[nanbield PATCH] arm/linux-yocto: backport patch to fix 6.5.13 networking issues

[nanbield PATCH] arm/linux-yocto: backport patch to fix 6.5.13 networking issues

[Jon Mason]

Linux kernel commit 9aea191c29e18f7c044a2f95a2da7f7b7fdd0449 (backported
to 6.5.13 as part of the stable process) introduces an bug, which is
preventing networking from functioning (and logging lots of errors in
dmesg).  Linux kernel commit 45b3fae4675dc1d4ee2d7aefa19d85ee4f891377
resolves the issue.

It is need for everything, but only applying for aarch64 to keep the
CI tooling happy.

Signed-off-by: Jon Mason <jon.mason@arm.com>
---
 ...randomize_layout-crash-in-struct-nei.patch | 46 +++++++++++++++++++
 .../linux/linux-yocto%.bbappend               |  3 ++
 2 files changed, 49 insertions(+)
 create mode 100644 meta-arm/recipes-kernel/linux/files/0001-neighbour-Fix-__randomize_layout-crash-in-struct-nei.patch

diff --git a/meta-arm/recipes-kernel/linux/files/0001-neighbour-Fix-__randomize_layout-crash-in-struct-nei.patch b/meta-arm/recipes-kernel/linux/files/0001-neighbour-Fix-__randomize_layout-crash-in-struct-nei.patch
new file mode 100644
index 000000000000..d622cbc6e4e1
--- /dev/null
+++ b/meta-arm/recipes-kernel/linux/files/0001-neighbour-Fix-__randomize_layout-crash-in-struct-nei.patch
@@ -0,0 +1,46 @@
+From 45b3fae4675dc1d4ee2d7aefa19d85ee4f891377 Mon Sep 17 00:00:00 2001
+From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
+Date: Sat, 25 Nov 2023 15:33:58 -0600
+Subject: [PATCH] neighbour: Fix __randomize_layout crash in struct neighbour
+
+Previously, one-element and zero-length arrays were treated as true
+flexible arrays, even though they are actually "fake" flex arrays.
+The __randomize_layout would leave them untouched at the end of the
+struct, similarly to proper C99 flex-array members.
+
+However, this approach changed with commit 1ee60356c2dc ("gcc-plugins:
+randstruct: Only warn about true flexible arrays"). Now, only C99
+flexible-array members will remain untouched at the end of the struct,
+while one-element and zero-length arrays will be subject to randomization.
+
+Fix a `__randomize_layout` crash in `struct neighbour` by transforming
+zero-length array `primary_key` into a proper C99 flexible-array member.
+
+Fixes: 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays")
+Closes: https://lore.kernel.org/linux-hardening/20231124102458.GB1503258@e124191.cambridge.arm.com/
+Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
+Reviewed-by: Kees Cook <keescook@chromium.org>
+Tested-by: Joey Gouly <joey.gouly@arm.com>
+Link: https://lore.kernel.org/r/ZWJoRsJGnCPdJ3+2@work
+Signed-off-by: Paolo Abeni <pabeni@redhat.com>
+
+Upstream-Status: Backport
+Signed-off-by: Jon Mason <jon.mason@arm.com>
+
+---
+ include/net/neighbour.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/include/net/neighbour.h b/include/net/neighbour.h
+index 07022bb0d44d..0d28172193fa 100644
+--- a/include/net/neighbour.h
++++ b/include/net/neighbour.h
+@@ -162,7 +162,7 @@ struct neighbour {
+ 	struct rcu_head		rcu;
+ 	struct net_device	*dev;
+ 	netdevice_tracker	dev_tracker;
+-	u8			primary_key[0];
++	u8			primary_key[];
+ } __randomize_layout;
+ 
+ struct neigh_ops {
diff --git a/meta-arm/recipes-kernel/linux/linux-yocto%.bbappend b/meta-arm/recipes-kernel/linux/linux-yocto%.bbappend
index c4e351bb39d4..76b6f4cf4023 100644
--- a/meta-arm/recipes-kernel/linux/linux-yocto%.bbappend
+++ b/meta-arm/recipes-kernel/linux/linux-yocto%.bbappend
@@ -1,5 +1,8 @@
 ARMFILESPATHS := "${THISDIR}/files:"
 
+FILESEXTRAPATHS:prepend:aarch64 = "${ARMFILESPATHS}"
+SRC_URI:append:aarch64 = " file://0001-neighbour-Fix-__randomize_layout-crash-in-struct-nei.patch"
+
 COMPATIBLE_MACHINE:generic-arm64 = "generic-arm64"
 FILESEXTRAPATHS:prepend:generic-arm64 = "${ARMFILESPATHS}"
 SRC_URI:append:generic-arm64 = " \
-- 
2.39.3 (Apple Git-146)

Re: [nanbield PATCH] arm/linux-yocto: backport patch to fix 6.5.13 networking issues

[Jon Mason]

On Tue, 12 Mar 2024 12:40:24 -0400, Jon Mason wrote:
> Linux kernel commit 9aea191c29e18f7c044a2f95a2da7f7b7fdd0449 (backported
> to 6.5.13 as part of the stable process) introduces an bug, which is
> preventing networking from functioning (and logging lots of errors in
> dmesg).  Linux kernel commit 45b3fae4675dc1d4ee2d7aefa19d85ee4f891377
> resolves the issue.
> 
> It is need for everything, but only applying for aarch64 to keep the
> CI tooling happy.
> 
> [...]

Applied, thanks!

[1/1] arm/linux-yocto: backport patch to fix 6.5.13 networking issues
      commit: 150169d01f2f57dcd65854a2a43aebef87ee8d98

Best regards,
-- 
Jon Mason <jon.mason@arm.com>