string: factorize skip_spaces and export it to be generally available
[safe/jmp/linux-2.6] / fs / binfmt_elf_fdpic.c
index fdeadab..79d2b1a 100644 (file)
@@ -25,6 +25,7 @@
 #include <linux/fcntl.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include <linux/security.h>
 #include <linux/highmem.h>
 #include <linux/highuid.h>
 #include <linux/personality.h>
@@ -167,9 +168,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
        struct elf_fdpic_params exec_params, interp_params;
        struct elf_phdr *phdr;
        unsigned long stack_size, entryaddr;
-#ifndef CONFIG_MMU
-       unsigned long fullsize;
-#endif
 #ifdef ELF_FDPIC_PLAT_INIT
        unsigned long dynaddr;
 #endif
@@ -285,20 +283,23 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
        }
 
        stack_size = exec_params.stack_size;
-       if (stack_size < interp_params.stack_size)
-               stack_size = interp_params.stack_size;
-
        if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
                executable_stack = EXSTACK_ENABLE_X;
        else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
                executable_stack = EXSTACK_DISABLE_X;
-       else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
-               executable_stack = EXSTACK_ENABLE_X;
-       else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
-               executable_stack = EXSTACK_DISABLE_X;
        else
                executable_stack = EXSTACK_DEFAULT;
 
+       if (stack_size == 0) {
+               stack_size = interp_params.stack_size;
+               if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
+                       executable_stack = EXSTACK_ENABLE_X;
+               else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
+                       executable_stack = EXSTACK_DISABLE_X;
+               else
+                       executable_stack = EXSTACK_DEFAULT;
+       }
+
        retval = -ENOEXEC;
        if (stack_size == 0)
                goto error;
@@ -379,7 +380,8 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
        down_write(&current->mm->mmap_sem);
        current->mm->start_brk = do_mmap(NULL, 0, stack_size,
                                         PROT_READ | PROT_WRITE | PROT_EXEC,
-                                        MAP_PRIVATE | MAP_ANONYMOUS | MAP_GROWSDOWN,
+                                        MAP_PRIVATE | MAP_ANONYMOUS |
+                                        MAP_UNINITIALIZED | MAP_GROWSDOWN,
                                         0);
 
        if (IS_ERR_VALUE(current->mm->start_brk)) {
@@ -389,11 +391,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
                goto error_kill;
        }
 
-       /* expand the stack mapping to use up the entire allocation granule */
-       fullsize = kobjsize((char *) current->mm->start_brk);
-       if (!IS_ERR_VALUE(do_mremap(current->mm->start_brk, stack_size,
-                                   fullsize, 0, 0)))
-               stack_size = fullsize;
        up_write(&current->mm->mmap_sem);
 
        current->mm->brk = current->mm->start_brk;
@@ -403,7 +400,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
        current->mm->start_stack = current->mm->start_brk + stack_size;
 #endif
 
-       compute_creds(bprm);
+       install_exec_creds(bprm);
        current->flags &= ~PF_FORKNOEXEC;
        if (create_elf_fdpic_tables(bprm, current->mm,
                                    &exec_params, &interp_params) < 0)
@@ -455,25 +452,42 @@ error_kill:
 }
 
 /*****************************************************************************/
+
+#ifndef ELF_BASE_PLATFORM
 /*
- * present useful information to the program
+ * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
+ * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
+ * will be copied to the user stack in the same manner as AT_PLATFORM.
+ */
+#define ELF_BASE_PLATFORM NULL
+#endif
+
+/*
+ * present useful information to the program by shovelling it onto the new
+ * process's stack
  */
 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
                                   struct mm_struct *mm,
                                   struct elf_fdpic_params *exec_params,
                                   struct elf_fdpic_params *interp_params)
 {
+       const struct cred *cred = current_cred();
        unsigned long sp, csp, nitems;
        elf_caddr_t __user *argv, *envp;
        size_t platform_len = 0, len;
-       char *k_platform;
-       char __user *u_platform, *p;
+       char *k_platform, *k_base_platform;
+       char __user *u_platform, *u_base_platform, *p;
        long hwcap;
        int loop;
+       int nr; /* reset for each csp adjustment */
 
