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commit 96939cec994070aa5df852c10fad5fc303a97ea3 upstream.
When a SYN containing the 'C' flag (deny join id0) was received, this
piece of information was not propagated to the path-manager.
Even if this flag is mainly set on the server side, a client can also
tell the server it cannot try to establish new subflows to the client's
initial IP address and port. The server's PM should then record such
info when received, and before sending events about the new connection.
Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received")
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-1-40…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
[ Conflicts in subflow.c, because of differences in the context, e.g.
introduced by commit 3a236aef280e ("mptcp: refactor passive socket
initialization"), which is not in this version. The same lines --
using 'mptcp_sk(new_msk)' instead of 'owner' -- can still be added
approximately at the same place, before calling
mptcp_pm_new_connection(). ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
---
net/mptcp/subflow.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 6bc36132d490..f67d8c98d58a 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -758,6 +758,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
*/
WRITE_ONCE(mptcp_sk(new_msk)->first, child);
+ if (mp_opt.deny_join_id0)
+ WRITE_ONCE(mptcp_sk(new_msk)->pm.remote_deny_join_id0, true);
+
/* new mpc subflow takes ownership of the newly
* created mptcp socket
*/
--
2.51.0
Currently this is hidden behind perfmon_capable() since this is
technically an info leak, given that this is a system wide metric.
However the granularity reported here is always PAGE_SIZE aligned, which
matches what the core kernel is already willing to expose to userspace
if querying how many free RAM pages there are on the system, and that
doesn't need any special privileges. In addition other drm drivers seem
happy to expose this.
The motivation here if with oneAPI where they want to use the system
wide 'used' reporting here, so not the per-client fdinfo stats. This has
also come up with some perf overlay applications wanting this
information.
Fixes: 1105ac15d2a1 ("drm/xe/uapi: restrict system wide accounting")
Signed-off-by: Matthew Auld <matthew.auld(a)intel.com>
Cc: Thomas Hellström <thomas.hellstrom(a)linux.intel.com>
Cc: Joshua Santosh <joshua.santosh.ranjan(a)intel.com>
Cc: José Roberto de Souza <jose.souza(a)intel.com>
Cc: Matthew Brost <matthew.brost(a)intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Cc: <stable(a)vger.kernel.org> # v6.8+
---
drivers/gpu/drm/xe/xe_query.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
index e1b603aba61b..2e9ff33ed2fe 100644
--- a/drivers/gpu/drm/xe/xe_query.c
+++ b/drivers/gpu/drm/xe/xe_query.c
@@ -276,8 +276,7 @@ static int query_mem_regions(struct xe_device *xe,
mem_regions->mem_regions[0].instance = 0;
mem_regions->mem_regions[0].min_page_size = PAGE_SIZE;
mem_regions->mem_regions[0].total_size = man->size << PAGE_SHIFT;
- if (perfmon_capable())
- mem_regions->mem_regions[0].used = ttm_resource_manager_usage(man);
+ mem_regions->mem_regions[0].used = ttm_resource_manager_usage(man);
mem_regions->num_mem_regions = 1;
for (i = XE_PL_VRAM0; i <= XE_PL_VRAM1; ++i) {
@@ -293,13 +292,11 @@ static int query_mem_regions(struct xe_device *xe,
mem_regions->mem_regions[mem_regions->num_mem_regions].total_size =
man->size;
- if (perfmon_capable()) {
- xe_ttm_vram_get_used(man,
- &mem_regions->mem_regions
- [mem_regions->num_mem_regions].used,
- &mem_regions->mem_regions
- [mem_regions->num_mem_regions].cpu_visible_used);
- }
+ xe_ttm_vram_get_used(man,
+ &mem_regions->mem_regions
+ [mem_regions->num_mem_regions].used,
+ &mem_regions->mem_regions
+ [mem_regions->num_mem_regions].cpu_visible_used);
mem_regions->mem_regions[mem_regions->num_mem_regions].cpu_visible_size =
xe_ttm_vram_get_cpu_visible_size(man);
--
2.51.0
commit 2293c57484ae64c9a3c847c8807db8c26a3a4d41 upstream.
