1 files changed, 113 insertions, 70 deletions

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 18d77297ccc8..7ab23e006e4c 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -34,6 +34,7 @@
 #include <linux/elf.h>
 #include <linux/elf-fdpic.h>
 #include <linux/elfcore.h>
+#include <linux/coredump.h>
 
 #include <asm/uaccess.h>
 #include <asm/param.h>
@@ -1216,26 +1217,6 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 #ifdef 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...
@@ -1313,35 +1294,35 @@ static int notesize(struct memelfnote *en)
 
 /* #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)
+#define DUMP_WRITE(addr, nr, foffset)   \
+        do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
 
-static int writenote(struct memelfnote *men, struct file *file)
+static int alignfile(struct file *file, loff_t *foffset)
 {
-        struct elf_note en;
+        static const char buf[4] = { 0, };
+        DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
+        return 1;
+}
 
+static int writenote(struct memelfnote *men, struct file *file,
+                        loff_t *foffset)
+{
+        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 */
+        DUMP_WRITE(&en, sizeof(en), foffset);
+        DUMP_WRITE(men->name, en.n_namesz, foffset);
+        if (!alignfile(file, foffset))
+                return 0;
+        DUMP_WRITE(men->data, men->datasz, foffset);
+        if (!alignfile(file, foffset))
+                return 0;
 
         return 1;
 }
 #undef DUMP_WRITE
-#undef DUMP_SEEK
-
-#define DUMP_WRITE(addr, nr)                            \
-        if ((size += (nr)) > cprm->limit ||             \
-            !dump_write(cprm->file, (addr), (nr)))      \
-                goto end_coredump;
 
 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
 {
@@ -1393,7 +1374,7 @@ static inline void fill_note(struct memelfnote *note, const char *name, int type
 
 /*
  * fill up all the fields in prstatus from the given task struct, except
- * registers which need to be filled up seperately.
+ * registers which need to be filled up separately.
  */
 static void fill_prstatus(struct elf_prstatus *prstatus,
                           struct task_struct *p, long signr)
@@ -1524,6 +1505,22 @@ static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
         return sz;
 }
 
+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;
+}
+
 /*
  * dump the segments for an MMU process
  */
@@ -1552,7 +1549,7 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size,
                                         err = -EIO;
                                 kunmap(page);
                                 page_cache_release(page);
-                        } else if (!dump_seek(file, file->f_pos + PAGE_SIZE))
+                        } else if (!dump_seek(file, PAGE_SIZE))
                                 err = -EFBIG;
                         if (err)
                                 goto out;
@@ -1588,6 +1585,17 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size,
 }
 #endif
 
+static size_t elf_core_vma_data_size(unsigned long mm_flags)
+{
+        struct vm_area_struct *vma;
+        size_t size = 0;
+
+        for (vma = current->mm->mmap; vma; vma = vma->vm_next)
+                if (maydump(vma, mm_flags))
+                        size += vma->vm_end - vma->vm_start;
+        return size;
+}
+
 /*
  * Actual dumper
  *
@@ -1605,7 +1613,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
         int i;
         struct vm_area_struct *vma;
         struct elfhdr *elf = NULL;
-        loff_t offset = 0, dataoff;
+        loff_t offset = 0, dataoff, foffset;
         int numnote;
         struct memelfnote *notes = NULL;
         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
@@ -1618,7 +1626,10 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 #endif
         int thread_status_size = 0;
         elf_addr_t *auxv;
-        unsigned long mm_flags;
+        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.
@@ -1683,12 +1694,18 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
         elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
 
         segs = current->mm->map_count;
-#ifdef ELF_CORE_EXTRA_PHDRS
-        segs += ELF_CORE_EXTRA_PHDRS;
-#endif
+        segs += elf_core_extra_phdrs();
+
+        /* 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;
 
         /* Set up header */
-        fill_elf_fdpic_header(elf, segs + 1);   /* including notes section */
+        fill_elf_fdpic_header(elf, e_phnum);
 
         has_dumped = 1;
         current->flags |= PF_DUMPCORE;
@@ -1727,13 +1744,12 @@ static int elf_fdpic_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;
                 int sz = 0;
 
                 for (i = 0; i < numnote; i++)
@@ -1741,20 +1757,38 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 
                 sz += thread_status_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));
         }
 
         /* 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;
+        offset += elf_core_vma_data_size(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 = current->mm->mmap; vma; vma = vma->vm_next) {
@@ -1767,7 +1801,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
                 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_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
                 phdr.p_memsz = sz;
                 offset += phdr.p_filesz;
                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
@@ -1777,16 +1811,18 @@ static int elf_fdpic_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 */
         for (i = 0; i < numnote; i++)
-                if (!writenote(notes + i, cprm->file))
+                if (!writenote(notes + i, cprm->file, &foffset))
                         goto end_coredump;
 
         /* write out the thread status notes section */
@@ -1795,20 +1831,27 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
                                 list_entry(t, struct elf_thread_status, list);
 
                 for (i = 0; i < tmp->num_notes; i++)
-                        if (!writenote(&tmp->notes[i], cprm->file))
+                        if (!writenote(&tmp->notes[i], cprm->file, &foffset))
                                 goto end_coredump;
         }
 
-        if (!dump_seek(cprm->file, dataoff))
+        if (!dump_seek(cprm->file, dataoff - foffset))
                 goto end_coredump;
 
         if (elf_fdpic_dump_segments(cprm->file, &size, &cprm->limit,
-                                    mm_flags) < 0)
+                                    cprm->mm_flags) < 0)
                 goto end_coredump;
 
-#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;
+        }
 
         if (cprm->file->f_pos != offset) {
                 /* Sanity check */
@@ -1826,7 +1869,7 @@ cleanup:
                 list_del(tmp);
                 kfree(list_entry(tmp, struct elf_thread_status, list));
         }
-
+        kfree(phdr4note);
         kfree(elf);
         kfree(prstatus);
         kfree(psinfo);