-       /* we're going to shovel a whole load of stuff onto the stack */
 #ifdef CONFIG_MMU
-       sp = bprm->p;
+       /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
+        * by the processes running on the same package. One thing we can do is
+        * to shuffle the initial stack for them, so we give the architecture
+        * an opportunity to do so here.
+        */
+       sp = arch_align_stack(bprm->p);
 #else
        sp = mm->start_stack;
 
@@ -482,11 +496,14 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
                return -EFAULT;
 #endif
 
-       /* get hold of platform and hardware capabilities masks for the machine
-        * we are running on.  In some cases (Sparc), this info is impossible
-        * to get, in others (i386) it is merely difficult.
-        */
        hwcap = ELF_HWCAP;
+
+       /*
+        * If this architecture has a platform capability string, copy it
+        * to userspace.  In some cases (Sparc), this info is impossible
+        * for userspace to get any other way, in others (i386) it is
+        * merely difficult.
+        */
        k_platform = ELF_PLATFORM;
        u_platform = NULL;
 
@@ -498,19 +515,20 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
                        return -EFAULT;
        }
 
-#if defined(__i386__) && defined(CONFIG_SMP)
-       /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
-        * by the processes running on the same package. One thing we can do is
-        * to shuffle the initial stack for them.
-        *
-        * the conditionals here are unneeded, but kept in to make the code
-        * behaviour the same as pre change unless we have hyperthreaded
-        * processors. This keeps Mr Marcelo Person happier but should be
-        * removed for 2.5
+       /*
+        * If this architecture has a "base" platform capability
+        * string, copy it to userspace.
         */
-       if (smp_num_siblings > 1)
-               sp = sp - ((current->pid % 64) << 7);
-#endif
+       k_base_platform = ELF_BASE_PLATFORM;
+       u_base_platform = NULL;
+
+       if (k_base_platform) {
+               platform_len = strlen(k_base_platform) + 1;
+               sp -= platform_len;
+               u_base_platform = (char __user *) sp;
+               if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
+                       return -EFAULT;
+       }
 
        sp &= ~7UL;
 
@@ -540,12 +558,13 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
        }
 
        /* force 16 byte _final_ alignment here for generality */
-#define DLINFO_ITEMS 13
+#define DLINFO_ITEMS 15
 
-       nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
-#ifdef DLINFO_ARCH_ITEMS
-       nitems += DLINFO_ARCH_ITEMS;
-#endif
+       nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
+               (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
+
+       if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
+               nitems++;
 
        csp = sp;
        sp -= nitems * 2 * sizeof(unsigned long);
@@ -557,39 +576,61 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
        sp -= sp & 15UL;
 
        /* put the ELF interpreter info on the stack */
-#define NEW_AUX_ENT(nr, id, val)                                       \
+#define NEW_AUX_ENT(id, val)                                           \
        do {                                                            \
                struct { unsigned long _id, _val; } __user *ent;        \
                                                                        \
                ent = (void __user *) csp;                              \
                __put_user((id), &ent[nr]._id);                         \
                __put_user((val), &ent[nr]._val);                       \
+               nr++;                                                   \
        } while (0)
 
+       nr = 0;
        csp -= 2 * sizeof(unsigned long);
-       NEW_AUX_ENT(0, AT_NULL, 0);
+       NEW_AUX_ENT(AT_NULL, 0);
        if (k_platform) {
+               nr = 0;
                csp -= 2 * sizeof(unsigned long);
-               NEW_AUX_ENT(0, AT_PLATFORM,
+               NEW_AUX_ENT(AT_PLATFORM,
                            (elf_addr_t) (unsigned long) u_platform);
        }
 
