nfsd: nfsd should drop CAP_MKNOD for non-root
[safe/jmp/linux-2.6] / fs / binfmt_elf_fdpic.c
index a4ff873..f3e72c5 100644 (file)
 #include <linux/file.h>
 #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>
 #include <linux/ptrace.h>
 #include <linux/init.h>
-#include <linux/smp_lock.h>
 #include <linux/elf.h>
 #include <linux/elf-fdpic.h>
 #include <linux/elfcore.h>
@@ -38,9 +40,6 @@
 #include <asm/pgalloc.h>
 
 typedef char *elf_caddr_t;
-#ifndef elf_addr_t
-#define elf_addr_t unsigned long
-#endif
 
 #if 0
 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
@@ -48,6 +47,12 @@ typedef char *elf_caddr_t;
 #define kdebug(fmt, ...) do {} while(0)
 #endif
 
+#if 0
+#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
+#else
+#define kdcore(fmt, ...) do {} while(0)
+#endif
+
 MODULE_LICENSE("GPL");
 
 static int load_elf_fdpic_binary(struct linux_binprm *, struct pt_regs *);
@@ -70,10 +75,16 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
                                             struct file *, struct mm_struct *);
 
+#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
+static int elf_fdpic_core_dump(long, struct pt_regs *, struct file *, unsigned long limit);
+#endif
+
 static struct linux_binfmt elf_fdpic_format = {
        .module         = THIS_MODULE,
        .load_binary    = load_elf_fdpic_binary,
-//     .core_dump      = elf_fdpic_core_dump,
+#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
+       .core_dump      = elf_fdpic_core_dump,
+#endif
        .min_coredump   = ELF_EXEC_PAGESIZE,
 };
 
@@ -87,7 +98,7 @@ static void __exit exit_elf_fdpic_binfmt(void)
        unregister_binfmt(&elf_fdpic_format);
 }
 
-module_init(init_elf_fdpic_binfmt);
+core_initcall(init_elf_fdpic_binfmt);
 module_exit(exit_elf_fdpic_binfmt);
 
 static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
@@ -126,8 +137,8 @@ static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
 
        retval = kernel_read(file, params->hdr.e_phoff,
                             (char *) params->phdrs, size);
-       if (retval < 0)
-               return retval;
+       if (unlikely(retval != size))
+               return retval < 0 ? retval : -ENOEXEC;
 
        /* determine stack size for this binary */
        phdr = params->phdrs;
@@ -157,9 +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
@@ -168,6 +176,8 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
        int executable_stack;
        int retval, i;
 
+       kdebug("____ LOAD %d ____", current->pid);
+
        memset(&exec_params, 0, sizeof(exec_params));
        memset(&interp_params, 0, sizeof(interp_params));
 
@@ -206,8 +216,11 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
                                             phdr->p_offset,
                                             interpreter_name,
                                             phdr->p_filesz);
-                       if (retval < 0)
+                       if (unlikely(retval != phdr->p_filesz)) {
+                               if (retval >= 0)
+                                       retval = -ENOEXEC;
                                goto error;
+                       }
 
                        retval = -ENOENT;
                        if (interpreter_name[phdr->p_filesz - 1] != '\0')
@@ -223,10 +236,21 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
                                goto error;
                        }
 
+                       /*
+                        * If the binary is not readable then enforce
+                        * mm->dumpable = 0 regardless of the interpreter's
+                        * permissions.
+                        */
+                       if (file_permission(interpreter, MAY_READ) < 0)
+                               bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
+
                        retval = kernel_read(interpreter, 0, bprm->buf,
                                             BINPRM_BUF_SIZE);
-                       if (retval < 0)
+                       if (unlikely(retval != BINPRM_BUF_SIZE)) {
+                               if (retval >= 0)
+                                       retval = -ENOEXEC;
                                goto error;
+                       }
 
                        interp_params.hdr = *((struct elfhdr *) bprm->buf);
                        break;
@@ -353,7 +377,7 @@ 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_ANON | MAP_GROWSDOWN,
+                                        MAP_PRIVATE | MAP_ANONYMOUS | MAP_GROWSDOWN,
                                         0);
 
        if (IS_ERR_VALUE(current->mm->start_brk)) {
@@ -363,11 +387,6 @@ 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 = ksize((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;
@@ -377,7 +396,7 @@ 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)
@@ -407,13 +426,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
        entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
        start_thread(regs, entryaddr, current->mm->start_stack);
 
