diff options
Diffstat (limited to 'xenolinux-2.4.23-sparse/fs/exec.c')
| -rw-r--r-- | xenolinux-2.4.23-sparse/fs/exec.c | 1148 |
1 files changed, 1148 insertions, 0 deletions
diff --git a/xenolinux-2.4.23-sparse/fs/exec.c b/xenolinux-2.4.23-sparse/fs/exec.c new file mode 100644 index 0000000000..4f512cbb24 --- /dev/null +++ b/xenolinux-2.4.23-sparse/fs/exec.c @@ -0,0 +1,1148 @@ +/* + * linux/fs/exec.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * #!-checking implemented by tytso. + */ +/* + * Demand-loading implemented 01.12.91 - no need to read anything but + * the header into memory. The inode of the executable is put into + * "current->executable", and page faults do the actual loading. Clean. + * + * Once more I can proudly say that linux stood up to being changed: it + * was less than 2 hours work to get demand-loading completely implemented. + * + * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, + * current->executable is only used by the procfs. This allows a dispatch + * table to check for several different types of binary formats. We keep + * trying until we recognize the file or we run out of supported binary + * formats. + */ + +#include <linux/config.h> +#include <linux/slab.h> +#include <linux/file.h> +#include <linux/mman.h> +#include <linux/a.out.h> +#include <linux/stat.h> +#include <linux/fcntl.h> +#include <linux/smp_lock.h> +#include <linux/init.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <linux/spinlock.h> +#include <linux/personality.h> +#include <linux/swap.h> +#include <linux/utsname.h> +#define __NO_VERSION__ +#include <linux/module.h> + +#include <asm/uaccess.h> +#include <asm/pgalloc.h> +#include <asm/mmu_context.h> + +#ifdef CONFIG_KMOD +#include <linux/kmod.h> +#endif + +int core_uses_pid; +char core_pattern[65] = "core"; +int core_setuid_ok = 0; +/* The maximal length of core_pattern is also specified in sysctl.c */ + +static struct linux_binfmt *formats; +static rwlock_t binfmt_lock = RW_LOCK_UNLOCKED; + +int register_binfmt(struct linux_binfmt * fmt) +{ + struct linux_binfmt ** tmp = &formats; + + if (!fmt) + return -EINVAL; + if (fmt->next) + return -EBUSY; + write_lock(&binfmt_lock); + while (*tmp) { + if (fmt == *tmp) { + write_unlock(&binfmt_lock); + return -EBUSY; + } + tmp = &(*tmp)->next; + } + fmt->next = formats; + formats = fmt; + write_unlock(&binfmt_lock); + return 0; +} + +int unregister_binfmt(struct linux_binfmt * fmt) +{ + struct linux_binfmt ** tmp = &formats; + + write_lock(&binfmt_lock); + while (*tmp) { + if (fmt == *tmp) { + *tmp = fmt->next; + write_unlock(&binfmt_lock); + return 0; + } + tmp = &(*tmp)->next; + } + write_unlock(&binfmt_lock); + return -EINVAL; +} + +static inline void put_binfmt(struct linux_binfmt * fmt) +{ + if (fmt->module) + __MOD_DEC_USE_COUNT(fmt->module); +} + +/* + * Note that a shared library must be both readable and executable due to + * security reasons. + * + * Also note that we take the address to load from from the file itself. + */ +asmlinkage long sys_uselib(const char * library) +{ + struct file * file; + struct nameidata nd; + int error; + + error = user_path_walk(library, &nd); + if (error) + goto out; + + error = -EINVAL; + if (!S_ISREG(nd.dentry->d_inode->i_mode)) + goto exit; + + error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC); + if (error) + goto exit; + + file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); + error = PTR_ERR(file); + if (IS_ERR(file)) + goto out; + + error = -ENOEXEC; + if(file->f_op && file->f_op->read) { + struct linux_binfmt * fmt; + + read_lock(&binfmt_lock); + for (fmt = formats ; fmt ; fmt = fmt->next) { + if (!fmt->load_shlib) + continue; + if (!try_inc_mod_count(fmt->module)) + continue; + read_unlock(&binfmt_lock); + error = fmt->load_shlib(file); + read_lock(&binfmt_lock); + put_binfmt(fmt); + if (error != -ENOEXEC) + break; + } + read_unlock(&binfmt_lock); + } + fput(file); +out: + return error; +exit: + path_release(&nd); + goto out; +} + +/* + * count() counts the number of arguments/envelopes + */ +static int count(char ** argv, int max) +{ + int i = 0; + + if (argv != NULL) { + for (;;) { + char * p; + + if (get_user(p, argv)) + return -EFAULT; + if (!p) + break; + argv++; + if(++i > max) + return -E2BIG; + } + } + return i; +} + +/* + * 'copy_strings()' copies argument/envelope strings from user + * memory to free pages in kernel mem. These are in a format ready + * to be put directly into the top of new user memory. + */ +int copy_strings(int argc,char ** argv, struct linux_binprm *bprm) +{ + struct page *kmapped_page = NULL; + char *kaddr = NULL; + int ret; + + while (argc-- > 0) { + char *str; + int len; + unsigned long pos; + + if (get_user(str, argv+argc) || + !(len = strnlen_user(str, bprm->p))) { + ret = -EFAULT; + goto out; + } + + if (bprm->p < len) { + ret = -E2BIG; + goto out; + } + + bprm->p -= len; + /* XXX: add architecture specific overflow check here. */ + pos = bprm->p; + + while (len > 0) { + int i, new, err; + int offset, bytes_to_copy; + struct page *page; + + offset = pos % PAGE_SIZE; + i = pos/PAGE_SIZE; + page = bprm->page[i]; + new = 0; + if (!page) { + page = alloc_page(GFP_HIGHUSER); + bprm->page[i] = page; + if (!page) { + ret = -ENOMEM; + goto out; + } + new = 1; + } + + if (page != kmapped_page) { + if (kmapped_page) + kunmap(kmapped_page); + kmapped_page = page; + kaddr = kmap(kmapped_page); + } + if (new && offset) + memset(kaddr, 0, offset); + bytes_to_copy = PAGE_SIZE - offset; + if (bytes_to_copy > len) { + bytes_to_copy = len; + if (new) + memset(kaddr+offset+len, 0, + PAGE_SIZE-offset-len); + } + err = copy_from_user(kaddr+offset, str, bytes_to_copy); + if (err) { + ret = -EFAULT; + goto out; + } + + pos += bytes_to_copy; + str += bytes_to_copy; + len -= bytes_to_copy; + } + } + ret = 0; +out: + if (kmapped_page) + kunmap(kmapped_page); + return ret; +} + +/* + * Like copy_strings, but get argv and its values from kernel memory. + */ +int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) +{ + int r; + mm_segment_t oldfs = get_fs(); + set_fs(KERNEL_DS); + r = copy_strings(argc, argv, bprm); + set_fs(oldfs); + return r; +} + +/* + * This routine is used to map in a page into an address space: needed by + * execve() for the initial stack and environment pages. + * + * tsk->mmap_sem is held for writing. + */ +void put_dirty_page(struct task_struct * tsk, struct page *page, unsigned long address) +{ + pgd_t * pgd; + pmd_t * pmd; + pte_t * pte; + struct vm_area_struct *vma; + pgprot_t prot = PAGE_COPY; + + if (page_count(page) != 1) + printk(KERN_ERR "mem_map disagrees with %p at %08lx\n", page, address); + pgd = pgd_offset(tsk->mm, address); + + spin_lock(&tsk->mm->page_table_lock); + pmd = pmd_alloc(tsk->mm, pgd, address); + if (!pmd) + goto out; + pte = pte_alloc(tsk->mm, pmd, address); + if (!pte) + goto out; + if (!pte_none(*pte)) + goto out; + lru_cache_add(page); + flush_dcache_page(page); + flush_page_to_ram(page); + /* lookup is cheap because there is only a single entry in the list */ + vma = find_vma(tsk->mm, address); + if (vma) + prot = vma->vm_page_prot; + set_pte(pte, pte_mkdirty(pte_mkwrite(mk_pte(page, prot)))); + XENO_flush_page_update_queue(); + tsk->mm->rss++; + spin_unlock(&tsk->mm->page_table_lock); + + /* no need for flush_tlb */ + return; +out: + spin_unlock(&tsk->mm->page_table_lock); + __free_page(page); + force_sig(SIGKILL, tsk); + return; +} + +int setup_arg_pages(struct linux_binprm *bprm) +{ + unsigned long stack_base; + struct vm_area_struct *mpnt; + int i; + + stack_base = STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE; + + bprm->p += stack_base; + if (bprm->loader) + bprm->loader += stack_base; + bprm->exec += stack_base; + + mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); + if (!mpnt) + return -ENOMEM; + + down_write(¤t->mm->mmap_sem); + { + mpnt->vm_mm = current->mm; + mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p; + mpnt->vm_end = STACK_TOP; + mpnt->vm_flags = VM_STACK_FLAGS; + mpnt->vm_page_prot = protection_map[VM_STACK_FLAGS & 0x7]; + mpnt->vm_ops = NULL; + mpnt->vm_pgoff = 0; + mpnt->vm_file = NULL; + mpnt->vm_private_data = (void *) 0; + insert_vm_struct(current->mm, mpnt); + current->mm->total_vm = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; + } + + for (i = 0 ; i < MAX_ARG_PAGES ; i++) { + struct page *page = bprm->page[i]; + if (page) { + bprm->page[i] = NULL; + put_dirty_page(current,page,stack_base); + } + stack_base += PAGE_SIZE; + } + up_write(¤t->mm->mmap_sem); + + return 0; +} + +struct file *open_exec(const char *name) +{ + struct nameidata nd; + struct inode *inode; + struct file *file; + int err = 0; + + err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_POSITIVE, &nd); + file = ERR_PTR(err); + if (!err) { + inode = nd.dentry->d_inode; + file = ERR_PTR(-EACCES); + if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && + S_ISREG(inode->i_mode)) { + int err = permission(inode, MAY_EXEC); + if (!err && !(inode->i_mode & 0111)) + err = -EACCES; + file = ERR_PTR(err); + if (!err) { + file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); + if (!IS_ERR(file)) { + err = deny_write_access(file); + if (err) { + fput(file); + file = ERR_PTR(err); + } + } +out: + return file; + } + } + path_release(&nd); + } + goto out; +} + +int kernel_read(struct file *file, unsigned long offset, + char * addr, unsigned long count) +{ + mm_segment_t old_fs; + loff_t pos = offset; + int result = -ENOSYS; + + if (!file->f_op->read) + goto fail; + old_fs = get_fs(); + set_fs(get_ds()); + result = file->f_op->read(file, addr, count, &pos); + set_fs(old_fs); +fail: + return result; +} + +static int exec_mmap(void) +{ + struct mm_struct * mm, * old_mm; + + old_mm = current->mm; + + mm = mm_alloc(); + if (mm) { + struct mm_struct *active_mm; + + if (init_new_context(current, mm)) { + mmdrop(mm); + return -ENOMEM; + } + + /* Add it to the list of mm's */ + spin_lock(&mmlist_lock); + list_add(&mm->mmlist, &init_mm.mmlist); + mmlist_nr++; + spin_unlock(&mmlist_lock); + + task_lock(current); + active_mm = current->active_mm; + current->mm = mm; + current->active_mm = mm; + task_unlock(current); + activate_mm(active_mm, mm); + mm_release(); + if (old_mm) { + if (active_mm != old_mm) BUG(); + mmput(old_mm); + return 0; + } + mmdrop(active_mm); + return 0; + } + return -ENOMEM; +} + +/* + * This function makes sure the current process has its own signal table, + * so that flush_signal_handlers can later reset the handlers without + * disturbing other processes. (Other processes might share the signal + * table via the CLONE_SIGNAL option to clone().) + */ + +static inline int make_private_signals(void) +{ + struct signal_struct * newsig; + + if (atomic_read(¤t->sig->count) <= 1) + return 0; + newsig = kmem_cache_alloc(sigact_cachep, GFP_KERNEL); + if (newsig == NULL) + return -ENOMEM; + spin_lock_init(&newsig->siglock); + atomic_set(&newsig->count, 1); + memcpy(newsig->action, current->sig->action, sizeof(newsig->action)); + spin_lock_irq(¤t->sigmask_lock); + current->sig = newsig; + spin_unlock_irq(¤t->sigmask_lock); + return 0; +} + +/* + * If make_private_signals() made a copy of the signal table, decrement the + * refcount of the original table, and free it if necessary. + * We don't do that in make_private_signals() so that we can back off + * in flush_old_exec() if an error occurs after calling make_private_signals(). + */ + +static inline void release_old_signals(struct signal_struct * oldsig) +{ + if (current->sig == oldsig) + return; + if (atomic_dec_and_test(&oldsig->count)) + kmem_cache_free(sigact_cachep, oldsig); +} + +/* + * These functions flushes out all traces of the currently running executable + * so that a new one can be started + */ + +static inline void flush_old_files(struct files_struct * files) +{ + long j = -1; + + write_lock(&files->file_lock); + for (;;) { + unsigned long set, i; + + j++; + i = j * __NFDBITS; + if (i >= files->max_fds || i >= files->max_fdset) + break; + set = files->close_on_exec->fds_bits[j]; + if (!set) + continue; + files->close_on_exec->fds_bits[j] = 0; + write_unlock(&files->file_lock); + for ( ; set ; i++,set >>= 1) { + if (set & 1) { + sys_close(i); + } + } + write_lock(&files->file_lock); + + } + write_unlock(&files->file_lock); +} + +/* + * An execve() will automatically "de-thread" the process. + * Note: we don't have to hold the tasklist_lock to test + * whether we migth need to do this. If we're not part of + * a thread group, there is no way we can become one + * dynamically. And if we are, we only need to protect the + * unlink - even if we race with the last other thread exit, + * at worst the list_del_init() might end up being a no-op. + */ +static inline void de_thread(struct task_struct *tsk) +{ + if (!list_empty(&tsk->thread_group)) { + write_lock_irq(&tasklist_lock); + list_del_init(&tsk->thread_group); + write_unlock_irq(&tasklist_lock); + } + + /* Minor oddity: this might stay the same. */ + tsk->tgid = tsk->pid; +} + +int flush_old_exec(struct linux_binprm * bprm) +{ + char * name; + int i, ch, retval; + struct signal_struct * oldsig; + struct files_struct * files; + + /* + * Make sure we have a private signal table + */ + oldsig = current->sig; + retval = make_private_signals(); + if (retval) goto flush_failed; + + /* + * Make sure we have private file handles. Ask the + * fork helper to do the work for us and the exit + * helper to do the cleanup of the old one. + */ + + files = current->files; /* refcounted so safe to hold */ + retval = unshare_files(); + if(retval) + goto flush_failed; + + /* + * Release all of the old mmap stuff + */ + retval = exec_mmap(); + if (retval) goto mmap_failed; + + /* This is the point of no return */ + steal_locks(files); + put_files_struct(files); + release_old_signals(oldsig); + + current->sas_ss_sp = current->sas_ss_size = 0; + + if (current->euid == current->uid && current->egid == current->gid) { + current->mm->dumpable = 1; + current->task_dumpable = 1; + } + name = bprm->filename; + for (i=0; (ch = *(name++)) != '\0';) { + if (ch == '/') + i = 0; + else + if (i < 15) + current->comm[i++] = ch; + } + current->comm[i] = '\0'; + + flush_thread(); + + de_thread(current); + + if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || + permission(bprm->file->f_dentry->d_inode,MAY_READ)) + current->mm->dumpable = 0; + + /* An exec changes our domain. We are no longer part of the thread + group */ + + current->self_exec_id++; + + flush_signal_handlers(current); + flush_old_files(current->files); + + return 0; + +mmap_failed: + put_files_struct(current->files); + current->files = files; +flush_failed: + spin_lock_irq(¤t->sigmask_lock); + if (current->sig != oldsig) { + kmem_cache_free(sigact_cachep, current->sig); + current->sig = oldsig; + } + spin_unlock_irq(¤t->sigmask_lock); + return retval; +} + +/* + * We mustn't allow tracing of suid binaries, unless + * the tracer has the capability to trace anything.. + */ +static inline int must_not_trace_exec(struct task_struct * p) +{ + return (p->ptrace & PT_PTRACED) && !(p->ptrace & PT_PTRACE_CAP); +} + +/* + * Fill the binprm structure from the inode. + * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes + */ +int prepare_binprm(struct linux_binprm *bprm) +{ + int mode; + struct inode * inode = bprm->file->f_dentry->d_inode; + + mode = inode->i_mode; + /* + * Check execute perms again - if the caller has CAP_DAC_OVERRIDE, + * vfs_permission lets a non-executable through + */ + if (!