[packages/kernel/LINUX_6_18] Rel 2; add fragnesia rfc v5 patch that for now
arekm
arekm at pld-linux.org
Sat May 16 23:02:48 CEST 2026
commit 447e397a4beacde3bc2ca12a8682cb4d44244f69
Author: Arkadiusz Miśkiewicz <arekm at maven.pl>
Date: Sat May 16 23:02:31 2026 +0200
Rel 2; add fragnesia rfc v5 patch that for now
kernel-small_fixes.patch | 168 +++++++++++++++++++++++++++++++++++++++++++++++
kernel.spec | 2 +-
2 files changed, 169 insertions(+), 1 deletion(-)
---
diff --git a/kernel.spec b/kernel.spec
index 3516cee6..c9cf0ff0 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -51,7 +51,7 @@
%define have_drm 0
%endif
-%define rel 1
+%define rel 2
%define basever 6.18
%define postver .31
diff --git a/kernel-small_fixes.patch b/kernel-small_fixes.patch
index 6806f98b..f8a0db43 100644
--- a/kernel-small_fixes.patch
+++ b/kernel-small_fixes.patch
@@ -1 +1,169 @@
; nothing for now
+Date: Sat, 16 May 2026 07:28:53 +0900
+From: Hyunwoo Kim <imv4bel at gmail.com>
+Subject: [PATCH net v5] net: skbuff: propagate shared-frag marker through
+ frag-transfer helpers
+
+Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail
+to propagate the SKBFL_SHARED_FRAG bit in skb_shinfo()->flags when
+moving frags from source to destination. __pskb_copy_fclone() defers
+the rest of the shinfo metadata to skb_copy_header() after copying
+frag descriptors, but that helper only carries over gso_{size,segs,
+type} and never touches skb_shinfo()->flags; skb_shift() moves frag
+descriptors directly and leaves flags untouched. As a result, 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.
+
+The same omission exists in skb_gro_receive() and skb_gro_receive_list().
+The former moves the incoming skb's frag descriptors into the
+accumulator's last sub-skb via two paths (a direct frag-move loop and
+the head_frag + memcpy path); the latter chains the incoming skb whole
+onto p's frag_list. Downstream skb_segment() reads only
+skb_shinfo(p)->flags, and skb_segment_list() reuses each sub-skb's
+shinfo as the nskb -- both p and lp must carry the marker.
+
+The same omission also exists in tcp_clone_payload(), which builds an
+MTU probe skb by moving frag descriptors from skbs on sk_write_queue
+into a freshly allocated nskb. The helper falls into the same family
+and warrants the same fix for consistency; no TCP TX-side in-place
+writer is currently known to reach a user page through this gap, but
+a future consumer depending on the marker would regress silently.
+
+The same omission exists in skb_segment(): the per-iteration flag
+merge takes only head_skb's flag, and the inner switch that rebinds
+frag_skb to list_skb on head_skb-frags exhaustion does not fold the
+new frag_skb's flag into nskb. Fold frag_skb's flag at both sites
+so segments drawing frags from frag_list members carry the marker.
+
+Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
+Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
+Suggested-by: Sabrina Dubroca <sd at queasysnail.net>
+Suggested-by: Sultan Alsawaf <sultan at kerneltoast.com>
+Suggested-by: Ben Hutchings <ben at decadent.org.uk>
+Suggested-by: Lin Ma <malin89 at huawei.com>
+Suggested-by: Jingguo Tan <tanjingguo at huawei.com>
+Suggested-by: Aaron Esau <aaron1esau at gmail.com>
+Cc: stable at vger.kernel.org
+Signed-off-by: Hyunwoo Kim <imv4bel at gmail.com>
+---
+Changes in v5:
+- Propagate SHARED_FRAG in skb_segment()
+- v4: https://lore.kernel.org/all/aga1VyHpHaUhnGZa@v4bel/
+
+Changes in v4:
+- Include the tcp_clone_payload() propagation suggested by Sabrina
+- Drop the skb_try_coalesce() change; addressed by commit f84eca581739.
+- v3: https://lore.kernel.org/all/agW4vC0r8QOUKtRT@v4bel/
+
+Changes in v3:
+- Include the skb_gro_receive() audit patch suggested by Sultan
+- v2: https://lore.kernel.org/all/agToIEDI4TaTNLRb@v4bel/
+
+Changes in v2:
+- Also propagate SHARED_FRAG in skb_try_coalesce() and skb_shift()
+- v1: https://lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/
+---
+ net/core/gro.c | 4 ++++
+ net/core/skbuff.c | 9 ++++++++-
+ net/ipv4/tcp_output.c | 1 +
+ 3 files changed, 13 insertions(+), 1 deletion(-)
+
+diff --git a/net/core/gro.c b/net/core/gro.c
+index 31d21de5b15a..9f8960789b2c 100644
+--- a/net/core/gro.c
++++ b/net/core/gro.c
+@@ -213,10 +213,12 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
+ p->data_len += len;
+ p->truesize += delta_truesize;
+ p->len += len;
++ skb_shinfo(p)->flags |= skbinfo->flags & SKBFL_SHARED_FRAG;
+ if (lp != p) {
+ lp->data_len += len;
+ lp->truesize += delta_truesize;
+ lp->len += len;
++ skb_shinfo(lp)->flags |= skbinfo->flags & SKBFL_SHARED_FRAG;
+ }
+ NAPI_GRO_CB(skb)->same_flow = 1;
+ return 0;
+@@ -244,6 +246,8 @@ int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
+ p->truesize += skb->truesize;
+ p->len += skb->len;
+
++ skb_shinfo(p)->flags |= skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
++
+ NAPI_GRO_CB(skb)->same_flow = 1;
+
+ return 0;
+diff --git a/net/core/skbuff.c b/net/core/skbuff.c
+index 9c4e8d331d6d..44ac121cfccb 100644
+--- a/net/core/skbuff.c
++++ b/net/core/skbuff.c
+@@ -2248,6 +2248,7 @@ 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)) {
+@@ -4349,6 +4350,8 @@ int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
+ tgt->ip_summed = CHECKSUM_PARTIAL;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+
++ skb_shinfo(tgt)->flags |= skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
++
+ skb_len_add(skb, -shiftlen);
+ skb_len_add(tgt, shiftlen);
+
+@@ -4959,7 +4962,8 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
+ skb_copy_from_linear_data_offset(head_skb, offset,
+ skb_put(nskb, hsize), hsize);
+
+- skb_shinfo(nskb)->flags |= skb_shinfo(head_skb)->flags &
++ skb_shinfo(nskb)->flags |= (skb_shinfo(head_skb)->flags |
++ skb_shinfo(frag_skb)->flags) &
+ SKBFL_SHARED_FRAG;
+
+ if (skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC))
+@@ -4976,6 +4980,9 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
++
++ skb_shinfo(nskb)->flags |= skb_shinfo(frag_skb)->flags & SKBFL_SHARED_FRAG;
++
+ if (!skb_headlen(list_skb)) {
+ BUG_ON(!nfrags);
+ } else {
+diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
+index f9d8755705f7..6e4bb411dc04 100644
+--- a/net/ipv4/tcp_output.c
++++ b/net/ipv4/tcp_output.c
+@@ -2626,6 +2626,7 @@ static int tcp_clone_payload(struct sock *sk, struct sk_buff *to,
+ todo = min_t(int, skb_frag_size(fragfrom),
+ probe_size - len);
+ len += todo;
++ skb_shinfo(to)->flags |= skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
+ if (lastfrag &&
+ skb_frag_page(fragfrom) == skb_frag_page(lastfrag) &&
+ skb_frag_off(fragfrom) == skb_frag_off(lastfrag) +
+--
+2.43.0
+
+
================================================================
---- gitweb:
http://git.pld-linux.org/gitweb.cgi/packages/kernel.git/commitdiff/447e397a4beacde3bc2ca12a8682cb4d44244f69
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