On Mon, 26 Sep 2011 09:56:44 -0500
shirishpargaonkar@xxxxxxxxx wrote:
> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>
>
> Add mount options backupuid and backugid.
>
> It allows an authenticated user to access files with the intent to back them
> up including their ACLs, who may not have access permission but has
> "Backup files and directories user right" on them (by virtue of being part
> of the built-in group Backup Operators.
>
> When mount options backupuid is specified, cifs client restricts the
> use of backup intents to the user whose effective user id is specified
> along with the mount option.
>
> When mount options backupgid is specified, cifs client restricts the
> use of backup intents to the users whose effective user id belongs to the
> group id specified along with the mount option.
>
> If an authenticated user is not part of the built-in group Backup Operators
> at the server, access to such files is denied, even if allowed by the client.
>
>
> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
> ---
> fs/cifs/cifs_fs_sb.h | 4 ++++
> fs/cifs/cifsacl.c | 18 ++++++++++++------
> fs/cifs/cifsglob.h | 7 ++++++-
> fs/cifs/cifsproto.h | 1 +
> fs/cifs/connect.c | 27 +++++++++++++++++++++++++++
> fs/cifs/dir.c | 10 ++++++++--
> fs/cifs/file.c | 12 ++++++++++--
> fs/cifs/link.c | 17 ++++++++++++-----
> fs/cifs/misc.c | 15 +++++++++++++++
> 9 files changed, 95 insertions(+), 16 deletions(-)
>
> diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
> index 7260e11..500d658 100644
> --- a/fs/cifs/cifs_fs_sb.h
> +++ b/fs/cifs/cifs_fs_sb.h
> @@ -43,6 +43,8 @@
> #define CIFS_MOUNT_STRICT_IO 0x40000 /* strict cache mode */
> #define CIFS_MOUNT_RWPIDFORWARD 0x80000 /* use pid forwarding for rw */
> #define CIFS_MOUNT_POSIXACL 0x100000 /* mirror of MS_POSIXACL in mnt_cifs_flags */
> +#define CIFS_MOUNT_CIFS_BACKUPUID 0x200000 /* backup intent bit for a user */
> +#define CIFS_MOUNT_CIFS_BACKUPGID 0x400000 /* backup intent bit for a group */
>
> struct cifs_sb_info {
> struct rb_root tlink_tree;
> @@ -55,6 +57,8 @@ struct cifs_sb_info {
> atomic_t active;
> uid_t mnt_uid;
> gid_t mnt_gid;
> + uid_t mnt_backupuid;
> + gid_t mnt_backupgid;
> mode_t mnt_file_mode;
> mode_t mnt_dir_mode;
> unsigned int mnt_cifs_flags;
> diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
> index d0f59fa..b244e07 100644
> --- a/fs/cifs/cifsacl.c
> +++ b/fs/cifs/cifsacl.c
> @@ -945,7 +945,7 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
> {
> struct cifs_ntsd *pntsd = NULL;
> int oplock = 0;
> - int xid, rc;
> + int xid, rc, create_options = 0;
> __u16 fid;
> struct cifs_tcon *tcon;
> struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
> @@ -956,9 +956,12 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
> tcon = tlink_tcon(tlink);
> xid = GetXid();
>
> - rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, READ_CONTROL, 0,
> - &fid, &oplock, NULL, cifs_sb->local_nls,
> - cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> + rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, READ_CONTROL,
> + create_options, &fid, &oplock, NULL, cifs_sb->local_nls,
> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> if (!rc) {
> rc = CIFSSMBGetCIFSACL(xid, tcon, fid, &pntsd, pacllen);
> CIFSSMBClose(xid, tcon, fid);
> @@ -995,7 +998,7 @@ static int set_cifs_acl_by_path(struct cifs_sb_info *cifs_sb, const char *path,
> struct cifs_ntsd *pnntsd, u32 acllen)
> {
> int oplock = 0;
> - int xid, rc;
> + int xid, rc, create_options = 0;
> __u16 fid;
> struct cifs_tcon *tcon;
> struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
> @@ -1006,7 +1009,10 @@ static int set_cifs_acl_by_path(struct cifs_sb_info *cifs_sb, const char *path,
> tcon = tlink_tcon(tlink);
> xid = GetXid();
>
> - rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, WRITE_DAC, 0,
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> + rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, WRITE_DAC, create_options,
> &fid, &oplock, NULL, cifs_sb->local_nls,
> cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> if (rc) {
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 95dad9d..fa2f80a 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -167,6 +167,8 @@ struct smb_vol {
> uid_t cred_uid;
> uid_t linux_uid;
> gid_t linux_gid;
> + uid_t backupuid;
> + gid_t backupgid;
> mode_t file_mode;
> mode_t dir_mode;
> unsigned secFlg;
> @@ -179,6 +181,8 @@ struct smb_vol {
> bool noperm:1;
> bool no_psx_acl:1; /* set if posix acl support should be disabled */
> bool cifs_acl:1;
> + bool backupuid_specified; /* mount option backupuid is specified */
> + bool backupgid_specified; /* mount option backupgid is specified */
> bool no_xattr:1; /* set if xattr (EA) support should be disabled*/
> bool server_ino:1; /* use inode numbers from server ie UniqueId */