(mode & 0111)) /* with at least _one_ execute bit set */ + return -EACCES; + if (bprm->file->f_op == NULL) + return -EACCES; + + bprm->e_uid = current->euid; + bprm->e_gid = current->egid; + + if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) { + /* Set-uid? */ + if (mode & S_ISUID) + bprm->e_uid = inode->i_uid; + + /* Set-gid? */ + /* + * If setgid is set but no group execute bit then this + * is a candidate for mandatory locking, not a setgid + * executable. + */ + if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) + bprm->e_gid = inode->i_gid; + } + + /* We don't have VFS support for capabilities yet */ + cap_clear(bprm->cap_inheritable); + cap_clear(bprm->cap_permitted); + cap_clear(bprm->cap_effective); + + /* To support inheritance of root-permissions and suid-root + * executables under compatibility mode, we raise all three + * capability sets for the file. + * + * If only the real uid is 0, we only raise the inheritable + * and permitted sets of the executable file. + */ + + if (!issecure(SECURE_NOROOT)) { + if (bprm->e_uid == 0 || current->uid == 0) { + cap_set_full(bprm->cap_inheritable); + cap_set_full(bprm->cap_permitted); + } + if (bprm->e_uid == 0) + cap_set_full(bprm->cap_effective); + } + + memset(bprm->buf,0,BINPRM_BUF_SIZE); + return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); +} + +/* + * This function is used to produce the new IDs and capabilities + * from the old ones and the file's capabilities. + * + * The formula used for evolving capabilities is: + * + * pI' = pI + * (***) pP' = (fP & X) | (fI & pI) + * pE' = pP' & fE [NB. fE is 0 or ~0] + * + * I=Inheritable, P=Permitted, E=Effective // p=process, f=file + * ' indicates post-exec(), and X is the global 'cap_bset'. + * + */ + +void compute_creds(struct linux_binprm *bprm) +{ + kernel_cap_t new_permitted, working; + int do_unlock = 0; + + new_permitted = cap_intersect(bprm->cap_permitted, cap_bset); + working = cap_intersect(bprm->cap_inheritable, + current->cap_inheritable); + new_permitted = cap_combine(new_permitted, working); + + if (bprm->e_uid != current->uid || bprm->e_gid != current->gid || + !cap_issubset(new_permitted, current->cap_permitted)) { + current->mm->dumpable = 0; + + lock_kernel(); + if (must_not_trace_exec(current) + || atomic_read(¤t->fs->count) > 1 + || atomic_read(¤t->files->count) > 1 + || atomic_read(¤t->sig->count) > 1) { + if(!capable(CAP_SETUID)) { + bprm->e_uid = current->uid; + bprm->e_gid = current->gid; + } + if(!capable(CAP_SETPCAP)) { + new_permitted = cap_intersect(new_permitted, + current->cap_permitted); + } + } + do_unlock = 1; + } + + + /* For init, we want to retain the capabilities set + * in the init_task struct. Thus we skip the usual + * capability rules */ + if (current->pid != 1) { + current->cap_permitted = new_permitted; + current->cap_effective = + cap_intersect(new_permitted, bprm->cap_effective); + } + + /* AUD: Audit candidate if current->cap_effective is set */ + + current->suid = current->euid = current->fsuid = bprm->e_uid; + current->sgid = current->egid = current->fsgid = bprm->e_gid; + + if(do_unlock) + unlock_kernel(); + current->keep_capabilities = 0; +} + + +void remove_arg_zero(struct linux_binprm *bprm) +{ + if (bprm->argc) { + unsigned long offset; + char * kaddr; + struct page *page; + + offset = bprm->p % PAGE_SIZE; + goto inside; + + while (bprm->p++, *(kaddr+offset++)) { + if (offset != PAGE_SIZE) + continue; + offset = 0; + kunmap(page); +inside: + page = bprm->page[bprm->p/PAGE_SIZE]; + kaddr = kmap(page); + } + kunmap(page); + bprm->argc--; + } +} + +/* + * cycle the list of binary formats handler, until one recognizes