| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20220310172019.850939-32-ira.weiny@intel.com>
Date: Thu, 10 Mar 2022 09:20:05 -0800
From: ira.weiny@...el.com
To: Dave Hansen <dave.hansen@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>,
Dan Williams <dan.j.williams@...el.com>
Cc: Ira Weiny <ira.weiny@...el.com>, Fenghua Yu <fenghua.yu@...el.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
"Shankar, Ravi V" <ravi.v.shankar@...el.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH V9 31/45] mm/pkeys: PKS testing, test pks_update_exception()
From: Ira Weiny <ira.weiny@...el.com>
A common use case for the custom fault callbacks will be for the
callback to warn of the violation and relax the permissions rather than
crash the kernel. pks_update_exception() was added for this purpose.
Add a test which uses pks_update_exception() to clear the pkey
permissions. Verify that the permissions are changed in the interrupted
thread.
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
Changes for V9
Update the commit message
Clean up test name
Add test_pks support
s/pks_mk_*/pks_set_*/
Simplify the use of globals for the faults
From Rick Edgecombe
Use WRITE_ONCE to protect against races with the fault
handler
s/RUN_FAULT_ABANDON/RUN_FAULT_CALLBACK
Changes for V8
New test developed just to double check for regressions while
reworking the code.
---
lib/pks/pks_test.c | 60 ++++++++++++++++++++++++++
tools/testing/selftests/x86/test_pks.c | 5 ++-
2 files changed, 64 insertions(+), 1 deletion(-)
diff --git a/lib/pks/pks_test.c b/lib/pks/pks_test.c
index 762f4a19cb7d..a9cd2a49abfa 100644
--- a/lib/pks/pks_test.c
+++ b/lib/pks/pks_test.c
@@ -49,6 +49,7 @@
#define ARM_CTX_SWITCH 2
#define CHECK_CTX_SWITCH 3
#define RUN_EXCEPTION 4
+#define RUN_EXCEPTION_UPDATE 5
#define RUN_CRASH_TEST 9
DECLARE_PER_CPU(u32, pkrs_cache);
@@ -64,6 +65,7 @@ struct pks_test_ctx {
void *test_page;
bool fault_seen;
bool validate_exp_handling;
+ bool validate_update_exp;
};
static bool check_pkey_val(u32 pk_reg, u8 pkey, u32 expected)
@@ -164,6 +166,16 @@ static void validate_exception(struct pks_test_ctx *ctx, u32 thread_pkrs)
}
}
+static bool handle_update_exception(struct pt_regs *regs, struct pks_test_ctx *ctx)
+{
+ pr_debug("Updating pkey %d during exception\n", ctx->pkey);
+
+ ctx->fault_seen = true;
+ pks_update_exception(regs, ctx->pkey, 0);
+
+ return true;
+}
+
/* Global data protected by test_run_lock */
struct pks_test_ctx *g_ctx_under_test;
@@ -190,6 +202,9 @@ bool pks_test_fault_callback(struct pt_regs *regs, unsigned long address,
if (!g_ctx_under_test)
return false;
+ if (g_ctx_under_test->validate_update_exp)
+ return handle_update_exception(regs, g_ctx_under_test);
+
if (g_ctx_under_test->validate_exp_handling) {
validate_exception(g_ctx_under_test, pkrs);
/*
@@ -518,6 +533,47 @@ static void check_ctx_switch(struct pks_session_data *sd)
}
}
+static bool run_exception_update(struct pks_session_data *sd)
+{
+ struct pks_test_ctx *ctx;
+
+ ctx = alloc_ctx(PKS_KEY_TEST);
+ if (IS_ERR(ctx))
+ return false;
+
+ set_ctx_data(sd, ctx);
+
+ ctx->fault_seen = false;
+ ctx->validate_update_exp = true;
+ pks_set_noaccess(ctx->pkey);
+
+ set_context_for_fault(ctx);
+
+ /* fault */
+ memcpy(ctx->test_page, ctx->data, 8);
+
+ if (!ctx->fault_seen) {
+ pr_err("Failed to see the callback\n");
+ return false;
+ }
+
+ ctx->fault_seen = false;
+ ctx->validate_update_exp = false;
+
+ set_context_for_fault(ctx);
+
+ /* no fault */
+ memcpy(ctx->test_page, ctx->data, 8);
+
+ if (ctx->fault_seen) {
+ pr_err("Pkey %d failed to be set RD/WR in the callback\n",
+ ctx->pkey);
+ return false;
+ }
+
+ return true;
+}
+
static ssize_t pks_read_file(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
@@ -584,6 +640,10 @@ static ssize_t pks_write_file(struct file *file, const char __user *user_buf,
pr_debug("Exception checking\n");
sd->last_test_pass = run_exception_test(file->private_data);
break;
+ case RUN_EXCEPTION_UPDATE:
+ pr_debug("Fault clear test\n");
+ sd->last_test_pass = run_exception_update(file->private_data);
+ break;
default:
pr_debug("Unknown test\n");
sd->last_test_pass = false;
diff --git a/tools/testing/selftests/x86/test_pks.c b/tools/testing/selftests/x86/test_pks.c
index 817df7a14923..243347e48228 100644
--- a/tools/testing/selftests/x86/test_pks.c
+++ b/tools/testing/selftests/x86/test_pks.c
@@ -36,6 +36,7 @@
#define ARM_CTX_SWITCH "2"
#define CHECK_CTX_SWITCH "3"
#define RUN_EXCEPTION "4"
+#define RUN_EXCEPTION_UPDATE "5"
#define RUN_CRASH_TEST "9"
time_t g_start_time;
@@ -63,6 +64,7 @@ enum {
TEST_SINGLE,
TEST_CTX_SWITCH,
TEST_EXCEPTION,
+ TEST_FAULT_CALLBACK,
MAX_TESTS,
} tests;
@@ -77,7 +79,8 @@ struct test_item {
{ "check_defaults", CHECK_DEFAULTS, do_simple_test },
{ "single", RUN_SINGLE, do_simple_test },
{ "context_switch", ARM_CTX_SWITCH, do_context_switch },
- { "exception", RUN_EXCEPTION, do_simple_test }
+ { "exception", RUN_EXCEPTION, do_simple_test },
+ { "exception_update", RUN_EXCEPTION_UPDATE, do_simple_test }
};
static char *get_test_name(int test_num)
--
2.35.1
Powered by blists - more mailing lists