diff options
Diffstat (limited to 'kernel/exec_domain.c')
| -rw-r--r-- | kernel/exec_domain.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/kernel/exec_domain.c b/kernel/exec_domain.c new file mode 100644 index 00000000000..867d6dbeb57 --- /dev/null +++ b/kernel/exec_domain.c @@ -0,0 +1,209 @@ +/* + * Handling of different ABIs (personalities). + * + * We group personalities into execution domains which have their + * own handlers for kernel entry points, signal mapping, etc... + * + * 2001-05-06 Complete rewrite, Christoph Hellwig (hch@infradead.org) + */ + +#include <linux/config.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/kmod.h> +#include <linux/module.h> +#include <linux/personality.h> +#include <linux/sched.h> +#include <linux/syscalls.h> +#include <linux/sysctl.h> +#include <linux/types.h> + + +static void default_handler(int, struct pt_regs *); + +static struct exec_domain *exec_domains = &default_exec_domain; +static DEFINE_RWLOCK(exec_domains_lock); + + +static u_long ident_map[32] = { + 0, 1, 2, 3, 4, 5, 6, 7, + 8, 9, 10, 11, 12, 13, 14, 15, + 16, 17, 18, 19, 20, 21, 22, 23, + 24, 25, 26, 27, 28, 29, 30, 31 +}; + +struct exec_domain default_exec_domain = { + .name = "Linux", /* name */ + .handler = default_handler, /* lcall7 causes a seg fault. */ + .pers_low = 0, /* PER_LINUX personality. */ + .pers_high = 0, /* PER_LINUX personality. */ + .signal_map = ident_map, /* Identity map signals. */ + .signal_invmap = ident_map, /* - both ways. */ +}; + + +static void +default_handler(int segment, struct pt_regs *regp) +{ + set_personality(0); + + if (current_thread_info()->exec_domain->handler != default_handler) + current_thread_info()->exec_domain->handler(segment, regp); + else + send_sig(SIGSEGV, current, 1); +} + +static struct exec_domain * +lookup_exec_domain(u_long personality) +{ + struct exec_domain * ep; + u_long pers = personality(personality); + + read_lock(&exec_domains_lock); + for (ep = exec_domains; ep; ep = ep->next) { + if (pers >= ep->pers_low && pers <= ep->pers_high) + if (try_module_get(ep->module)) + goto out; + } + +#ifdef CONFIG_KMOD + read_unlock(&exec_domains_lock); + request_module("personality-%ld", pers); + read_lock(&exec_domains_lock); + + for (ep = exec_domains; ep; ep = ep->next) { + if (pers >= ep->pers_low && pers <= ep->pers_high) + if (try_module_get(ep->module)) + goto out; + } +#endif + + ep = &default_exec_domain; +out: + read_unlock(&exec_domains_lock); + return (ep); +} + +int +register_exec_domain(struct exec_domain *ep) +{ + struct exec_domain *tmp; + int err = -EBUSY; + + if (ep == NULL) + return -EINVAL; + + if (ep->next != NULL) + return -EBUSY; + + write_lock(&exec_domains_lock); + for (tmp = exec_domains; tmp; tmp = tmp->next) { + if (tmp == ep) + goto out; + } + + ep->next = exec_domains; + exec_domains = ep; + err = 0; + +out: + write_unlock(&exec_domains_lock); + return (err); +} + +int +unregister_exec_domain(struct exec_domain *ep) +{ + struct exec_domain **epp; + + epp = &exec_domains; + write_lock(&exec_domains_lock); + for (epp = &exec_domains; *epp; epp = &(*epp)->next) { + if (ep == *epp) + goto unregister; + } + write_unlock(&exec_domains_lock); + return -EINVAL; + +unregister: + *epp = ep->next; + ep->next = NULL; + write_unlock(&exec_domains_lock); + return 0; +} + +int +__set_personality(u_long personality) +{ + struct exec_domain *ep, *oep; + + ep = lookup_exec_domain(personality); + if (ep == current_thread_info()->exec_domain) { + current->personality = personality; + return 0; + } + + if (atomic_read(¤t->fs->count) != 1) { + struct fs_struct *fsp, *ofsp; + + fsp = copy_fs_struct(current->fs); + if (fsp == NULL) { + module_put(ep->module); + return -ENOMEM; + } + + task_lock(current); + ofsp = current->fs; + current->fs = fsp; + task_unlock(current); + + put_fs_struct(ofsp); + } + + /* + * At that point we are guaranteed to be the sole owner of + * current->fs. + */ + + current->personality = personality; + oep = current_thread_info()->exec_domain; + current_thread_info()->exec_domain = ep; + set_fs_altroot(); + + module_put(oep->module); + return 0; +} + +int +get_exec_domain_list(char *page) +{ + struct exec_domain *ep; + int len = 0; + + read_lock(&exec_domains_lock); + for (ep = exec_domains; ep && len < PAGE_SIZE - 80; ep = ep->next) + len += sprintf(page + len, "%d-%d\t%-16s\t[%s]\n", + ep->pers_low, ep->pers_high, ep->name, + module_name(ep->module)); + read_unlock(&exec_domains_lock); + return (len); +} + +asmlinkage long +sys_personality(u_long personality) +{ + u_long old = current->personality; + + if (personality != 0xffffffff) { + set_personality(personality); + if (current->personality != personality) + return -EINVAL; + } + + return (long)old; +} + + +EXPORT_SYMBOL(register_exec_domain); +EXPORT_SYMBOL(unregister_exec_domain); +EXPORT_SYMBOL(__set_personality); |