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Subject[PATCH 15/17] AFS: Implement the PSetTokens pioctl
Date
Implement the PSetTokens pioctl for AFS.  This will submit a security token for
caching.

This can be tested with the OpenAFS userspace tools using the klog program,
which should add a key to the session keyring with something like:

[root@andromeda ~]# echo password | klog -pipe admin
[root@andromeda ~]# keyctl show
Session Keyring
-3 --alswrv 0 0 keyring: _ses
147139749 --alswrv 0 -1 \_ keyring: _uid.0
457362442 --als--v 0 0 \_ rxrpc: cambridge.redhat.com
Note that 'klog -setpag' is not supported by this patch as there's currently
no way for a process to replace its parent process's session keyring.

Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/afs/cell.c | 15 ++++
fs/afs/internal.h | 1
fs/afs/pioctl.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/afscall.h | 14 ++++
include/linux/venus.h | 1
5 files changed, 208 insertions(+), 0 deletions(-)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index e19c13f..b900fc7 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -227,6 +227,21 @@ int afs_cell_init(char *rootcell)
}

/*
+ * get a reference to the root cell
+ */
+struct afs_cell *afs_get_root_cell(void)
+{
+ struct afs_cell *cell;
+
+ read_lock(&afs_cells_lock);
+ cell = afs_cell_root;
+ afs_get_cell(cell);
+ read_unlock(&afs_cells_lock);
+
+ return cell;
+}
+
+/*
* lookup a cell record
*/
struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 9a8e8a2..cf08782 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -467,6 +467,7 @@ extern struct list_head afs_proc_cells;

#define afs_get_cell(C) do { atomic_inc(&(C)->usage); } while(0)
extern int afs_cell_init(char *);
+extern struct afs_cell *afs_get_root_cell(void);
extern struct afs_cell *afs_cell_create(const char *, char *);
extern struct afs_cell *afs_cell_lookup(const char *, unsigned);
extern struct afs_cell *afs_grab_cell(struct afs_cell *);
diff --git a/fs/afs/pioctl.c b/fs/afs/pioctl.c
index ffbec0c..e6ea69f 100644
--- a/fs/afs/pioctl.c
+++ b/fs/afs/pioctl.c
@@ -2,6 +2,8 @@
*
* Copyright (C) 2008 Jacob Thebault-Spieker <summatusmentis@gmail.com>
*
+ * Modified by David Howells <dhowells@redhat.com>
+ *
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
@@ -12,6 +14,10 @@
#include <linux/pioctl.h>
#include <linux/venus.h>
#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/key.h>
+#include <linux/keyctl.h>
+#include <keys/rxrpc-type.h>
#include "internal.h"

/*
@@ -219,6 +225,173 @@ long afs_pioctl(struct dentry *dentry, int cmd, struct vice_ioctl *arg)
}

