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Message-ID: <4656DFD8.8070504@hitachi.com>
Date: Fri, 25 May 2007 22:08:40 +0900
From: "Kawai, Hidehiro" <hidehiro.kawai.ez@...achi.com>
To: linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Cc: dhowells@...hat.com, holt@....com, alan@...rguk.ukuu.org.uk,
masami.hiramatsu.pt@...achi.com, yumiko.sugita.yf@...achi.com,
soshima@...hat.com, haoki@...hat.com
Subject: [PATCH 4/7] ELF: enable core dump filtering
This patch enables core dump filtering for ELF-formatted core file.
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>
---
fs/binfmt_elf.c | 30 +++++++++++++++++++++---------
1 files changed, 21 insertions(+), 9 deletions(-)
Index: linux-2.6.22-rc2-mm1/fs/binfmt_elf.c
===================================================================
--- linux-2.6.22-rc2-mm1.orig/fs/binfmt_elf.c
+++ linux-2.6.22-rc2-mm1/fs/binfmt_elf.c
@@ -1189,7 +1189,7 @@ static int dump_seek(struct file *file,
*
* 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)
{
/* The vma can be set up to tell us the answer directly. */
if (vma->vm_flags & VM_ALWAYSDUMP)
@@ -1199,15 +1199,19 @@ static int maydump(struct vm_area_struct
if (vma->vm_flags & (VM_IO | VM_RESERVED))
return 0;
- /* Dump shared memory only if mapped from an anonymous file. */
- if (vma->vm_flags & VM_SHARED)
- return vma->vm_file->f_path.dentry->d_inode->i_nlink == 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)
+ return test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
+ else
+ return test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
+ }
- /* 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)
- return 0;
+ return test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
- return 1;
+ return test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
}
/* An ELF note in memory */
@@ -1499,6 +1503,7 @@ static int elf_core_dump(long signr, str
#endif
int thread_status_size = 0;
elf_addr_t *auxv;
+ unsigned long mm_flags;
/*
* We no longer stop all VM operations.
@@ -1638,6 +1643,13 @@ static int elf_core_dump(long signr, str
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 = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
@@ -1650,7 +1662,7 @@ static int elf_core_dump(long signr, str
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;
@@ -1693,7 +1705,7 @@ static int elf_core_dump(long signr, str
vma = next_vma(vma, gate_vma)) {
unsigned long addr;
- if (!maydump(vma))
+ if (!maydump(vma, mm_flags))
continue;
for (addr = vma->vm_start;
-
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