-       if (unlikely(current->ptrace & PT_PTRACED)) {
-               if (current->ptrace & PT_TRACE_EXEC)
-                       ptrace_notify((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
-               else
-                       send_sig(SIGTRAP, current, 0);
-       }
-
        retval = 0;
 
 error:
@@ -436,25 +448,42 @@ error_kill:
 }
 
 /*****************************************************************************/
+
+#ifndef ELF_BASE_PLATFORM
+/*
+ * 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
+ * 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;
 
@@ -463,11 +492,14 @@ 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;
 
@@ -479,19 +511,20 @@ 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;
 
@@ -521,12 +554,13 @@ 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);
@@ -538,39 +572,61 @@ 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).
         */
@@ -601,8 +657,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
        p = (char __user *) current->mm->arg_start;
        for (loop = bprm->argc; loop > 0; loop--) {
                __put_user((elf_caddr_t) p, argv++);
-               len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
-               if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
+               len = strnlen_user(p, MAX_ARG_STRLEN);
+               if (!len || len > MAX_ARG_STRLEN)
                        return -EINVAL;
                p += len;
        }
@@ -613,8 +669,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
        current->mm->env_start = (unsigned long) p;
        for (loop = bprm->envc; loop > 0; loop--) {
                __put_user((elf_caddr_t)(unsigned long) p, envp++);
-               len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
-               if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
+               len = strnlen_user(p, MAX_ARG_STRLEN);
+               if (!len || len > MAX_ARG_STRLEN)
                        return -EINVAL;
                p += len;
        }
@@ -695,12 +751,11 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
                return -ELIBBAD;
 
        size = sizeof(*loadmap) + nloads * sizeof(*seg);
-       loadmap = kmalloc(size, GFP_KERNEL);
+       loadmap = kzalloc(size, GFP_KERNEL);
        if (!loadmap)
                return -ENOMEM;
 
        params->loadmap = loadmap;
-       memset(loadmap, 0, size);
 
        loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
        loadmap->nsegs = nloads;
@@ -844,7 +899,7 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 
 dynamic_error:
        printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
-              what, file->f_dentry->d_inode->i_ino);
+              what, file->f_path.dentry->d_inode->i_ino);
        return -ELIBBAD;
 }
 