the image + */ +int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) +{ + int try,retval=0; + struct linux_binfmt *fmt; +#ifdef __alpha__ + /* handle /sbin/loader.. */ + { + struct exec * eh = (struct exec *) bprm->buf; + + if (!bprm->loader && eh->fh.f_magic == 0x183 && + (eh->fh.f_flags & 0x3000) == 0x3000) + { + struct file * file; + unsigned long loader; + + allow_write_access(bprm->file); + fput(bprm->file); + bprm->file = NULL; + + loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); + + file = open_exec("/sbin/loader"); + retval = PTR_ERR(file); + if (IS_ERR(file)) + return retval; + + /* Remember if the application is TASO. */ + bprm->sh_bang = eh->ah.entry < 0x100000000; + + bprm->file = file; + bprm->loader = loader; + retval = prepare_binprm(bprm); + if (retval<0) + return retval; + /* should call search_binary_handler recursively here, + but it does not matter */ + } + } +#endif + /* kernel module loader fixup */ + /* so we don't try to load run modprobe in kernel space. */ + set_fs(USER_DS); + for (try=0; try<2; try++) { + read_lock(&binfmt_lock); + for (fmt = formats ; fmt ; fmt = fmt->next) { + int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; + if (!fn) + continue; + if (!try_inc_mod_count(fmt->module)) + continue; + read_unlock(&binfmt_lock); + retval = fn(bprm, regs); + if (retval >= 0) { + put_binfmt(fmt); + allow_write_access(bprm->file); + if (bprm->file) + fput(bprm->file); + bprm->file = NULL; + current->did_exec = 1; + return retval; + } + read_lock(&binfmt_lock); + put_binfmt(fmt); + if (retval != -ENOEXEC) + break; + if (!bprm->file) { + read_unlock(&binfmt_lock); + return retval; + } + } + read_unlock(&binfmt_lock); + if (retval != -ENOEXEC) { + break; +#ifdef CONFIG_KMOD + }else{ +#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) + char modname[20]; + if (printable(bprm->buf[0]) && + printable(bprm->buf[1]) && + printable(bprm->buf[2]) && + printable(bprm->buf[3])) + break; /* -ENOEXEC */ + sprintf(modname, "binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); + request_module(modname); +#endif + } + } + return retval; +} + + +/* + * sys_execve() executes a new program. + */ +int do_execve(char * filename, char ** argv, char ** envp, struct pt_regs * regs) +{ + struct linux_binprm bprm; + struct file *file; + int retval; + int i; + + file = open_exec(filename); + + retval = PTR_ERR(file); + if (IS_ERR(file)) + return retval; + + bprm.p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); + memset(bprm.page, 0, MAX_ARG_PAGES*sizeof(bprm.page[0])); + + bprm.file = file; + bprm.filename = filename; + bprm.sh_bang = 0; + bprm.loader = 0; + bprm.exec = 0; + if ((bprm.argc = count(argv, bprm.p / sizeof(void *))) < 0) { + allow_write_access(file); + fput(file); + return bprm.argc; + } + + if ((bprm.envc = count(envp, bprm.p / sizeof(void *))) < 0) { + allow_write_access(file); + fput(file); + return bprm.envc; + } + + retval = prepare_binprm(&bprm); + if (retval < 0) + goto out; + + retval = copy_strings_kernel(1, &bprm.filename, &bprm); + if (retval < 0) + goto out; + + bprm.exec = bprm.p; + retval = copy_strings(bprm.envc, envp, &bprm); + if (retval < 0) + goto out; + + retval = copy_strings(bprm.argc, argv, &bprm); + if (retval < 0) + goto out; + + retval = search_binary_handler(&bprm,regs); + if (retval >= 0) + /* execve success */ + return retval; + +out: + /* Something went wrong, return the inode and free the argument pages*/ + allow_write_access(bprm.file); + if (bprm.file) + fput(bprm.file); + + for (i = 0 ; i < MAX_ARG_PAGES ; i++) { + struct page * page = bprm.page[i]; + if (page) + __free_page(page); + } + + return retval; +} + +void set_binfmt(struct linux_binfmt *new) +{ + struct linux_binfmt *old = current->binfmt; + if (new && new->module) + __MOD_INC_USE_COUNT(new->module); + current->binfmt = new; + if (old && old->module) + __MOD_DEC_USE_COUNT(old->module); +} + +#define CORENAME_MAX_SIZE 64 + +/* format_corename will inspect the pattern parameter, and output a + * name into corename, which must have space for at least + * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. + */ +void format_corename(char *corename, const char *pattern, long signr) +{ + const char *pat_ptr = pattern; + char *out_ptr = corename; + char *const out_end = corename + CORENAME_MAX_SIZE; + int rc; + int pid_in_pattern = 0; + + /* Repeat as long as we have more pattern to process and more output + space */ + while (*pat_ptr) { + if (*pat_ptr != '%') { + if (out_ptr == out_end) + goto out; + *out_ptr++ = *pat_ptr++; + } else { + switch (*++pat_ptr) { + case 0: + goto out; + /* Double percent, output one percent */ + case '%': + if (out_ptr == out_end) + goto out; + *out_ptr++ = '%'; + break; + /* pid */ + case 'p': + pid_in_pattern = 1; + rc = snprintf(out_ptr, out_end - out_ptr, + "%d", current->pid); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + /* uid */ + case 'u': + rc = snprintf(out_ptr, out_end - out_ptr, + "%d", current->uid); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + /* gid */ + case 'g': + rc = snprintf(out_ptr, out_end - out_ptr, + "%d", current->gid); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + /* signal that caused the coredump */ + case 's': + rc = snprintf(out_ptr, out_end - out_ptr, + "%ld", signr); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + /* UNIX time of coredump */ + case 't': { + struct timeval tv; + do_gettimeofday(&tv); + rc = snprintf(out_ptr, out_end - out_ptr, + "%ld", tv.tv_sec); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + } + /* hostname */ + case 'h': + down_read(&uts_sem); + rc = snprintf(out_ptr, out_end - out_ptr, + "%s", system_utsname.nodename); + up_read(&uts_sem); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + /* executable */ + case 'e': + rc = snprintf(out_ptr, out_end - out_ptr, + "%s", current->comm); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + break; + default: + break; + } + ++pat_ptr; + } + } + /* Backward compatibility with core_uses_pid: + * + * If core_pattern does not include a %p (as is the default) + * and core_uses_pid is set, then .%pid will be appended to + * the filename */ + if (!pid_in_pattern + && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { + rc = snprintf(out_ptr, out_end - out_ptr, + ".%d", current->pid); + if (rc > out_end - out_ptr) + goto out; + out_ptr += rc; + } + out: + *out_ptr = 0; +} + +int do_coredump(long signr, struct pt_regs * regs) +{ + struct linux_binfmt * binfmt; + char corename[CORENAME_MAX_SIZE + 1]; + struct file * file; + struct inode * inode; + int retval = 0; + int fsuid = current->fsuid; + + lock_kernel(); + binfmt = current->binfmt; + if (!binfmt || !binfmt->core_dump) + goto fail; + if (!is_dumpable(current)) + { + if(!core_setuid_ok || !current->task_dumpable) + goto fail; + current->fsuid = 0; + } + current->mm->dumpable = 0; + if (current->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) + goto fail; + + format_corename(corename, core_pattern, signr); + file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW, 0600); + if (IS_ERR(file)) + goto fail; + inode = file->f_dentry->d_inode; + if (inode->i_nlink > 1) + goto close_fail; /* multiple links - don't dump */ + if (d_unhashed(file->f_dentry)) + goto close_fail; + + if (!S_ISREG(inode->i_mode)) + goto close_fail; + if (!file->f_op) + goto close_fail; + if (!file->f_op->write) + goto close_fail; + if (do_truncate(file->f_dentry, 0) != 0) + goto close_fail; + + retval = binfmt->core_dump(signr, regs, file); + +close_fail: + filp_close(file, NULL); +fail: + if (fsuid != current->fsuid) + current->fsuid = fsuid; + unlock_kernel(); + return retval; +} |