LINUX: Revert group changes on keyring failure

On Linux kernels that support keyrings, when we setpag we try to add
the PAG to the session keyring and to the supplemental group list.
Currently, if we fail to add the PAG to the keyring (which may happen
due to key quotas, or possibly other reasons), we return failure but
the group list is still modified with the new PAG in it.

Therefore, if the keyring-based approach fails, the new PAG may still
be in use, but there are no keyring keys associated with that PAG, so
the PAG may never get destroyed. This can cause a large number of PAGs
to accumulate over time, causing performance problems.

So, change this so that, in the event that keyring installation fails,
we revert the group list back to what it was before we touched it.
Also mark all unixusers with the new PAG as expired, in case one got
created during processing. Thus, the new PAG never gets used.

Change-Id: I61993edf705209e1a5d8dee638a9003690017c35
Reviewed-on: http://gerrit.openafs.org/5238
Tested-by: Derrick Brashear <shadow@dementix.org>
Reviewed-by: Derrick Brashear <shadow@dementix.org>

diff --git a/src/afs/LINUX/osi_groups.c b/src/afs/LINUX/osi_groups.c
index 144f0e3..6c727f3 100644 (file)
--- a/src/afs/LINUX/osi_groups.c
+++ b/src/afs/LINUX/osi_groups.c
@@ -141,7 +141,7 @@ afs_setgroups(cred_t **cr, struct group_info *group_info, int change_parent)
 
 int
 __setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
-         int change_parent)
+         int change_parent, struct group_info **old_groups)
 {
     struct group_info *group_info;
     struct group_info *tmp;
@@ -152,12 +152,16 @@ __setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
     *newpag = (pagvalue == -1 ? genpag() : pagvalue);
     afs_linux_pag_to_groups(*newpag, group_info, &tmp);
 
-    put_group_info(group_info);
-    group_info = tmp;
+    if (old_groups) {
+       *old_groups = group_info;
+    } else {
+       put_group_info(group_info);
+       group_info = NULL;
+    }
 
-    afs_setgroups(cr, group_info, change_parent);
+    afs_setgroups(cr, tmp, change_parent);
 
-    put_group_info(group_info);
+    put_group_info(tmp);
 
     return 0;
 }
@@ -235,10 +239,11 @@ setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
        int change_parent)
 {
     int code;
+    struct group_info *old_groups = NULL;
 
     AFS_STATCNT(setpag);
 
-    code = __setpag(cr, pagvalue, newpag, change_parent);
+    code = __setpag(cr, pagvalue, newpag, change_parent, &old_groups);
 
 #ifdef LINUX_KEYRING_SUPPORT
     if (code == 0 && afs_cr_rgid(*cr) != NFSXLATOR_CRED) {
@@ -265,6 +270,18 @@ setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
     }
 #endif /* LINUX_KEYRING_SUPPORT */
 
+    if (code) {
+       if (old_groups) {
+           afs_setgroups(cr, old_groups, change_parent);
+           put_group_info(old_groups);
+           old_groups = NULL;
+       }
+       if (*newpag > -1) {
+           afs_MarkUserExpired(*newpag);
+           *newpag = -1;
+       }
+    }
+
     return code;
 }
 
@@ -290,7 +307,7 @@ afs_xsetgroups(int gidsetsize, gid_t * grouplist)
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
        /* re-install old pag if there's room. */
-       code = __setpag(&cr, old_pag, &junk, 0);
+       code = __setpag(&cr, old_pag, &junk, 0, NULL);
     }
     crfree(cr);
 
@@ -321,7 +338,7 @@ afs_xsetgroups32(int gidsetsize, gid_t * grouplist)
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
        /* re-install old pag if there's room. */
-       code = __setpag(&cr, old_pag, &junk, 0);
+       code = __setpag(&cr, old_pag, &junk, 0, NULL);
     }
     crfree(cr);
 
@@ -350,7 +367,7 @@ asmlinkage long afs32_xsetgroups(int gidsetsize, gid_t *grouplist)
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
        /* re-install old pag if there's room. */
-       code = __setpag(&cr, old_pag, &junk, 0);
+       code = __setpag(&cr, old_pag, &junk, 0, NULL);
     }
     crfree(cr);
     
@@ -387,7 +404,7 @@ afs32_xsetgroups(int gidsetsize, u16 * grouplist)
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
        /* re-install old pag if there's room. */
-       code = __setpag(&cr, old_pag, &junk, 0);
+       code = __setpag(&cr, old_pag, &junk, 0, NULL);
     }
     crfree(cr);
     
@@ -422,7 +439,7 @@ afs32_xsetgroups32(int gidsetsize, gid_t * grouplist)
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
        /* re-install old pag if there's room. */
-       code = __setpag(&cr, old_pag, &junk, 0);
+       code = __setpag(&cr, old_pag, &junk, 0, NULL);
     }
     crfree(cr);
 
@@ -575,7 +592,7 @@ osi_get_keyring_pag(afs_ucred_t *cred)
                if (afs_linux_cred_is_current(cred) &&
                     ((keyring_pag >> 24) & 0xff) == 'A' &&
                    keyring_pag != afs_linux_pag_from_groups(current_group_info())) {
-                       __setpag(&cred, keyring_pag, &newpag, 0);
+                       __setpag(&cred, keyring_pag, &newpag, 0, NULL);
                }
            }
            key_put(key);

diff --git a/src/afs/LINUX/osi_prototypes.h b/src/afs/LINUX/osi_prototypes.h
index 755911d..316065f 100644 (file)
--- a/src/afs/LINUX/osi_prototypes.h
+++ b/src/afs/LINUX/osi_prototypes.h
@@ -94,7 +94,7 @@ extern void afs_fill_inode(struct inode *ip, struct vattr *vattr);
 extern void osi_keyring_init(void);
 extern void osi_keyring_shutdown(void);
 extern int __setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
-                   int change_parent);
+                   int change_parent, struct group_info **old_groups);
 #ifdef LINUX_KEYRING_SUPPORT
 extern afs_int32 osi_get_keyring_pag(afs_ucred_t *);
 extern struct key_type key_type_afs_pag;