diff options
| author | Csaba Henk <csaba@redhat.com> | 2017-07-05 17:48:37 +0200 |
|---|---|---|
| committer | Jeff Darcy <jeff@pl.atyp.us> | 2017-07-06 18:26:08 +0000 |
| commit | e14ea3f5c37475e12a3b7fb7bd3165b0a4e77c51 (patch) | |
| tree | 7ef467ec7fa1761379a101ada475f504c479a42f /libglusterfs/src/common-utils.h | |
| parent | fc73ae5f81ef5926e3dc2311db116250d0f2a321 (diff) | |
groups: don't allocate auxiliary gid list on stack
When glusterfs wants to retrieve the list of auxiliary gids
of a user, it typically allocates a sufficiently big gid_t
array on stack and calls getgrouplist(3) with it. However,
"sufficiently big" means to be of maximum supported gid list
size, which in GlusterFS is GF_MAX_AUX_GROUPS = 64k.
That means a 64k * sizeof(gid_t) = 256k allocation, which is
big enough to overflow the stack in certain cases.
A further observation is that stack allocation of the gid list
brings no gain, as in all cases the content of the gid list
eventually gets copied over to a heap allocated buffer.
So we add a convenience wrapper of getgrouplist to libglusterfs
called gf_getgrouplist which calls getgrouplist with a sufficiently
big heap allocated buffer (it takes care of the allocation too).
We are porting all the getgrouplist invocations to gf_getgrouplist
and thus eliminate the huge stack allocation.
BUG: 1464327
Change-Id: Icea76d0d74dcf2f87d26cb299acc771ca3b32d2b
Signed-off-by: Csaba Henk <csaba@redhat.com>
Reviewed-on: https://review.gluster.org/17706
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Diffstat (limited to 'libglusterfs/src/common-utils.h')
| -rw-r--r-- | libglusterfs/src/common-utils.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/libglusterfs/src/common-utils.h b/libglusterfs/src/common-utils.h index c3c5ec77350..6a260c090c8 100644 --- a/libglusterfs/src/common-utils.h +++ b/libglusterfs/src/common-utils.h @@ -918,4 +918,7 @@ get_ip_from_addrinfo (struct addrinfo *addr, char **ip); int close_fds_except (int *fdv, size_t count); + +int +gf_getgrouplist (const char *user, gid_t group, gid_t **groups); #endif /* _COMMON_UTILS_H */ |