Messages in this thread | | | Date | Thu, 19 Nov 2009 14:35:03 -0800 | From | John Johansen <> | Subject | Re: [PATCH 00/23] Removal of binary sysctl support |
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Eric W. Biederman wrote: > Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> writes: > >> Hello. >> >> Eric W. Biederman wrote: >>>> Indeed. TOMOYO and AppArmor need a hint for prepending "/proc" prefix. >>>> A simple implementation which adds one bit to task_struct is shown below. >>>> In this way, not only the file permission checks inside dentry_open() >>>> but also the directory permission checks inside vfs_path_lookup() can be >>>> prepended "/proc" prefix. AppArmor might want to prepend "/proc" inside >>>> vfs_path_lookup(). >>> There don't appear to be any security hooks in vfs_path_lookup(). >>> >> OK. Then, AppArmor won't be confused. >> >>> Instead of current->in_sysctl we can just look at the path and see if >>> it is the root of the mount chain and if the fs is proc. >>> >>> Something like: >>> >>> diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c >>> index 5f2e332..0b55faa 100644 >>> --- a/security/tomoyo/realpath.c >>> +++ b/security/tomoyo/realpath.c >>> @@ -108,6 +108,15 @@ int tomoyo_realpath_from_path2(struct path *path, char *newname, >>> spin_unlock(&dcache_lock); >>> path_put(&root); >>> path_put(&ns_root); >>> + /* Prepend "/proc" prefix if using internal proc vfs mount. */ >>> + if (!IS_ERR(sp) && (path->mnt->mnt_parent == path->mnt) && >>> + (strcmp(path->mnt->mnt_sb->s_type->name, "proc") == 0)) { >>> + sp -= 5; >>> + if (sp >= newname) >>> + memcpy(sp, "/proc", 5); >>> + else >>> + sp = ERR_PTR(-ENOMEM); >>> + } >>> } >>> if (IS_ERR(sp)) >>> error = PTR_ERR(sp); >> Above patch works. Please proceed. Thank you. >> >> Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> >> >> Why not to use path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC rather than >> strcmp(path->mnt->mnt_sb->s_type->name, "proc") == 0 ? > > Brain short circuit. > The patch look good to me too.
Acked-by: John Johansen <john.johansen@canonical.com>
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