During the connection establishment, a peer can tell the other one that
it cannot establish new subflows to the initial IP address and port by
setting the 'C' flag [1]. Doing so makes sense when the sender is behind
a strict NAT, operating behind a legacy Layer 4 load balancer, or using
anycast IP address for example.
When this 'C' flag is set, the path-managers must then not try to
establish new subflows to the other peer's initial IP address and port.
The in-kernel PM has access to this info, but the userspace PM didn't.
The RFC8684 [1] is strict about that:
(...) therefore the receiver MUST NOT try to open any additional
subflows toward this address and port.
So it is important to tell the userspace about that as it is responsible
for the respect of this flag.
When a new connection is created and established, the Netlink events
now contain the existing but not currently used 'flags' attribute. When
MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows
to the initial IP address and port -- info that are also part of the
event -- can be established.
Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1]
Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment")
Reported-by: Marek Majkowski <marek(a)cloudflare.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
[ Conflicts in mptcp_pm.yaml, because the indentation has been modified
in commit ec362192aa9e ("netlink: specs: fix up indentation errors"),
which is not in this version. Applying the same modifications, but at
a different level. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
---
Documentation/netlink/specs/mptcp_pm.yaml | 4 ++--
include/uapi/linux/mptcp.h | 2 ++
include/uapi/linux/mptcp_pm.h | 4 ++--
net/mptcp/pm_netlink.c | 7 +++++++
4 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml
index 7e295bad8b29..a670a9bbe01b 100644
--- a/Documentation/netlink/specs/mptcp_pm.yaml
+++ b/Documentation/netlink/specs/mptcp_pm.yaml
@@ -28,13 +28,13 @@ definitions:
traffic-patterns it can take a long time until the
MPTCP_EVENT_ESTABLISHED is sent.
Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport,
- dport, server-side.
+ dport, server-side, [flags].
-
name: established
doc: >-
A MPTCP connection is established (can start new subflows).
Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport,
- dport, server-side.
+ dport, server-side, [flags].
-
name: closed
doc: >-
diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 67d015df8893..5fd5b4cf75ca 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -31,6 +31,8 @@
#define MPTCP_INFO_FLAG_FALLBACK _BITUL(0)
#define MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED _BITUL(1)
+#define MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 _BITUL(0)
+
#define MPTCP_PM_ADDR_FLAG_SIGNAL (1 << 0)
#define MPTCP_PM_ADDR_FLAG_SUBFLOW (1 << 1)
#define MPTCP_PM_ADDR_FLAG_BACKUP (1 << 2)
diff --git a/include/uapi/linux/mptcp_pm.h b/include/uapi/linux/mptcp_pm.h
index 6ac84b2f636c..7359d34da446 100644
--- a/include/uapi/linux/mptcp_pm.h
+++ b/include/uapi/linux/mptcp_pm.h
@@ -16,10 +16,10 @@
* good time to allocate memory and send ADD_ADDR if needed. Depending on the
* traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED
* is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6,
- * sport, dport, server-side.
+ * sport, dport, server-side, [flags].
* @MPTCP_EVENT_ESTABLISHED: A MPTCP connection is established (can start new
* subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6,
- * sport, dport, server-side.
+ * sport, dport, server-side, [flags].
* @MPTCP_EVENT_CLOSED: A MPTCP connection has stopped. Attribute: token.
* @MPTCP_EVENT_ANNOUNCED: A new address has been announced by the peer.
* Attributes: token, rem_id, family, daddr4 | daddr6 [, dport].
