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![Sergey Vlasov](/assets/img/avatar_default.png)
If the change of personality does not lead to change of exec domain, __set_personality() returned without releasing the module reference acquired by lookup_exec_domain(). Signed-off-by: Sergey Vlasov <vsu@altlinux.ru> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
210 lines
4.4 KiB
C
210 lines
4.4 KiB
C
/*
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* Handling of different ABIs (personalities).
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*
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* We group personalities into execution domains which have their
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* own handlers for kernel entry points, signal mapping, etc...
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*
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* 2001-05-06 Complete rewrite, Christoph Hellwig (hch@infradead.org)
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*/
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#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/kmod.h>
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#include <linux/module.h>
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#include <linux/personality.h>
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#include <linux/sched.h>
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#include <linux/syscalls.h>
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#include <linux/sysctl.h>
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#include <linux/types.h>
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static void default_handler(int, struct pt_regs *);
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static struct exec_domain *exec_domains = &default_exec_domain;
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static DEFINE_RWLOCK(exec_domains_lock);
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static u_long ident_map[32] = {
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0, 1, 2, 3, 4, 5, 6, 7,
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8, 9, 10, 11, 12, 13, 14, 15,
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16, 17, 18, 19, 20, 21, 22, 23,
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24, 25, 26, 27, 28, 29, 30, 31
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};
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struct exec_domain default_exec_domain = {
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.name = "Linux", /* name */
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.handler = default_handler, /* lcall7 causes a seg fault. */
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.pers_low = 0, /* PER_LINUX personality. */
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.pers_high = 0, /* PER_LINUX personality. */
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.signal_map = ident_map, /* Identity map signals. */
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.signal_invmap = ident_map, /* - both ways. */
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};
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static void
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default_handler(int segment, struct pt_regs *regp)
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{
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set_personality(0);
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if (current_thread_info()->exec_domain->handler != default_handler)
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current_thread_info()->exec_domain->handler(segment, regp);
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else
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send_sig(SIGSEGV, current, 1);
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}
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static struct exec_domain *
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lookup_exec_domain(u_long personality)
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{
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struct exec_domain * ep;
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u_long pers = personality(personality);
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read_lock(&exec_domains_lock);
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for (ep = exec_domains; ep; ep = ep->next) {
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if (pers >= ep->pers_low && pers <= ep->pers_high)
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if (try_module_get(ep->module))
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goto out;
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}
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#ifdef CONFIG_KMOD
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read_unlock(&exec_domains_lock);
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request_module("personality-%ld", pers);
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read_lock(&exec_domains_lock);
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for (ep = exec_domains; ep; ep = ep->next) {
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if (pers >= ep->pers_low && pers <= ep->pers_high)
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if (try_module_get(ep->module))
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goto out;
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}
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#endif
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ep = &default_exec_domain;
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out:
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read_unlock(&exec_domains_lock);
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return (ep);
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}
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int
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register_exec_domain(struct exec_domain *ep)
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{
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struct exec_domain *tmp;
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int err = -EBUSY;
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if (ep == NULL)
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return -EINVAL;
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if (ep->next != NULL)
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return -EBUSY;
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write_lock(&exec_domains_lock);
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for (tmp = exec_domains; tmp; tmp = tmp->next) {
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if (tmp == ep)
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goto out;
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}
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ep->next = exec_domains;
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exec_domains = ep;
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err = 0;
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out:
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write_unlock(&exec_domains_lock);
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return (err);
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}
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int
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unregister_exec_domain(struct exec_domain *ep)
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{
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struct exec_domain **epp;
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epp = &exec_domains;
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write_lock(&exec_domains_lock);
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for (epp = &exec_domains; *epp; epp = &(*epp)->next) {
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if (ep == *epp)
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goto unregister;
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}
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write_unlock(&exec_domains_lock);
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return -EINVAL;
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unregister:
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*epp = ep->next;
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ep->next = NULL;
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write_unlock(&exec_domains_lock);
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return 0;
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}
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int
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__set_personality(u_long personality)
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{
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struct exec_domain *ep, *oep;
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ep = lookup_exec_domain(personality);
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if (ep == current_thread_info()->exec_domain) {
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current->personality = personality;
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module_put(ep->module);
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return 0;
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}
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if (atomic_read(¤t->fs->count) != 1) {
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struct fs_struct *fsp, *ofsp;
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fsp = copy_fs_struct(current->fs);
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if (fsp == NULL) {
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module_put(ep->module);
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return -ENOMEM;
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}
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task_lock(current);
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ofsp = current->fs;
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current->fs = fsp;
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task_unlock(current);
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put_fs_struct(ofsp);
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}
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/*
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* At that point we are guaranteed to be the sole owner of
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* current->fs.
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*/
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current->personality = personality;
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oep = current_thread_info()->exec_domain;
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current_thread_info()->exec_domain = ep;
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set_fs_altroot();
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module_put(oep->module);
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return 0;
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}
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int
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get_exec_domain_list(char *page)
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{
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struct exec_domain *ep;
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int len = 0;
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read_lock(&exec_domains_lock);
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for (ep = exec_domains; ep && len < PAGE_SIZE - 80; ep = ep->next)
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len += sprintf(page + len, "%d-%d\t%-16s\t[%s]\n",
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ep->pers_low, ep->pers_high, ep->name,
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module_name(ep->module));
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read_unlock(&exec_domains_lock);
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return (len);
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}
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asmlinkage long
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sys_personality(u_long personality)
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{
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u_long old = current->personality;
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if (personality != 0xffffffff) {
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set_personality(personality);
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if (current->personality != personality)
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return -EINVAL;
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}
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return (long)old;
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}
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EXPORT_SYMBOL(register_exec_domain);
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EXPORT_SYMBOL(unregister_exec_domain);
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EXPORT_SYMBOL(__set_personality);
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