diff options
| -rw-r--r-- | fs/exec.c | 20 | ||||
| -rw-r--r-- | include/linux/capability.h | 1 | ||||
| -rw-r--r-- | kernel/capability.c | 16 |
3 files changed, 33 insertions, 4 deletions
diff --git a/fs/exec.c b/fs/exec.c index 3479fdd4a6e7..3a6de10d3891 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -56,6 +56,7 @@ #include <linux/pipe_fs_i.h> #include <linux/oom.h> #include <linux/compat.h> +#include <linux/user_namespace.h> #include <asm/uaccess.h> #include <asm/mmu_context.h> @@ -1130,8 +1131,22 @@ EXPORT_SYMBOL(flush_old_exec); void would_dump(struct linux_binprm *bprm, struct file *file) { - if (inode_permission(file_inode(file), MAY_READ) < 0) + struct inode *inode = file_inode(file); + if (inode_permission(inode, MAY_READ) < 0) { + struct user_namespace *old, *user_ns; bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; + + /* Ensure mm->user_ns contains the executable */ + user_ns = old = bprm->mm->user_ns; + while ((user_ns != &init_user_ns) && + !privileged_wrt_inode_uidgid(user_ns, inode)) + user_ns = user_ns->parent; + + if (old != user_ns) { + bprm->mm->user_ns = get_user_ns(user_ns); + put_user_ns(old); + } + } } EXPORT_SYMBOL(would_dump); @@ -1161,7 +1176,6 @@ void setup_new_exec(struct linux_binprm * bprm) !gid_eq(bprm->cred->gid, current_egid())) { current->pdeath_signal = 0; } else { - would_dump(bprm, bprm->file); if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) set_dumpable(current->mm, suid_dumpable); } @@ -1593,6 +1607,8 @@ static int do_execveat_common(int fd, struct filename *filename, if (retval < 0) goto out; + would_dump(bprm, bprm->file); + retval = exec_binprm(bprm); if (retval < 0) goto out; diff --git a/include/linux/capability.h b/include/linux/capability.h index 7d38697c7e63..2654f75a4c46 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -247,6 +247,7 @@ static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap) return true; } #endif /* CONFIG_MULTIUSER */ +extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode); extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); diff --git a/kernel/capability.c b/kernel/capability.c index dfa0e4528b0b..4984e1f552eb 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -457,6 +457,19 @@ bool file_ns_capable(const struct file *file, struct user_namespace *ns, EXPORT_SYMBOL(file_ns_capable); /** + * privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode? + * @ns: The user namespace in question + * @inode: The inode in question + * + * Return true if the inode uid and gid are within the namespace. + */ +bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode) +{ + return kuid_has_mapping(ns, inode->i_uid) && + kgid_has_mapping(ns, inode->i_gid); +} + +/** * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped * @inode: The inode in question * @cap: The capability in question @@ -469,8 +482,7 @@ bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) { struct user_namespace *ns = current_user_ns(); - return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && - kgid_has_mapping(ns, inode->i_gid); + return ns_capable(ns, cap) && privileged_wrt_inode_uidgid(ns, inode); } EXPORT_SYMBOL(capable_wrt_inode_uidgid); |