lkml.org 
[lkml]   [2020]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH v3 36/39] kasan, arm64: print report from tag fault handler
From
Add error reporting for hardware tag-based KASAN. When CONFIG_KASAN_HW_TAGS
is enabled, print KASAN report from the arm64 tag fault handler.

SAS bits aren't set in ESR for all faults reported in EL1, so it's
impossible to find out the size of the access the caused the fault.
Adapt KASAN reporting code to handle this case.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
Change-Id: I3780fe7db6e075dff2937d3d8508f55c9322b095
---
arch/arm64/mm/fault.c | 14 ++++++++++++++
mm/kasan/report.c | 11 ++++++++---
2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index d110f382dacf..1c314e6f7918 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -14,6 +14,7 @@
#include <linux/mm.h>
#include <linux/hardirq.h>
#include <linux/init.h>
+#include <linux/kasan.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/page-flags.h>
@@ -295,10 +296,23 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
do_exit(SIGKILL);
}

+#ifdef CONFIG_KASAN_HW_TAGS
static void report_tag_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
+ bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
+
+ /*
+ * SAS bits aren't set for all faults reported in EL1, so we can't
+ * find out access size.
+ */
+ kasan_report(addr, 0, is_write, regs->pc);
}
+#else
+/* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */
+static inline void report_tag_fault(unsigned long addr, unsigned int esr,
+ struct pt_regs *regs) { }
+#endif

static void __do_kernel_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 3924127b4786..f8817d5685a7 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -60,9 +60,14 @@ static void print_error_description(struct kasan_access_info *info)
{
pr_err("BUG: KASAN: %s in %pS\n",
get_bug_type(info), (void *)info->ip);
- pr_err("%s of size %zu at addr %px by task %s/%d\n",
- info->is_write ? "Write" : "Read", info->access_size,
- info->access_addr, current->comm, task_pid_nr(current));
+ if (info->access_size)
+ pr_err("%s of size %zu at addr %px by task %s/%d\n",
+ info->is_write ? "Write" : "Read", info->access_size,
+ info->access_addr, current->comm, task_pid_nr(current));
+ else
+ pr_err("%s at addr %px by task %s/%d\n",
+ info->is_write ? "Write" : "Read",
+ info->access_addr, current->comm, task_pid_nr(current));
}

static DEFINE_SPINLOCK(report_lock);
--
2.28.0.681.g6f77f65b4e-goog
\
 
 \ /
  Last update: 2020-09-25 00:53    [W:0.471 / U:0.372 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site