From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Wed, 22 May 2024 23:14:08 +0000 (-0400)
Subject: bcachefs: Fix unsafety in bch2_dirent_name_bytes()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2195b755ebd23992c5758d2d02a8080eac2baeca;p=linux.git

bcachefs: Fix unsafety in bch2_dirent_name_bytes()

Reported-by: syzbot+84fa6fb8c7f98b93cdea@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---

diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index 6bbf9a7d9e4d2..c67460d8205db 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -15,6 +15,9 @@
 
 static unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
 {
+	if (bkey_val_bytes(d.k) < offsetof(struct bch_dirent, d_name))
+		return 0;
+
 	unsigned bkey_u64s = bkey_val_u64s(d.k);
 	unsigned bkey_bytes = bkey_u64s * sizeof(u64);
 	u64 last_u64 = ((u64*)d.v)[bkey_u64s - 1];