From 6b6b456e82e052212ae7c9ef06cb78cd36b05362 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Wed, 18 Jan 2017 16:25:24 +0000 Subject: arm64/ptrace: Reject attempts to set incomplete hardware breakpoint fields [ Upstream commit ad9e202aa1ce571b1d7fed969d06f66067f8a086 ] 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: # 3.7.x- Fixes: 478fcb2cdb23 ("arm64: Debugging support") Signed-off-by: Dave Martin Acked-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin --- arch/arm64/kernel/ptrace.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch') diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index a9749cdcdb14..f7738bbc8c3f 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -450,6 +450,8 @@ 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) @@ -459,6 +461,8 @@ 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) -- cgit v1.2.3