+       if (k_base_platform) {
+               nr = 0;
+               csp -= 2 * sizeof(unsigned long);
+               NEW_AUX_ENT(AT_BASE_PLATFORM,
+                           (elf_addr_t) (unsigned long) u_base_platform);
+       }
+
+       if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
+               nr = 0;
+               csp -= 2 * sizeof(unsigned long);
+               NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
+       }
+
+       nr = 0;
        csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
-       NEW_AUX_ENT( 0, AT_HWCAP,       hwcap);
-       NEW_AUX_ENT( 1, AT_PAGESZ,      PAGE_SIZE);
-       NEW_AUX_ENT( 2, AT_CLKTCK,      CLOCKS_PER_SEC);
-       NEW_AUX_ENT( 3, AT_PHDR,        exec_params->ph_addr);
-       NEW_AUX_ENT( 4, AT_PHENT,       sizeof(struct elf_phdr));
-       NEW_AUX_ENT( 5, AT_PHNUM,       exec_params->hdr.e_phnum);
-       NEW_AUX_ENT( 6, AT_BASE,        interp_params->elfhdr_addr);
-       NEW_AUX_ENT( 7, AT_FLAGS,       0);
-       NEW_AUX_ENT( 8, AT_ENTRY,       exec_params->entry_addr);
-       NEW_AUX_ENT( 9, AT_UID,         (elf_addr_t) current->uid);
-       NEW_AUX_ENT(10, AT_EUID,        (elf_addr_t) current->euid);
-       NEW_AUX_ENT(11, AT_GID,         (elf_addr_t) current->gid);
-       NEW_AUX_ENT(12, AT_EGID,        (elf_addr_t) current->egid);
+       NEW_AUX_ENT(AT_HWCAP,   hwcap);
+       NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
+       NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
+       NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
+       NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
+       NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
+       NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
+       NEW_AUX_ENT(AT_FLAGS,   0);
+       NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
+       NEW_AUX_ENT(AT_UID,     (elf_addr_t) cred->uid);
+       NEW_AUX_ENT(AT_EUID,    (elf_addr_t) cred->euid);
+       NEW_AUX_ENT(AT_GID,     (elf_addr_t) cred->gid);
+       NEW_AUX_ENT(AT_EGID,    (elf_addr_t) cred->egid);
+       NEW_AUX_ENT(AT_SECURE,  security_bprm_secureexec(bprm));
+       NEW_AUX_ENT(AT_EXECFN,  bprm->exec);
 
 #ifdef ARCH_DLINFO
+       nr = 0;
+       csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
+
        /* ARCH_DLINFO must come last so platform specific code can enforce
         * special alignment requirements on the AUXV if necessary (eg. PPC).
         */
@@ -935,9 +976,12 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(
                        params->elfhdr_addr = seg->addr;
 
                /* clear any space allocated but not loaded */
-               if (phdr->p_filesz < phdr->p_memsz)
-                       clear_user((void *) (seg->addr + phdr->p_filesz),
-                                  phdr->p_memsz - phdr->p_filesz);
+               if (phdr->p_filesz < phdr->p_memsz) {
+                       ret = clear_user((void *) (seg->addr + phdr->p_filesz),
+                                        phdr->p_memsz - phdr->p_filesz);
+                       if (ret)
+                               return ret;
+               }
 
                if (mm) {
                        if (phdr->p_flags & PF_X) {
@@ -977,7 +1021,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
        struct elf32_fdpic_loadseg *seg;
        struct elf32_phdr *phdr;
        unsigned long load_addr, delta_vaddr;
-       int loop, dvset;
+       int loop, dvset, ret;
 
        load_addr = params->load_addr;
        delta_vaddr = 0;
@@ -1077,7 +1121,9 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
                 * PT_LOAD */
                if (prot & PROT_WRITE && disp > 0) {
                        kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
-                       clear_user((void __user *) maddr, disp);
+                       ret = clear_user((void __user *) maddr, disp);
+                       if (ret)
+                               return ret;
                        maddr += disp;
                }
 
@@ -1112,15 +1158,19 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
                if (prot & PROT_WRITE && excess1 > 0) {
                        kdebug("clear[%d] ad=%lx sz=%lx",
                               loop, maddr + phdr->p_filesz, excess1);
-                       clear_user((void __user *) maddr + phdr->p_filesz,
-                                  excess1);
+                       ret = clear_user((void __user *) maddr + phdr->p_filesz,
+                                        excess1);
+                       if (ret)
+                               return ret;
                }
 