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index b763729b85e0..463c2e7956d5 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -2211,6 +2211,7 @@ static int mptcp_event_created(struct sk_buff *skb,
const struct sock *ssk)
{
int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token));
+ u16 flags = 0;
if (err)
return err;
@@ -2218,6 +2219,12 @@ static int mptcp_event_created(struct sk_buff *skb,
if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side)))
return -EMSGSIZE;
+ if (READ_ONCE(msk->pm.remote_deny_join_id0))
+ flags |= MPTCP_PM_EV_FLAG_DENY_JOIN_ID0;
+
+ if (flags && nla_put_u16(skb, MPTCP_ATTR_FLAGS, flags))
+ return -EMSGSIZE;
+
return mptcp_event_add_subflow(skb, ssk);
}
--
2.51.0
commit 2293c57484ae64c9a3c847c8807db8c26a3a4d41 upstream.
During the connection establishment, a peer can tell the other one that
it cannot establish new subflows to the initial IP address and port by
setting the 'C' flag [1]. Doing so makes sense when the sender is behind
a strict NAT, operating behind a legacy Layer 4 load balancer, or using
anycast IP address for example.
When this 'C' flag is set, the path-managers must then not try to
establish new subflows to the other peer's initial IP address and port.
The in-kernel PM has access to this info, but the userspace PM didn't.
The RFC8684 [1] is strict about that:
(...) therefore the receiver MUST NOT try to open any additional
subflows toward this address and port.
So it is important to tell the userspace about that as it is responsible
for the respect of this flag.
When a new connection is created and established, the Netlink events
now contain the existing but not currently used 'flags' attribute. When
MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows
to the initial IP address and port -- info that are also part of the
event -- can be established.
Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1]
Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment")
Reported-by: Marek Majkowski <marek(a)cloudflare.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
[ Conflicts in mptcp_pm.yaml, because the indentation has been modified
in commit ec362192aa9e ("netlink: specs: fix up indentation errors"),
which is not in this version. Applying the same modifications, but at
a different level. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
---
Documentation/netlink/specs/mptcp_pm.yaml | 4 ++--
include/uapi/linux/mptcp.h | 2 ++
include/uapi/linux/mptcp_pm.h | 4 ++--
net/mptcp/pm_netlink.c | 7 +++++++
4 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml
index ecfe5ee33de2..c77f32cfcae9 100644
--- a/Documentation/netlink/specs/mptcp_pm.yaml
+++ b/Documentation/netlink/specs/mptcp_pm.yaml
@@ -28,13 +28,13 @@ definitions:
traffic-patterns it can take a long time until the
MPTCP_EVENT_ESTABLISHED is sent.
Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport,
- dport, server-side.
+ dport, server-side, [flags].
-
name: established
doc: >-
A MPTCP connection is established (can start new subflows).
Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport,
- dport, server-side.
+ dport, server-side, [flags].
-
name: closed
doc: >-
diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 67d015df8893..5fd5b4cf75ca 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -31,6 +31,8 @@
#define MPTCP_INFO_FLAG_FALLBACK _BITUL(0)
#define MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED _BITUL(1)
+#define MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 _BITUL(0)
+
#define MPTCP_PM_ADDR_FLAG_SIGNAL (1 << 0)
#define MPTCP_PM_ADDR_FLAG_SUBFLOW (1 << 1)
#define MPTCP_PM_ADDR_FLAG_BACKUP (1 << 2)
diff --git a/include/uapi/linux/mptcp_pm.h b/include/uapi/linux/mptcp_pm.h
index 6ac84b2f636c..7359d34da446 100644
--- a/include/uapi/linux/mptcp_pm.h
+++ b/include/uapi/linux/mptcp_pm.h
@@ -16,10 +16,10 @@
* good time to allocate memory and send ADD_ADDR if needed. Depending on the
* traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED
* is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6,
- * sport, dport, server-side.
+ * sport, dport, server-side, [flags].
* @MPTCP_EVENT_ESTABLISHED: A MPTCP connection is established (can start new
* subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6,
- * sport, dport, server-side.
+ * sport, dport, server-side, [flags].
