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Apply Fragnesia fixes

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(cherry picked from commit 527de344c7)
This commit is contained in:
Koichiro Iwao 2026-05-15 04:06:05 +00:00
parent 7e436cbe54
commit b91ed68b31
2 changed files with 76 additions and 5 deletions
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64
SOURCES/1103-net-skbuff-propagate-shared-frag-marker.patch Normal file
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@ -0,0 +1,64 @@
From: Andrew Lukoshko <alukoshko@almalinux.org>
Subject: [PATCH AlmaLinux 10] net: skbuff: propagate shared-frag marker through pskb_copy()
Backport of upstream patch posted at
https://lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/
(sibling to the xfrm/esp shared-frag fix upstream commit f4c50a4034e6,
already merged into 6.12.0-124.56.1 via the c10s import).
__pskb_copy_fclone() shallow-copies the source's frag descriptors and
bumps each page's refcount via skb_frag_ref(), then defers the rest
of the shinfo metadata to skb_copy_header(). That helper only carries
over gso_{size,segs,type} and never touches skb_shinfo()->flags, so
the destination skb keeps a reference to the same externally-owned or
page-cache-backed pages while reporting skb_has_shared_frag() as
false.
The mismatch is harmful in any in-place writer that uses
skb_has_shared_frag() to decide whether shared pages must be detoured
through skb_cow_data(). ESP input is one such writer (esp4.c,
esp6.c), and a single nft 'dup to <local>' rule -- or any other
nf_dup_ipv4() / xt_TEE caller -- is enough to land a pskb_copy()'d
skb in esp_input() with the marker stripped, letting an unprivileged
user write into the page cache of a root-owned read-only file via
authencesn-ESN stray writes.
Set SKBFL_SHARED_FRAG on the destination whenever frag descriptors
were actually moved from the source. skb_copy() and skb_copy_expand()
share skb_copy_header() too but linearize all paged data into freshly
allocated head storage and emerge with nr_frags == 0, so
skb_has_shared_frag() returns false on its own; they need no change.
Verified to apply with `patch -p1 -F0` (no offset, no fuzz, no rejects)
against kernel-6.12.0-124.56.1.el10_1.
Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
Reported-by: William Bowling <vakzz@zellic.io>
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Andrew Lukoshko <alukoshko@almalinux.org>
---
net/core/skbuff.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2123,6 +2123,7 @@ struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
skb_frag_ref(skb, i);
}
skb_shinfo(n)->nr_frags = i;
+ skb_shinfo(n)->flags |= skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
}
if (skb_has_frag_list(skb)) {
@@ -6028,6 +6029,8 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
from_shinfo->frags,
from_shinfo->nr_frags * sizeof(skb_frag_t));
to_shinfo->nr_frags += from_shinfo->nr_frags;
+ if (from_shinfo->nr_frags)
+ to_shinfo->flags |= from_shinfo->flags & SKBFL_SHARED_FRAG;
if (!skb_cloned(from))
from_shinfo->nr_frags = 0;
--
2.43.0

17
SPECS/raspberrypi2.spec
View File

@ -11,7 +11,7 @@ ExclusiveArch: aarch64
%define local_version v8
%define bcmmodel 2711
%define extra_version 5
%define extra_version 6
# This originally implies Kernel 4.x for RPi 2 and is not appropriate now.
# Be careful to change this not to disturb the seamless package update.
@ -52,11 +52,14 @@ Source2000: cpupower.service
Source2001: cpupower.config
Source2002: kvm_stat.logrotate
# AlmaLinux patches
## CVE-2026-31431
## CVE-2026-31431: Copy Fail
Patch1100: 1100-CVE-2026-31431-crypto-Copy-Fail-fixes.patch
## Dirty Frag
## CVE-2026-43284: Dirty Frag
Patch1101: 1101-xfrm-esp-avoid-in-place-decrypt-shared-skb-frags.patch
## CVE-2026-43500 Dirty Frag
Patch1102: 1102-rxrpc-linearize-paged-frags.patch
## CVE-2026-46300: Fragnesia
Patch1103: 1103-net-skbuff-propagate-shared-frag-marker.patch
BuildRequires: kmod, patch, bash, coreutils, tar
BuildRequires: bzip2, xz, findutils, gzip, m4, perl, perl-Carp, make, diffutils, gawk
@ -239,6 +242,7 @@ glibc package.
%patch -P 1100 -p1
%patch -P 1101 -p1
%patch -P 1102 -p1
%patch -P 1103 -p1
perl -p -i -e "s/^EXTRAVERSION.*/EXTRAVERSION = -%{release}/" Makefile
perl -p -i -e "s/^CONFIG_LOCALVERSION=.*/CONFIG_LOCALVERSION=/" arch/%{Arch}/configs/bcm2711_defconfig
perl -p -i -e "s/^CONFIG_LOCALVERSION=.*/CONFIG_LOCALVERSION=/" arch/%{Arch}/configs/bcm2712_defconfig
@ -543,9 +547,12 @@ cp $(ls -1 /boot/config-kernel-*-*|sort -V|tail -1) /boot/config-kernel.inc
%endif
%changelog
* Thu May 14 2026 Koichiro Iwao <meta@almalinux.org> - 6.12.47-20250916.v8.6
- net: skbuff: propagate shared-frag marker through pskb_copy() {CVE-2026-46300}
* Fri May 08 2026 Koichiro Iwao <meta@almalinux.org> - 6.12.47-20250916.v8.5
- rxrpc: linearize incoming DATA packet when it has paged frags
- xfrm: esp: avoid in-place decrypt on shared skb frags
- rxrpc: linearize incoming DATA packet when it has paged frags {CVE-2026-43500}
- xfrm: esp: avoid in-place decrypt on shared skb frags {CVE-2026-43284}
* Thu Apr 30 2026 Koichiro Iwao <meta@almalinux.org> - 6.12.47-20250916.v8.4
- Update CVE-2026-31431 patch to include more upstream commits