Re: [PATCH 18/43] userns: Convert group_info values from gid_t to kgid_t.

Serge E. Hallyn
2012-04-18T18:48:43Z

Quoting Eric W. Beiderman (ebiederm@xmission.com):
> From: Eric W. Biederman <ebiederm@xmission.com>
>
> As a first step to converting struct cred to be all kuid_t and kgid_t
> values convert the group values stored in group_info to always be
> kgid_t values. Unless user namespaces are used this change should
> have no effect.
>
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> ---
> arch/s390/kernel/compat_linux.c | 13 ++++++++-
> fs/nfsd/auth.c | 5 ++-
> fs/proc/array.c | 5 +++-
> include/linux/cred.h | 9 ++++---
> kernel/groups.c | 48 +++++++++++++++++++-----------------
> kernel/uid16.c | 14 +++++++++-
> net/ipv4/ping.c | 11 ++++++--
> net/sunrpc/auth_generic.c | 4 +-
> net/sunrpc/auth_gss/svcauth_gss.c | 7 ++++-
> net/sunrpc/auth_unix.c | 15 ++++++++---
> net/sunrpc/svcauth_unix.c | 18 ++++++++++---
> security/keys/permission.c | 3 +-
> 12 files changed, 103 insertions(+), 49 deletions(-)
>
> diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
> index ab64bdb..5baac18 100644
> --- a/arch/s390/kernel/compat_linux.c
> +++ b/arch/s390/kernel/compat_linux.c
> @@ -173,11 +173,14 @@ asmlinkage long sys32_setfsgid16(u16 gid)
>
> static int groups16_to_user(u16 __user *grouplist, struct group_info *group_info)
> {
> + struct user_namespace *user_ns = current_user_ns();
> int i;
> u16 group;
> + kgid_t kgid;
>
> for (i = 0; i < group_info->ngroups; i++) {
> - group = (u16)GROUP_AT(group_info, i);
> + kgid = GROUP_AT(group_info, i);
> + group = (u16)from_kgid_munged(user_ns, kgid);
> if (put_user(group, grouplist+i))
> return -EFAULT;
> }
> @@ -187,13 +190,19 @@ static int groups16_to_user(u16 __user *grouplist, struct group_info *group_info
>
> static int groups16_from_user(struct group_info *group_info, u16 __user *grouplist)
> {
> + struct user_namespace *user_ns = current_user_ns();
> int i;
> u16 group;

need

kgid_t kgid;

here

>
> for (i = 0; i < group_info->ngroups; i++) {
> if (get_user(group, grouplist+i))
> return -EFAULT;
> - GROUP_AT(group_info, i) = (gid_t)group;
> +
> + kgid = make_kgid(user_ns, (gid_t)group);
> + if (!gid_valid(kgid))
> + return -EINVAL;
> +
> + GROUP_AT(group_info, i) = kgid;
> }
>
> return 0;
> diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
> index 79717a4..204438c 100644
> --- a/fs/nfsd/auth.c
> +++ b/fs/nfsd/auth.c
> @@ -1,6 +1,7 @@
> /* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> */
>
> #include <linux/sched.h>
> +#include <linux/user_namespace.h>
> #include "nfsd.h"
> #include "auth.h"
>
> @@ -56,8 +57,8 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
> goto oom;
>
> for (i = 0; i < rqgi->ngroups; i++) {
> - if (!GROUP_AT(rqgi, i))
> - GROUP_AT(gi, i) = exp->ex_anon_gid;
> + if (gid_eq(GLOBAL_ROOT_GID, GROUP_AT(rqgi, i)))
> + GROUP_AT(gi, i) = make_kgid(&init_user_ns, exp->ex_anon_gid);
> else
> GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
> }
> diff --git a/fs/proc/array.c b/fs/proc/array.c
> index f9bd395..36a0a91 100644
> --- a/fs/proc/array.c
> +++ b/fs/proc/array.c
> @@ -81,6 +81,7 @@
> #include <linux/pid_namespace.h>
> #include <linux/ptrace.h>
