From 19791a7ca674fb3009bb068260e852a2f05b605c Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 25 Apr 2018 17:13:40 +0100 Subject: arm64: fix possible spectre-v1 in ptrace_hbp_get_event() It's possible for userspace to control idx. Sanitize idx when using it as an array index. Found by smatch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Will Deacon --- arch/arm64/kernel/ptrace.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 7a832ce6552f..7ff81fed46e1 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -249,15 +250,20 @@ static struct perf_event *ptrace_hbp_get_event(unsigned int note_type, switch (note_type) { case NT_ARM_HW_BREAK: - if (idx < ARM_MAX_BRP) - bp = tsk->thread.debug.hbp_break[idx]; + if (idx >= ARM_MAX_BRP) + goto out; + idx = array_index_nospec(idx, ARM_MAX_BRP); + bp = tsk->thread.debug.hbp_break[idx]; break; case NT_ARM_HW_WATCH: - if (idx < ARM_MAX_WRP) - bp = tsk->thread.debug.hbp_watch[idx]; + if (idx >= ARM_MAX_WRP) + goto out; + idx = array_index_nospec(idx, ARM_MAX_WRP); + bp = tsk->thread.debug.hbp_watch[idx]; break; } +out: return bp; } -- cgit v1.2.3-55-g7522