> bool direct_io:1;
> @@ -219,7 +223,8 @@ struct smb_vol {
> CIFS_MOUNT_OVERR_GID | CIFS_MOUNT_DYNPERM | \
> CIFS_MOUNT_NOPOSIXBRL | CIFS_MOUNT_NOSSYNC | \
> CIFS_MOUNT_FSCACHE | CIFS_MOUNT_MF_SYMLINKS | \
> - CIFS_MOUNT_MULTIUSER | CIFS_MOUNT_STRICT_IO)
> + CIFS_MOUNT_MULTIUSER | CIFS_MOUNT_STRICT_IO | \
> + CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID)
>
> #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
> MS_NODEV | MS_SYNCHRONOUS)
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index 8df28e9..937c78e 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -90,6 +90,7 @@ extern int SendReceiveBlockingLock(const unsigned int xid,
> 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 backup_cred(struct cifs_sb_info *);
> extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof);
> extern void cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset,
> unsigned int bytes_written);
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index f4af4cc..a16c1a8 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -827,6 +827,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
> {
> char *value, *data, *end;
> char *mountdata_copy = NULL, *options;
> + int err;
> unsigned int temp_len, i, j;
> char separator[2];
> short int override_uid = -1;
> @@ -883,6 +884,8 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
> cFYI(1, "Null separator not allowed");
> }
> }
> + vol->backupuid_specified = false; /* no backup intent for a user */
> + vol->backupgid_specified = false; /* no backup intent for a group */
>
> while ((data = strsep(&options, separator)) != NULL) {
> if (!*data)
> @@ -1442,6 +1445,22 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
> vol->mfsymlinks = true;
> } else if (strnicmp(data, "multiuser", 8) == 0) {
> vol->multiuser = true;
> + } else if (!strnicmp(data, "backupuid", 9) && value && *value) {
> + err = kstrtouint(value, 0, &vol->backupuid);
> + if (err < 0) {
> + cERROR(1, "%s: Invalid backupuid value",
> + __func__);
> + goto cifs_parse_mount_err;
> + }
> + vol->backupuid_specified = true;
> + } else if (!strnicmp(data, "backupgid", 9) && value && *value) {
> + err = kstrtouint(value, 0, &vol->backupgid);
> + if (err < 0) {
> + cERROR(1, "%s: Invalid backupgid value",
> + __func__);
> + goto cifs_parse_mount_err;
> + }
> + vol->backupgid_specified = true;
> } else
> printk(KERN_WARNING "CIFS: Unknown mount option %s\n",
> data);
> @@ -2733,6 +2752,10 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
>
> cifs_sb->mnt_uid = pvolume_info->linux_uid;
> cifs_sb->mnt_gid = pvolume_info->linux_gid;
> + if (pvolume_info->backupuid_specified)
> + cifs_sb->mnt_backupuid = pvolume_info->backupuid;
> + if (pvolume_info->backupgid_specified)
> + cifs_sb->mnt_backupgid = pvolume_info->backupgid;
> cifs_sb->mnt_file_mode = pvolume_info->file_mode;
> cifs_sb->mnt_dir_mode = pvolume_info->dir_mode;
> cFYI(1, "file mode: 0x%x dir mode: 0x%x",
> @@ -2763,6 +2786,10 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
> cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RWPIDFORWARD;
> if (pvolume_info->cifs_acl)
> cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
> + if (pvolume_info->backupuid_specified)
> + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUPUID;
> + if (pvolume_info->backupgid_specified)
> + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUPGID;
> if (pvolume_info->override_uid)
> cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
> if (pvolume_info->override_gid)
> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> index 72d448b..0a818a6 100644
> --- a/fs/cifs/dir.c
> +++ b/fs/cifs/dir.c
> @@ -244,6 +244,9 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
> if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
> create_options |= CREATE_OPTION_READONLY;
>
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> if (tcon->ses->capabilities & CAP_NT_SMBS)
> rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
> desiredAccess, create_options,
> @@ -357,6 +360,7 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
> {
> int rc = -EPERM;
> int xid;
> + int create_options = CREATE_NOT_DIR | CREATE_OPTION_SPECIAL;
> struct cifs_sb_info *cifs_sb;
> struct tcon_link *tlink;
> struct cifs_tcon *pTcon;
> @@ -431,9 +435,11 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
> return rc;
> }
>
> - /* FIXME: would WRITE_OWNER | WRITE_DAC be better? */
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_CREATE,
> - GENERIC_WRITE, CREATE_NOT_DIR | CREATE_OPTION_SPECIAL,
> + GENERIC_WRITE, create_options,
> &fileHandle, &oplock, buf, cifs_sb->local_nls,
> cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
We really ought to turn the above idiom into a
macro cifs_sb_mapchar(cifs_sb), or something along
those lines. That's really outside the scope of
this patch though.
