Patch "ksmbd: avoid duplicate negotiate ctx offset increments" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ksmbd: avoid duplicate negotiate ctx offset increments

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ksmbd-avoid-duplicate-negotiate-ctx-offset-increment.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 4924fc112ba07a4b6bda253325d9fcae7447c09b
Author: David Disseldorp <ddiss@xxxxxxx>
Date:   Sun Dec 31 16:12:34 2023 +0900

    ksmbd: avoid duplicate negotiate ctx offset increments
    
    [ Upstream commit a12a07a85aff72e19520328f78b1c64d2281a1ec ]
    
    Both pneg_ctxt and ctxt_size change in unison, with each adding the
    length of the previously added context, rounded up to an eight byte
    boundary.
    Drop pneg_ctxt increments and instead use the ctxt_size offset when
    passing output pointers to per-context helper functions. This slightly
    simplifies offset tracking and shaves off a few text bytes.
    Before (x86-64 gcc 7.5):
       text    data     bss     dec     hex filename
     213234    8677     672  222583   36577 ksmbd.ko
    
    After:
       text    data     bss     dec     hex filename
     213218    8677     672  222567   36567 ksmbd.ko
    
    Signed-off-by: David Disseldorp <ddiss@xxxxxxx>
    Acked-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
    Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index c7d43c83d2335..92e6570972437 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -838,7 +838,7 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn,
 				  struct smb2_negotiate_rsp *rsp,
 				  void *smb2_buf_len)
 {
-	char *pneg_ctxt = (char *)rsp +
+	char * const pneg_ctxt = (char *)rsp +
 			le32_to_cpu(rsp->NegotiateContextOffset);
 	int neg_ctxt_cnt = 1;
 	int ctxt_size;
@@ -849,21 +849,17 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn,
 			   conn->preauth_info->Preauth_HashId);
 	inc_rfc1001_len(smb2_buf_len, AUTH_GSS_PADDING);
 	ctxt_size = sizeof(struct smb2_preauth_neg_context);
-	/* Round to 8 byte boundary */
-	pneg_ctxt += round_up(sizeof(struct smb2_preauth_neg_context), 8);
 
 	if (conn->cipher_type) {
+		/* Round to 8 byte boundary */
 		ctxt_size = round_up(ctxt_size, 8);
 		ksmbd_debug(SMB,
 			    "assemble SMB2_ENCRYPTION_CAPABILITIES context\n");
-		build_encrypt_ctxt((struct smb2_encryption_neg_context *)pneg_ctxt,
+		build_encrypt_ctxt((struct smb2_encryption_neg_context *)
+				   (pneg_ctxt + ctxt_size),
 				   conn->cipher_type);
 		neg_ctxt_cnt++;
 		ctxt_size += sizeof(struct smb2_encryption_neg_context) + 2;
-		/* Round to 8 byte boundary */
-		pneg_ctxt +=
-			round_up(sizeof(struct smb2_encryption_neg_context) + 2,
-				 8);
 	}
 
 	if (conn->compress_algorithm) {
@@ -871,31 +867,29 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn,
 		ksmbd_debug(SMB,
 			    "assemble SMB2_COMPRESSION_CAPABILITIES context\n");
 		/* Temporarily set to SMB3_COMPRESS_NONE */
-		build_compression_ctxt((struct smb2_compression_capabilities_context *)pneg_ctxt,
+		build_compression_ctxt((struct smb2_compression_capabilities_context *)
+				       (pneg_ctxt + ctxt_size),
 				       conn->compress_algorithm);
 		neg_ctxt_cnt++;
 		ctxt_size += sizeof(struct smb2_compression_capabilities_context) + 2;
-		/* Round to 8 byte boundary */
-		pneg_ctxt += round_up(sizeof(struct smb2_compression_capabilities_context) + 2,
-				      8);
 	}
 
 	if (conn->posix_ext_supported) {
 		ctxt_size = round_up(ctxt_size, 8);
 		ksmbd_debug(SMB,
 			    "assemble SMB2_POSIX_EXTENSIONS_AVAILABLE context\n");
-		build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);
+		build_posix_ctxt((struct smb2_posix_neg_context *)
+				 (pneg_ctxt + ctxt_size));
 		neg_ctxt_cnt++;
 		ctxt_size += sizeof(struct smb2_posix_neg_context);
-		/* Round to 8 byte boundary */
-		pneg_ctxt += round_up(sizeof(struct smb2_posix_neg_context), 8);
 	}
 
 	if (conn->signing_negotiated) {
 		ctxt_size = round_up(ctxt_size, 8);
 		ksmbd_debug(SMB,
 			    "assemble SMB2_SIGNING_CAPABILITIES context\n");
-		build_sign_cap_ctxt((struct smb2_signing_capabilities *)pneg_ctxt,
+		build_sign_cap_ctxt((struct smb2_signing_capabilities *)
+				    (pneg_ctxt + ctxt_size),
 				    conn->signing_algorithm);
 		neg_ctxt_cnt++;
 		ctxt_size += sizeof(struct smb2_signing_capabilities) + 2;