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linux/debian/patches/patchset-pf/smb/0002-ksmbd-prevent-out-of-bounds-stream-writes-by-validat.patch
2025-05-09 12:55:05 +03:00

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From fb87d390de327c76b11ed544de83771118f7b0c5 Mon Sep 17 00:00:00 2001
From: Norbert Szetei <norbert@doyensec.com>
Date: Fri, 2 May 2025 08:21:58 +0900
Subject: ksmbd: prevent out-of-bounds stream writes by validating *pos
ksmbd_vfs_stream_write() did not validate whether the write offset
(*pos) was within the bounds of the existing stream data length (v_len).
If *pos was greater than or equal to v_len, this could lead to an
out-of-bounds memory write.
This patch adds a check to ensure *pos is less than v_len before
proceeding. If the condition fails, -EINVAL is returned.
Cc: stable@vger.kernel.org
Signed-off-by: Norbert Szetei <norbert@doyensec.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
fs/smb/server/vfs.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -443,6 +443,13 @@ static int ksmbd_vfs_stream_write(struct
goto out;
}
+ if (v_len <= *pos) {
+ pr_err("stream write position %lld is out of bounds (stream length: %zd)\n",
+ *pos, v_len);
+ err = -EINVAL;
+ goto out;
+ }
+
if (v_len < size) {
wbuf = kvzalloc(size, KSMBD_DEFAULT_GFP);
if (!wbuf) {