> #include <linux/tracehook.h>
> +#include <linux/user_namespace.h>
>
> #include <asm/pgtable.h>
> #include <asm/processor.h>
> @@ -161,6 +162,7 @@ static inline const char *get_task_state(struct task_struct *tsk)
> static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
> struct pid *pid, struct task_struct *p)
> {
> + struct user_namespace *user_ns = current_user_ns();
> struct group_info *group_info;
> int g;
> struct fdtable *fdt = NULL;
> @@ -205,7 +207,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
> task_unlock(p);
>
> for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
> - seq_printf(m, "%d ", GROUP_AT(group_info, g));
> + seq_printf(m, "%d ",
> + from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
> put_cred(cred);
>
> seq_putc(m, '\n');
> diff --git a/include/linux/cred.h b/include/linux/cred.h
> index 2c60ec8..0ab3cda 100644
> --- a/include/linux/cred.h
> +++ b/include/linux/cred.h
> @@ -17,6 +17,7 @@
> #include <linux/key.h>
> #include <linux/selinux.h>
> #include <linux/atomic.h>
> +#include <linux/uidgid.h>
>
> struct user_struct;
> struct cred;
> @@ -26,14 +27,14 @@ struct inode;
> * COW Supplementary groups list
> */
> #define NGROUPS_SMALL 32
> -#define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(gid_t)))
> +#define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(kgid_t)))
>
> struct group_info {
> atomic_t usage;
> int ngroups;
> int nblocks;
> - gid_t small_block[NGROUPS_SMALL];
> - gid_t *blocks[0];
> + kgid_t small_block[NGROUPS_SMALL];
> + kgid_t *blocks[0];
> };
>
> /**
> @@ -66,7 +67,7 @@ extern struct group_info init_groups;
> extern void groups_free(struct group_info *);
> extern int set_current_groups(struct group_info *);
> extern int set_groups(struct cred *, struct group_info *);
> -extern int groups_search(const struct group_info *, gid_t);
> +extern int groups_search(const struct group_info *, kgid_t);
>
> /* access the groups "array" with this macro */
> #define GROUP_AT(gi, i) \
> diff --git a/kernel/groups.c b/kernel/groups.c
> index 99b53d1..84156f2 100644
> --- a/kernel/groups.c
> +++ b/kernel/groups.c
> @@ -31,7 +31,7 @@ struct group_info *groups_alloc(int gidsetsize)
> group_info->blocks[0] = group_info->small_block;
> else {
> for (i = 0; i < nblocks; i++) {
> - gid_t *b;
> + kgid_t *b;
> b = (void *)__get_free_page(GFP_USER);
> if (!b)
> goto out_undo_partial_alloc;
> @@ -66,18 +66,15 @@ EXPORT_SYMBOL(groups_free);
> static int groups_to_user(gid_t __user *grouplist,
> const struct group_info *group_info)
> {
> + struct user_namespace *user_ns = current_user_ns();
> int i;
> unsigned int count = group_info->ngroups;
>
> - for (i = 0; i < group_info->nblocks; i++) {
> - unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
> - unsigned int len = cp_count * sizeof(*grouplist);
> -
> - if (copy_to_user(grouplist, group_info->blocks[i], len))
> + for (i = 0; i < count; i++) {
> + gid_t gid;
> + gid = from_kgid_munged(user_ns, GROUP_AT(group_info, i));
> + if (put_user(gid, grouplist+i))
> return -EFAULT;
> -
> - grouplist += NGROUPS_PER_BLOCK;
> - count -= cp_count;
> }
> return 0;
> }
> @@ -86,18 +83,21 @@ static int groups_to_user(gid_t __user *grouplist,
> static int groups_from_user(struct group_info *group_info,
