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eb3e28c1e8
linux/fs/cifs/smb2file.c
Kees Cook eb3e28c1e8 smb3: Replace smb2pdu 1-element arrays with flex-arrays 
The kernel is globally removing the ambiguous 0-length and 1-element
arrays in favor of flexible arrays, so that we can gain both compile-time
and run-time array bounds checking[1].

Replace the trailing 1-element array with a flexible array in the
following structures:

	struct smb2_err_rsp
	struct smb2_tree_connect_req
	struct smb2_negotiate_rsp
	struct smb2_sess_setup_req
	struct smb2_sess_setup_rsp
	struct smb2_read_req
	struct smb2_read_rsp
	struct smb2_write_req
	struct smb2_write_rsp
	struct smb2_query_directory_req
	struct smb2_query_directory_rsp
	struct smb2_set_info_req
	struct smb2_change_notify_rsp
	struct smb2_create_rsp
	struct smb2_query_info_req
	struct smb2_query_info_rsp

Replace the trailing 1-element array with a flexible array, but leave
the existing structure padding:

	struct smb2_file_all_info
	struct smb2_lock_req

Adjust all related size calculations to match the changes to sizeof().

No machine code output or .data section differences are produced after
these changes.

[1] For lots of details, see both:
    https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
    https://people.kernel.org/kees/bounded-flexible-arrays-in-c

Cc: Steve French <sfrench@samba.org>
Cc: Paulo Alcantara <pc@cjr.nz>
Cc: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-02-20 17:25:43 -06:00

