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authorNeilBrown <neilb@suse.de>2011-10-25 10:25:49 +1100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-11-11 09:44:30 -0800
commit819bac2f91d8ae8433bd5beb85797bb0c63cbaa2 (patch)
treeb726970db5676764fcf4057744b5b87971ece32f
parent3911ea7beedc6fbcce9235bda520749a6dfd4c57 (diff)
downloadlinux-linaro-precise-819bac2f91d8ae8433bd5beb85797bb0c63cbaa2.tar.gz
NFS/sunrpc: don't use a credential with extra groups.
commit dc6f55e9f8dac4b6479be67c5c9128ad37bb491f upstream. The sunrpc layer keeps a cache of recently used credentials and 'unx_match' is used to find the credential which matches the current process. However unx_match allows a match when the cached credential has extra groups at the end of uc_gids list which are not in the process group list. So if a process with a list of (say) 4 group accesses a file and gains access because of the last group in the list, then another process with the same uid and gid, and a gid list being the first tree of the gids of the original process tries to access the file, it will be granted access even though it shouldn't as the wrong rpc credential will be used. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/sunrpc/auth_unix.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index 4cb70dc6e7a..e50502d8ceb 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -129,6 +129,9 @@ unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
for (i = 0; i < groups ; i++)
if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
return 0;
+ if (groups < NFS_NGROUPS &&
+ cred->uc_gids[groups] != NOGROUP)
+ return 0;
return 1;
}