From: Dave Martin <Dave.Martin@xxxxxxx>
We cannot preserve partial fields for hardware breakpoints, because
the values written by userspace to the hardware breakpoint
registers can't subsequently be recovered intact from the hardware.
So, just reject attempts to write incomplete fields with -EINVAL.
Cc: <stable@xxxxxxxxxxxxxxx> # 3.7.x-
Fixes: 478fcb2cdb23 ("arm64: Debugging support")
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
Acked-by: Will Deacon <Will.Deacon@xxxxxxx>
---
arch/arm64/kernel/ptrace.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 91c4719..a22161c 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -551,6 +551,8 @@ static int hw_break_set(struct task_struct *target,
/* (address, ctrl) registers */
limit = regset->n * regset->size;
while (count && offset < limit) {
+ if (count < PTRACE_HBP_ADDR_SZ)
+ return -EINVAL;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
offset, offset + PTRACE_HBP_ADDR_SZ);
if (ret)
@@ -560,6 +562,8 @@ static int hw_break_set(struct task_struct *target,
return ret;
offset += PTRACE_HBP_ADDR_SZ;
+ if (!count)
+ break;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
offset, offset + PTRACE_HBP_CTRL_SZ);
if (ret)
--
2.1.4
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