From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793701297; b=xEOq0RjmpiupQ7tHnnVsvpWNAmeDKcQEHC6W/k/k/0XOqab9UfpiPFx4zhdJMn3VMS+r uvDCSaRQbquKqDC6l1pMc9PG0SV9DH+gqhOCRVPJ1033amuNAA5rYrruLwNOKlcUNif2o NjJKpnIrf0VUsrqGVvi4ZpCqvCfiW7s9ZWIxtOiPpPg5z59Qrft7iYiTVh94PezHk06s1 eno1PStg7kUX7B1MFNAIUZD/WOkf4sNjZOvFuv8xh3LjzIQOXtwbwKuKgW6E6ZwByvxUb nqTdugSH0Eg/ize1bRPyJx4/2Zz/sKtTg35FUrDJcuabollu70opNbNrkWS3u5WFqYA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793701297; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=0PoabQsPWBYMTpHaoXBqagNlCFqrEBv4uXhBogkRGd4=; b=FKhc8QbnaGnUh0ZT1OgSi+W0zGCamRmZfUz1UoVnXjS52KkQuDm5c7AtCmcwI+JHk00f O993ht6hoAIuo3OiSRM4K3ijPPPVR3qMhiswPSGUhj2Hs88xLmvfo4UxjXKMtMsAAh5kI 1W11f6Zpy5b4qD/PLIx7aaN8aA0ugKlRH/AOBdJRmV62oL+Q+hADfeP+skTZNVyhllVvr vOo3BhmQpVdUtwbvut+jNCZ/+bfWsZDeAem8XiOFGzQ2DPH77jw0uU79cv+oSaOk9u7sD SfGAbfN5qkBrbdngc3S/4KGz+h5BaTcvGd/IxBdvRVbDyZa6eNty2ZvjGUHXUb5L6Rg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zxzYhRWt; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 438C5606B10E for ; Tue, 3 Nov 2026 10:21:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zxzYhRWt Received: by smtp.kernel.org (Postfix) with ESMTPSA id C87AD1F000C1; Tue, 3 Nov 2026 10:21:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793701297; bh=0PoabQsPWBYMTpHaoXBqagNlCFqrEBv4uXhBogkRGd4=; h=Subject:To:Cc:From:Date; b=zxzYhRWtk5osCFI8OHuy17fT2zQPogZ6ULDuVC2GNGlBAXJsQSKvP1s+X/Qd4qQ0q 1M9ejM5X1HiKTuBiMzfgdNX3Ddv+epT/kVQaamtBcj/GUCtBmp/Sc9pAXBiZVFjZfo DKVDJNPbcnGXIPS2WWyM+G5pOhLKCkUCuoKoOpuI= Subject: FAILED: patch "[PATCH] ksmbd: fix named stream write and EOF handling" failed to apply to 7.3-stable tree To: charsyam@gmail.com,linkinjeon@kernel.org Cc: From: Date: Tue, 03 Nov 2026 11:21:30 +0100 Message-ID: <2026110330-handbook-dreadlock-76b4@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 7.3-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 . 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-7.3.y git checkout FETCH_HEAD git cherry-pick -x 02165c8d402392278a5cd2cf97645ed73a7ad4a1 # git commit -s git send-email --to '' --in-reply-to '2026110330-handbook-dreadlock-76b4@gregkh' --subject-prefix 'PATCH 7.3.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 02165c8d402392278a5cd2cf97645ed73a7ad4a1 Mon Sep 17 00:00:00 2001 From: DaeMyung Kang Date: Wed, 7 Oct 2026 22:13:51 +0900 Subject: [PATCH] ksmbd: fix named stream write and EOF handling An SMB WRITE to an existing named stream can silently discard data after its written range. ksmbd stores streams as xattr values, but the write path passes offset + count as the length of the replacement xattr even when the old stream is longer. Writing 26 bytes at offset 0 to a 60-byte stream reports 26 bytes written while discarding the remaining 34 bytes. Keep the existing xattr length when an in-place write ends before EOF. Reject writes that cross XATTR_SIZE_MAX rather than storing only the portion that fits while reporting the full requested count. Commit 4ea0bb8aaedf ("ksmbd: handle set/get info file for streamed file") intentionally skipped ordinary inode truncation for stream handles: an EOF SetInfo on an ADS had truncated the base file. That fixed the base file corruption but left stream EOF changes reporting success without resizing the stream. Handle these requests by resizing only the stream xattr; the base file size remains untouched. Zero-fill stream extensions. This is needed alongside the write fix: a short write's accidental truncation previously masked an ignored explicit EOF change. The stream resize helper returns xattr errors directly rather than using the base-file truncate path's EBADF conversion. Fixes: f44158485826 ("cifsd: add file operations") Fixes: 4ea0bb8aaedf ("ksmbd: handle set/get info file for streamed file") Cc: stable@vger.kernel.org Signed-off-by: DaeMyung Kang Signed-off-by: Namjae Jeon diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index a400f9912896..0fb146b612f0 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -8578,6 +8578,8 