* fs/attr.c patch
@ 2011-05-19 11:57 samsonov
2011-05-19 14:50 ` Serge E. Hallyn
0 siblings, 1 reply; 4+ messages in thread
From: samsonov @ 2011-05-19 11:57 UTC (permalink / raw)
To: linux-kernel
--- ./linux-2.6.33.4.orig/fs/attr.c 2010-05-13 02:04:27.000000000 +0400
+++ ./linux-2.6.33.4/fs/attr.c 2011-05-19 15:43:14.533672804 +0400
@@ -35,9 +35,7 @@
/* Make sure caller can chgrp. */
if ((ia_valid & ATTR_GID) &&
- (current_fsuid() != inode->i_uid ||
- (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
- !capable(CAP_CHOWN))
+ !(in_group_p(attr->ia_gid) && is_owner_or_cap(inode)))
goto error;
/* Make sure a caller can chmod. */
I think that fileowner can change group of file.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: fs/attr.c patch
2011-05-19 11:57 fs/attr.c patch samsonov
@ 2011-05-19 14:50 ` Serge E. Hallyn
0 siblings, 0 replies; 4+ messages in thread
From: Serge E. Hallyn @ 2011-05-19 14:50 UTC (permalink / raw)
To: samsonov; +Cc: linux-kernel
But you're removing the ability for a process with CAP_CHOWN to
chgrp all files.
You also change behavior (which may be wrong) when doing chgrp to
which would cause no change but the group is not in_group_p(),
which might break current users.
Quoting samsonov@krista.ru (samsonov@krista.ru):
> --- ./linux-2.6.33.4.orig/fs/attr.c 2010-05-13 02:04:27.000000000 +0400
> +++ ./linux-2.6.33.4/fs/attr.c 2011-05-19 15:43:14.533672804 +0400
> @@ -35,9 +35,7 @@
>
> /* Make sure caller can chgrp. */
> if ((ia_valid & ATTR_GID) &&
> - (current_fsuid() != inode->i_uid ||
> - (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
> - !capable(CAP_CHOWN))
> + !(in_group_p(attr->ia_gid) && is_owner_or_cap(inode)))
> goto error;
>
> /* Make sure a caller can chmod. */
>
> I think that fileowner can change group of file.
>
>
>
>
> --
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: fs/attr.c patch
2021-09-10 12:14 Павел Самсонов
@ 2021-09-10 12:29 ` Carlos Maiolino
0 siblings, 0 replies; 4+ messages in thread
From: Carlos Maiolino @ 2021-09-10 12:29 UTC (permalink / raw)
To: Павел
Самсонов
Cc: linux-fsdevel
On Fri, Sep 10, 2021 at 03:14:44PM +0300, Павел Самсонов wrote:
>
Please, follow the submitting patches guide included in the documentation:
Documentation/process/submitting-patches.rst
Also, please be sure to describe why {are you changing/do you want to change} the argument from inode to dentry.
--
Carlos
^ permalink raw reply [flat|nested] 4+ messages in thread
* fs/attr.c patch
@ 2021-09-10 12:14 Павел Самсонов
2021-09-10 12:29 ` Carlos Maiolino
0 siblings, 1 reply; 4+ messages in thread
From: Павел Самсонов @ 2021-09-10 12:14 UTC (permalink / raw)
To: linux-fsdevel; +Cc: viro
[-- Attachment #1: Type: text/plain, Size: 1 bytes --]
[-- Attachment #2: 0001-Signed-off-by-Pavel-Samsonov-pvsamsonov76-gmail.com.patch --]
[-- Type: text/x-patch, Size: 4623 bytes --]
From 07b6f881080fa18ac404054d43b99433275fe966 Mon Sep 17 00:00:00 2001
From: Pavel Samsonov <pvsamsonov76@gmail.com>
Date: Fri, 10 Sep 2021 14:53:39 +0300
Subject: [PATCH] Signed-off-by: Pavel Samsonov <pvsamsonov76@gmail.com>
The patch changes the argument of chown_ok, chgrp_ok ...
functions from inode to dentry.
