coredump masking: ELF-FDPIC: enable core dump filtering
This patch enables core dump filtering for ELF-FDPIC-formatted core file.
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 1a6c8e2..2f5d8db 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1181,8 +1181,10 @@
*
* I think we should skip something. But I am not sure how. H.J.
*/
-static int maydump(struct vm_area_struct *vma)
+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);
@@ -1197,27 +1199,35 @@
return 0;
}
- /* Dump shared memory only if mapped from an anonymous file. */
+ /* 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) {
- kdcore("%08lx: %08lx: no (share)", vma->vm_start, vma->vm_flags);
- return 1;
+ 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;
}
- kdcore("%08lx: %08lx: no (share)", vma->vm_start, vma->vm_flags);
- return 0;
+ 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
- /* If it hasn't been written to, don't write it out */
+ /* By default, if it hasn't been written to, don't write it out */
if (!vma->anon_vma) {
- kdcore("%08lx: %08lx: no (!anon)", vma->vm_start, vma->vm_flags);
- return 0;
+ 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
- kdcore("%08lx: %08lx: yes", vma->vm_start, vma->vm_flags);
- return 1;
+ 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 */
@@ -1457,14 +1467,14 @@
*/
#ifdef CONFIG_MMU
static int elf_fdpic_dump_segments(struct file *file, size_t *size,
- unsigned long *limit)
+ 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))
+ if (!maydump(vma, mm_flags))
continue;
for (addr = vma->vm_start;
@@ -1512,14 +1522,14 @@
*/
#ifndef CONFIG_MMU
static int elf_fdpic_dump_segments(struct file *file, size_t *size,
- unsigned long *limit)
+ 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;
- if (!maydump(vma))
+ if (!maydump(vma, mm_flags))
continue;
if ((*size += PAGE_SIZE) > *limit)
@@ -1570,6 +1580,7 @@
struct vm_list_struct *vml;
#endif
elf_addr_t *auxv;
+ unsigned long mm_flags;
/*
* We no longer stop all VM operations.
@@ -1707,6 +1718,13 @@
/* 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 (
#ifdef CONFIG_MMU
@@ -1728,7 +1746,7 @@
phdr.p_offset = offset;
phdr.p_vaddr = vma->vm_start;
phdr.p_paddr = 0;
- phdr.p_filesz = maydump(vma) ? sz : 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;
@@ -1762,7 +1780,7 @@
DUMP_SEEK(dataoff);
- if (elf_fdpic_dump_segments(file, current->mm, &size, &limit) < 0)
+ if (elf_fdpic_dump_segments(file, &size, &limit, mm_flags) < 0)
goto end_coredump;
#ifdef ELF_CORE_WRITE_EXTRA_DATA