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

["Serge E. Hallyn" <serge@hallyn.com>]

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
> 
> _______________________________________________
> Containers mailing list
> Containers@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/containers