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    Subject[PATCH 59/59] CRED: Wrap task credential accesses in the core kernel
    Date
    Wrap access to task credentials so that they can be separated more easily from
    the task_struct during the introduction of COW creds.

    Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

    Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
    sense to use RCU directly rather than a convenient wrapper; these will be
    addressed by later patches.

    Signed-off-by: David Howells <dhowells@redhat.com>
    Reviewed-by: James Morris <jmorris@namei.org>
    Acked-by: Serge Hallyn <serue@us.ibm.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: linux-audit@redhat.com
    Cc: containers@lists.linux-foundation.org
    Cc: linux-mm@kvack.org
    ---

    kernel/acct.c | 7 +++----
    kernel/auditsc.c | 6 ++++--
    kernel/cgroup.c | 9 +++++----
    kernel/futex.c | 8 +++++---
    kernel/futex_compat.c | 3 ++-
    kernel/ptrace.c | 15 +++++++++------
    kernel/sched.c | 11 +++++++----
    kernel/signal.c | 15 +++++++++------
    kernel/sys.c | 16 ++++++++--------
    kernel/sysctl.c | 2 +-
    kernel/timer.c | 8 ++++----
    kernel/user_namespace.c | 2 +-
    mm/mempolicy.c | 7 +++++--
    mm/migrate.c | 7 +++++--
    mm/shmem.c | 8 ++++----
    15 files changed, 72 insertions(+), 52 deletions(-)


    diff --git a/kernel/acct.c b/kernel/acct.c
    index f6006a6..d57b7cb 100644
    --- a/kernel/acct.c
    +++ b/kernel/acct.c
    @@ -530,15 +530,14 @@ static void do_acct_process(struct bsd_acct_struct *acct,
    do_div(elapsed, AHZ);
    ac.ac_btime = get_seconds() - elapsed;
    /* we really need to bite the bullet and change layout */
    - ac.ac_uid = current->uid;
    - ac.ac_gid = current->gid;
    + current_uid_gid(&ac.ac_uid, &ac.ac_gid);
    #if ACCT_VERSION==2
    ac.ac_ahz = AHZ;
    #endif
    #if ACCT_VERSION==1 || ACCT_VERSION==2
    /* backward-compatible 16 bit fields */
    - ac.ac_uid16 = current->uid;
    - ac.ac_gid16 = current->gid;
    + ac.ac_uid16 = ac.ac_uid;
    + ac.ac_gid16 = ac.ac_gid;
    #endif
    #if ACCT_VERSION==3
    ac.ac_pid = task_tgid_nr_ns(current, ns);
    diff --git a/kernel/auditsc.c b/kernel/auditsc.c
    index cf5bc2f..e7d7061 100644
    --- a/kernel/auditsc.c
    +++ b/kernel/auditsc.c
    @@ -2440,7 +2440,8 @@ void audit_core_dumps(long signr)
    {
    struct audit_buffer *ab;
    u32 sid;
    - uid_t auid = audit_get_loginuid(current);
    + uid_t auid = audit_get_loginuid(current), uid;
    + gid_t gid;
    unsigned int sessionid = audit_get_sessionid(current);

    if (!audit_enabled)
    @@ -2450,8 +2451,9 @@ void audit_core_dumps(long signr)
    return;

    ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND);
    + current_uid_gid(&uid, &gid);
    audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
    - auid, current->uid, current->gid, sessionid);
    + auid, uid, gid, sessionid);
    security_task_getsecid(current, &sid);
    if (sid) {
    char *ctx = NULL;
    diff --git a/kernel/cgroup.c b/kernel/cgroup.c
    index 13932ab..9f5a62a 100644
    --- a/kernel/cgroup.c
    +++ b/kernel/cgroup.c
    @@ -573,8 +573,8 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)

    if (inode) {
    inode->i_mode = mode;
    - inode->i_uid = current->fsuid;
    - inode->i_gid = current->fsgid;
    + inode->i_uid = current_fsuid();
    + inode->i_gid = current_fsgid();
    inode->i_blocks = 0;
    inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info;
    @@ -1276,6 +1276,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
    static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
    {
    struct task_struct *tsk;
    + uid_t euid;
    int ret;

    if (pid) {
    @@ -1288,8 +1289,8 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
    get_task_struct(tsk);
    rcu_read_unlock();

