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

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxx>.

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 eebff19acaa35820cb09ce2ccb3d21bee2156ffb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023112205-eleven-enrich-934c@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

eebff19acaa3 ("ksmbd: fix slab out of bounds write in smb_inherit_dacl()")

thanks,

greg k-h

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

>From eebff19acaa35820cb09ce2ccb3d21bee2156ffb Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Date: Sun, 5 Nov 2023 12:46:24 +0900
Subject: [PATCH] ksmbd: fix slab out of bounds write in smb_inherit_dacl()

slab out-of-bounds write is caused by that offsets is bigger than pntsd
allocation size. This patch add the check to validate 3 offsets using
allocation size.

Reported-by: zdi-disclosures@xxxxxxxxxxxxxx # ZDI-CAN-22271
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>

diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c
index 6c0305be895e..51b8bfab7481 100644
--- a/fs/smb/server/smbacl.c
+++ b/fs/smb/server/smbacl.c
@@ -1107,6 +1107,7 @@ int smb_inherit_dacl(struct ksmbd_conn *conn,
 		struct smb_acl *pdacl;
 		struct smb_sid *powner_sid = NULL, *pgroup_sid = NULL;
 		int powner_sid_size = 0, pgroup_sid_size = 0, pntsd_size;
+		int pntsd_alloc_size;
 
 		if (parent_pntsd->osidoffset) {
 			powner_sid = (struct smb_sid *)((char *)parent_pntsd +
@@ -1119,9 +1120,10 @@ int smb_inherit_dacl(struct ksmbd_conn *conn,
 			pgroup_sid_size = 1 + 1 + 6 + (pgroup_sid->num_subauth * 4);
 		}
 
-		pntsd = kzalloc(sizeof(struct smb_ntsd) + powner_sid_size +
-				pgroup_sid_size + sizeof(struct smb_acl) +
-				nt_size, GFP_KERNEL);
+		pntsd_alloc_size = sizeof(struct smb_ntsd) + powner_sid_size +
+			pgroup_sid_size + sizeof(struct smb_acl) + nt_size;
+
+		pntsd = kzalloc(pntsd_alloc_size, GFP_KERNEL);
 		if (!pntsd) {
 			rc = -ENOMEM;
 			goto free_aces_base;
@@ -1136,6 +1138,27 @@ int smb_inherit_dacl(struct ksmbd_conn *conn,
 		pntsd->gsidoffset = parent_pntsd->gsidoffset;
 		pntsd->dacloffset = parent_pntsd->dacloffset;
 
+		if ((u64)le32_to_cpu(pntsd->osidoffset) + powner_sid_size >
+		    pntsd_alloc_size) {
+			rc = -EINVAL;
+			kfree(pntsd);
+			goto free_aces_base;
+		}
+
+		if ((u64)le32_to_cpu(pntsd->gsidoffset) + pgroup_sid_size >
+		    pntsd_alloc_size) {
+			rc = -EINVAL;
+			kfree(pntsd);
+			goto free_aces_base;
+		}
+
+		if ((u64)le32_to_cpu(pntsd->dacloffset) + sizeof(struct smb_acl) + nt_size >
+		    pntsd_alloc_size) {
+			rc = -EINVAL;
+			kfree(pntsd);
+			goto free_aces_base;
+		}
+
 		if (pntsd->osidoffset) {
 			struct smb_sid *owner_sid = (struct smb_sid *)((char *)pntsd +
 					le32_to_cpu(pntsd->osidoffset));