FAILED: patch "[PATCH] ksmbd: fix slab-out-of-bounds in smb_strndup_from_utf16()" failed to apply to 5.15-stable tree - Linux-stable-mirror

2 Jan 2024

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x d10c77873ba1e9e6b91905018e29e196fd5f863d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024010241-define-gangly-9bf9@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
d10c77873ba1 ("ksmbd: fix slab-out-of-bounds in smb_strndup_from_utf16()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From d10c77873ba1e9e6b91905018e29e196fd5f863d Mon Sep 17 00:00:00 2001
From: Namjae Jeon linkinjeon@kernel.org
Date: Wed, 20 Dec 2023 15:52:11 +0900
Subject: [PATCH] ksmbd: fix slab-out-of-bounds in smb_strndup_from_utf16()
If ->NameOffset/Length is bigger than ->CreateContextsOffset/Length,
ksmbd_check_message doesn't validate request buffer it correctly.
So slab-out-of-bounds warning from calling smb_strndup_from_utf16()
in smb2_open() could happen. If ->NameLength is non-zero, Set the larger
of the two sums (Name and CreateContext size) as the offset and length of
the data area.
Reported-by: Yang Chaoming lometsj@live.com
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon linkinjeon@kernel.org
Signed-off-by: Steve French stfrench@microsoft.com

diff --git a/fs/smb/server/smb2misc.c b/fs/smb/server/smb2misc.c
index 23bd3d1209df..03dded29a980 100644
--- a/fs/smb/server/smb2misc.c
+++ b/fs/smb/server/smb2misc.c
@@ -106,16 +106,25 @@ static int smb2_get_data_area_len(unsigned int *off, unsigned int *len,
    	break;
    case SMB2_CREATE:
    {
+		unsigned short int name_off =
+			le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
+		unsigned short int name_len =
+			le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
+
    	if (((struct smb2_create_req *)hdr)->CreateContextsLength) {
    		*off = le32_to_cpu(((struct smb2_create_req *)
    			hdr)->CreateContextsOffset);
    		*len = le32_to_cpu(((struct smb2_create_req *)
    			hdr)->CreateContextsLength);
-			break;
+			if (!name_len)
+				break;
+
+			if (name_off + name_len < (u64)*off + *len)
+				break;
    	}
-		*off = le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
-		*len = le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
+		*off = name_off;
+		*len = name_len;
    	break;
    }
    case SMB2_QUERY_INFO:

    