* @MPTCP_EVENT_CLOSED: A MPTCP connection has stopped. Attribute: token.
* @MPTCP_EVENT_ANNOUNCED: A new address has been announced by the peer.
* Attributes: token, rem_id, family, daddr4 | daddr6 [, dport].
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 50aaf259959a..ce7d42d3bd00 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -408,6 +408,7 @@ static int mptcp_event_created(struct sk_buff *skb,
const struct sock *ssk)
{
int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token));
+ u16 flags = 0;
if (err)
return err;
@@ -415,6 +416,12 @@ static int mptcp_event_created(struct sk_buff *skb,
if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side)))
return -EMSGSIZE;
+ if (READ_ONCE(msk->pm.remote_deny_join_id0))
+ flags |= MPTCP_PM_EV_FLAG_DENY_JOIN_ID0;
+
+ if (flags && nla_put_u16(skb, MPTCP_ATTR_FLAGS, flags))
+ return -EMSGSIZE;
+
return mptcp_event_add_subflow(skb, ssk);
}
--
2.51.0
Hi Sasha,
Thank you for maintaining the stable versions with Greg!
If I remember well, you run some scripts on your side to maintain the
queue/* branches in the linux-stable-rc Git tree [1], is that correct?
These branches have not been updated for a bit more than 3 weeks. Is it
normal?
Personally, I find them useful. But if it is just me, I can work without
them.
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/…
Cheers,
Matt
--
Sponsored by the NGI0 Core fund.
The patch titled
Subject: kmsan: Fix out-of-bounds access to shadow memory
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
kmsan-fix-out-of-bounds-access-to-shadow-memory.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Eric Biggers <ebiggers(a)kernel.org>
Subject: kmsan: Fix out-of-bounds access to shadow memory
Date: Thu, 11 Sep 2025 12:58:58 -0700
Running sha224_kunit on a KMSAN-enabled kernel results in a crash in
kmsan_internal_set_shadow_origin():
BUG: unable to handle page fault for address: ffffbc3840291000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0
Oops: 0000 [#1] SMP NOPTI
CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary)
Tainted: [N]=TEST
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100
[...]
Call Trace:
<TASK>
__msan_memset+0xee/0x1a0
sha224_final+0x9e/0x350
test_hash_buffer_overruns+0x46f/0x5f0
? kmsan_get_shadow_origin_ptr+0x46/0xa0
? __pfx_test_hash_buffer_overruns+0x10/0x10
kunit_try_run_case+0x198/0xa00
This occurs when memset() is called on a buffer that is not 4-byte aligned
and extends to the end of a guard page, i.e. the next page is unmapped.
The bug is that the loop at the end of kmsan_internal_set_shadow_origin()
accesses the wrong shadow memory bytes when the address is not 4-byte
aligned. Since each 4 bytes are associated with an origin, it rounds the
address and size so that it can access all the origins that contain the
buffer. However, when it checks the corresponding shadow bytes for a
particular origin, it incorrectly uses the original unrounded shadow
address. This results in reads from shadow memory beyond the end of the
buffer's shadow memory, which crashes when that memory is not mapped.
To fix this, correctly align the shadow address before accessing the 4
shadow bytes corresponding to each origin.