---
fs/attr.c | 45 +++++++++++++++++++++++++++++++++++++--------
1 file changed, 37 insertions(+), 8 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index 473d21b3a86d..de1898c19bde 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -21,7 +21,7 @@
/**
* chown_ok - verify permissions to chown inode
* @mnt_userns: user namespace of the mount @inode was found from
- * @inode: inode to check permissions on
+ * @dentry: dentry to check permissions on
* @uid: uid to chown @inode to
*
* If the inode has been found through an idmapped mount the user namespace of
@@ -31,9 +31,11 @@
* performed on the raw inode simply passs init_user_ns.
*/
static bool chown_ok(struct user_namespace *mnt_userns,
- const struct inode *inode,
+ const struct dentry *dentry,
kuid_t uid)
{
+ struct inode *inode = d_inode(dentry);
+
kuid_t kuid = i_uid_into_mnt(mnt_userns, inode);
if (uid_eq(current_fsuid(), kuid) && uid_eq(uid, kuid))
return true;
@@ -48,7 +50,7 @@ static bool chown_ok(struct user_namespace *mnt_userns,
/**
* chgrp_ok - verify permissions to chgrp inode
* @mnt_userns: user namespace of the mount @inode was found from
- * @inode: inode to check permissions on
+ * @dentry: dentry to check permissions on
* @gid: gid to chown @inode to
*
* If the inode has been found through an idmapped mount the user namespace of
@@ -58,8 +60,10 @@ static bool chown_ok(struct user_namespace *mnt_userns,
* performed on the raw inode simply passs init_user_ns.
*/
static bool chgrp_ok(struct user_namespace *mnt_userns,
- const struct inode *inode, kgid_t gid)
+ const struct dentry *dentry, kgid_t gid)
{
+ struct inode *inode = d_inode(dentry);
+
kgid_t kgid = i_gid_into_mnt(mnt_userns, inode);
if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode)) &&
(in_group_p(gid) || gid_eq(gid, kgid)))
@@ -72,6 +76,27 @@ static bool chgrp_ok(struct user_namespace *mnt_userns,
return false;
}
+/**
+ * fowner_ok - verify permissions to chmod inode
+ * @mnt_userns: user namespace of the mount @inode was found from
+ * @dentry: dentry to check permissions on
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then
+ * take care to map the inode according to @mnt_userns before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply passs init_user_ns.
+ */
+static bool fowner_ok(struct user_namespace *mnt_userns,
+ const struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+
+ if (inode_owner_or_capable(mnt_userns, inode))
+ return true;
+ return false;
+}
+
/**
* setattr_prepare - check if attribute changes to a dentry are allowed
* @mnt_userns: user namespace of the mount the inode was found from
@@ -114,27 +139,31 @@ int setattr_prepare(struct user_namespace *mnt_userns, struct dentry *dentry,
goto kill_priv;
/* Make sure a caller can chown. */
- if ((ia_valid & ATTR_UID) && !chown_ok(mnt_userns, inode, attr->ia_uid))
+ if ((ia_valid & ATTR_UID) && !chown_ok(mnt_userns, dentry, attr->ia_uid))
return -EPERM;
/* Make sure caller can chgrp. */
- if ((ia_valid & ATTR_GID) && !chgrp_ok(mnt_userns, inode, attr->ia_gid))
+ if ((ia_valid & ATTR_GID) && !chgrp_ok(mnt_userns, dentry, attr->ia_gid))
return -EPERM;
/* Make sure a caller can chmod. */
if (ia_valid & ATTR_MODE) {
- if (!inode_owner_or_capable(mnt_userns, inode))
+ if (!fowner_ok(mnt_userns, dentry))
return -EPERM;
/* Also check the setgid bit! */
if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
i_gid_into_mnt(mnt_userns, inode)) &&
!capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))
attr->ia_mode &= ~S_ISGID;
+ /* Also check the setuid bit! */
+ if (!(capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID) ||
+ uid_eq(current_fsuid(), inode->i_uid)))
+ attr->ia_mode &= ~S_ISUID;
}
/* Check for setting the inode time. */
if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
- if (!inode_owner_or_capable(mnt_userns, inode))
+ if (!fowner_ok(mnt_userns, dentry))
return -EPERM;
}
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-09-10 12:29 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2011-05-19 11:57 fs/attr.c patch samsonov
2011-05-19 14:50 ` Serge E. Hallyn
2021-09-10 12:14 Павел Самсонов
2021-09-10 12:29 ` Carlos Maiolino
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