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    SubjectRe: [Patch 1/2] selinux: ajust rules for ATTR_FORCE
    Date
    [Sorry if this killed thread. My ISP seems to be stopping email server
    now. I've read this email from web archive.]

    >> @@ -2711,12 +2711,17 @@ static int selinux_inode_permission(stru
    >> static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
    >> {
    >> const struct cred *cred = current_cred();
    >> + unsigned int ia_valid = iattr->ia_valid;
    >>
    >> - if (iattr->ia_valid & ATTR_FORCE)
    >> - return 0;
    >> + /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */
    >> + if (ia_valid & ATTR_FORCE) {
    >> + ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE);
    >> + if (!ia_valid)
    >> + return 0;
    >>
    >
    > So if I read this correctly, (ATTR_FORCE| ATTR_KILL_SUID|ATTR_MODE) will
    > not return here, since 'ia_valid' will be ATTR_FORCE finally.
    >
    > I think you forgot to clear ATTR_FORCE here...

    Whoops, good catch. Fortunately, it doesn't seem to have actual problem,
    but it's bug obviously, and sorry for that. Fixed patch was attached.

    Thanks.
    --
    OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>


    [PATCH] selinux: adjust rules for ATTR_FORCE

    From: Amerigo Wang <amwang@redhat.com>

    As suggested by OGAWA Hirofumi in thread: http://lkml.org/lkml/2009/8/7/132,
    we should let selinux_inode_setattr() to match our ATTR_* rules.
    ATTR_FORCE should not force things like ATTR_SIZE.

    Cc: Stephen Smalley <sds@tycho.nsa.gov>
    Cc: Eric Paris <eparis@redhat.com>
    Signed-off-by: WANG Cong <amwang@redhat.com>
    [tweaks]
    Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
    ---

    security/selinux/hooks.c | 14 ++++++++++----
    1 file changed, 10 insertions(+), 4 deletions(-)

    diff -puN security/selinux/hooks.c~selinux-truncate-fix security/selinux/hooks.c
    --- linux-2.6/security/selinux/hooks.c~selinux-truncate-fix 2009-08-18 06:27:58.000000000 +0900
    +++ linux-2.6-hirofumi/security/selinux/hooks.c 2009-08-18 16:10:50.000000000 +0900
    @@ -2711,12 +2711,18 @@ static int selinux_inode_permission(stru
    static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
    {
    const struct cred *cred = current_cred();
    + unsigned int ia_valid = iattr->ia_valid;

    - if (iattr->ia_valid & ATTR_FORCE)
    - return 0;
    + /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */
    + if (ia_valid & ATTR_FORCE) {
    + ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE |
    + ATTR_FORCE);
    + if (!ia_valid)
    + return 0;
    + }

    - if (iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
    - ATTR_ATIME_SET | ATTR_MTIME_SET))
    + if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
    + ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET))
    return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR);

    return dentry_has_perm(cred, NULL, dentry, FILE__WRITE);
    _

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