Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753122AbbH2Kt6 (ORCPT ); Sat, 29 Aug 2015 06:49:58 -0400 Received: from mout01.posteo.de ([185.67.36.65]:44015 "EHLO mout01.posteo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737AbbH2Kt4 (ORCPT ); Sat, 29 Aug 2015 06:49:56 -0400 Date: Sat, 29 Aug 2015 12:43:04 +0200 From: Dongsu Park To: Peter Hurley Cc: Al Viro , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Josh Triplett , David Howells , Alban Crequy , Alexey Dobriyan Subject: Re: [PATCH v2] devpts: allow mounting with uid/gid of uint32_t Message-ID: <20150829104304.GA2841@posteo.de> References: <882a878038efb5fed381be5d4817ff44d90703d5.1439904209.git.dpark@posteo.net> <692839ff7158dbb96dd20ce8e36c13f85fa64fd7.1439910753.git.dpark@posteo.net> <55E0B786.70101@hurleysoftware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <55E0B786.70101@hurleysoftware.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6138 Lines: 197 On 28.08.2015 15:33, Peter Hurley wrote: > On 08/18/2015 11:18 AM, Dongsu Park wrote: > > --- > > fs/devpts/inode.c | 20 ++++++++++++++++---- > > 1 file changed, 16 insertions(+), 4 deletions(-) > > > > diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c > > index c35ffdc12bba..49272fae40a7 100644 > > --- a/fs/devpts/inode.c > > +++ b/fs/devpts/inode.c > > @@ -188,23 +188,35 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) > > token = match_token(p, tokens, args); > > switch (token) { > > case Opt_uid: > > - if (match_int(&args[0], &option)) > > match_int() => make_kuid/kgid is a widespread pattern in filesystems > for handling uid/gid mount parameters. > > How about adding a for-purpose string-to-uid/gid function, rather than > open-coding? Yeah, that sounds like a good idea. Do you mean probably something like this? (on top of -mm tree) Thanks, Dongsu ---- >From ccfa5db398ba5ac31c5e0128e88abca1f6d1e6f5 Mon Sep 17 00:00:00 2001 Message-Id: From: Dongsu Park Date: Sat, 29 Aug 2015 12:35:01 +0200 Subject: [PATCH v3] devpts: allow mounting with uid/gid of uint32_t To allow devpts to be mounted with options of uid/gid of uint32_t, we need to make use of general parsing API instead of match_int(). So introduce kstrto{uid,gid}(), wrappers around kstrtouint() as well as make_k{uid,gid}() calls. And then make devpts parse options only using kstrto{uid,gid}(). Doing that, mounting devpts with uid or gid > (2^31 - 1) will work as expected, e.g.: # mount -t devpts devpts /tmp/devptsdir -o \ newinstance,ptmxmode=0666,mode=620,uid=3598450688,gid=3598450693 It was originally by reported on github issue tracker of systemd: https://github.com/systemd/systemd/issues/956 ==== from v2: * rebase on top of -mm tree * split common parts for parsing uid/gid into kstrto{uid,gid}() * fix minor format. * continue to use kstrtouint() suggested by Alexey Dobriyan. from v1: fix patch format correctly Cc: Alexey Dobriyan Reported-by: Alban Crequy Suggested-by: Peter Hurley Signed-off-by: Dongsu Park --- fs/devpts/inode.c | 19 +++++++++---------- include/linux/parse-integer.h | 4 ++++ lib/kstrtox.c | 40 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 53 insertions(+), 10 deletions(-) diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index c35ffdc12bba..fbbd71005dcb 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -181,6 +181,7 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) substring_t args[MAX_OPT_ARGS]; int token; int option; + int rc; if (!*p) continue; @@ -188,20 +189,18 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) token = match_token(p, tokens, args); switch (token) { case Opt_uid: - if (match_int(&args[0], &option)) - return -EINVAL; - uid = make_kuid(current_user_ns(), option); - if (!uid_valid(uid)) - return -EINVAL; + rc = kstrtouid(args[0].from, &uid); + if (rc) + return rc; + opts->uid = uid; opts->setuid = 1; break; case Opt_gid: - if (match_int(&args[0], &option)) - return -EINVAL; - gid = make_kgid(current_user_ns(), option); - if (!gid_valid(gid)) - return -EINVAL; + rc = kstrtogid(args[0].from, &gid); + if (rc) + return rc; + opts->gid = gid; opts->setgid = 1; break; diff --git a/include/linux/parse-integer.h b/include/linux/parse-integer.h index ba620cdf3df6..2cdc4f418e00 100644 --- a/include/linux/parse-integer.h +++ b/include/linux/parse-integer.h @@ -2,6 +2,7 @@ #define _PARSE_INTEGER_H #include #include +#include /* * int parse_integer(const char *s, unsigned int base, T *val); @@ -155,6 +156,9 @@ static inline int __must_check kstrtos8(const char *s, unsigned int base, s8 *re return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res); } +int __must_check kstrtouid(const char *uidstr, kuid_t *kuid); +int __must_check kstrtogid(const char *gidstr, kgid_t *kgid); + int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res); int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res); int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res); diff --git a/lib/kstrtox.c b/lib/kstrtox.c index 1698b286d954..4c376716a72e 100644 --- a/lib/kstrtox.c +++ b/lib/kstrtox.c @@ -17,6 +17,8 @@ #include #include #include +#include +#include #include #include "kstrtox.h" @@ -81,6 +83,44 @@ int f(const char __user *s, size_t count, unsigned int base, type *res) \ } \ EXPORT_SYMBOL(f) +int kstrtouid(const char *uidstr, kuid_t *kuid) +{ + uid_t uidval; + kuid_t kuidtmp; + + int rc = kstrtouint(uidstr, 0, &uidval); + + if (rc) + return rc; + + kuidtmp = make_kuid(current_user_ns(), uidval); + if (!uid_valid(kuidtmp)) + return -EINVAL; + + *kuid = kuidtmp; + return 0; +} +EXPORT_SYMBOL(kstrtouid); + +int kstrtogid(const char *gidstr, kgid_t *kgid) +{ + gid_t gidval; + kgid_t kgidtmp; + + int rc = kstrtouint(gidstr, 0, &gidval); + + if (rc) + return rc; + + kgidtmp = make_kgid(current_user_ns(), gidval); + if (!gid_valid(kgidtmp)) + return -EINVAL; + + *kgid = kgidtmp; + return 0; +} +EXPORT_SYMBOL(kstrtogid); + kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long); kstrto_from_user(kstrtoll_from_user, kstrtoll, long long); kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/