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authorMasami Hiramatsu <mhiramat@redhat.com>2010-03-05 13:44:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-06 11:26:46 -0800
commit30736a4d43f4af7f1a7836d6a266be17082195c4 (patch)
tree54e388cdaf4795bdb7651be03c50bba67eb0b43a /fs/binfmt_elf.c
parent8d9032bbe4671dc481261ccd4e161cd96e54b118 (diff)
coredump: pass mm->flags as a coredump parameter for consistency
Pass mm->flags as a coredump parameter for consistency. --- 1787 if (mm->core_state || !get_dumpable(mm)) { <- (1) 1788 up_write(&mm->mmap_sem); 1789 put_cred(cred); 1790 goto fail; 1791 } 1792 [...] 1798 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ <-(2) 1799 flag = O_EXCL; /* Stop rewrite attacks */ 1800 cred->fsuid = 0; /* Dump root private */ 1801 } --- Since dumpable bits are not protected by lock, there is a chance to change these bits between (1) and (2). To solve this issue, this patch copies mm->flags to coredump_params.mm_flags at the beginning of do_coredump() and uses it instead of get_dumpable() while dumping core. This copy is also passed to binfmt->core_dump, since elf*_core_dump() uses dump_filter bits in mm->flags. [akpm@linux-foundation.org: fix merge] Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/binfmt_elf.c')
-rw-r--r--fs/binfmt_elf.c14
1 files changed, 3 insertions, 11 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 78de530cfb0..535e763ab1a 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1882,7 +1882,6 @@ 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;
@@ -1957,14 +1956,7 @@ static int elf_core_dump(struct coredump_params *cprm)
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, mm_flags);
+ offset += elf_core_vma_data_size(gate_vma, cprm->mm_flags);
offset += elf_core_extra_data_size();
e_shoff = offset;
@@ -1995,7 +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;
@@ -2030,7 +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;