[PATCH 4.9 12/16] metag/ptrace: Provide default TXSTATUS for short NT_PRSTATUS

Greg Kroah-Hartman
2017-03-30T10:17:43Z

From: Dave Martin <Dave.Martin@arm.com>

commit 5fe81fe98123ce41265c65e95d34418d30d005d1 upstream.

Ensure that if userspace supplies insufficient data to PTRACE_SETREGSET
to fill TXSTATUS, a well-defined default value is used, based on the
task's current value.

Suggested-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/metag/kernel/ptrace.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

--- a/arch/metag/kernel/ptrace.c
+++ b/arch/metag/kernel/ptrace.c
@@ -24,6 +24,16 @@
* user_regset definitions.
*/

+static unsigned long user_txstatus(const struct pt_regs *regs)
+{
+ unsigned long data = (unsigned long)regs->ctx.Flags;
+
+ if (regs->ctx.SaveMask & TBICTX_CBUF_BIT)
+ data |= USER_GP_REGS_STATUS_CATCH_BIT;
+
+ return data;
+}
+
int metag_gp_regs_copyout(const struct pt_regs *regs,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
@@ -62,9 +72,7 @@ int metag_gp_regs_copyout(const struct p
if (ret)
goto out;
/* TXSTATUS */
- data = (unsigned long)regs->ctx.Flags;
- if (regs->ctx.SaveMask & TBICTX_CBUF_BIT)
- data |= USER_GP_REGS_STATUS_CATCH_BIT;
+ data = user_txstatus(regs);
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&data, 4*25, 4*26);
if (ret)
@@ -119,6 +127,7 @@ int metag_gp_regs_copyin(struct pt_regs
if (ret)
goto out;
/* TXSTATUS */
+ data = user_txstatus(regs);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&data, 4*25, 4*26);
if (ret)