@@ -923,8 +978,11 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(
 
                if (mm) {
                        if (phdr->p_flags & PF_X) {
-                               mm->start_code = seg->addr;
-                               mm->end_code = seg->addr + phdr->p_memsz;
+                               if (!mm->start_code) {
+                                       mm->start_code = seg->addr;
+                                       mm->end_code = seg->addr +
+                                               phdr->p_memsz;
+                               }
                        } else if (!mm->start_data) {
                                mm->start_data = seg->addr;
 #ifndef CONFIG_MMU
@@ -1105,8 +1163,10 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 
                if (mm) {
                        if (phdr->p_flags & PF_X) {
-                               mm->start_code = maddr;
-                               mm->end_code = maddr + phdr->p_memsz;
+                               if (!mm->start_code) {
+                                       mm->start_code = maddr;
+                                       mm->end_code = maddr + phdr->p_memsz;
+                               }
                        } else if (!mm->start_data) {
                                mm->start_data = maddr;
                                mm->end_data = maddr + phdr->p_memsz;
@@ -1118,3 +1178,653 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 
        return 0;
 }
+
+/*****************************************************************************/
+/*
+ * ELF-FDPIC core dumper
+ *
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@sw.oz.au>
+ *
+ * Modelled on fs/binfmt_elf.c core dumper
+ */
+#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
+
+/*
+ * These are the only things you should do on a core-file: use only these
+ * functions to write out all the necessary info.
+ */
+static int dump_write(struct file *file, const void *addr, int nr)
+{
+       return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+}
+
+static int dump_seek(struct file *file, loff_t off)
+{
+       if (file->f_op->llseek) {
+               if (file->f_op->llseek(file, off, SEEK_SET) != off)
+                       return 0;
+       } else {
+               file->f_pos = off;
+       }
+       return 1;
+}
+
+/*
+ * Decide whether a segment is worth dumping; default is yes to be
+ * sure (missing info is worse than too much; etc).
+ * Personally I'd include everything, and use the coredump limit...
+ *
+ * I think we should skip something. But I am not sure how. H.J.
+ */
+static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
+{
+       int dump_ok;
+
+       /* Do not dump I/O mapped devices or special mappings */
+       if (vma->vm_flags & (VM_IO | VM_RESERVED)) {
+               kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
+               return 0;
+       }
+
+       /* If we may not read the contents, don't allow us to dump
+        * them either. "dump_write()" can't handle it anyway.
+        */
+       if (!(vma->vm_flags & VM_READ)) {
+               kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
+               return 0;
+       }
+
+       /* By default, dump shared memory if mapped from an anonymous file. */
+       if (vma->vm_flags & VM_SHARED) {
+               if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0) {
+                       dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
+                       kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
+                              vma->vm_flags, dump_ok ? "yes" : "no");
+                       return dump_ok;
+               }
+
+               dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
+               kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
+                      vma->vm_flags, dump_ok ? "yes" : "no");
+               return dump_ok;
+       }
+
+#ifdef CONFIG_MMU
+       /* By default, if it hasn't been written to, don't write it out */
+       if (!vma->anon_vma) {
+               dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
+               kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
+                      vma->vm_flags, dump_ok ? "yes" : "no");
+               return dump_ok;
+       }
+#endif
+
+       dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
+       kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
+              dump_ok ? "yes" : "no");
+       return dump_ok;
+}
+
+/* An ELF note in memory */
+struct memelfnote
+{
+       const char *name;
+       int type;
+       unsigned int datasz;
+       void *data;
+};
+
+static int notesize(struct memelfnote *en)
+{
+       int sz;
+
+       sz = sizeof(struct elf_note);
+       sz += roundup(strlen(en->name) + 1, 4);
+       sz += roundup(en->datasz, 4);
+
+       return sz;
+}
+
+/* #define DEBUG */
+
+#define DUMP_WRITE(addr, nr)   \
+       do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
+#define DUMP_SEEK(off) \
+       do { if (!dump_seek(file, (off))) return 0; } while(0)
+