Link: https://lkml.kernel.org/r/20250911195858.394235-1-ebiggers@kernel.org
Fixes: 2ef3cec44c60 ("kmsan: do not wipe out origin when doing partial unpoisoning")
Signed-off-by: Eric Biggers <ebiggers(a)kernel.org>
Tested-by: Alexander Potapenko <glider(a)google.com>
Reviewed-by: Alexander Potapenko <glider(a)google.com>
Cc: Dmitriy Vyukov <dvyukov(a)google.com>
Cc: Marco Elver <elver(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/kmsan/core.c | 10 +++++++---
mm/kmsan/kmsan_test.c | 16 ++++++++++++++++
2 files changed, 23 insertions(+), 3 deletions(-)
--- a/mm/kmsan/core.c~kmsan-fix-out-of-bounds-access-to-shadow-memory
+++ a/mm/kmsan/core.c
@@ -195,7 +195,8 @@ void kmsan_internal_set_shadow_origin(vo
u32 origin, bool checked)
{
u64 address = (u64)addr;
- u32 *shadow_start, *origin_start;
+ void *shadow_start;
+ u32 *aligned_shadow, *origin_start;
size_t pad = 0;
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size));
@@ -214,9 +215,12 @@ void kmsan_internal_set_shadow_origin(vo
}
__memset(shadow_start, b, size);
- if (!IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) {
+ if (IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) {
+ aligned_shadow = shadow_start;
+ } else {
pad = address % KMSAN_ORIGIN_SIZE;
address -= pad;
+ aligned_shadow = shadow_start - pad;
size += pad;
}
size = ALIGN(size, KMSAN_ORIGIN_SIZE);
@@ -230,7 +234,7 @@ void kmsan_internal_set_shadow_origin(vo
* corresponding shadow slot is zero.
*/
for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++) {
- if (origin || !shadow_start[i])
+ if (origin || !aligned_shadow[i])
origin_start[i] = origin;
}
}
--- a/mm/kmsan/kmsan_test.c~kmsan-fix-out-of-bounds-access-to-shadow-memory
+++ a/mm/kmsan/kmsan_test.c
@@ -556,6 +556,21 @@ DEFINE_TEST_MEMSETXX(16)
DEFINE_TEST_MEMSETXX(32)
DEFINE_TEST_MEMSETXX(64)
+/* Test case: ensure that KMSAN does not access shadow memory out of bounds. */
+static void test_memset_on_guarded_buffer(struct kunit *test)
+{
+ void *buf = vmalloc(PAGE_SIZE);
+
+ kunit_info(test,
+ "memset() on ends of guarded buffer should not crash\n");
+
+ for (size_t size = 0; size <= 128; size++) {
+ memset(buf, 0xff, size);
+ memset(buf + PAGE_SIZE - size, 0xff, size);
+ }
+ vfree(buf);
+}
+
static noinline void fibonacci(int *array, int size, int start)
{
if (start < 2 || (start == size))
@@ -677,6 +692,7 @@ static struct kunit_case kmsan_test_case
KUNIT_CASE(test_memset16),
KUNIT_CASE(test_memset32),
KUNIT_CASE(test_memset64),
+ KUNIT_CASE(test_memset_on_guarded_buffer),
KUNIT_CASE(test_long_origin_chain),
KUNIT_CASE(test_stackdepot_roundtrip),
KUNIT_CASE(test_unpoison_memory),
_
Patches currently in -mm which might be from ebiggers(a)kernel.org are
kmsan-fix-out-of-bounds-access-to-shadow-memory.patch
The patch titled
Subject: Squashfs: fix uninit-value in squashfs_get_parent
has been added to the -mm mm-nonmm-unstable branch. Its filename is
squashfs-fix-uninit-value-in-squashfs_get_parent.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Phillip Lougher <phillip(a)squashfs.org.uk>
Subject: Squashfs: fix uninit-value in squashfs_get_parent
Date: Fri, 19 Sep 2025 00:33:08 +0100
Syzkaller reports a "KMSAN: uninit-value in squashfs_get_parent" bug.
This is caused by open_by_handle_at() being called with a file handle
containing an invalid parent inode number. In particular the inode number
is that of a symbolic link, rather than a directory.
Squashfs_get_parent() gets called with that symbolic link inode, and
accesses the parent member field.
unsigned int parent_ino = squashfs_i(inode)->parent;
Because non-directory inodes in Squashfs do not have a parent value, this
is uninitialised, and this causes an uninitialised value access.
The fix is to initialise parent with the invalid inode 0, which will cause
an EINVAL error to be returned.
Regular inodes used to share the parent field with the block_list_start
field. This is removed in this commit to enable the parent field to
contain the invalid inode number 0.
