coredump: pass mm->flags as a coredump parameter for consistency
authorMasami Hiramatsu <mhiramat@redhat.com>
Fri, 5 Mar 2010 21:44:12 +0000 (13:44 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 6 Mar 2010 19:26:46 +0000 (11:26 -0800)
commit30736a4d43f4af7f1a7836d6a266be17082195c4
tree54e388cdaf4795bdb7651be03c50bba67eb0b43a
parent8d9032bbe4671dc481261ccd4e161cd96e54b118
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>
fs/binfmt_elf.c
fs/binfmt_elf_fdpic.c
fs/exec.c
include/linux/binfmts.h