From 7288e1187ba935996232246916418c64bb88da30 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 23 Jan 2014 15:55:32 -0800 Subject: 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 Acked-by: Kees Cook Cc: Alex Kelly Cc: "Eric W. Biederman" Cc: Josh Triplett Cc: Petr Matousek Cc: Vasily Kulikov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) (limited to 'fs/exec.c') 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; } /* -- cgit