+static int writenote(struct memelfnote *men, struct file *file)
+{
+       struct elf_note en;
+
+       en.n_namesz = strlen(men->name) + 1;
+       en.n_descsz = men->datasz;
+       en.n_type = men->type;
+
+       DUMP_WRITE(&en, sizeof(en));
+       DUMP_WRITE(men->name, en.n_namesz);
+       /* XXX - cast from long long to long to avoid need for libgcc.a */
+       DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));      /* XXX */
+       DUMP_WRITE(men->data, men->datasz);
+       DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));      /* XXX */
+
+       return 1;
+}
+#undef DUMP_WRITE
+#undef DUMP_SEEK
+
+#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)
+{
+       memcpy(elf->e_ident, ELFMAG, SELFMAG);
+       elf->e_ident[EI_CLASS] = ELF_CLASS;
+       elf->e_ident[EI_DATA] = ELF_DATA;
+       elf->e_ident[EI_VERSION] = EV_CURRENT;
+       elf->e_ident[EI_OSABI] = ELF_OSABI;
+       memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
+
+       elf->e_type = ET_CORE;
+       elf->e_machine = ELF_ARCH;
+       elf->e_version = EV_CURRENT;
+       elf->e_entry = 0;
+       elf->e_phoff = sizeof(struct elfhdr);
+       elf->e_shoff = 0;
+       elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
+       elf->e_ehsize = sizeof(struct elfhdr);
+       elf->e_phentsize = sizeof(struct elf_phdr);
+       elf->e_phnum = segs;
+       elf->e_shentsize = 0;
+       elf->e_shnum = 0;
+       elf->e_shstrndx = 0;
+       return;
+}
+
+static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
+{
+       phdr->p_type = PT_NOTE;
+       phdr->p_offset = offset;
+       phdr->p_vaddr = 0;
+       phdr->p_paddr = 0;
+       phdr->p_filesz = sz;
+       phdr->p_memsz = 0;
+       phdr->p_flags = 0;
+       phdr->p_align = 0;
+       return;
+}
+
+static inline void fill_note(struct memelfnote *note, const char *name, int type,
+               unsigned int sz, void *data)
+{
+       note->name = name;
+       note->type = type;
+       note->datasz = sz;
+       note->data = data;
+       return;
+}
+
+/*
+ * fill up all the fields in prstatus from the given task struct, except
+ * registers which need to be filled up seperately.
+ */
+static void fill_prstatus(struct elf_prstatus *prstatus,
+                         struct task_struct *p, long signr)
+{
+       prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
+       prstatus->pr_sigpend = p->pending.signal.sig[0];
+       prstatus->pr_sighold = p->blocked.sig[0];
+       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.  It shows the
+                * group-wide total, not its individual thread total.
+                */
+               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);
+       }
+       cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
+       cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
+
+       prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
+       prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
+}
+
+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 */
+       memset(psinfo, 0, sizeof(struct elf_prpsinfo));
+
+       len = mm->arg_end - mm->arg_start;
+       if (len >= ELF_PRARGSZ)
+               len = ELF_PRARGSZ - 1;
+       if (copy_from_user(&psinfo->pr_psargs,
+                          (const char __user *) mm->arg_start, len))
+               return -EFAULT;
+       for (i = 0; i < len; i++)
+               if (psinfo->pr_psargs[i] == 0)
+                       psinfo->pr_psargs[i] = ' ';
+       psinfo->pr_psargs[len] = 0;
+
+       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);
+
+       i = p->state ? ffz(~p->state) + 1 : 0;
+       psinfo->pr_state = i;
+       psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
+       psinfo->pr_zomb = psinfo->pr_sname == 'Z';
+       psinfo->pr_nice = task_nice(p);
+       psinfo->pr_flag = p->flags;
+       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;
+}
+
+/* Here is the structure in which status of each thread is captured. */
+struct elf_thread_status
+{
+       struct list_head list;
+       struct elf_prstatus prstatus;   /* NT_PRSTATUS */
+       elf_fpregset_t fpu;             /* NT_PRFPREG */
+       struct task_struct *thread;
+#ifdef ELF_CORE_COPY_XFPREGS
+       elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
+#endif
+       struct memelfnote notes[3];
+       int num_notes;
+};
+
+/*
+ * In order to add the specific thread information for the elf file format,
+ * we need to keep a linked list of every thread's pr_status and then create
+ * a single section for them in the final core file.
+ */
+static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
+{
+       struct task_struct *p = t->thread;
+       int sz = 0;
+
+       t->num_notes = 0;
+
+       fill_prstatus(&t->prstatus, p, signr);
+       elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
+
+       fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
+                 &t->prstatus);
+       t->num_notes++;
+       sz += notesize(&t->notes[0]);
+
+       t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
+       if (t->prstatus.pr_fpvalid) {
