diff options
| author |   Oleg Nesterov <oleg@redhat.com> | 2014-01-23 15:55:32 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-23 16:37:01 -0800 |
| commit | 7288e1187ba935996232246916418c64bb88da30 (patch) | |
| tree | ced1754f48f918acca47a0c4f4c3a5c8f35db39d /fs/exec.c | |
| parent | coredump: set_dumpable: fix the theoretical race with itself (diff) | |
| download | linux-dev-7288e1187ba935996232246916418c64bb88da30.tar.xz linux-dev-7288e1187ba935996232246916418c64bb88da30.zip | |
coredump: kill MMF_DUMPABLE and MMF_DUMP_SECURELY
Nobody actually needs MMF_DUMPABLE/MMF_DUMP_SECURELY, they are only used
to enforce the encoding of SUID_DUMP_* enum in mm->flags &
MMF_DUMPABLE_MASK.
Now that set_dumpable() updates both bits atomically we can kill them and
simply store the value "as is" in 2 lower bits.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alex Kelly <alex.page.kelly@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Vasily Kulikov <segoon@openwall.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 | 21 |
1 files changed, 6 insertions, 15 deletions
diff --git a/fs/exec.c b/fs/exec.c index f039386499db..f798da06abac 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1613,33 +1613,24 @@ void set_binfmt(struct linux_binfmt *new) EXPORT_SYMBOL(set_binfmt); /* - * set_dumpable converts traditional three-value dumpable to two flags and - * stores them into mm->flags. + * set_dumpable stores three-value SUID_DUMP_* into mm->flags. */ void set_dumpable(struct mm_struct *mm, int value) { unsigned long old, new; + if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) + return; + do { old = ACCESS_ONCE(mm->flags); - new = old & ~MMF_DUMPABLE_MASK; - - switch (value) { - case SUID_DUMP_ROOT: - new |= (1 << MMF_DUMP_SECURELY); - case SUID_DUMP_USER: - new |= (1<< MMF_DUMPABLE); - } - + new = (old & ~MMF_DUMPABLE_MASK) | value; } while (cmpxchg(&mm->flags, old, new) != old); } int __get_dumpable(unsigned long mm_flags) { - int ret; - - ret = mm_flags & MMF_DUMPABLE_MASK; - return (ret > SUID_DUMP_USER) ? SUID_DUMP_ROOT : ret; + return mm_flags & MMF_DUMPABLE_MASK; } /* |