1 files changed, 90 insertions, 61 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index fd5b2ea5d299..535e763ab1a6 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -31,6 +31,7 @@
 #include <linux/random.h>
 #include <linux/elf.h>
 #include <linux/utsname.h>
+#include <linux/coredump.h>
 #include <asm/uaccess.h>
 #include <asm/param.h>
 #include <asm/page.h>
@@ -1085,36 +1086,6 @@ out:
  * Modelled on fs/exec.c:aout_core_dump()
  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
  */
-/*
- * 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 && file->f_op->llseek != no_llseek) {
-                if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
-                        return 0;
-        } else {
-                char *buf = (char *)get_zeroed_page(GFP_KERNEL);
-                if (!buf)
-                        return 0;
-                while (off > 0) {
-                        unsigned long n = off;
-                        if (n > PAGE_SIZE)
-                                n = PAGE_SIZE;
-                        if (!dump_write(file, buf, n))
-                                return 0;
-                        off -= n;
-                }
-                free_page((unsigned long)buf);
-        }
-        return 1;
-}
 
 /*
  * Decide what to dump of a segment, part, all or none.
@@ -1249,11 +1220,6 @@ static int writenote(struct memelfnote *men, struct file *file,
 }
 #undef DUMP_WRITE
 
-#define DUMP_WRITE(addr, nr)                            \
-        if ((size += (nr)) > cprm->limit ||             \
-            !dump_write(cprm->file, (addr), (nr)))      \
-                goto end_coredump;
-
 static void fill_elf_header(struct elfhdr *elf, int segs,
                             u16 machine, u32 flags, u8 osabi)
 {
@@ -1872,6 +1838,34 @@ static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
         return gate_vma;
 }
 
+static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
+                             elf_addr_t e_shoff, int segs)
+{
+        elf->e_shoff = e_shoff;
+        elf->e_shentsize = sizeof(*shdr4extnum);
+        elf->e_shnum = 1;
+        elf->e_shstrndx = SHN_UNDEF;
+
+        memset(shdr4extnum, 0, sizeof(*shdr4extnum));
+
+        shdr4extnum->sh_type = SHT_NULL;
+        shdr4extnum->sh_size = elf->e_shnum;
+        shdr4extnum->sh_link = elf->e_shstrndx;
+        shdr4extnum->sh_info = segs;
+}
+
+static size_t elf_core_vma_data_size(struct vm_area_struct *gate_vma,
+                                     unsigned long mm_flags)
+{
+        struct vm_area_struct *vma;
+        size_t size = 0;
+
+        for (vma = first_vma(current, gate_vma); vma != NULL;
+             vma = next_vma(vma, gate_vma))
+                size += vma_dump_size(vma, mm_flags);
+        return size;
+}
+
 /*
  * Actual dumper
  *
@@ -1888,8 +1882,11 @@ static int elf_core_dump(struct coredump_params *cprm)
         struct vm_area_struct *vma, *gate_vma;
         struct elfhdr *elf = NULL;
         loff_t offset = 0, dataoff, foffset;
-        unsigned long mm_flags;
         struct elf_note_info info;
+        struct elf_phdr *phdr4note = NULL;
+        struct elf_shdr *shdr4extnum = NULL;
+        Elf_Half e_phnum;
+        elf_addr_t e_shoff;
 
         /*
          * We no longer stop all VM operations.
@@ -1912,20 +1909,25 @@ static int elf_core_dump(struct coredump_params *cprm)
          * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
          */
         segs = current->mm->map_count;
-#ifdef ELF_CORE_EXTRA_PHDRS
-        segs += ELF_CORE_EXTRA_PHDRS;
-#endif
+        segs += elf_core_extra_phdrs();
 
         gate_vma = get_gate_vma(current);
         if (gate_vma != NULL)
                 segs++;
 