+               fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
+                         &t->fpu);
+               t->num_notes++;
+               sz += notesize(&t->notes[1]);
+       }
+
+#ifdef ELF_CORE_COPY_XFPREGS
+       if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
+               fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
+                         sizeof(t->xfpu), &t->xfpu);
+               t->num_notes++;
+               sz += notesize(&t->notes[2]);
+       }
+#endif
+       return sz;
+}
+
+/*
+ * dump the segments for an MMU process
+ */
+#ifdef CONFIG_MMU
+static int elf_fdpic_dump_segments(struct file *file, size_t *size,
+                          unsigned long *limit, unsigned long mm_flags)
+{
+       struct vm_area_struct *vma;
+
+       for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
+               unsigned long addr;
+
+               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;
+                               }
+                               kunmap(page);
+                               page_cache_release(page);
+                       }
+               }
+       }
+
+       return 0;
+
+end_coredump:
+       return -EFBIG;
+}
+#endif
+
+/*
+ * dump the segments for a NOMMU process
+ */
+#ifndef CONFIG_MMU
+static int elf_fdpic_dump_segments(struct file *file, size_t *size,
+                          unsigned long *limit, unsigned long mm_flags)
+{
+       struct vm_area_struct *vma;
+
+       for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
+               if (!maydump(vma, mm_flags))
+                       continue;
+
+               if ((*size += PAGE_SIZE) > *limit)
+                       return -EFBIG;
+
+               if (!dump_write(file, (void *) vma->vm_start,
+                               vma->vm_end - vma->vm_start))
+                       return -EIO;
+       }
+
+       return 0;
+}
+#endif
+
+/*
+ * Actual dumper
+ *
+ * This is a two-pass process; first we find the offsets of the bits,
+ * and then they are actually written out.  If we run out of core limit
+ * we just truncate.
+ */
+static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
+                              struct file *file, unsigned long limit)
+{
+#define        NUM_NOTES       6
+       int has_dumped = 0;
+       mm_segment_t fs;
+       int segs;
+       size_t size = 0;
+       int i;
+       struct vm_area_struct *vma;
+       struct elfhdr *elf = NULL;
+       loff_t offset = 0, dataoff;
+       int numnote;
+       struct memelfnote *notes = NULL;
+       struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
+       struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
+       LIST_HEAD(thread_list);
+       struct list_head *t;
+       elf_fpregset_t *fpu = NULL;
+#ifdef ELF_CORE_COPY_XFPREGS
+       elf_fpxregset_t *xfpu = NULL;
+#endif
+       int thread_status_size = 0;
+       elf_addr_t *auxv;
+       unsigned long mm_flags;
+
+       /*
+        * We no longer stop all VM operations.
+        *
+        * This is because those proceses that could possibly change map_count
+        * or the mmap / vma pages are now blocked in do_exit on current
+        * finishing this core dump.
+        *
+        * Only ptrace can touch these memory addresses, but it doesn't change
+        * the map_count or the pages allocated. So no possibility of crashing
+        * exists while dumping the mm->vm_next areas to the core file.
+        */
+
+       /* alloc memory for large data structures: too large to be on stack */
+       elf = kmalloc(sizeof(*elf), GFP_KERNEL);
+       if (!elf)
+               goto cleanup;
+       prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
+       if (!prstatus)
+               goto cleanup;
+       psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
+       if (!psinfo)
+               goto cleanup;
+       notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
+       if (!notes)
+               goto cleanup;
+       fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
+       if (!fpu)
+               goto cleanup;
+#ifdef ELF_CORE_COPY_XFPREGS
+       xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
+       if (!xfpu)
+               goto cleanup;
+#endif
+
+       if (signr) {
+               struct core_thread *ct;
+               struct elf_thread_status *tmp;
+
+               for (ct = current->mm->core_state->dumper.next;
+                                               ct; ct = ct->next) {
+                       tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
+                       if (!tmp)
+                               goto cleanup;
+
+                       tmp->thread = ct->task;
+                       list_add(&tmp->list, &thread_list);
+               }
+
+               list_for_each(t, &thread_list) {
+                       struct elf_thread_status *tmp;
+                       int sz;
+
+                       tmp = list_entry(t, struct elf_thread_status, list);
+                       sz = elf_dump_thread_status(signr, tmp);
+                       thread_status_size += sz;
