From: Dave Martin <[email protected]>
commit ad9e202aa1ce571b1d7fed969d06f66067f8a086 upstream.
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.
Fixes: 478fcb2cdb23 ("arm64: Debugging support")
Signed-off-by: Dave Martin <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>
---
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 777763d..015775a 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -464,6 +464,8 @@ 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)
@@ -473,6 +475,8 @@ 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)
--
2.8.0.rc2.1.gbe9624a