Link: https://lkml.kernel.org/r/20250918233308.293861-1-phillip@squashfs.org.uk
Fixes: 122601408d20 ("Squashfs: export operations")
Signed-off-by: Phillip Lougher <phillip(a)squashfs.org.uk>
Reported-by: syzbot+157bdef5cf596ad0da2c(a)syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68cc2431.050a0220.139b6.0001.GAE@google.com/
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/squashfs/inode.c | 7 +++++++
fs/squashfs/squashfs_fs_i.h | 2 +-
2 files changed, 8 insertions(+), 1 deletion(-)
--- a/fs/squashfs/inode.c~squashfs-fix-uninit-value-in-squashfs_get_parent
+++ a/fs/squashfs/inode.c
@@ -169,6 +169,7 @@ int squashfs_read_inode(struct inode *in
squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
squashfs_i(inode)->block_list_start = block;
squashfs_i(inode)->offset = offset;
+ squashfs_i(inode)->parent = 0;
inode->i_data.a_ops = &squashfs_aops;
TRACE("File inode %x:%x, start_block %llx, block_list_start "
@@ -216,6 +217,7 @@ int squashfs_read_inode(struct inode *in
squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
squashfs_i(inode)->block_list_start = block;
squashfs_i(inode)->offset = offset;
+ squashfs_i(inode)->parent = 0;
inode->i_data.a_ops = &squashfs_aops;
TRACE("File inode %x:%x, start_block %llx, block_list_start "
@@ -296,6 +298,7 @@ int squashfs_read_inode(struct inode *in
inode->i_mode |= S_IFLNK;
squashfs_i(inode)->start = block;
squashfs_i(inode)->offset = offset;
+ squashfs_i(inode)->parent = 0;
if (type == SQUASHFS_LSYMLINK_TYPE) {
__le32 xattr;
@@ -333,6 +336,7 @@ int squashfs_read_inode(struct inode *in
set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
rdev = le32_to_cpu(sqsh_ino->rdev);
init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
+ squashfs_i(inode)->parent = 0;
TRACE("Device inode %x:%x, rdev %x\n",
SQUASHFS_INODE_BLK(ino), offset, rdev);
@@ -357,6 +361,7 @@ int squashfs_read_inode(struct inode *in
set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
rdev = le32_to_cpu(sqsh_ino->rdev);
init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
+ squashfs_i(inode)->parent = 0;
TRACE("Device inode %x:%x, rdev %x\n",
SQUASHFS_INODE_BLK(ino), offset, rdev);
@@ -377,6 +382,7 @@ int squashfs_read_inode(struct inode *in
inode->i_mode |= S_IFSOCK;
set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
init_special_inode(inode, inode->i_mode, 0);
+ squashfs_i(inode)->parent = 0;
break;
}
case SQUASHFS_LFIFO_TYPE:
@@ -396,6 +402,7 @@ int squashfs_read_inode(struct inode *in
inode->i_op = &squashfs_inode_ops;
set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
init_special_inode(inode, inode->i_mode, 0);
+ squashfs_i(inode)->parent = 0;
break;
}
default:
--- a/fs/squashfs/squashfs_fs_i.h~squashfs-fix-uninit-value-in-squashfs_get_parent
+++ a/fs/squashfs/squashfs_fs_i.h
@@ -16,6 +16,7 @@ struct squashfs_inode_info {
u64 xattr;
unsigned int xattr_size;
int xattr_count;
+ int parent;
union {
struct {
u64 fragment_block;
@@ -27,7 +28,6 @@ struct squashfs_inode_info {
u64 dir_idx_start;
int dir_idx_offset;
int dir_idx_cnt;
- int parent;
};
};
struct inode vfs_inode;
_
Patches currently in -mm which might be from phillip(a)squashfs.org.uk are
squashfs-fix-uninit-value-in-squashfs_get_parent.patch