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cifs: have find_readable/writable_file filter by fsuid
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When we implement multiuser mounts, we'll need to filter filehandles
by fsuid. Add a flag for multiuser mounts and code to filter by
fsuid when it's set.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Jeff Layton authored and Steve French committed Oct 6, 2010
1 parent 13cfb73 commit 6508d90
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Showing 6 changed files with 35 additions and 16 deletions.
3 changes: 2 additions & 1 deletion fs/cifs/cifs_fs_sb.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#define CIFS_MOUNT_NOSSYNC 0x4000 /* don't do slow SMBflush on every sync*/
#define CIFS_MOUNT_FSCACHE 0x8000 /* local caching enabled */
#define CIFS_MOUNT_MF_SYMLINKS 0x10000 /* Minshall+French Symlinks enabled */
#define CIFS_MOUNT_MULTIUSER 0x20000 /* multiuser mount */

struct cifs_sb_info {
struct cifsTconInfo *ptcon; /* primary mount */
Expand All @@ -48,7 +49,7 @@ struct cifs_sb_info {
gid_t mnt_gid;
mode_t mnt_file_mode;
mode_t mnt_dir_mode;
int mnt_cifs_flags;
unsigned int mnt_cifs_flags;
int prepathlen;
char *prepath; /* relative path under the share to mount to */
#ifdef CONFIG_CIFS_DFS_UPCALL
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4 changes: 2 additions & 2 deletions fs/cifs/cifsacl.c
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Expand Up @@ -615,7 +615,7 @@ static struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
struct cifsFileInfo *open_file = NULL;

if (inode)
open_file = find_readable_file(CIFS_I(inode));
open_file = find_readable_file(CIFS_I(inode), true);
if (!open_file)
return get_cifs_acl_by_path(cifs_sb, path, pacllen);

Expand Down Expand Up @@ -685,7 +685,7 @@ static int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,

cFYI(DBG2, "set ACL for %s from mode 0x%x", path, inode->i_mode);

open_file = find_readable_file(CIFS_I(inode));
open_file = find_readable_file(CIFS_I(inode), true);
if (!open_file)
return set_cifs_acl_by_path(cifs_sb, path, pnntsd, acllen);

Expand Down
4 changes: 2 additions & 2 deletions fs/cifs/cifsproto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -78,9 +78,9 @@ extern int checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length);
extern bool is_valid_oplock_break(struct smb_hdr *smb,
struct TCP_Server_Info *);
extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof);
extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *);
extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, bool);
#ifdef CONFIG_CIFS_EXPERIMENTAL
extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *);
extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *, bool);
#endif
extern unsigned int smbCalcSize(struct smb_hdr *ptr);
extern unsigned int smbCalcSize_LE(struct smb_hdr *ptr);
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1 change: 1 addition & 0 deletions fs/cifs/dir.c
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Expand Up @@ -144,6 +144,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file,

pCifsFile->netfid = fileHandle;
pCifsFile->pid = current->tgid;
pCifsFile->uid = current_fsuid();
pCifsFile->pInode = igrab(newinode);
pCifsFile->mnt = mnt;
pCifsFile->pfile = file;
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33 changes: 25 additions & 8 deletions fs/cifs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1168,9 +1168,15 @@ static ssize_t cifs_write(struct file *file, const char *write_data,
}

#ifdef CONFIG_CIFS_EXPERIMENTAL
struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode)
struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
bool fsuid_only)
{
struct cifsFileInfo *open_file = NULL;
struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);

/* only filter by fsuid on multiuser mounts */
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
fsuid_only = false;

read_lock(&GlobalSMBSeslock);
/* we could simply get the first_list_entry since write-only entries
Expand All @@ -1179,6 +1185,8 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode)
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
if (open_file->closePend)
continue;
if (fsuid_only && open_file->uid != current_fsuid())
continue;
if (open_file->pfile && ((open_file->pfile->f_flags & O_RDWR) ||
(open_file->pfile->f_flags & O_RDONLY))) {
if (!open_file->invalidHandle) {
Expand All @@ -1198,9 +1206,11 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode)
}
#endif

struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode,
bool fsuid_only)
{
struct cifsFileInfo *open_file;
struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
bool any_available = false;
int rc;

Expand All @@ -1214,13 +1224,19 @@ struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
return NULL;
}

/* only filter by fsuid on multiuser mounts */
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
fsuid_only = false;

read_lock(&GlobalSMBSeslock);
refind_writable:
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
if (open_file->closePend ||
(!any_available && open_file->pid != current->tgid))
if (open_file->closePend)
continue;
if (!any_available && open_file->pid != current->tgid)
continue;
if (fsuid_only && open_file->uid != current_fsuid())
continue;

if (open_file->pfile &&
((open_file->pfile->f_flags & O_RDWR) ||
(open_file->pfile->f_flags & O_WRONLY))) {
Expand Down Expand Up @@ -1315,7 +1331,7 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
if (mapping->host->i_size - offset < (loff_t)to)
to = (unsigned)(mapping->host->i_size - offset);

open_file = find_writable_file(CIFS_I(mapping->host));
open_file = find_writable_file(CIFS_I(mapping->host), false);
if (open_file) {
bytes_written = cifs_write(open_file->pfile, write_data,
to-from, &offset);
Expand Down Expand Up @@ -1388,7 +1404,7 @@ static int cifs_writepages(struct address_space *mapping,
* but it'll at least handle the return. Maybe it should be
* a BUG() instead?
*/
open_file = find_writable_file(CIFS_I(mapping->host));
open_file = find_writable_file(CIFS_I(mapping->host), false);
if (!open_file) {
kfree(iov);
return generic_writepages(mapping, wbc);
Expand Down Expand Up @@ -1505,7 +1521,8 @@ static int cifs_writepages(struct address_space *mapping,
break;
}
if (n_iov) {
open_file = find_writable_file(CIFS_I(mapping->host));
open_file = find_writable_file(CIFS_I(mapping->host),
false);
if (!open_file) {
cERROR(1, "No writable handles for inode");
rc = -EBADF;
Expand Down
6 changes: 3 additions & 3 deletions fs/cifs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -963,7 +963,7 @@ cifs_set_file_info(struct inode *inode, struct iattr *attrs, int xid,
/*
* If the file is already open for write, just use that fileid
*/
open_file = find_writable_file(cifsInode);
open_file = find_writable_file(cifsInode, true);
if (open_file) {
netfid = open_file->netfid;
netpid = open_file->pid;
Expand Down Expand Up @@ -1813,7 +1813,7 @@ cifs_set_file_size(struct inode *inode, struct iattr *attrs,
* writebehind data than the SMB timeout for the SetPathInfo
* request would allow
*/
open_file = find_writable_file(cifsInode);
open_file = find_writable_file(cifsInode, true);
if (open_file) {
__u16 nfid = open_file->netfid;
__u32 npid = open_file->pid;
Expand Down Expand Up @@ -1978,7 +1978,7 @@ cifs_setattr_unix(struct dentry *direntry, struct iattr *attrs)
args->ctime = NO_CHANGE_64;

args->device = 0;
open_file = find_writable_file(cifsInode);
open_file = find_writable_file(cifsInode, true);
if (open_file) {
u16 nfid = open_file->netfid;
u32 npid = open_file->pid;
Expand Down

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