Subject: FAILED: patch "[PATCH] hfs/hfsplus: fix u32 overflow in" failed to apply to 6.18-stable tree
To: tristan@talencesecurity.com,slava@dubeyko.com
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Tue, 14 Jul 2026 17:48:26 +0200
Message-ID: <2026071426-subplot-sinister-60df@gregkh>
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The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 966cb76fb2857a4242cab6ea2ea17acf818a3da7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071426-subplot-sinister-60df@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 966cb76fb2857a4242cab6ea2ea17acf818a3da7 Mon Sep 17 00:00:00 2001
From: Tristan Madani <tristan@talencesecurity.com>
Date: Tue, 5 May 2026 11:12:58 +0000
Subject: [PATCH] hfs/hfsplus: fix u32 overflow in
 check_and_correct_requested_length

check_and_correct_requested_length() compares (off + len) against
node_size using u32 arithmetic.  When the caller passes a large len
value (e.g. from an underflowed subtraction in hfs_brec_remove()),
off + len can wrap past 2^32 and produce a small result, causing the
bounds check to pass when it should fail.

For example, with off=14 and len=0xFFFFFFF2 (underflowed from
data_off - keyoffset - size in hfs_brec_remove), off + len wraps to 6,
which is less than a typical node_size of 512, so the check passes and
the subsequent memmove reads ~4GB past the node buffer.

Fix this by widening the addition to u64 before comparing against
node_size.  This prevents the u32 wrap while keeping the logic
straightforward.

Reported-by: syzbot+6df204b70bf3261691c5@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6df204b70bf3261691c5
Tested-by: syzbot+6df204b70bf3261691c5@syzkaller.appspotmail.com
Reported-by: syzbot+e76bf3d19b85350571ac@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e76bf3d19b85350571ac
Tested-by: syzbot+e76bf3d19b85350571ac@syzkaller.appspotmail.com
Fixes: a431930c9bac ("hfs: fix slab-out-of-bounds in hfs_bnode_read()")
Cc: stable@vger.kernel.org
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20260505111300.3592757-2-tristmd@gmail.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>

diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c
index b0165de7640d..3a8a3878d7b0 100644
--- a/fs/hfs/bnode.c
+++ b/fs/hfs/bnode.c
@@ -41,7 +41,7 @@ u32 check_and_correct_requested_length(struct hfs_bnode *node, u32 off, u32 len)
 
 	node_size = node->tree->node_size;
 
-	if ((off + len) > node_size) {
+	if ((u64)off + len > node_size) {
 		u32 new_len = node_size - off;
 
 		pr_err("requested length has been corrected: "
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 3545b8dbf11c..0e4268de9e60 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -600,7 +600,7 @@ u32 check_and_correct_requested_length(struct hfs_bnode *node, u32 off, u32 len)
 
 	node_size = node->tree->node_size;
 
-	if ((off + len) > node_size) {
+	if ((u64)off + len > node_size) {
 		u32 new_len = node_size - off;
 
 		pr_err("requested length has been corrected: "