    - if ((current->euid) && (current->euid != tsk->uid)
    - && (current->euid != tsk->suid)) {
    + euid = current_euid();
    + if (euid && euid != tsk->uid && euid != tsk->suid) {
    put_task_struct(tsk);
    return -EACCES;
    }
    diff --git a/kernel/futex.c b/kernel/futex.c
    index 7d1136e..a28b82b 100644
    --- a/kernel/futex.c
    +++ b/kernel/futex.c
    @@ -439,10 +439,11 @@ static void free_pi_state(struct futex_pi_state *pi_state)
    static struct task_struct * futex_find_get_task(pid_t pid)
    {
    struct task_struct *p;
    + uid_t euid = current_euid();

    rcu_read_lock();
    p = find_task_by_vpid(pid);
    - if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
    + if (!p || (euid != p->euid && euid != p->uid))
    p = ERR_PTR(-ESRCH);
    else
    get_task_struct(p);
    @@ -1826,6 +1827,7 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr,
    {
    struct robust_list_head __user *head;
    unsigned long ret;
    + uid_t euid = current_euid();

    if (!futex_cmpxchg_enabled)
    return -ENOSYS;
    @@ -1841,8 +1843,8 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr,
    if (!p)
    goto err_unlock;
    ret = -EPERM;
    - if ((current->euid != p->euid) && (current->euid != p->uid) &&
    - !capable(CAP_SYS_PTRACE))
    + if (euid != p->euid && euid != p->uid &&
    + !capable(CAP_SYS_PTRACE))
    goto err_unlock;
    head = p->robust_list;
    rcu_read_unlock();
    diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
    index 04ac3a9..3254d4e 100644
    --- a/kernel/futex_compat.c
    +++ b/kernel/futex_compat.c
    @@ -135,6 +135,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
    {
    struct compat_robust_list_head __user *head;
    unsigned long ret;
    + uid_t euid = current_euid();

    if (!futex_cmpxchg_enabled)
    return -ENOSYS;
    @@ -150,7 +151,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
    if (!p)
    goto err_unlock;
    ret = -EPERM;
    - if ((current->euid != p->euid) && (current->euid != p->uid) &&
    + if (euid != p->euid && euid != p->uid &&
    !capable(CAP_SYS_PTRACE))
    goto err_unlock;
    head = p->compat_robust_list;
    diff --git a/kernel/ptrace.c b/kernel/ptrace.c
    index 356699a..0dafab1 100644
    --- a/kernel/ptrace.c
    +++ b/kernel/ptrace.c
    @@ -123,16 +123,19 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
    * because setting up the necessary parent/child relationship
    * or halting the specified task is impossible.
    */
    + uid_t uid;
    + gid_t gid;
    int dumpable = 0;
    /* Don't let security modules deny introspection */
    if (task == current)
    return 0;
    - if (((current->uid != task->euid) ||
    - (current->uid != task->suid) ||
    - (current->uid != task->uid) ||
    - (current->gid != task->egid) ||
    - (current->gid != task->sgid) ||
    - (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
    + current_uid_gid(&uid, &gid);
    + if ((uid != task->euid ||
    + uid != task->suid ||
    + uid != task->uid ||
    + gid != task->egid ||
    + gid != task->sgid ||
    + gid != task->gid) && !capable(CAP_SYS_PTRACE))
    return -EPERM;
    smp_rmb();
    if (task->mm)
    diff --git a/kernel/sched.c b/kernel/sched.c
    index 4a7da9e..58690f3 100644
    --- a/kernel/sched.c
    +++ b/kernel/sched.c
    @@ -5008,6 +5008,7 @@ static int __sched_setscheduler(struct task_struct *p, int policy,
    unsigned long flags;
    const struct sched_class *prev_class = p->sched_class;
    struct rq *rq;
    + uid_t euid;

    /* may grab non-irq protected spin_locks */
    BUG_ON(in_interrupt());
    @@ -5060,8 +5061,9 @@ recheck:
    return -EPERM;

    /* can't change other user's priorities */
    - if ((current->euid != p->euid) &&
    - (current->euid != p->uid))
    + euid = current_euid();
    + if (euid != p->euid &&
    + euid != p->uid)
    return -EPERM;
    }

    @@ -5272,6 +5274,7 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
    cpumask_t cpus_allowed;
    cpumask_t new_mask = *in_mask;
    struct task_struct *p;
    + uid_t euid;
    int retval;

    get_online_cpus();
    @@ -5292,9 +5295,9 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
    get_task_struct(p);
    read_unlock(&tasklist_lock);

