From: Ravi Bangoria ravi.bangoria@linux.ibm.com
[ Upstream commit 9b6b7c680cc20971444d9f836e49fc98848bcd0a ]
When kernel is compiled with CONFIG_HAVE_HW_BREAKPOINT=N, user can still create watchpoint using PPC_PTRACE_SETHWDEBUG, with limited functionalities. But, such watchpoints are never firing because of the missing privilege settings. Fix that.
It's safe to set HW_BRK_TYPE_PRIV_ALL because we don't really leak any kernel address in signal info. Setting HW_BRK_TYPE_PRIV_ALL will also help to find scenarios when kernel accesses user memory.
Reported-by: Pedro Miraglia Franco de Carvalho pedromfc@linux.ibm.com Suggested-by: Pedro Miraglia Franco de Carvalho pedromfc@linux.ibm.com Signed-off-by: Ravi Bangoria ravi.bangoria@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20200902042945.129369-4-ravi.bangoria@linux.ibm.co... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/ptrace/ptrace-noadv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c index 697c7e4b5877f..57a0ab822334f 100644 --- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c +++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c @@ -217,7 +217,7 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf return -EIO;
brk.address = ALIGN_DOWN(bp_info->addr, HW_BREAKPOINT_SIZE); - brk.type = HW_BRK_TYPE_TRANSLATE; + brk.type = HW_BRK_TYPE_TRANSLATE | HW_BRK_TYPE_PRIV_ALL; brk.len = DABR_MAX_LEN; if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ) brk.type |= HW_BRK_TYPE_READ;