Re: [PATCH 27/43] userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs

Serge E. Hallyn
2012-04-18T19:02:41Z

Quoting Eric W. Beiderman (ebiederm@xmission.com):
> From: Eric W. Biederman <ebiederm@xmission.com>
>
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> ---
> fs/attr.c | 8 ++++----
> fs/exec.c | 10 +++++-----
> fs/fcntl.c | 6 +++---
> fs/ioprio.c | 4 ++--
> fs/locks.c | 2 +-
> fs/namei.c | 8 ++++----
> include/linux/quotaops.h | 4 ++--
> 7 files changed, 21 insertions(+), 21 deletions(-)
>
> diff --git a/fs/attr.c b/fs/attr.c
> index 73f69a6..2f094c6 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -47,14 +47,14 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr)
>
> /* Make sure a caller can chown. */
> if ((ia_valid & ATTR_UID) &&
> - (current_fsuid() != inode->i_uid ||
> - attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
> + (!uid_eq(current_fsuid(), inode->i_uid) ||
> + !uid_eq(attr->ia_uid, inode->i_uid)) && !capable(CAP_CHOWN))
> return -EPERM;
>
> /* 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)) &&
> + (!uid_eq(current_fsuid(), inode->i_uid) ||
> + (!in_group_p(attr->ia_gid) && gid_eq(attr->ia_gid, inode->i_gid))) &&
> !capable(CAP_CHOWN))
> return -EPERM;
>
> diff --git a/fs/exec.c b/fs/exec.c
> index 9a1d9f0..00ae2ef 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1139,7 +1139,7 @@ void setup_new_exec(struct linux_binprm * bprm)
> /* This is the point of no return */
> current->sas_ss_sp = current->sas_ss_size = 0;
>
> - if (current_euid() == current_uid() && current_egid() == current_gid())
> + if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid()))
> set_dumpable(current->mm, 1);
> else
> set_dumpable(current->mm, suid_dumpable);
> @@ -1153,8 +1153,8 @@ void setup_new_exec(struct linux_binprm * bprm)
> current->mm->task_size = TASK_SIZE;
>
> /* install the new credentials */
> - if (bprm->cred->uid != current_euid() ||
> - bprm->cred->gid != current_egid()) {
> + if (!uid_eq(bprm->cred->uid, current_euid()) ||
> + !gid_eq(bprm->cred->gid, current_egid())) {
> current->pdeath_signal = 0;
> } else {
> would_dump(bprm, bprm->file);
> @@ -2120,7 +2120,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
> if (__get_dumpable(cprm.mm_flags) == 2) {
> /* Setuid core dump mode */
> flag = O_EXCL; /* Stop rewrite attacks */
> - cred->fsuid = 0; /* Dump root private */
> + cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */

Sorry, one more - can this be the per-ns root uid? The coredumps should
be ok to belong to privileged users in the namespace right?

> }
>
> retval = coredump_wait(exit_code, &core_state);
> @@ -2221,7 +2221,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
> * Dont allow local users get cute and trick others to coredump
> * into their pre-created files.
> */
> - if (inode->i_uid != current_fsuid())
> + if (!uid_eq(inode->i_uid, current_fsuid()))
> goto close_fail;
> if (!cprm.file->f_op || !cprm.file->f_op->write)
> goto close_fail;
> diff --git a/fs/fcntl.c b/fs/fcntl.c
> index 75e7c1f..d078b75 100644
> --- a/fs/fcntl.c
> +++ b/fs/fcntl.c
> @@ -532,9 +532,9 @@ static inline int sigio_perm(struct task_struct *p,
>
> rcu_read_lock();
> cred = __task_cred(p);
> - ret = ((fown->euid == 0 ||
> - fown->euid == cred->suid || fown->euid == cred->uid ||
> - fown->uid == cred->suid || fown->uid == cred->uid) &&
> + ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
> + uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
> + uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
> !security_file_send_sigiotask(p, fown, sig));
> rcu_read_unlock();
> return ret;
> diff --git a/fs/ioprio.c b/fs/ioprio.c
> index 2072e41..5e6dbe89 100644
> --- a/fs/ioprio.c
> +++ b/fs/ioprio.c
> @@ -37,8 +37,8 @@ int set_task_ioprio(struct task_struct *task, int ioprio)
>
> rcu_read_lock();
> tcred = __task_cred(task);
> - if (tcred->uid != cred->euid &&
> - tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) {
> + if (!uid_eq(tcred->uid, cred->euid) &&
> + !uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) {
> rcu_read_unlock();
> return -EPERM;
> }
> diff --git a/fs/locks.c b/fs/locks.c
> index 637694b..3e946cd 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1445,7 +1445,7 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
> struct inode *inode = dentry->d_inode;
> int error;
>
> - if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE))
> + if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
> return -EACCES;
> if (!S_ISREG(inode->i_mode))
> return -EINVAL;
> diff --git a/fs/namei.c b/fs/namei.c
> index 941c436..86512b4 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -228,7 +228,7 @@ static int acl_permission_check(struct inode *inode, int mask)
> {
> unsigned int mode = inode->i_mode;
>
> - if (likely(current_fsuid() == inode->i_uid))
> + if (likely(uid_eq(current_fsuid(), inode->i_uid)))
> mode >>= 6;
> else {
> if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
> @@ -1956,13 +1956,13 @@ static int user_path_parent(int dfd, const char __user *path,
> */
> static inline int check_sticky(struct inode *dir, struct inode *inode)
> {
> - uid_t fsuid = current_fsuid();
> + kuid_t fsuid = current_fsuid();
>
> if (!(dir->i_mode & S_ISVTX))
> return 0;
> - if (inode->i_uid == fsuid)
> + if (uid_eq(inode->i_uid, fsuid))
> return 0;
> - if (dir->i_uid == fsuid)
> + if (uid_eq(dir->i_uid, fsuid))
> return 0;
> return !inode_capable(inode, CAP_FOWNER);
> }
> diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
> index d93f95e..17b9773 100644
> --- a/include/linux/quotaops.h
> +++ b/include/linux/quotaops.h
> @@ -22,8 +22,8 @@ static inline struct quota_info *sb_dqopt(struct super_block *sb)
> static inline bool is_quota_modification(struct inode *inode, struct iattr *ia)
> {
> return (ia->ia_valid & ATTR_SIZE && ia->ia_size != inode->i_size) ||
> - (ia->ia_valid & ATTR_UID && ia->ia_uid != inode->i_uid) ||
> - (ia->ia_valid & ATTR_GID && ia->ia_gid != inode->i_gid);
> + (ia->ia_valid & ATTR_UID && !uid_eq(ia->ia_uid, inode->i_uid)) ||
> + (ia->ia_valid & ATTR_GID && !gid_eq(ia->ia_gid, inode->i_gid));
> }
>
> #if defined(CONFIG_QUOTA)
> --
> 1.7.2.5
>
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