+        /* for notes section */
+        segs++;
+
+        /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
+         * this, kernel supports extended numbering. Have a look at
+         * include/linux/elf.h for further information. */
+        e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
+
         /*
          * Collect all the non-memory information about the process for the
          * notes.  This also sets up the file header.
          */
-        if (!fill_note_info(elf, segs + 1, /* including notes section */
-                            &info, cprm->signr, cprm->regs))
+        if (!fill_note_info(elf, e_phnum, &info, cprm->signr, cprm->regs))
                 goto cleanup;
 
         has_dumped = 1;
@@ -1934,31 +1936,47 @@ static int elf_core_dump(struct coredump_params *cprm)
         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 */
+        offset += segs * sizeof(struct elf_phdr);       /* Program headers */
         foffset = offset;
 
         /* Write notes phdr entry */
         {
-                struct elf_phdr phdr;
                 size_t sz = get_note_info_size(&info);
 
                 sz += elf_coredump_extra_notes_size();
 
-                fill_elf_note_phdr(&phdr, sz, offset);
+                phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
+                if (!phdr4note)
+                        goto end_coredump;
+
+                fill_elf_note_phdr(phdr4note, sz, offset);
                 offset += sz;
-                DUMP_WRITE(&phdr, sizeof(phdr));
         }
 
         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;
+        offset += elf_core_vma_data_size(gate_vma, cprm->mm_flags);
+        offset += elf_core_extra_data_size();
+        e_shoff = offset;
+
+        if (e_phnum == PN_XNUM) {
+                shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
+                if (!shdr4extnum)
+                        goto end_coredump;
+                fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
+        }
+
+        offset = dataoff;
+
+        size += sizeof(*elf);
+        if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
+                goto end_coredump;
+
+        size += sizeof(*phdr4note);
+        if (size > cprm->limit
+            || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note)))
+                goto end_coredump;
 
         /* Write program headers for segments dump */
         for (vma = first_vma(current, gate_vma); vma != NULL;
@@ -1969,7 +1987,7 @@ static int elf_core_dump(struct coredump_params *cprm)
                 phdr.p_offset = offset;
                 phdr.p_vaddr = vma->vm_start;
                 phdr.p_paddr = 0;
-                phdr.p_filesz = vma_dump_size(vma, mm_flags);
+                phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags);
                 phdr.p_memsz = vma->vm_end - vma->vm_start;
                 offset += phdr.p_filesz;
                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
@@ -1979,12 +1997,14 @@ static int elf_core_dump(struct coredump_params *cprm)
                         phdr.p_flags |= PF_X;
                 phdr.p_align = ELF_EXEC_PAGESIZE;
 
-                DUMP_WRITE(&phdr, sizeof(phdr));
+                size += sizeof(phdr);
+                if (size > cprm->limit
+                    || !dump_write(cprm->file, &phdr, sizeof(phdr)))
+                        goto end_coredump;
         }
 
-#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
-        ELF_CORE_WRITE_EXTRA_PHDRS;
-#endif
+        if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
+                goto end_coredump;
 
         /* write out the notes section */
         if (!write_note_info(&info, cprm->file, &foffset))
@@ -2002,7 +2022,7 @@ static int elf_core_dump(struct coredump_params *cprm)
                 unsigned long addr;
                 unsigned long end;
 
-                end = vma->vm_start + vma_dump_size(vma, mm_flags);
+                end = vma->vm_start + vma_dump_size(vma, cprm->mm_flags);
 
                 for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
                         struct page *page;
@@ -2023,15 +2043,24 @@ static int elf_core_dump(struct coredump_params *cprm)
                 }
         }
 
-#ifdef ELF_CORE_WRITE_EXTRA_DATA
-        ELF_CORE_WRITE_EXTRA_DATA;
-#endif
+        if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
+                goto end_coredump;
+
+        if (e_phnum == PN_XNUM) {
+                size += sizeof(*shdr4extnum);
+                if (size > cprm->limit
+                    || !dump_write(cprm->file, shdr4extnum,
+                                   sizeof(*shdr4extnum)))
+                        goto end_coredump;
+        }
 
 end_coredump:
         set_fs(fs);
 
 cleanup:
         free_note_info(&info);
+        kfree(shdr4extnum);
+        kfree(phdr4note);
         kfree(elf);
 out:
         return has_dumped;