* terms of the GNU Lesser General Public License
* (see cit/LGPL or http://www.gnu.org/licenses/lgpl.html)
*
- * Cplant(TM) Copyright 1998-2003 Sandia Corporation.
+ * Cplant(TM) Copyright 1998-2006 Sandia Corporation.
* Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
* license for use of this work by or on behalf of the US Government.
* Export of this program may require a license from the United States
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
+#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/queue.h>
#include "sysio.h"
+#include "mount.h"
+#include "fs.h"
+#include "inode.h"
#include "sysio-symbols.h"
+/*
+ * Use a persistent buffer for gids. No, not a cache. We just want to
+ * avoid calling malloc over, and over, and...
+ */
+static gid_t *gids = NULL;
+static int gidslen = 0;
+
+/*
+ * Check given access type on given inode.
+ */
int
-SYSIO_INTERFACE_NAME(access)(const char *path, int amode)
+_sysio_check_permission(struct pnode *pno, struct creds *crp, int amode)
{
- gid_t *list, *entry;
- size_t n;
- int err = 0;
- unsigned mask, mode;
- struct stat stbuf;
- SYSIO_INTERFACE_DISPLAY_BLOCK;
-
- SYSIO_INTERFACE_ENTER;
- err = 0;
+ mode_t mask;
+ struct inode *ino;
+ int err;
+ struct intnl_stat *stat;
+ gid_t *gids;
+ int ngids;
+ int group_matched;
/*
* Check amode.
*/
if ((amode & (R_OK|W_OK|X_OK)) != amode)
- SYSIO_INTERFACE_RETURN(-1, -EINVAL);
-
- n = getgroups(0, NULL);
- list = NULL;
- if (n) {
- list = malloc(n * sizeof(gid_t));
- if (!list) {
- err = -ENOMEM;
- goto out;
- }
- }
- err = getgroups(n, list);
- if (err != (int ) n)
- goto out;
+ return -EINVAL;
- err = SYSIO_INTERFACE_NAME(stat)(path, &stbuf);
- if (err) {
- err = -errno;
- goto out;
- }
if (!amode)
- SYSIO_INTERFACE_RETURN(0, 0);
-
+ return 0;
mask = 0;
if (amode & R_OK)
if (amode & X_OK)
mask |= S_IXUSR;
- mode = stbuf.st_mode;
- if (stbuf.st_uid == getuid() && (mode & mask) == mask)
- goto out;
+ ino = pno->p_base->pb_ino;
+ assert(ino);
- mask >>= 3;
- if (stbuf.st_gid == getgid() && (mode & mask) == mask)
- goto out;
+ err = -EACCES; /* assume error */
+ stat = &ino->i_stbuf;
+ do {
+#ifdef _SYSIO_ROOT_UID
+ /*
+ * Root?
+ */
+ if (_sysio_is_root(crp)) {
+ err = 0;
+ break;
+ }
+#endif
- entry = list;
- while (n--)
- if (stbuf.st_gid == *entry++ && (mode & mask) == mask)
- goto out;
+ /*
+ * Owner?
+ */
+ if (stat->st_uid == crp->creds_uid) {
+ if ((stat->st_mode & mask) == mask)
+ err = 0;
+ break;
+ }
- mask >>= 3;
- if ((mode & mask) == mask)
- goto out;
+ /*
+ * Group?
+ */
+ mask >>= 3;
+ group_matched = 0;
+ gids = crp->creds_gids;
+ ngids = crp->creds_ngids;
+ while (ngids) {
+ ngids--;
+ if (stat->st_gid == *gids++) {
+ group_matched = 1;
+ if ((stat->st_mode & mask) == mask)
+ err = 0;
+ }
+ }
+ if (group_matched)
+ break;
- err = -EACCES;
+ /*
+ * Other?
+ */
+ mask >>= 3;
+ if ((stat->st_mode & mask) == mask)
+ err = 0;
+ } while (0);
+ if (err)
+ return err;
-out:
- if (list)
- free(list);
+ /*
+ * Check for RO access to the file due to mount
+ * options.
+ */
+ if (amode & W_OK && IS_RDONLY(pno))
+ return -EROFS;
+
+ return 0;
+}
+
+/*
+ * Cache groups.
+ */
+static int
+_sysio_ldgroups(gid_t gid0, gid_t **gidsp, int *gidslenp)
+{
+ int n, i;
+ void *p;
+
+ n = *gidslenp;
+ if (n < 8) {
+ *gidsp = NULL;
+ n = 8;
+ }
+ for (;;) {
+ /*
+ * This is far more expensive than I would like. Each time
+ * called it has to go to some length to acquire the
+ * current uid and groups membership. We can't just cache
+ * the result, either. The caller could have altered something
+ * asynchronously. Wish we had easy access to this info.
+ */
+ if (n > *gidslenp) {
+ p = realloc(*gidsp, (size_t )n * sizeof(gid_t));
+ if (!p)
+ return -errno;
+ *gidsp = p;
+ *gidslenp = n;
+ }
+ (*gidsp)[0] = gid0;
+ i = getgroups(n - 1, *gidsp + 1);
+ if (i < 0) {
+ if (errno != EINVAL)
+ return -errno;
+ if (INT_MAX / 2 < n)
+ return -EINVAL;
+ n *= 2;
+ continue;
+ }
+ break;
+ }
+ return i;
+}
+
+/*
+ * Get current credentials.
+ */
+static int
+_sysio_ldcreds(uid_t uid, gid_t gid, struct creds *crp)
+{
+ int n;
+
+ n = _sysio_ldgroups(gid, &gids, &gidslen);
+ if (n < 0)
+ return n;
+ crp->creds_uid = uid;
+ crp->creds_gids = gids;
+ crp->creds_ngids = n;
+
+ return 0;
+}
+
+/*
+ * Determine if a given access is permitted to a given file.
+ */
+int
+_sysio_permitted(struct pnode *pno, int amode)
+{
+ struct creds cr;
+ int err;
+
+ err = _sysio_ldcreds(geteuid(), getegid(), &cr);
+ if (err < 0)
+ return err;
+ err = _sysio_check_permission(pno, &cr, amode);
+ return err;
+}
+#ifdef ZERO_SUM_MEMORY
+/*
+ * Clean up persistent resource on shutdown.
+ */
+void
+_sysio_access_shutdown()
+{
+
+ if (gids)
+ free(gids);
+ gids = NULL;
+ gidslen = 0;
+}
+#endif
+
+int
+SYSIO_INTERFACE_NAME(access)(const char *path, int amode)
+{
+ struct intent intent;
+ int err;
+ struct pnode *pno;
+ struct creds cr;
+
+ SYSIO_INTERFACE_DISPLAY_BLOCK;
+
+ SYSIO_INTERFACE_ENTER;
+
+ INTENT_INIT(&intent, INT_GETATTR, NULL, NULL);
+ err = _sysio_namei(_sysio_cwd, path, 0, &intent, &pno);
+ if (err)
+ SYSIO_INTERFACE_RETURN(-1, err);
+ err = _sysio_ldcreds(geteuid(), getegid(), &cr);
+ if (err < 0)
+ goto out;
+ err =
+ _sysio_check_permission(pno, &cr, amode);
+out:
+ P_RELE(pno);
SYSIO_INTERFACE_RETURN(err ? -1 : 0, err);
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff