diff options
Diffstat (limited to 'kernel/exec_domain.c')
| -rw-r--r-- | kernel/exec_domain.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/kernel/exec_domain.c b/kernel/exec_domain.c new file mode 100644 index 000000000000..1daf64cc19b6 --- /dev/null +++ b/kernel/exec_domain.c @@ -0,0 +1,163 @@ +#include <linux/mm.h> +#include <linux/smp_lock.h> +#include <linux/module.h> + +static asmlinkage void no_lcall7(int segment, struct pt_regs * regs); + + +static unsigned 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 = { + "Linux", /* name */ + no_lcall7, /* lcall7 causes a seg fault. */ + 0, 0xff, /* All personalities. */ + ident_map, /* Identity map signals. */ + ident_map, /* - both ways. */ + NULL, /* No usage counter. */ + NULL /* Nothing after this in the list. */ +}; + +static struct exec_domain *exec_domains = &default_exec_domain; +static rwlock_t exec_domains_lock = RW_LOCK_UNLOCKED; + +static asmlinkage void no_lcall7(int segment, struct pt_regs * regs) +{ + /* + * This may have been a static linked SVr4 binary, so we would have the + * personality set incorrectly. Check to see whether SVr4 is available, + * and use it, otherwise give the user a SEGV. + */ + set_personality(PER_SVR4); + + if (current->exec_domain && current->exec_domain->handler + && current->exec_domain->handler != no_lcall7) { + current->exec_domain->handler(segment, regs); + return; + } + + send_sig(SIGSEGV, current, 1); +} + +static struct exec_domain *lookup_exec_domain(unsigned long personality) +{ + unsigned long pers = personality & PER_MASK; + struct exec_domain *it; + + read_lock(&exec_domains_lock); + for (it=exec_domains; it; it=it->next) + if (pers >= it->pers_low && pers <= it->pers_high) { + if (!try_inc_mod_count(it->module)) + continue; + read_unlock(&exec_domains_lock); + return it; + } + read_unlock(&exec_domains_lock); + + /* Should never get this far. */ + printk(KERN_ERR "No execution domain for personality 0x%02lx\n", pers); + return NULL; +} + +int register_exec_domain(struct exec_domain *it) +{ + struct exec_domain *tmp; + + if (!it) + return -EINVAL; + if (it->next) + return -EBUSY; + write_lock(&exec_domains_lock); + for (tmp=exec_domains; tmp; tmp=tmp->next) + if (tmp == it) { + write_unlock(&exec_domains_lock); + return -EBUSY; + } + it->next = exec_domains; + exec_domains = it; + write_unlock(&exec_domains_lock); + return 0; +} + +int unregister_exec_domain(struct exec_domain *it) +{ + struct exec_domain ** tmp; + + tmp = &exec_domains; + write_lock(&exec_domains_lock); + while (*tmp) { + if (it == *tmp) { + *tmp = it->next; + it->next = NULL; + write_unlock(&exec_domains_lock); + return 0; + } + tmp = &(*tmp)->next; + } + write_unlock(&exec_domains_lock); + return -EINVAL; +} + +void __set_personality(unsigned long personality) +{ + struct exec_domain *it, *prev; + + it = lookup_exec_domain(personality); + if (it == current->exec_domain) { + current->personality = personality; + return; + } + if (!it) + return; + if (atomic_read(¤t->fs->count) != 1) { + struct fs_struct *new = copy_fs_struct(current->fs); + struct fs_struct *old; + if (!new) { + put_exec_domain(it); + return; + } + task_lock(current); + old = current->fs; + current->fs = new; + task_unlock(current); + put_fs_struct(old); + } + /* + * At that point we are guaranteed to be the sole owner of + * current->fs. + */ + current->personality = personality; + prev = current->exec_domain; + current->exec_domain = it; + set_fs_altroot(); + put_exec_domain(prev); +} + +asmlinkage long sys_personality(unsigned long personality) +{ + int ret = current->personality; + if (personality != 0xffffffff) { + set_personality(personality); + if (current->personality != personality) + ret = -EINVAL; + } + return ret; +} + +int get_exec_domain_list(char * page) +{ + int len = 0; + struct exec_domain * e; + + read_lock(&exec_domains_lock); + for (e=exec_domains; e && len < PAGE_SIZE - 80; e=e->next) + len += sprintf(page+len, "%d-%d\t%-16s\t[%s]\n", + e->pers_low, e->pers_high, e->name, + e->module ? e->module->name : "kernel"); + read_unlock(&exec_domains_lock); + return len; +} |