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[68.48.65.54]) by smtp.gmail.com with ESMTPSA id af79cd13be357-92ee5cfdbc7sm89500985a.22.2026.07.09.19.32.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jul 2026 19:32:01 -0700 (PDT) From: Michael Bommarito To: Hans de Goede Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] vboxsf: validate directory entry name length Date: Thu, 9 Jul 2026 22:31:56 -0400 Message-ID: <20260710023156.3749541-1-michael.bommarito@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Shared-folder dir entries carry host-reported size and length fields. vboxsf_dir_emit() checks that name.size fits in the returned buffer, but later passes name.length to vboxsf_nlscpy() or dir_emit() unchecked, so malformed host data can make the guest read past the shfl_string buffer. Reject entries whose name.length exceeds name.size before either consumer. Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support") Assisted-by: Claude:claude-fable-5 Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito --- fs/vboxsf/dir.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/vboxsf/dir.c b/fs/vboxsf/dir.c index 42bedc4ec7af7..702d243169936 100644 --- a/fs/vboxsf/dir.c +++ b/fs/vboxsf/dir.c @@ -129,6 +129,8 @@ static bool vboxsf_dir_emit(struct file *dir, struct dir_context *ctx) end = &info->name.string.utf8[info->name.size]; if (WARN_ON(end > (b->buf + b->used))) return false; + if (info->name.length > info->name.size) + return false; /* Info now points to the right entry, emit it. */ d_type = vboxsf_get_d_type(info->info.attr.mode); -- 2.53.0