/*
+ * Set a user's rxkad authentication tokens
+ */
+static long afs_PSetTokens(struct vice_ioctl *arg)
+{
+ struct rxrpc_key_data_v2 *payload;
+ struct clear_token details;
+ struct afs_cell *cell;
+ const char *cp;
+ key_ref_t keyring_r, key_r;
+ size_t in_size, loop;
+ void *in, *in_next, *ticket;
+ char *cellname, *keyname, *dp;
+ long ret;
+ u32 tktlen, tmp, flag;
+
+ _enter("");
+
+ /* decode the argument block */
+ in_next = arg->in;
+ in_size = arg->in_size;
+
+#define CHECK(n) \
+ do { \
+ if (in_size < (n)) \
+ goto underflow; \
+ in = in_next; \
+ in_size -= (n); \
+ in_next += (n); \
+ } while(0)
+
+#define DECODE(to) \
+ do { \
+ CHECK(sizeof(*(to))); \
+ memcpy(to, in, sizeof(*(to))); \
+ } while(0)
+
+ DECODE(&tktlen);
+ _debug("tktlen: %u", tktlen);
+ if (tktlen > INT_MAX)
+ goto invalid;
+ CHECK(tktlen);
+ ticket = in;
+ DECODE(&tmp);
+ _debug("clear token %u", tmp);
+ if (tmp != sizeof(struct clear_token))
+ goto invalid;
+ DECODE(&details);
+ _debug("ah:%x vi:%x bts:%x ets:%x (e-b:%u) (CT:%lx)",
+ details.auth_handle, details.vice_id,
+ details.begin_timestamp, details.end_timestamp,
+ details.end_timestamp - details.begin_timestamp,
+ CURRENT_TIME.tv_sec);
+ if (details.vice_id == UINT_MAX)
+ goto invalid;
+ if (details.auth_handle == UINT_MAX)
+ details.auth_handle = 999;
+
+ /* flags and cellname are optional, defaulting to the root cell */
+ _debug("in_size: %zu", in_size);
+ if (in_size != 0) {
+ DECODE(&flag);
+ _debug("flag: %x", flag);
+
+ if (flag & 0x8000) {
+ /* the caller wants us to give our parent a new PAG
+ * - we don't support this currently
+ */
+ _leave(" = -EACCES");
+ return -EACCES;
+ }
+
+ /* remainder is cell name */
+ CHECK(sizeof(char));
+ cellname = in;
+ for (loop = 0; loop < in_size; loop++)
+ if (!isprint(cellname[loop]))
+ goto invalid;
+
+ if (cellname[loop] != '\0')
+ goto invalid;
+ cell = NULL;
+
+ _debug("cellname: %s", cellname);
+ } else {
+ cell = afs_get_root_cell();
+ cellname = cell->name;
+ flag = 1;
+ }
+
+#undef DECODE
+#undef CHECK
+
+ /* construct the key name */
+ ret = -ENOMEM;
+ keyname = kmalloc(4 + strlen(cellname) + 1, GFP_KERNEL);
+ if (!keyname)
+ goto error_nokeyname;
+
+ memcpy(keyname, "afs@", 4);
+ dp = keyname + 4;
+ cp = cellname;
+ while (*cp)
+ *dp++ = toupper(*cp++);
+ *dp = 0;
+
+ /* we install the authentication token as a key */
+ payload = kmalloc(sizeof(*payload) + tktlen, GFP_KERNEL);
+ if (!payload)
+ goto error_nopayload;
+
+ payload->kif_version = 2;
+ payload->security_index = RXRPC_SECURITY_RXKAD;
+ payload->ticket_length = tktlen;
+ payload->vice_id = details.vice_id;
+ payload->start = details.begin_timestamp;
+ payload->expiry = details.end_timestamp;
+ payload->kvno = details.auth_handle;
+ memcpy(payload->session_key, details.session_key, 8);
+ memcpy(payload->ticket, ticket, tktlen);
+
+ /* add the key to the session keyring */
+ keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 1, 0,
+ WANT_KEY_WRITE);
+ if (IS_ERR(keyring_r)) {
+ _debug("keyring lookup failed");
+ ret = PTR_ERR(keyring_r);
+ goto error;
+ }
+
+ /* create or update the requested key and add it to the target
+ * keyring */
+ key_r = key_create_or_update(keyring_r, "rxrpc", keyname,
+ payload, sizeof(*payload) + tktlen,
+ KEY_PERM_UNDEF, KEY_ALLOC_IN_QUOTA);
+ key_ref_put(keyring_r);
+
+ if (IS_ERR(key_r)) {
+ _debug("key create failed");
+ ret = PTR_ERR(key_r);
+ goto error;
+ }
+
+ _debug("key serial: %x", key_ref_to_ptr(key_r)->serial);
+
+ key_ref_put(key_r);
+ arg->out_size = 0;
+ ret = 0;
+
+error:
+ kfree(payload);
+error_nopayload:
+ kfree(keyname);
+error_nokeyname:
+ afs_put_cell(cell);
+ _leave(" = %ld", ret);
+ return ret;
+
+underflow:
+ _leave(" = -EINVAL [short arg]");
+ return -EINVAL;
+
+invalid:
+ _leave(" = -EINVAL [invalid arg]");
+ return -EINVAL;
+}
+
+/*
* The AFS pathless pioctl handler
*/
long afs_pathless_pioctl(int cmd, struct vice_ioctl *arg)
@@ -231,6 +404,10 @@ long afs_pathless_pioctl(int cmd, struct vice_ioctl *arg)
#define VIOC_COMMAND(nr) (_VICEIOCTL(nr) & ~IOCSIZE_MASK)

switch (cmd & ~IOCSIZE_MASK) {
+ case VIOC_COMMAND(PSetTokens):
+ ret = afs_PSetTokens(arg);
+ break;
+
default:
printk(KERN_DEBUG "AFS: Unsupported pioctl command %x\n", cmd);
ret = -EOPNOTSUPP;
diff --git a/include/linux/afscall.h b/include/linux/afscall.h
index 00054f0..7635aab 100644
--- a/include/linux/afscall.h
+++ b/include/linux/afscall.h
@@ -2,6 +2,8 @@
*
* Copyright (C) 2008 Jacob Thebault-Spieker <summatusmentis@gmail.com>
*
+ * Modified by David Howells <dhowells@redhat.com>
+ *
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
@@ -14,6 +16,7 @@
#define AFSCALL_PIOCTL 0x14

/* pioctl commands */
+#define PSetTokens 3 /* get authentication tokens for user */
#define PGetVolStat 4 /* get volume status */
#define PWhereIs 14 /* find out where a volume is located */
#define PGetFID 22 /* get file ID */
@@ -40,4 +43,15 @@ struct VolumeStatus {
int PartMaxBlocks; /* size of volume's partition */
};

+/*
+ * User details when getting or submitting a token
+ */
+struct clear_token {
+ u32 auth_handle; /* key version number */
+ u8 session_key[8]; /* session encryption key */
+ u32 vice_id; /* client/user ID */
+ u32 begin_timestamp; /* time_t at which ticket starts */
+ u32 end_timestamp; /* time_t at which ticket expires */
+};
+
#endif /* _LINUX_AFSCALL_H */
diff --git a/include/linux/venus.h b/include/linux/venus.h
index ea8e468..b90e5f2 100644
--- a/include/linux/venus.h
+++ b/include/linux/venus.h
@@ -17,6 +17,7 @@
/*
* pioctl commands (not usable as ioctls)
*/
+#define VIOCSETTOK _VICEIOCTL(PSetTokens)
#define VIOCGETVOLSTAT _VICEIOCTL(PGetVolStat)
#define VIOCWHEREIS _VICEIOCTL(PWhereIs)
#define VIOCGETFID _VICEIOCTL(PGetFID)


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