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authorOleg Nesterov <oleg@redhat.com>2014-01-23 15:55:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-23 16:37:01 -0800
commit7288e1187ba935996232246916418c64bb88da30 (patch)
treeced1754f48f918acca47a0c4f4c3a5c8f35db39d /fs
parentabacd2fe3ca10b3ade57f3634053241a660002c2 (diff)
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')
-rw-r--r--fs/exec.c21
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;
}
/*

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