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author | Masami Hiramatsu <mhiramat@redhat.com> | 2010-03-05 13:44:12 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-06 11:26:46 -0800 |
commit | 30736a4d43f4af7f1a7836d6a266be17082195c4 (patch) | |
tree | 54e388cdaf4795bdb7651be03c50bba67eb0b43a /fs/binfmt_elf.c | |
parent | 8d9032bbe4671dc481261ccd4e161cd96e54b118 (diff) | |
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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.c | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 78de530..535e763 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; |