Viewing file:  exec_domain.c (6.47 KB) -rw-r--r--
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/*
* 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/sysctl.h>
#include <linux/types.h>
static void default_handler(int, struct pt_regs *);
static struct exec_domain *exec_domains = &default_exec_domain;
static rwlock_t exec_domains_lock = RW_LOCK_UNLOCKED;
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 = {
"Linux", /* name */
default_handler, /* lcall7 causes a seg fault. */
0, 0, /* PER_LINUX personality. */
ident_map, /* Identity map signals. */
ident_map, /* - both ways. */
};
static void
default_handler(int segment, struct pt_regs *regp)
{
u_long pers = 0;
/*
* This may have been a static linked SVr4 binary, so we would
* have the personality set incorrectly. Or it might have been
* a Solaris/x86 binary. We can tell which because the former
* uses lcall7, while the latter used lcall 0x27.
* Try to find or load the appropriate personality, and fall back
* to just forcing a SEGV.
*
* XXX: this is IA32-specific and should be moved to the MD-tree.
*/
switch (segment) {
#ifdef __i386__
case 0x07:
pers = abi_defhandler_lcall7;
break;
case 0x27:
pers = PER_SOLARIS;
break;
#endif
}
set_personality(pers);
if (current->exec_domain->handler != default_handler)
current->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_inc_mod_count(ep->module))
goto out;
}
#ifdef CONFIG_KMOD
read_unlock(&exec_domains_lock);
{
char buffer[30];
sprintf(buffer, "personality-%ld", pers);
request_module(buffer);
}
read_lock(&exec_domains_lock);
for (ep = exec_domains; ep; ep = ep->next) {
if (pers >= ep->pers_low && pers <= ep->pers_high)
if (try_inc_mod_count(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->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) {
put_exec_domain(ep);
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->exec_domain;
current->exec_domain = ep;
set_fs_altroot();
put_exec_domain(oep);
printk(KERN_DEBUG "[%s:%d]: set personality to %lx\n",
current->comm, current->pid, personality);
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,
ep->module ? ep->module->name : "kernel");
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);
/*
* We have to have all sysctl handling for the Linux-ABI
* in one place as the dynamic registration of sysctls is
* horribly crufty in Linux <= 2.4.
*
* I hope the new sysctl schemes discussed for future versions
* will obsolete this.
*
* --hch
*/
u_long abi_defhandler_coff = PER_SCOSVR3;
u_long abi_defhandler_elf = PER_LINUX;
u_long abi_defhandler_lcall7 = PER_SVR4;
u_long abi_defhandler_libcso = PER_SVR4;
u_int abi_traceflg;
int abi_fake_utsname;
static struct ctl_table abi_table[] = {
{ABI_DEFHANDLER_COFF, "defhandler_coff", &abi_defhandler_coff,
sizeof(int), 0644, NULL, &proc_doulongvec_minmax},
{ABI_DEFHANDLER_ELF, "defhandler_elf", &abi_defhandler_elf,
sizeof(int), 0644, NULL, &proc_doulongvec_minmax},
{ABI_DEFHANDLER_LCALL7, "defhandler_lcall7", &abi_defhandler_lcall7,
sizeof(int), 0644, NULL, &proc_doulongvec_minmax},
{ABI_DEFHANDLER_LIBCSO, "defhandler_libcso", &abi_defhandler_libcso,
sizeof(int), 0644, NULL, &proc_doulongvec_minmax},
{ABI_TRACE, "trace", &abi_traceflg,
sizeof(u_int), 0644, NULL, &proc_dointvec},
{ABI_FAKE_UTSNAME, "fake_utsname", &abi_fake_utsname,
sizeof(int), 0644, NULL, &proc_dointvec},
{0}
};
static struct ctl_table abi_root_table[] = {
{CTL_ABI, "abi", NULL, 0, 0555, abi_table},
{0}
};
static int __init
abi_register_sysctl(void)
{
register_sysctl_table(abi_root_table, 1);
return 0;
}
__initcall(abi_register_sysctl);
EXPORT_SYMBOL(abi_defhandler_coff);
EXPORT_SYMBOL(abi_defhandler_elf);
EXPORT_SYMBOL(abi_defhandler_lcall7);
EXPORT_SYMBOL(abi_defhandler_libcso);
EXPORT_SYMBOL(abi_traceflg);
EXPORT_SYMBOL(abi_fake_utsname);
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