diff options
author | Masami Hiramatsu <mhiramat@redhat.com> | 2010-03-05 22:44:12 +0100 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-06 20:26:46 +0100 |
commit | 30736a4d43f4af7f1a7836d6a266be17082195c4 (patch) | |
tree | 54e388cdaf4795bdb7651be03c50bba67eb0b43a /fs/exec.c | |
parent | elf coredump: add extended numbering support (diff) | |
download | linux-30736a4d43f4af7f1a7836d6a266be17082195c4.tar.xz linux-30736a4d43f4af7f1a7836d6a266be17082195c4.zip |
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/exec.c')
-rw-r--r-- | fs/exec.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/fs/exec.c b/fs/exec.c index da2b31dc4e1c..89d4080c1435 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1748,14 +1748,19 @@ void set_dumpable(struct mm_struct *mm, int value) } } -int get_dumpable(struct mm_struct *mm) +static int __get_dumpable(unsigned long mm_flags) { int ret; - ret = mm->flags & 0x3; + ret = mm_flags & MMF_DUMPABLE_MASK; return (ret >= 2) ? 2 : ret; } +int get_dumpable(struct mm_struct *mm) +{ + return __get_dumpable(mm->flags); +} + static void wait_for_dump_helpers(struct file *file) { struct pipe_inode_info *pipe; @@ -1799,6 +1804,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) .signr = signr, .regs = regs, .limit = rlimit(RLIMIT_CORE), + /* + * We must use the same mm->flags while dumping core to avoid + * inconsistency of bit flags, since this flag is not protected + * by any locks. + */ + .mm_flags = mm->flags, }; audit_core_dumps(signr); @@ -1817,7 +1828,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) /* * If another thread got here first, or we are not dumpable, bail out. */ - if (mm->core_state || !get_dumpable(mm)) { + if (mm->core_state || !__get_dumpable(cprm.mm_flags)) { up_write(&mm->mmap_sem); put_cred(cred); goto fail; @@ -1828,7 +1839,8 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) * process nor do we know its entire history. We only know it * was tainted so we dump it as root in mode 2. */ - if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ + if (__get_dumpable(cprm.mm_flags) == 2) { + /* Setuid core dump mode */ flag = O_EXCL; /* Stop rewrite attacks */ cred->fsuid = 0; /* Dump root private */ } |