372 lines
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// SPDX-License-Identifier: LGPL-2.1
/*
*
* Copyright (C) International Business Machines Corp., 2002, 2011
* Author(s): Steve French (sfrench@us.ibm.com),
* Pavel Shilovsky ((pshilovsky@samba.org) 2012
*
*/
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <asm/div64.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "fscache.h"
#include "smb2proto.h"
#include "smb2status.h"
static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov)
{
struct smb2_err_rsp *err = iov->iov_base;
struct smb2_symlink_err_rsp *sym = ERR_PTR(-EINVAL);
u32 len;
if (err->ErrorContextCount) {
struct smb2_error_context_rsp *p, *end;
len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
ErrorContextData) +
sizeof(struct smb2_symlink_err_rsp));
if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err) + 1)
return ERR_PTR(-EINVAL);
p = (struct smb2_error_context_rsp *)err->ErrorData;
end = (struct smb2_error_context_rsp *)((u8 *)err + iov->iov_len);
do {
if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) {
sym = (struct smb2_symlink_err_rsp *)&p->ErrorContextData;
break;
}
cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n",
__func__, le32_to_cpu(p->ErrorId));
len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);
p = (struct smb2_error_context_rsp *)((u8 *)&p->ErrorContextData + len);
} while (p < end);
} else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) &&
iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) {
sym = (struct smb2_symlink_err_rsp *)err->ErrorData;
}
if (!IS_ERR(sym) && (le32_to_cpu(sym->SymLinkErrorTag) != SYMLINK_ERROR_TAG ||
le32_to_cpu(sym->ReparseTag) != IO_REPARSE_TAG_SYMLINK))
sym = ERR_PTR(-EINVAL);
return sym;
}
int smb2_parse_symlink_response(struct cifs_sb_info *cifs_sb, const struct kvec *iov, char **path)
{
struct smb2_symlink_err_rsp *sym;
unsigned int sub_offs, sub_len;
unsigned int print_offs, print_len;
char *s;
if (!cifs_sb || !iov || !iov->iov_base || !iov->iov_len || !path)
return -EINVAL;
sym = symlink_data(iov);
if (IS_ERR(sym))
return PTR_ERR(sym);
sub_len = le16_to_cpu(sym->SubstituteNameLength);
sub_offs = le16_to_cpu(sym->SubstituteNameOffset);
print_len = le16_to_cpu(sym->PrintNameLength);
print_offs = le16_to_cpu(sym->PrintNameOffset);
if (iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offs + sub_len ||
iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + print_offs + print_len)
return -EINVAL;
s = cifs_strndup_from_utf16((char *)sym->PathBuffer + sub_offs, sub_len, true,
cifs_sb->local_nls);
if (!s)
return -ENOMEM;
convert_delimiter(s, '/');
cifs_dbg(FYI, "%s: symlink target: %s\n", __func__, s);
*path = s;
return 0;
}
int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32 *oplock, void *buf)
{
int rc;
__le16 *smb2_path;
__u8 smb2_oplock;
struct cifs_open_info_data *data = buf;
struct smb2_file_all_info file_info = {};
struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
struct kvec err_iov = {};
int err_buftype = CIFS_NO_BUFFER;
struct cifs_fid *fid = oparms->fid;
struct network_resiliency_req nr_ioctl_req;
smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
if (smb2_path == NULL)
return -ENOMEM;
oparms->desired_access |= FILE_READ_ATTRIBUTES;
smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
&err_buftype);
if (rc && data) {
struct smb2_hdr *hdr = err_iov.iov_base;
if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
goto out;
if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
&data->symlink_target);
if (!rc) {
memset(smb2_data, 0, sizeof(*smb2_data));
oparms->create_options |= OPEN_REPARSE_POINT;
rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
NULL, NULL, NULL);
oparms->create_options &= ~OPEN_REPARSE_POINT;
}
}
}
if (rc)
goto out;
if (oparms->tcon->use_resilient) {
/* default timeout is 0, servers pick default (120 seconds) */
nr_ioctl_req.Timeout =
cpu_to_le32(oparms->tcon->handle_timeout);
nr_ioctl_req.Reserved = 0;
rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
CIFSMaxBufSize, NULL, NULL /* no return info */);
if (rc == -EOPNOTSUPP) {
cifs_dbg(VFS,
"resiliency not supported by server, disabling\n");
oparms->tcon->use_resilient = false;
} else if (rc)
cifs_dbg(FYI, "error %d setting resiliency\n", rc);
rc = 0;
}
if (smb2_data) {
/* if open response does not have IndexNumber field - get it */
if (smb2_data->IndexNumber == 0) {
rc = SMB2_get_srv_num(xid, oparms->tcon,
fid->persistent_fid,
fid->volatile_fid,
&smb2_data->IndexNumber);
if (rc) {
/*
* let get_inode_info disable server inode
* numbers
*/
smb2_data->IndexNumber = 0;
rc = 0;
}
}
memcpy(&data->fi, smb2_data, sizeof(data->fi));
}
*oplock = smb2_oplock;
out:
free_rsp_buf(err_buftype, err_iov.iov_base);
kfree(smb2_path);
return rc;
}
int
smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
const unsigned int xid)
{
int rc = 0, stored_rc;
unsigned int max_num, num = 0, max_buf;
struct smb2_lock_element *buf, *cur;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
struct cifsLockInfo *li, *tmp;
__u64 length = 1 + flock->fl_end - flock->fl_start;
struct list_head tmp_llist;
INIT_LIST_HEAD(&tmp_llist);
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
* and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
if (max_buf < sizeof(struct smb2_lock_element))
return -EINVAL;
BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
max_num = max_buf / sizeof(struct smb2_lock_element);
buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
if (!buf)
return -ENOMEM;
cur = buf;
cifs_down_write(&cinode->lock_sem);
list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
if (flock->fl_start > li->offset ||
(flock->fl_start + length) <
(li->offset + li->length))
continue;
if (current->tgid != li->pid)
/*
* flock and OFD lock are associated with an open
* file description, not the process.
*/
if (!(flock->fl_flags & (FL_FLOCK | FL_OFDLCK)))
continue;
if (cinode->can_cache_brlcks) {
/*
* We can cache brlock requests - simply remove a lock
* from the file's list.
*/
list_del(&li->llist);
cifs_del_lock_waiters(li);
kfree(li);
continue;
}
cur->Length = cpu_to_le64(li->length);
cur->Offset = cpu_to_le64(li->offset);
cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
/*
* We need to save a lock here to let us add it again to the
* file's list if the unlock range request fails on the server.
*/
list_move(&li->llist, &tmp_llist);
if (++num == max_num) {
stored_rc = smb2_lockv(xid, tcon,
cfile->fid.persistent_fid,
cfile->fid.volatile_fid,
current->tgid, num, buf);
if (stored_rc) {
/*
* We failed on the unlock range request - add
* all locks from the tmp list to the head of
* the file's list.
*/
cifs_move_llist(&tmp_llist,
&cfile->llist->locks);
rc = stored_rc;
} else
/*
* The unlock range request succeed - free the
* tmp list.
*/
cifs_free_llist(&tmp_llist);
cur = buf;
num = 0;
} else
cur++;
}
if (num) {
stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
cfile->fid.volatile_fid, current->tgid,
num, buf);
if (stored_rc) {
cifs_move_llist(&tmp_llist, &cfile->llist->locks);
rc = stored_rc;
} else
cifs_free_llist(&tmp_llist);
}
up_write(&cinode->lock_sem);
kfree(buf);
return rc;
}
static int
smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
struct smb2_lock_element *buf, unsigned int max_num)
{
int rc = 0, stored_rc;
struct cifsFileInfo *cfile = fdlocks->cfile;
struct cifsLockInfo *li;
unsigned int num = 0;
struct smb2_lock_element *cur = buf;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
list_for_each_entry(li, &fdlocks->locks, llist) {
cur->Length = cpu_to_le64(li->length);
cur->Offset = cpu_to_le64(li->offset);
cur->Flags = cpu_to_le32(li->type |
SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
if (++num == max_num) {
stored_rc = smb2_lockv(xid, tcon,
cfile->fid.persistent_fid,
cfile->fid.volatile_fid,
current->tgid, num, buf);
if (stored_rc)
rc = stored_rc;
cur = buf;
num = 0;
} else
cur++;
}
if (num) {
stored_rc = smb2_lockv(xid, tcon,
cfile->fid.persistent_fid,
cfile->fid.volatile_fid,
current->tgid, num, buf);
if (stored_rc)
rc = stored_rc;
}
return rc;
}
int
smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
{
int rc = 0, stored_rc;
unsigned int xid;
unsigned int max_num, max_buf;
struct smb2_lock_element *buf;
struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
struct cifs_fid_locks *fdlocks;
xid = get_xid();
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
* and check it for zero before using.
*/
max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
if (max_buf < sizeof(struct smb2_lock_element)) {
free_xid(xid);
return -EINVAL;
}
BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
max_num = max_buf / sizeof(struct smb2_lock_element);
buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
if (!buf) {
free_xid(xid);
return -ENOMEM;
}
list_for_each_entry(fdlocks, &cinode->llist, llist) {
stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
if (stored_rc)
rc = stored_rc;
}
kfree(buf);
free_xid(xid);
return rc;
}
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