coredump masking: reimplementation of dumpable using two flags
This patch changes mm_struct.dumpable to a pair of bit flags.
set_dumpable() converts three-value dumpable to two flags and stores it into
lower two bits of mm_struct.flags instead of mm_struct.dumpable.
get_dumpable() behaves in the opposite way.
[akpm@linux-foundation.org: export set_dumpable]
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h
index db81ba4..6251c764 100644
--- a/include/asm-ia64/processor.h
+++ b/include/asm-ia64/processor.h
@@ -295,9 +295,9 @@
regs->ar_bspstore = current->thread.rbs_bot; \
regs->ar_fpsr = FPSR_DEFAULT; \
regs->loadrs = 0; \
- regs->r8 = current->mm->dumpable; /* set "don't zap registers" flag */ \
+ regs->r8 = get_dumpable(current->mm); /* set "don't zap registers" flag */ \
regs->r12 = new_sp - 16; /* allocate 16 byte scratch area */ \
- if (unlikely(!current->mm->dumpable)) { \
+ if (unlikely(!get_dumpable(current->mm))) { \
/* \
* Zap scratch regs to avoid leaking bits between processes with different \
* uid/privileges. \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 731edaca..8dbd083 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -345,6 +345,13 @@
(mm)->hiwater_vm = (mm)->total_vm; \
} while (0)
+extern void set_dumpable(struct mm_struct *mm, int value);
+extern int get_dumpable(struct mm_struct *mm);
+
+/* mm flags */
+#define MMF_DUMPABLE 0 /* core dump is permitted */
+#define MMF_DUMP_SECURELY 1 /* core file is readable only by root */
+
struct mm_struct {
struct vm_area_struct * mmap; /* list of VMAs */
struct rb_root mm_rb;
@@ -402,7 +409,7 @@
unsigned int token_priority;
unsigned int last_interval;
- unsigned char dumpable:2;
+ unsigned long flags; /* Must use atomic bitops to access the bits */
/* coredumping support */
int core_waiters;