    + euid = current_euid();
    retval = -EPERM;
    - if ((current->euid != p->euid) && (current->euid != p->uid) &&
    - !capable(CAP_SYS_NICE))
    + if (euid != p->euid && euid != p->uid && !capable(CAP_SYS_NICE))
    goto out_unlock;

    retval = security_task_setscheduler(p, 0, NULL);
    diff --git a/kernel/signal.c b/kernel/signal.c
    index bf40ecc..141d2b9 100644
    --- a/kernel/signal.c
    +++ b/kernel/signal.c
    @@ -567,6 +567,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
    struct task_struct *t)
    {
    struct pid *sid;
    + uid_t uid, euid;
    int error;

    if (!valid_signal(sig))
    @@ -579,8 +580,10 @@ static int check_kill_permission(int sig, struct siginfo *info,
    if (error)
    return error;

    - if ((current->euid ^ t->suid) && (current->euid ^ t->uid) &&
    - (current->uid ^ t->suid) && (current->uid ^ t->uid) &&
    + uid = current_uid();
    + euid = current_euid();
    + if ((euid ^ t->suid) && (euid ^ t->uid) &&
    + (uid ^ t->suid) && (uid ^ t->uid) &&
    !capable(CAP_KILL)) {
    switch (sig) {
    case SIGCONT:
    @@ -844,7 +847,7 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
    q->info.si_errno = 0;
    q->info.si_code = SI_USER;
    q->info.si_pid = task_pid_vnr(current);
    - q->info.si_uid = current->uid;
    + q->info.si_uid = current_uid();
    break;
    case (unsigned long) SEND_SIG_PRIV:
    q->info.si_signo = sig;
    @@ -1597,7 +1600,7 @@ void ptrace_notify(int exit_code)
    info.si_signo = SIGTRAP;
    info.si_code = exit_code;
    info.si_pid = task_pid_vnr(current);
    - info.si_uid = current->uid;
    + info.si_uid = current_uid();

    /* Let the debugger run. */
    spin_lock_irq(&current->sighand->siglock);
    @@ -2210,7 +2213,7 @@ sys_kill(pid_t pid, int sig)
    info.si_errno = 0;
    info.si_code = SI_USER;
    info.si_pid = task_tgid_vnr(current);
    - info.si_uid = current->uid;
    + info.si_uid = current_uid();

    return kill_something_info(sig, &info, pid);
    }
    @@ -2227,7 +2230,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig)
    info.si_errno = 0;
    info.si_code = SI_TKILL;
    info.si_pid = task_tgid_vnr(current);
    - info.si_uid = current->uid;
    + info.si_uid = current_uid();

    rcu_read_lock();
    p = find_task_by_vpid(pid);
    diff --git a/kernel/sys.c b/kernel/sys.c
    index 234d945..f82827d 100644
    --- a/kernel/sys.c
    +++ b/kernel/sys.c
    @@ -114,10 +114,10 @@ void (*pm_power_off_prepare)(void);

    static int set_one_prio(struct task_struct *p, int niceval, int error)
    {
    + uid_t euid = current_euid();
    int no_nice;

    - if (p->uid != current->euid &&
    - p->euid != current->euid && !capable(CAP_SYS_NICE)) {
    + if (p->uid != euid && p->euid != euid && !capable(CAP_SYS_NICE)) {
    error = -EPERM;
    goto out;
    }
    @@ -176,16 +176,16 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)
    case PRIO_USER:
    user = current->user;
    if (!who)
    - who = current->uid;
    + who = current_uid();
    else
    - if ((who != current->uid) && !(user = find_user(who)))
    + if (who != current_uid() && !(user = find_user(who)))
    goto out_unlock; /* No processes for this user */

    do_each_thread(g, p)
    if (p->uid == who)
    error = set_one_prio(p, niceval, error);
    while_each_thread(g, p);
    - if (who != current->uid)
    + if (who != current_uid())
    free_uid(user); /* For find_user() */
    break;
    }
    @@ -238,9 +238,9 @@ asmlinkage long sys_getpriority(int which, int who)
    case PRIO_USER:
    user = current->user;
    if (!who)
    - who = current->uid;
    + who = current_uid();
    else
    - if ((who != current->uid) && !(user = find_user(who)))
    + if (who != current_uid() && !(user = find_user(who)))
    goto out_unlock; /* No processes for this user */

    do_each_thread(g, p)
    @@ -250,7 +250,7 @@ asmlinkage long sys_getpriority(int which, int who)
    retval = niceval;
    }
    while_each_thread(g, p);
    - if (who != current->uid)
    + if (who != current_uid())
    free_uid(user); /* for find_user() */
    break;
    }
    diff --git a/kernel/sysctl.c b/kernel/sysctl.c
    index deceea0..9e4c8d3 100644
    --- a/kernel/sysctl.c
    +++ b/kernel/sysctl.c
    @@ -1667,7 +1667,7 @@ out:

