From 59275a0c037ed6fabd6354730f1e3104264ab719 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 24 Apr 2018 13:11:22 +0100 Subject: arm64: ptrace: remove addr_limit manipulation We transiently switch to KERNEL_DS in compat_ptrace_gethbpregs() and compat_ptrace_sethbpregs(), but in either case this is pointless as we don't perform any uaccess during this window. let's rip out the redundant addr_limit manipulation. Acked-by: Catalin Marinas Signed-off-by: Mark Rutland Cc: Will Deacon Signed-off-by: Will Deacon --- arch/arm64/kernel/ptrace.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'arch/arm64/kernel/ptrace.c') diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 71d99af24ef2..7a832ce6552f 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1458,9 +1458,7 @@ static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num, { int ret; u32 kdata; - mm_segment_t old_fs = get_fs(); - set_fs(KERNEL_DS); /* Watchpoint */ if (num < 0) { ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata); @@ -1471,7 +1469,6 @@ static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num, } else { ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata); } - set_fs(old_fs); if (!ret) ret = put_user(kdata, data); @@ -1484,7 +1481,6 @@ static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num, { int ret; u32 kdata = 0; - mm_segment_t old_fs = get_fs(); if (num == 0) return 0; @@ -1493,12 +1489,10 @@ static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num, if (ret) return ret; - set_fs(KERNEL_DS); if (num < 0) ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata); else ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata); - set_fs(old_fs); return ret; } -- cgit v1.2.3 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(-) (limited to 'arch/arm64/kernel/ptrace.c') 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