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Message-Id: <20180108125920.532971027@linuxfoundation.org>
Date: Mon, 8 Jan 2018 13:59:28 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Thiago Rafael Becker <thiago.becker@...il.com>,
Matthew Wilcox <mawilcox@...rosoft.com>,
NeilBrown <neilb@...e.com>,
"J. Bruce Fields" <bfields@...ldses.org>,
Al Viro <viro@...iv.linux.org.uk>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.9 08/21] kernel: make groups_sort calling a responsibility group_info allocators
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thiago Rafael Becker <thiago.becker@...il.com>
commit bdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758 upstream.
In testing, we found that nfsd threads may call set_groups in parallel
for the same entry cached in auth.unix.gid, racing in the call of
groups_sort, corrupting the groups for that entry and leading to
permission denials for the client.
This patch:
- Make groups_sort globally visible.
- Move the call to groups_sort to the modifiers of group_info
- Remove the call to groups_sort from set_groups
Link: http://lkml.kernel.org/r/20171211151420.18655-1-thiago.becker@gmail.com
Signed-off-by: Thiago Rafael Becker <thiago.becker@...il.com>
Reviewed-by: Matthew Wilcox <mawilcox@...rosoft.com>
Reviewed-by: NeilBrown <neilb@...e.com>
Acked-by: "J. Bruce Fields" <bfields@...ldses.org>
Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/s390/kernel/compat_linux.c | 1 +
fs/nfsd/auth.c | 3 +++
include/linux/cred.h | 1 +
kernel/groups.c | 5 +++--
kernel/uid16.c | 1 +
net/sunrpc/auth_gss/gss_rpc_xdr.c | 1 +
net/sunrpc/auth_gss/svcauth_gss.c | 1 +
net/sunrpc/svcauth_unix.c | 2 ++
8 files changed, 13 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -263,6 +263,7 @@ COMPAT_SYSCALL_DEFINE2(s390_setgroups16,
return retval;
}
+ groups_sort(group_info);
retval = set_current_groups(group_info);
put_group_info(group_info);
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -59,6 +59,9 @@ int nfsd_setuser(struct svc_rqst *rqstp,
gi->gid[i] = exp->ex_anon_gid;
else
gi->gid[i] = rqgi->gid[i];
+
+ /* Each thread allocates its own gi, no race */
+ groups_sort(gi);
}
} else {
gi = get_group_info(rqgi);
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -82,6 +82,7 @@ extern int set_current_groups(struct gro
extern void set_groups(struct cred *, struct group_info *);
extern int groups_search(const struct group_info *, kgid_t);
extern bool may_setgroups(void);
+extern void groups_sort(struct group_info *);
/*
* The security context of a task
--- a/kernel/groups.c
+++ b/kernel/groups.c
@@ -77,7 +77,7 @@ static int groups_from_user(struct group
}
/* a simple Shell sort */
-static void groups_sort(struct group_info *group_info)
+void groups_sort(struct group_info *group_info)
{
int base, max, stride;
int gidsetsize = group_info->ngroups;
@@ -103,6 +103,7 @@ static void groups_sort(struct group_inf
stride /= 3;
}
}
+EXPORT_SYMBOL(groups_sort);
/* a simple bsearch */
int groups_search(const struct group_info *group_info, kgid_t grp)
@@ -134,7 +135,6 @@ int groups_search(const struct group_inf
void set_groups(struct cred *new, struct group_info *group_info)
{
put_group_info(new->group_info);
- groups_sort(group_info);
get_group_info(group_info);
new->group_info = group_info;
}
@@ -218,6 +218,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsi
return retval;
}
+ groups_sort(group_info);
retval = set_current_groups(group_info);
put_group_info(group_info);
--- a/kernel/uid16.c
+++ b/kernel/uid16.c
@@ -190,6 +190,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidset
return retval;
}
+ groups_sort(group_info);
retval = set_current_groups(group_info);
put_group_info(group_info);
--- a/net/sunrpc/auth_gss/gss_rpc_xdr.c
+++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c
@@ -231,6 +231,7 @@ static int gssx_dec_linux_creds(struct x
goto out_free_groups;
creds->cr_group_info->gid[i] = kgid;
}
+ groups_sort(creds->cr_group_info);
return 0;
out_free_groups:
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -481,6 +481,7 @@ static int rsc_parse(struct cache_detail
goto out;
rsci.cred.cr_group_info->gid[i] = kgid;
}
+ groups_sort(rsci.cred.cr_group_info);
/* mech name */
len = qword_get(&mesg, buf, mlen);
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -520,6 +520,7 @@ static int unix_gid_parse(struct cache_d
ug.gi->gid[i] = kgid;
}
+ groups_sort(ug.gi);
ugp = unix_gid_lookup(cd, uid);
if (ugp) {
struct cache_head *ch;
@@ -819,6 +820,7 @@ svcauth_unix_accept(struct svc_rqst *rqs
kgid_t kgid = make_kgid(&init_user_ns, svc_getnl(argv));
cred->cr_group_info->gid[i] = kgid;
}
+ groups_sort(cred->cr_group_info);
if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {
*authp = rpc_autherr_badverf;
return SVC_DENIED;
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