 #else
                if (excess > 0) {
                        kdebug("clear[%d] ad=%lx sz=%lx",
                               loop, maddr + phdr->p_filesz, excess);
-                       clear_user((void *) maddr + phdr->p_filesz, excess);
+                       ret = clear_user((void *) maddr + phdr->p_filesz, excess);
+                       if (ret)
+                               return ret;
                }
 #endif
 
@@ -1279,9 +1329,6 @@ static int writenote(struct memelfnote *men, struct file *file)
 #define DUMP_WRITE(addr, nr)   \
        if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
                goto end_coredump;
-#define DUMP_SEEK(off) \
-       if (!dump_seek(file, (off))) \
-               goto end_coredump;
 
 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
 {
@@ -1341,25 +1388,22 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
        prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
        prstatus->pr_sigpend = p->pending.signal.sig[0];
        prstatus->pr_sighold = p->blocked.sig[0];
+       rcu_read_lock();
+       prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+       rcu_read_unlock();
        prstatus->pr_pid = task_pid_vnr(p);
-       prstatus->pr_ppid = task_pid_vnr(p->parent);
        prstatus->pr_pgrp = task_pgrp_vnr(p);
        prstatus->pr_sid = task_session_vnr(p);
        if (thread_group_leader(p)) {
+               struct task_cputime cputime;
+
                /*
-                * This is the record for the group leader.  Add in the
-                * cumulative times of previous dead threads.  This total
-                * won't include the time of each live thread whose state
-                * is included in the core dump.  The final total reported
-                * to our parent process when it calls wait4 will include
-                * those sums as well as the little bit more time it takes
-                * this and each other thread to finish dying after the
-                * core dump synchronization phase.
+                * This is the record for the group leader.  It shows the
+                * group-wide total, not its individual thread total.
                 */
-               cputime_to_timeval(cputime_add(p->utime, p->signal->utime),
-                                  &prstatus->pr_utime);
-               cputime_to_timeval(cputime_add(p->stime, p->signal->stime),
-                                  &prstatus->pr_stime);
+               thread_group_cputime(p, &cputime);
+               cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
+               cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
        } else {
                cputime_to_timeval(p->utime, &prstatus->pr_utime);
                cputime_to_timeval(p->stime, &prstatus->pr_stime);
@@ -1374,6 +1418,7 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
                       struct mm_struct *mm)
 {
+       const struct cred *cred;
        unsigned int i, len;
 
        /* first copy the parameters from user space */
@@ -1390,8 +1435,10 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
                        psinfo->pr_psargs[i] = ' ';
        psinfo->pr_psargs[len] = 0;
 
+       rcu_read_lock();
+       psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+       rcu_read_unlock();
        psinfo->pr_pid = task_pid_vnr(p);
-       psinfo->pr_ppid = task_pid_vnr(p->parent);
        psinfo->pr_pgrp = task_pgrp_vnr(p);
        psinfo->pr_sid = task_session_vnr(p);
 
@@ -1401,8 +1448,11 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
        psinfo->pr_zomb = psinfo->pr_sname == 'Z';
        psinfo->pr_nice = task_nice(p);
        psinfo->pr_flag = p->flags;
-       SET_UID(psinfo->pr_uid, p->uid);
-       SET_GID(psinfo->pr_gid, p->gid);
+       rcu_read_lock();
+       cred = __task_cred(p);
+       SET_UID(psinfo->pr_uid, cred->uid);
+       SET_GID(psinfo->pr_gid, cred->gid);
+       rcu_read_unlock();
        strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
 
        return 0;
@@ -1469,6 +1519,7 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size,
                           unsigned long *limit, unsigned long mm_flags)
 {
        struct vm_area_struct *vma;
+       int err = 0;
 
        for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
                unsigned long addr;
@@ -1476,43 +1527,26 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size,
                if (!maydump(vma, mm_flags))
                        continue;
 