> gid_t __user *grouplist)
> {
> + struct user_namespace *user_ns = current_user_ns();
> int i;
> unsigned int count = group_info->ngroups;
>
> - for (i = 0; i < group_info->nblocks; i++) {
> - unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
> - unsigned int len = cp_count * sizeof(*grouplist);
> -
> - if (copy_from_user(group_info->blocks[i], grouplist, len))
> + for (i = 0; i < count; i++) {
> + gid_t gid;
> + kgid_t kgid;
> + if (get_user(gid, grouplist+i))
> return -EFAULT;
>
> - grouplist += NGROUPS_PER_BLOCK;
> - count -= cp_count;
> + kgid = make_kgid(user_ns, gid);
> + if (!gid_valid(kgid))
> + return -EINVAL;
> +
> + GROUP_AT(group_info, i) = kgid;
> }
> return 0;
> }
> @@ -117,9 +117,9 @@ static void groups_sort(struct group_info *group_info)
> for (base = 0; base < max; base++) {
> int left = base;
> int right = left + stride;
> - gid_t tmp = GROUP_AT(group_info, right);
> + kgid_t tmp = GROUP_AT(group_info, right);
>
> - while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
> + while (left >= 0 && gid_gt(GROUP_AT(group_info, left), tmp)) {
> GROUP_AT(group_info, right) =
> GROUP_AT(group_info, left);
> right = left;
> @@ -132,7 +132,7 @@ static void groups_sort(struct group_info *group_info)
> }
>
> /* a simple bsearch */
> -int groups_search(const struct group_info *group_info, gid_t grp)
> +int groups_search(const struct group_info *group_info, kgid_t grp)
> {
> unsigned int left, right;
>
> @@ -143,9 +143,9 @@ int groups_search(const struct group_info *group_info, gid_t grp)
> right = group_info->ngroups;
> while (left < right) {
> unsigned int mid = (left+right)/2;
> - if (grp > GROUP_AT(group_info, mid))
> + if (gid_gt(grp, GROUP_AT(group_info, mid)))
> left = mid + 1;
> - else if (grp < GROUP_AT(group_info, mid))
> + else if (gid_lt(grp, GROUP_AT(group_info, mid)))
> right = mid;
> else
> return 1;
> @@ -262,7 +262,8 @@ int in_group_p(gid_t grp)
> int retval = 1;
>
> if (grp != cred->fsgid)
> - retval = groups_search(cred->group_info, grp);
> + retval = groups_search(cred->group_info,
> + make_kgid(cred->user_ns, grp));
> return retval;
> }
>
> @@ -274,7 +275,8 @@ int in_egroup_p(gid_t grp)
> int retval = 1;
>
> if (grp != cred->egid)
> - retval = groups_search(cred->group_info, grp);
> + retval = groups_search(cred->group_info,
> + make_kgid(cred->user_ns, grp));
> return retval;
> }
>
> diff --git a/kernel/uid16.c b/kernel/uid16.c
> index 51c6e89..e530bc3 100644
> --- a/kernel/uid16.c
> +++ b/kernel/uid16.c
> @@ -134,11 +134,14 @@ SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
> static int groups16_to_user(old_gid_t __user *grouplist,
> struct group_info *group_info)
> {
> + struct user_namespace *user_ns = current_user_ns();
> int i;
> old_gid_t group;
> + kgid_t kgid;
>
> for (i = 0; i < group_info->ngroups; i++) {
> - group = high2lowgid(GROUP_AT(group_info, i));
> + kgid = GROUP_AT(group_info, i);
> + group = high2lowgid(from_kgid_munged(user_ns, kgid));
> if (put_user(group, grouplist+i))
> return -EFAULT;
> }
> @@ -149,13 +152,20 @@ static int groups16_to_user(old_gid_t __user *grouplist,
> static int groups16_from_user(struct group_info *group_info,
> old_gid_t __user *grouplist)
> {