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp, newsize = le64_to_cpu(file_eof_info->EndOfFile); inode = file_inode(fp->filp); + if (ksmbd_stream_fd(fp)) + return ksmbd_vfs_stream_truncate(fp, newsize); /* * If FILE_END_OF_FILE_INFORMATION of set_info_file is called @@ -8586,8 +8588,7 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp, * truncate of some filesystem like FAT32 fill zero data in * truncated range. */ - if (inode->i_sb->s_magic != MSDOS_SUPER_MAGIC && - ksmbd_stream_fd(fp) == false) { + if (inode->i_sb->s_magic != MSDOS_SUPER_MAGIC) { ksmbd_debug(SMB, "truncated to newsize %lld\n", newsize); rc = ksmbd_vfs_truncate(work, fp, newsize); if (rc) { diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index 2e2c554bc2c1..8bb93196acb9 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -388,23 +388,21 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos, const struct cred *saved_cred; char *stream_buf = NULL, *wbuf; const struct mnt_idmap *idmap = file_mnt_idmap(fp->filp); - size_t size; + size_t size, write_end; ssize_t v_len; int err = 0; ksmbd_debug(VFS, "write stream data pos : %llu, count : %zd\n", *pos, count); - if (*pos >= XATTR_SIZE_MAX) { + if (*pos < 0 || *pos >= XATTR_SIZE_MAX) { pr_err("stream write position %lld is out of bounds\n", *pos); return -EINVAL; } - size = *pos + count; - if (size > XATTR_SIZE_MAX) { - size = XATTR_SIZE_MAX; - count = XATTR_SIZE_MAX - *pos; - } + if (count > XATTR_SIZE_MAX - *pos) + return -EFBIG; + write_end = *pos + count; saved_cred = override_creds(fp->filp->f_cred); v_len = ksmbd_vfs_getcasexattr(idmap, @@ -417,6 +415,8 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos, err = v_len; goto out_revert; } + /* Preserve the tail of an existing stream on an in-place write. */ + size = max_t(size_t, v_len, write_end); if (v_len < size) { wbuf = kvzalloc(size, KSMBD_DEFAULT_GFP); @@ -445,13 +445,69 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos, if (err < 0) goto out; else - fp->stream.pos = size; + fp->stream.pos = write_end; err = 0; out: kvfree(stream_buf); return err; } +/** + * ksmbd_vfs_stream_truncate() - change the length of a named stream + * @fp: stream file handle + * @newsize: new stream length + * + * Resize the stream xattr without changing the base inode size. + * + * Return: 0 on success, otherwise a negative error code + */ +int ksmbd_vfs_stream_truncate(struct ksmbd_file *fp, loff_t newsize) +{ + const struct cred *saved_cred; + const struct mnt_idmap *idmap = file_mnt_idmap(fp->filp); + char *stream_buf = NULL, *new_buf = NULL; + ssize_t v_len; + int err; + + if (newsize < 0) + return -EINVAL; + if (newsize > XATTR_SIZE_MAX) + return -EFBIG; + + saved_cred = override_creds(fp->filp->f_cred); + v_len = ksmbd_vfs_getcasexattr(idmap, fp->filp->f_path.dentry, + fp->stream.name, fp->stream.size, + &stream_buf); + if (v_len < 0) { + err = v_len; + goto out; + } + if (v_len == newsize) { + err = 0; + goto out; + } + + new_buf = stream_buf; + if (newsize > v_len) { + new_buf = kvzalloc(newsize, KSMBD_DEFAULT_GFP); + if (!new_buf) { + err = -ENOMEM; + goto out; + } + if (v_len) + memcpy(new_buf, stream_buf, v_len); + } + + err = ksmbd_vfs_setxattr(idmap, &fp->filp->f_path, fp->stream.name, + new_buf, newsize, 0, true); + if (new_buf != stream_buf) + kvfree(new_buf); +out: + kvfree(stream_buf); + revert_creds(saved_cred); + return err; +} + /** * ksmbd_vfs_write() - vfs helper for smb file write * @work: work diff --git a/fs/smb/server/vfs.h b/fs/smb/server/vfs.h index 216c76291fc1..7e545d13a3ff 100644 --- a/fs/smb/server/vfs.h +++ b/fs/smb/server/vfs.h @@ -83,6 +83,7 @@ int ksmbd_vfs_read(struct ksmbd_work *work, struct ksmbd_file *fp, size_t count, int ksmbd_vfs_write(struct ksmbd_work *work, struct ksmbd_file *fp, char *buf, size_t count, loff_t *pos, bool sync, ssize_t *written); +int ksmbd_vfs_stream_truncate(struct ksmbd_file *fp, loff_t newsize); int ksmbd_vfs_fsync(struct ksmbd_work *work, u64 fid, u64 p_id); int ksmbd_vfs_remove_file(struct ksmbd_work *work, const struct path *path); int ksmbd_vfs_link(struct ksmbd_work *work,