+               }
+       }
+
+       /* now collect the dump for the current */
+       fill_prstatus(prstatus, current, signr);
+       elf_core_copy_regs(&prstatus->pr_reg, regs);
+
+       segs = current->mm->map_count;
+#ifdef ELF_CORE_EXTRA_PHDRS
+       segs += ELF_CORE_EXTRA_PHDRS;
+#endif
+
+       /* Set up header */
+       fill_elf_fdpic_header(elf, segs + 1);   /* including notes section */
+
+       has_dumped = 1;
+       current->flags |= PF_DUMPCORE;
+
+       /*
+        * Set up the notes in similar form to SVR4 core dumps made
+        * with info from their /proc.
+        */
+
+       fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
+       fill_psinfo(psinfo, current->group_leader, current->mm);
+       fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
+
+       numnote = 2;
+
+       auxv = (elf_addr_t *) current->mm->saved_auxv;
+
+       i = 0;
+       do
+               i += 2;
+       while (auxv[i - 2] != AT_NULL);
+       fill_note(&notes[numnote++], "CORE", NT_AUXV,
+                 i * sizeof(elf_addr_t), auxv);
+
+       /* Try to dump the FPU. */
+       if ((prstatus->pr_fpvalid =
+            elf_core_copy_task_fpregs(current, regs, fpu)))
+               fill_note(notes + numnote++,
+                         "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
+#ifdef ELF_CORE_COPY_XFPREGS
+       if (elf_core_copy_task_xfpregs(current, xfpu))
+               fill_note(notes + numnote++,
+                         "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
+#endif
+
+       fs = get_fs();
+       set_fs(KERNEL_DS);
+
+       DUMP_WRITE(elf, sizeof(*elf));
+       offset += sizeof(*elf);                         /* Elf header */
+       offset += (segs+1) * sizeof(struct elf_phdr);   /* Program headers */
+
+       /* Write notes phdr entry */
+       {
+               struct elf_phdr phdr;
+               int sz = 0;
+
+               for (i = 0; i < numnote; i++)
+                       sz += notesize(notes + i);
+
+               sz += thread_status_size;
+
+               fill_elf_note_phdr(&phdr, sz, offset);
+               offset += sz;
+               DUMP_WRITE(&phdr, sizeof(phdr));
+       }
+
+       /* Page-align dumped data */
+       dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
+
+       /*
+        * We must use the same mm->flags while dumping core to avoid
+        * inconsistency between the program headers and bodies, otherwise an
+        * unusable core file can be generated.
+        */
+       mm_flags = current->mm->flags;
+
+       /* write program headers for segments dump */
+       for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
+               struct elf_phdr phdr;
+               size_t sz;
+
+               sz = vma->vm_end - vma->vm_start;
+
+               phdr.p_type = PT_LOAD;
+               phdr.p_offset = offset;
+               phdr.p_vaddr = vma->vm_start;
+               phdr.p_paddr = 0;
+               phdr.p_filesz = maydump(vma, mm_flags) ? sz : 0;
+               phdr.p_memsz = sz;
+               offset += phdr.p_filesz;
+               phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
+               if (vma->vm_flags & VM_WRITE)
+                       phdr.p_flags |= PF_W;
+               if (vma->vm_flags & VM_EXEC)
+                       phdr.p_flags |= PF_X;
+               phdr.p_align = ELF_EXEC_PAGESIZE;
+
+               DUMP_WRITE(&phdr, sizeof(phdr));
+       }
+
+#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
+       ELF_CORE_WRITE_EXTRA_PHDRS;
+#endif
+
+       /* write out the notes section */
+       for (i = 0; i < numnote; i++)
+               if (!writenote(notes + i, file))
+                       goto end_coredump;
+
+       /* write out the thread status notes section */
+       list_for_each(t, &thread_list) {
+               struct elf_thread_status *tmp =
+                               list_entry(t, struct elf_thread_status, list);
+
+               for (i = 0; i < tmp->num_notes; i++)
+                       if (!writenote(&tmp->notes[i], file))
+                               goto end_coredump;
+       }
+
+       DUMP_SEEK(dataoff);
+
+       if (elf_fdpic_dump_segments(file, &size, &limit, mm_flags) < 0)
+               goto end_coredump;
+
+#ifdef ELF_CORE_WRITE_EXTRA_DATA
+       ELF_CORE_WRITE_EXTRA_DATA;
+#endif
+
+       if (file->f_pos != offset) {
+               /* Sanity check */
+               printk(KERN_WARNING
+                      "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
+                      file->f_pos, offset);
+       }
+
+end_coredump:
+       set_fs(fs);
+
+cleanup:
+       while (!list_empty(&thread_list)) {
+               struct list_head *tmp = thread_list.next;
+               list_del(tmp);
+               kfree(list_entry(tmp, struct elf_thread_status, list));
+       }
+
+       kfree(elf);
+       kfree(prstatus);
+       kfree(psinfo);
+       kfree(notes);
+       kfree(fpu);
+#ifdef ELF_CORE_COPY_XFPREGS
+       kfree(xfpu);
+#endif
+       return has_dumped;
+#undef NUM_NOTES
+}
+
+#endif         /* USE_ELF_CORE_DUMP */