with commit c5b2063c65d0
>>>
>>> Please see [...]
>> Greg, JFYI, I noticed that this announcement did not refer to the fix in
>> mainline (944d5fe50f3f03 ("sched/membarrier: reduce the ability to
>> hammer on sys_membarrier")) while most of the others do that. I don't
>> care at all, just noticed this by chance and wanted to let you know in
>> case it's due to a bug in a script or something. I hope there is not a
>> good reason for that difference I just failed to spot... (if that's the
>> case: apologies in advance for the noise!).
> 
> The json entry will be updated when the commit shows up in a tagged
> release (i.e. the next -rc release), and then when the real release
> happens from Linus (i.e. 6.8), it will be updated then as well.
> 
> But for now, the mainline commit is not in any "real" release so we
> can't reference it here in the message or in the json record as per the
> rules from CVE.

Ohh, interesting and somewhat understandable.

Thx for your answer!

Ciao, Thorsten

Re: CVE-2024-26602: sched/membarrier: reduce the ability to hammer on sys_membarrier

[Greg Kroah-Hartman]

On Sun, Feb 25, 2024 at 10:47:28AM +0100, Greg Kroah-Hartman wrote:
> On Sun, Feb 25, 2024 at 10:31:19AM +0100, Thorsten Leemhuis wrote:
> > On 24.02.24 15:57, Greg Kroah-Hartman wrote:
> > > Description
> > > ===========
> > > 
> > > In the Linux kernel, the following vulnerability has been resolved:
> > > 
> > > sched/membarrier: reduce the ability to hammer on sys_membarrier
> > > 
> > > On some systems, sys_membarrier can be very expensive, causing overall
> > > slowdowns for everything.  So put a lock on the path in order to
> > > serialize the accesses to prevent the ability for this to be called at
> > > too high of a frequency and saturate the machine.
> > > 
> > > The Linux kernel CVE team has assigned CVE-2024-26602 to this issue.
> > > 
> > > 
> > > Affected and fixed versions
> > > ===========================
> > > 
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 4.19.307 with commit 3cd139875e9a
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.4.269 with commit 2441a64070b8
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.10.210 with commit db896bbe4a9c
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 5.15.149 with commit 50fb4e17df31
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.1.79 with commit 24ec7504a08a
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.6.18 with commit b6a2a9cbb675
> > > 	Issue introduced in 4.14 with commit c5f58bd58f43 and fixed in 6.7.6 with commit c5b2063c65d0
> > >
> > > Please see [...]
> > Greg, JFYI, I noticed that this announcement did not refer to the fix in
> > mainline (944d5fe50f3f03 ("sched/membarrier: reduce the ability to
> > hammer on sys_membarrier")) while most of the others do that. I don't
> > care at all, just noticed this by chance and wanted to let you know in
> > case it's due to a bug in a script or something. I hope there is not a
> > good reason for that difference I just failed to spot... (if that's the
> > case: apologies in advance for the noise!).
> 
> The json entry will be updated when the commit shows up in a tagged
> release (i.e. the next -rc release), and then when the real release
> happens from Linus (i.e. 6.8), it will be updated then as well.

It is now updated on the cve.org website at:
	https://www.cve.org/CVERecord/?id=CVE-2024-26602
and in the cve git repo record as well:
	https://git.kernel.org/pub/scm/linux/security/vulns.git/diff/cve/published/2024/CVE-2024-26602.mbox

thanks,

greg k-h