> + struct user_namespace *user_ns = current_user_ns();
> int i;
> old_gid_t group;
> + kgid_t kgid;
>
> for (i = 0; i < group_info->ngroups; i++) {
> if (get_user(group, grouplist+i))
> return -EFAULT;
> - GROUP_AT(group_info, i) = low2highgid(group);
> +
> + kgid = make_kgid(user_ns, low2highgid(group));
> + if (!gid_valid(kgid))
> + return -EINVAL;
> +
> + GROUP_AT(group_info, i) = kgid;
> }
>
> return 0;
> diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
> index 50009c7..9d3044f 100644
> --- a/net/ipv4/ping.c
> +++ b/net/ipv4/ping.c
> @@ -205,17 +205,22 @@ static int ping_init_sock(struct sock *sk)
> gid_t range[2];
> struct group_info *group_info = get_current_groups();
> int i, j, count = group_info->ngroups;
> + kgid_t low, high;
>
> inet_get_ping_group_range_net(net, range, range+1);
> + low = make_kgid(&init_user_ns, range[0]);
> + high = make_kgid(&init_user_ns, range[1]);
> + if (!gid_valid(low) || !gid_valid(high) || gid_lt(high, low))
> + return -EACCES;
> +
> if (range[0] <= group && group <= range[1])
> return 0;
>
> for (i = 0; i < group_info->nblocks; i++) {
> int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
> -
> for (j = 0; j < cp_count; j++) {
> - group = group_info->blocks[i][j];
> - if (range[0] <= group && group <= range[1])
> + kgid_t gid = group_info->blocks[i][j];
> + if (gid_lte(low, gid) && gid_lte(gid, high))
> return 0;
> }
>
> diff --git a/net/sunrpc/auth_generic.c b/net/sunrpc/auth_generic.c
> index 75762f3..6ed6f20 100644
> --- a/net/sunrpc/auth_generic.c
> +++ b/net/sunrpc/auth_generic.c
> @@ -160,8 +160,8 @@ generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
> if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
> goto out_nomatch;
> for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
> - if (GROUP_AT(gcred->acred.group_info, i) !=
> - GROUP_AT(acred->group_info, i))
> + if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
> + GROUP_AT(acred->group_info, i)))
> goto out_nomatch;
> }
> out_match:
> diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
> index 1600cfb..28b62db 100644
> --- a/net/sunrpc/auth_gss/svcauth_gss.c
> +++ b/net/sunrpc/auth_gss/svcauth_gss.c
> @@ -41,6 +41,7 @@
> #include <linux/types.h>
> #include <linux/module.h>
> #include <linux/pagemap.h>
> +#include <linux/user_namespace.h>
>
> #include <linux/sunrpc/auth_gss.h>
> #include <linux/sunrpc/gss_err.h>
> @@ -470,9 +471,13 @@ static int rsc_parse(struct cache_detail *cd,
> status = -EINVAL;
> for (i=0; i<N; i++) {
> gid_t gid;
> + kgid_t kgid;
> if (get_int(&mesg, &gid))
> goto out;
> - GROUP_AT(rsci.cred.cr_group_info, i) = gid;
> + kgid = make_kgid(&init_user_ns, gid);
> + if (!gid_valid(kgid))
> + goto out;
> + GROUP_AT(rsci.cred.cr_group_info, i) = kgid;
> }
>
> /* mech name */
> diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
> index e50502d..52c5abd 100644
> --- a/net/sunrpc/auth_unix.c
> +++ b/net/sunrpc/auth_unix.c
> @@ -12,6 +12,7 @@
> #include <linux/module.h>
> #include <linux/sunrpc/clnt.h>
> #include <linux/sunrpc/auth.h>
> +#include <linux/user_namespace.h>
>
> #define NFS_NGROUPS 16
>
> @@ -78,8 +79,11 @@ unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
> groups = NFS_NGROUPS;
>
