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authorManinder Singh <maninder1.s@samsung.com>2023-06-08 05:31:18 +0200
committerLuis Chamberlain <mcgrof@kernel.org>2023-06-08 21:27:20 +0200
commitb06e9318bfd03f531b918bd27b63f1eb88c21729 (patch)
treed7dd7103a5e39bd4698bfe10815a86df8fba23aa /kernel/ksyms_common.c
parentkallsyms: remove unsed API lookup_symbol_attrs (diff)
downloadlinux-b06e9318bfd03f531b918bd27b63f1eb88c21729.tar.xz
linux-b06e9318bfd03f531b918bd27b63f1eb88c21729.zip
kallsyms: move kallsyms_show_value() out of kallsyms.c
function kallsyms_show_value() is used by other parts like modules_open(), kprobes_read() etc. which can work in case of !KALLSYMS also. e.g. as of now lsmod do not show module address if KALLSYMS is disabled. since kallsyms_show_value() defination is not present, it returns false in !KALLSYMS. / # lsmod test 12288 0 - Live 0x0000000000000000 (O) So kallsyms_show_value() can be made generic without dependency on KALLSYMS. Thus moving out function to a new file ksyms_common.c. With this patch code is just moved to new file and no functional change. Co-developed-by: Onkarnath <onkarnath.1@samsung.com> Signed-off-by: Onkarnath <onkarnath.1@samsung.com> Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Diffstat (limited to 'kernel/ksyms_common.c')
-rw-r--r--kernel/ksyms_common.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/kernel/ksyms_common.c b/kernel/ksyms_common.c
new file mode 100644
index 000000000000..3840fa1c9c86
--- /dev/null
+++ b/kernel/ksyms_common.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ksyms_common.c: A split of kernel/kallsyms.c
+ * Contains a few generic function definations independent of config KALLSYMS.
+ */
+#include <linux/kallsyms.h>
+#include <linux/security.h>
+
+#ifdef CONFIG_KALLSYMS
+static inline int kallsyms_for_perf(void)
+{
+#ifdef CONFIG_PERF_EVENTS
+ extern int sysctl_perf_event_paranoid;
+
+ if (sysctl_perf_event_paranoid <= 1)
+ return 1;
+#endif
+ return 0;
+}
+
+/*
+ * We show kallsyms information even to normal users if we've enabled
+ * kernel profiling and are explicitly not paranoid (so kptr_restrict
+ * is clear, and sysctl_perf_event_paranoid isn't set).
+ *
+ * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to
+ * block even that).
+ */
+bool kallsyms_show_value(const struct cred *cred)
+{
+ switch (kptr_restrict) {
+ case 0:
+ if (kallsyms_for_perf())
+ return true;
+ fallthrough;
+ case 1:
+ if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
+ CAP_OPT_NOAUDIT) == 0)
+ return true;
+ fallthrough;
+ default:
+ return false;
+ }
+}
+#endif