    static int test_perm(int mode, int op)
    {
    - if (!current->euid)
    + if (!current_euid())
    mode >>= 6;
    else if (in_egroup_p(0))
    mode >>= 3;
    diff --git a/kernel/timer.c b/kernel/timer.c
    index 56becf3..b54e464 100644
    --- a/kernel/timer.c
    +++ b/kernel/timer.c
    @@ -1123,25 +1123,25 @@ asmlinkage long sys_getppid(void)
    asmlinkage long sys_getuid(void)
    {
    /* Only we change this so SMP safe */
    - return current->uid;
    + return current_uid();
    }

    asmlinkage long sys_geteuid(void)
    {
    /* Only we change this so SMP safe */
    - return current->euid;
    + return current_euid();
    }

    asmlinkage long sys_getgid(void)
    {
    /* Only we change this so SMP safe */
    - return current->gid;
    + return current_gid();
    }

    asmlinkage long sys_getegid(void)
    {
    /* Only we change this so SMP safe */
    - return current->egid;
    + return current_egid();
    }

    #endif
    diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
    index 532858f..f82730a 100644
    --- a/kernel/user_namespace.c
    +++ b/kernel/user_namespace.c
    @@ -38,7 +38,7 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
    }

    /* Reset current->user with a new one */
    - new_user = alloc_uid(ns, current->uid);
    + new_user = alloc_uid(ns, current_uid());
    if (!new_user) {
    free_uid(ns->root_user);
    kfree(ns);
    diff --git a/mm/mempolicy.c b/mm/mempolicy.c
    index 8336905..27bcf7e 100644
    --- a/mm/mempolicy.c
    +++ b/mm/mempolicy.c
    @@ -1110,6 +1110,7 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
    nodemask_t old;
    nodemask_t new;
    nodemask_t task_nodes;
    + uid_t uid, euid;
    int err;

    err = get_nodes(&old, old_nodes, maxnode);
    @@ -1139,8 +1140,10 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
    * capabilities, superuser privileges or the same
    * userid as the target process.
    */
    - if ((current->euid != task->suid) && (current->euid != task->uid) &&
    - (current->uid != task->suid) && (current->uid != task->uid) &&
    + uid = current_uid();
    + euid = current_euid();
    + if (euid != task->suid && euid != task->uid &&
    + uid != task->suid && uid != task->uid &&
    !capable(CAP_SYS_NICE)) {
    err = -EPERM;
    goto out;
    diff --git a/mm/migrate.c b/mm/migrate.c
    index f9897ba..e6223d1 100644
    --- a/mm/migrate.c
    +++ b/mm/migrate.c
    @@ -990,6 +990,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
    nodemask_t task_nodes;
    struct mm_struct *mm;
    struct page_to_node *pm = NULL;
    + uid_t uid, euid;

    /* Check flags */
    if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
    @@ -1017,8 +1018,10 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
    * capabilities, superuser privileges or the same
    * userid as the target process.
    */
    - if ((current->euid != task->suid) && (current->euid != task->uid) &&
    - (current->uid != task->suid) && (current->uid != task->uid) &&
    + uid = current_uid();
    + euid = current_euid();
    + if (euid != task->suid && euid != task->uid &&
    + uid != task->suid && uid != task->uid &&
    !capable(CAP_SYS_NICE)) {
    err = -EPERM;
    goto out2;
    diff --git a/mm/shmem.c b/mm/shmem.c
    index 04fb4f1..c935bb4 100644
    --- a/mm/shmem.c
    +++ b/mm/shmem.c
    @@ -1510,8 +1510,8 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
    inode = new_inode(sb);
    if (inode) {
    inode->i_mode = mode;
    - inode->i_uid = current->fsuid;
    - inode->i_gid = current->fsgid;
    + inode->i_uid = current_fsuid();
    + inode->i_gid = current_fsgid();
    inode->i_blocks = 0;
    inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
    inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    @@ -2275,8 +2275,8 @@ static int shmem_fill_super(struct super_block *sb,
    sbinfo->max_blocks = 0;
    sbinfo->max_inodes = 0;
    sbinfo->mode = S_IRWXUGO | S_ISVTX;
    - sbinfo->uid = current->fsuid;
    - sbinfo->gid = current->fsgid;
    + sbinfo->uid = current_fsuid();
    + sbinfo->gid = current_fsgid();
    sbinfo->mpol = NULL;
    sb->s_fs_info = sbinfo;



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