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authorNiels de Vos <ndevos@redhat.com>2014-03-20 18:13:49 +0100
committerVijay Bellur <vbellur@redhat.com>2014-04-08 10:50:52 -0700
commit8235de189845986a535d676b1fd2c894b9c02e52 (patch)
tree6f5ea06d6b0b9b3f8091e0b9e7b34a7158afe3d1 /xlators/nfs
parent07df69edc8165d875edd42a4080a494e09b98de5 (diff)
rpc: warn and truncate grouplist if RPC/AUTH can not hold everything
The GlusterFS protocol currently uses AUTH_GLUSTERFS_V2 in the RPC/AUTH header. This header contains the uid, gid and auxiliary groups of the user/process that accesses the Gluster Volume. The AUTH_GLUSTERFS_V2 structure allows up to 65535 auxiliary groups to be passed on. Unfortunately, the RPC/AUTH header is limited to 400 bytes by the RPC specification: http://tools.ietf.org/html/rfc5531#section-8.2 In order to not cause complete failures on the client-side when trying to encode a AUTH_GLUSTERFS_V2 that would result in more than 400 bytes, we can calculate the expected size of the other elements: 1 | pid 1 | uid 1 | gid 1 | groups_len XX | groups_val (GF_MAX_AUX_GROUPS=65535) 1 | lk_owner_len YY | lk_owner_val (GF_MAX_LOCK_OWNER_LEN=1024) ----+------------------------------------------- 5 | total xdr-units one XDR-unit is defined as BYTES_PER_XDR_UNIT = 4 bytes MAX_AUTH_BYTES = 400 is the maximum, this is 100 xdr-units. XX + YY can be 95 to fill the 100 xdr-units. Note that the on-wire protocol has tighter requirements than the internal structures. It is possible for xlators to use more groups and a bigger lk_owner than that can be sent by a GlusterFS-client. This change prevents overflows when allocating the RPC/AUTH header. Two new macros are introduced to calculate the number of groups that fit in the RPC/AUTH header, when taking the size of the lk_owner in account. In case the list of groups exceeds the maximum possible, only the first groups are passed over the RPC/GlusterFS protocol to the bricks. A warning is added to the logs, so that most system administrators will get informed. The reducing of the number of groups is not a new inventions. The RPC/AUTH header (AUTH_SYS or AUTH_UNIX) that NFS uses has a limit of 16 groups. Most, if not all, NFS-clients will reduce any bigger number of groups to 16. (nfs.server-aux-gids can be used to workaround the limit of 16 groups, but the Gluster NFS-server will be limited to a maximum of 93 groups, or fewer in case the lk_owner structure contains more items.) Change-Id: I8410e59d0fd246d601b54b961d3ae9cb5a858c10 BUG: 1053579 Signed-off-by: Niels de Vos <ndevos@redhat.com> Reviewed-on: http://review.gluster.org/7202 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Harshavardhana <harsha@harshavardhana.net> Reviewed-by: Santosh Pradhan <spradhan@redhat.com> Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Diffstat (limited to 'xlators/nfs')
-rw-r--r--xlators/nfs/server/src/nfs-fops.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/xlators/nfs/server/src/nfs-fops.c b/xlators/nfs/server/src/nfs-fops.c
index 14bc0f3..b91f73a 100644
--- a/xlators/nfs/server/src/nfs-fops.c
+++ b/xlators/nfs/server/src/nfs-fops.c
@@ -30,6 +30,8 @@
#include <libgen.h>
#include <semaphore.h>
+static int gf_auth_max_groups_nfs_log = 0;
+
void
nfs_fix_groups (xlator_t *this, call_stack_t *root)
{
@@ -39,6 +41,7 @@ nfs_fix_groups (xlator_t *this, call_stack_t *root)
gid_t mygroups[GF_MAX_AUX_GROUPS];
int ngroups;
int i;
+ int max_groups;
struct nfs_state *priv = this->private;
const gid_list_t *agl;
gid_list_t gl;
@@ -47,10 +50,22 @@ nfs_fix_groups (xlator_t *this, call_stack_t *root)
return;
}
+ /* RPC enforces the GF_AUTH_GLUSTERFS_MAX_GROUPS limit */
+ max_groups = GF_AUTH_GLUSTERFS_MAX_GROUPS(root->lk_owner.len);
+
agl = gid_cache_lookup(&priv->gid_cache, root->uid, 0, 0);
if (agl) {
- for (ngroups = 0; ngroups < agl->gl_count; ngroups++)
+ if (agl->gl_count > max_groups) {
+ GF_LOG_OCCASIONALLY (gf_auth_max_groups_nfs_log,
+ this->name, GF_LOG_WARNING,
+ "too many groups, reducing %d -> %d",
+ agl->gl_count, max_groups);
+ }
+
+ for (ngroups = 0; ngroups < agl->gl_count
+ && ngroups <= max_groups; ngroups++) {
root->groups[ngroups] = agl->gl_list[ngroups];
+ }
root->ngrps = ngroups;
gid_cache_release(&priv->gid_cache, agl);
return;
@@ -92,6 +107,16 @@ nfs_fix_groups (xlator_t *this, call_stack_t *root)
GF_FREE(gl.gl_list);
}
+ /* RPC enforces the GF_AUTH_GLUSTERFS_MAX_GROUPS limit */
+ if (ngroups > max_groups) {
+ GF_LOG_OCCASIONALLY (gf_auth_max_groups_nfs_log,
+ this->name, GF_LOG_WARNING,
+ "too many groups, reducing %d -> %d",
+ ngroups, max_groups);
+
+ ngroups = max_groups;
+ }
+
/* Copy data to the frame. */
for (i = 0; i < ngroups; ++i) {
gf_log (this->name, GF_LOG_TRACE,