-               for (addr = vma->vm_start;
-                    addr < vma->vm_end;
-                    addr += PAGE_SIZE
-                    ) {
-                       struct vm_area_struct *vma;
-                       struct page *page;
-
-                       if (get_user_pages(current, current->mm, addr, 1, 0, 1,
-                                          &page, &vma) <= 0) {
-                               DUMP_SEEK(file->f_pos + PAGE_SIZE);
-                       }
-                       else if (page == ZERO_PAGE(0)) {
-                               page_cache_release(page);
-                               DUMP_SEEK(file->f_pos + PAGE_SIZE);
-                       }
-                       else {
-                               void *kaddr;
-
-                               flush_cache_page(vma, addr, page_to_pfn(page));
-                               kaddr = kmap(page);
-                               if ((*size += PAGE_SIZE) > *limit ||
-                                   !dump_write(file, kaddr, PAGE_SIZE)
-                                   ) {
-                                       kunmap(page);
-                                       page_cache_release(page);
-                                       return -EIO;
-                               }
+               for (addr = vma->vm_start; addr < vma->vm_end;
+                                                       addr += PAGE_SIZE) {
+                       struct page *page = get_dump_page(addr);
+                       if (page) {
+                               void *kaddr = kmap(page);
+                               *size += PAGE_SIZE;
+                               if (*size > *limit)
+                                       err = -EFBIG;
+                               else if (!dump_write(file, kaddr, PAGE_SIZE))
+                                       err = -EIO;
                                kunmap(page);
                                page_cache_release(page);
-                       }
+                       } else if (!dump_seek(file, file->f_pos + PAGE_SIZE))
+                               err = -EFBIG;
+                       if (err)
+                               goto out;
                }
        }
-
-       return 0;
-
-end_coredump:
-       return -EFBIG;
+out:
+       return err;
 }
 #endif
 
@@ -1523,11 +1557,9 @@ end_coredump:
 static int elf_fdpic_dump_segments(struct file *file, size_t *size,
                           unsigned long *limit, unsigned long mm_flags)
 {
-       struct vm_list_struct *vml;
-
-       for (vml = current->mm->context.vmlist; vml; vml = vml->next) {
-       struct vm_area_struct *vma = vml->vma;
+       struct vm_area_struct *vma;
 
+       for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
                if (!maydump(vma, mm_flags))
                        continue;
 
@@ -1573,9 +1605,6 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
        elf_fpxregset_t *xfpu = NULL;
 #endif
        int thread_status_size = 0;
-#ifndef CONFIG_MMU
-       struct vm_list_struct *vml;
-#endif
        elf_addr_t *auxv;
        unsigned long mm_flags;
 
@@ -1641,13 +1670,7 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
        fill_prstatus(prstatus, current, signr);
        elf_core_copy_regs(&prstatus->pr_reg, regs);
 
-#ifdef CONFIG_MMU
        segs = current->mm->map_count;
-#else
-       segs = 0;
-       for (vml = current->mm->context.vmlist; vml; vml = vml->next)
-           segs++;
-#endif
 #ifdef ELF_CORE_EXTRA_PHDRS
        segs += ELF_CORE_EXTRA_PHDRS;
 #endif
@@ -1722,20 +1745,10 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
        mm_flags = current->mm->flags;
 
        /* write program headers for segments dump */
-       for (
-#ifdef CONFIG_MMU
-               vma = current->mm->mmap; vma; vma = vma->vm_next
-#else
-                       vml = current->mm->context.vmlist; vml; vml = vml->next
-#endif
-            ) {
+       for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
                struct elf_phdr phdr;
                size_t sz;
 
-#ifndef CONFIG_MMU
-               vma = vml->vma;
-#endif
-
                sz = vma->vm_end - vma->vm_start;
 
                phdr.p_type = PT_LOAD;
@@ -1774,7 +1787,8 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
                                goto end_coredump;
        }
 
-       DUMP_SEEK(dataoff);
+       if (!dump_seek(file, dataoff))
+               goto end_coredump;
 
        if (elf_fdpic_dump_segments(file, &size, &limit, mm_flags) < 0)
                goto end_coredump;