> cred->uc_gid = acred->gid;
> - for (i = 0; i < groups; i++)
> - cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
> + for (i = 0; i < groups; i++) {
> + gid_t gid;
> + gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i));
> + cred->uc_gids[i] = gid;
> + }
> if (i < NFS_NGROUPS)
> cred->uc_gids[i] = NOGROUP;
>
> @@ -126,9 +130,12 @@ unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
> groups = acred->group_info->ngroups;
> if (groups > NFS_NGROUPS)
> groups = NFS_NGROUPS;
> - for (i = 0; i < groups ; i++)
> - if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
> + for (i = 0; i < groups ; i++) {
> + gid_t gid;
> + gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i));
> + if (cred->uc_gids[i] != gid)
> return 0;
> + }
> if (groups < NFS_NGROUPS &&
> cred->uc_gids[groups] != NOGROUP)
> return 0;
> diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
> index 521d8f7..71ec853 100644
> --- a/net/sunrpc/svcauth_unix.c
> +++ b/net/sunrpc/svcauth_unix.c
> @@ -14,6 +14,7 @@
> #include <net/sock.h>
> #include <net/ipv6.h>
> #include <linux/kernel.h>
> +#include <linux/user_namespace.h>
> #define RPCDBG_FACILITY RPCDBG_AUTH
>
> #include <linux/sunrpc/clnt.h>
> @@ -530,11 +531,15 @@ static int unix_gid_parse(struct cache_detail *cd,
>
> for (i = 0 ; i < gids ; i++) {
> int gid;
> + kgid_t kgid;
> rv = get_int(&mesg, &gid);
> err = -EINVAL;
> if (rv)
> goto out;
> - GROUP_AT(ug.gi, i) = gid;
> + kgid = make_kgid(&init_user_ns, gid);
> + if (!gid_valid(kgid))
> + goto out;
> + GROUP_AT(ug.gi, i) = kgid;
> }
>
> ugp = unix_gid_lookup(cd, uid);
> @@ -563,6 +568,7 @@ static int unix_gid_show(struct seq_file *m,
> struct cache_detail *cd,
> struct cache_head *h)
> {
> + struct user_namespace *user_ns = current_user_ns();
> struct unix_gid *ug;
> int i;
> int glen;
> @@ -580,7 +586,7 @@ static int unix_gid_show(struct seq_file *m,
>
> seq_printf(m, "%u %d:", ug->uid, glen);
> for (i = 0; i < glen; i++)
> - seq_printf(m, " %d", GROUP_AT(ug->gi, i));
> + seq_printf(m, " %d", from_kgid_munged(user_ns, GROUP_AT(ug->gi, i)));
> seq_printf(m, "\n");
> return 0;
> }
> @@ -831,8 +837,12 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
> cred->cr_group_info = groups_alloc(slen);
> if (cred->cr_group_info == NULL)
> return SVC_CLOSE;
> - for (i = 0; i < slen; i++)
> - GROUP_AT(cred->cr_group_info, i) = svc_getnl(argv);
> + for (i = 0; i < slen; i++) {
> + kgid_t kgid = make_kgid(&init_user_ns, svc_getnl(argv));
> + if (!gid_valid(kgid))
> + goto badcred;
> + GROUP_AT(cred->cr_group_info, i) = kgid;
> + }
> if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {
> *authp = rpc_autherr_badverf;
> return SVC_DENIED;
> diff --git a/security/keys/permission.c b/security/keys/permission.c
> index e146cbd..5442900 100644
> --- a/security/keys/permission.c
> +++ b/security/keys/permission.c
> @@ -53,7 +53,8 @@ int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
> goto use_these_perms;
> }
>
> - ret = groups_search(cred->group_info, key->gid);
> + ret = groups_search(cred->group_info,
> + make_kgid(current_user_ns(), key->gid));
> if (ret) {
> kperm = key->perm >> 8;
> goto use_these_perms;
> --
> 1.7.2.5
>
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