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=1794061838; b=UJbgjCgkVH5QEbBK29V9pn4Ia4/IAuzl2K376pBKuEelCauFSRu2Bk62+vrkx7olrkXx zsg3XrBGZNGpV54JebjhTydWWEassdJamiB/4RnsQPDUD5dIurK1NCeFj7VwsDydiSQXr tEG7nsrELx7p+Z4Wm4YGBC9UKikgqDfV1LhoqNE5Shv21qNjInHSeTEp9QbUDT3mQImQ9 LeF0qSU7RcpasYN6rRtqdzvzqtGODBUZXyqhVIqdEy61xra3dJGH8Nb2lI5UJJUtRNsd+ 86BvRJUxywVqi0EmWxY3d1zhW3iomRSjiT1ecx0Kp/0iwvQ/Z8/zOTuTqCspMQJP8nw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061838; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=hOAKEbXfriQWK6BspwcxoLMpHbv4u0sjpPJhjnxzKcA=; b=C5MROXGfrCYrlObb9igBmRZ74bNqDCdV5bQZ7FGGEjhGWKH3v5PD4i47bEbK5e9i/vvx OFs6LHOE5xNdaUVwj7hYEqbTuvErN89wSOx9ziAvUazG+4JFfoFxTC7P6EZ1VEoVdEnrq ACtSR3IL8PgprZ9v/bUfasfkZ+lneGhM6U9unDWXY5tOzuYlaPMLqoWY/KoEbFMTrUX24 wHNr+hul9LEqY17z3uDj3c4H770Bnyz5K1heToA860+nTEyZMDDRNWTNgEMjZrJ0Z7SQq 7b/KEaGjLVjU3IzkW6IAti43BQ7sQ2NpkoWSUFOg2sQ/4Em2sLos1ouVHw8y1eKlSPw== 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=sOEV7c7I; 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 324C4606A32C; Sat, 7 Nov 2026 14:30:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=sOEV7c7I Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF75A1F008A1; Sat, 7 Nov 2026 14:30:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061838; bh=hOAKEbXfriQWK6BspwcxoLMpHbv4u0sjpPJhjnxzKcA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sOEV7c7Izh4uF/6BMg8UyJ4yYk6Zv5bgkrisGdiB5MrMqEyBAc7CC56HefM2EBV9e 1f7MbBzq2wpihp3YoEBiLnUMpDR7hXc2HBmGHqSxdwZAXATE+9ifWvAXfCgdyIpmag J5u1RVcNUV3JFiAiDFq0ysvCs47sux5sqI5KDOHo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, DaeMyung Kang , Namjae Jeon , Sasha Levin Subject: [PATCH 6.12 0857/1536] ksmbd: fix named stream write and EOF handling Date: Sat, 7 Nov 2026 08:47:53 -0500 Message-ID: <20261107135021.620185666@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore 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-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: DaeMyung Kang [ Upstream commit 02165c8d402392278a5cd2cf97645ed73a7ad4a1 ] 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 [ sashal: adapted fp->stream.pos updates to fp->filp->f_pos because the separate stream position field is absent ] Signed-off-by: Sasha Levin --- fs/smb/server/smb2pdu.c | 2 ++ fs/smb/server/vfs.c | 72 ++++++++++++++++++++++++++++++++++++----- fs/smb/server/vfs.h | 1 + 3 files changed, 67 insertions(+), 8 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index d6e7740790397..4e0f43051d9e0 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -6577,6 +6577,8 @@ 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 diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index 21ae65b2d3e4b..dafb92aa39a6c 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -416,23 +416,21 @@ 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; 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, @@ -445,6 +443,8 @@ 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); @@ -473,13 +473,69 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos, if (err < 0) goto out; - fp->filp->f_pos = *pos; + fp->filp->f_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; + 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 d0e05eca8616e..397dd2dd09886 100644 --- a/fs/smb/server/vfs.h +++ b/fs/smb/server/vfs.h @@ -82,6 +82,7 @@ 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, -- 2.53.0