> if (rc)
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 9f41a10..97e4be3 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -174,6 +174,7 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
> int rc;
> int desiredAccess;
> int disposition;
> + int create_options = CREATE_NOT_DIR;
> FILE_ALL_INFO *buf;
>
> desiredAccess = cifs_convert_flags(f_flags);
> @@ -210,9 +211,12 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
> if (!buf)
> return -ENOMEM;
>
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> if (tcon->ses->capabilities & CAP_NT_SMBS)
> rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
> - desiredAccess, CREATE_NOT_DIR, pnetfid, poplock, buf,
> + desiredAccess, create_options, pnetfid, poplock, buf,
> cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
> & CIFS_MOUNT_MAP_SPECIAL_CHR);
> else
> @@ -465,6 +469,7 @@ static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
> char *full_path = NULL;
> int desiredAccess;
> int disposition = FILE_OPEN;
> + int create_options = CREATE_NOT_DIR;
> __u16 netfid;
>
> xid = GetXid();
> @@ -524,6 +529,9 @@ static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
>
> desiredAccess = cifs_convert_flags(pCifsFile->f_flags);
>
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> /* Can not refresh inode by passing in file_info buf to be returned
> by SMBOpen and then calling get_inode_info with returned buf
> since file might have write behind data that needs to be flushed
> @@ -531,7 +539,7 @@ static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
> that inode was not dirty locally we could do this */
>
> rc = CIFSSMBOpen(xid, tcon, full_path, disposition, desiredAccess,
> - CREATE_NOT_DIR, &netfid, &oplock, NULL,
> + create_options, &netfid, &oplock, NULL,
> cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
> CIFS_MOUNT_MAP_SPECIAL_CHR);
> if (rc) {
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index db3f18c..8693b5d 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -183,14 +183,20 @@ CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
> static int
> CIFSCreateMFSymLink(const int xid, struct cifs_tcon *tcon,
> const char *fromName, const char *toName,
> - const struct nls_table *nls_codepage, int remap)
> + struct cifs_sb_info *cifs_sb)
> {
> int rc;
> int oplock = 0;
> + int remap;
> + int create_options = CREATE_NOT_DIR;
> __u16 netfid = 0;
> u8 *buf;
> unsigned int bytes_written = 0;
> struct cifs_io_parms io_parms;
> + struct nls_table *nls_codepage;
> +
> + nls_codepage = cifs_sb->local_nls;
> + remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;
>
> buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
> if (!buf)
> @@ -202,8 +208,11 @@ CIFSCreateMFSymLink(const int xid, struct cifs_tcon *tcon,
> return rc;
> }
>
> + if (backup_cred(cifs_sb))
> + create_options |= CREATE_OPEN_BACKUP_INTENT;
> +
> rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
> - CREATE_NOT_DIR, &netfid, &oplock, NULL,
> + create_options, &netfid, &oplock, NULL,
> nls_codepage, remap);
> if (rc != 0) {
> kfree(buf);
> @@ -559,9 +568,7 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
> /* BB what if DFS and this volume is on different share? BB */
> if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
> rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
> - cifs_sb->local_nls,
> - cifs_sb->mnt_cifs_flags &
> - CIFS_MOUNT_MAP_SPECIAL_CHR);
> + cifs_sb);
> else if (pTcon->unix_ext)
> rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
> cifs_sb->local_nls);
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index 7c16933..a117c04 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -676,3 +676,18 @@ void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
> cinode->clientCanCacheRead = false;
> }
> }
> +
> +bool
> +backup_cred(struct cifs_sb_info *cifs_sb)
> +{
> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
> + if (cifs_sb->mnt_backupuid == current_fsuid())
> + return true;
> + }
> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
> + if (in_group_p(cifs_sb->mnt_backupgid))
> + return true;
> + }
> +
> + return false;
> +}
Looks good to me:
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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