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Message-Id: <20230608033119.1543638-1-maninder1.s@samsung.com>
Date: Thu, 8 Jun 2023 09:01:18 +0530
From: Maninder Singh <maninder1.s@...sung.com>
To: ast@...nel.org, daniel@...earbox.net, john.fastabend@...il.com,
andrii@...nel.org, martin.lau@...ux.dev, song@...nel.org,
yhs@...com, kpsingh@...nel.org, sdf@...gle.com, haoluo@...gle.com,
jolsa@...nel.org, thunder.leizhen@...wei.com, mcgrof@...nel.org,
boqun.feng@...il.com, vincenzopalazzodev@...il.com,
ojeda@...nel.org, jgross@...e.com, brauner@...nel.org,
michael.christie@...cle.com, samitolvanen@...gle.com,
glider@...gle.com, peterz@...radead.org, keescook@...omium.org,
stephen.s.brennan@...cle.com, alan.maguire@...cle.com,
pmladek@...e.com
Cc: linux-kernel@...r.kernel.org, bpf@...r.kernel.org,
Maninder Singh <maninder1.s@...sung.com>,
Onkarnath <onkarnath.1@...sung.com>
Subject: [PATCH v5 1/2] 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@...sung.com>
Signed-off-by: Onkarnath <onkarnath.1@...sung.com>
Signed-off-by: Maninder Singh <maninder1.s@...sung.com>
Reviewed-by: Zhen Lei <thunder.leizhen@...wei.com>
---
earlier conversations:(then it has dependancy on other change, but that
was stashed from linux-next, now it can be pushed)
https://lore.kernel.org/lkml/202205111525.92B1C597@keescook/T/
https://lkml.org/lkml/2022/4/13/47
v1 -> v2: separate out bpf and kallsyms change
v2 -> v3: make kallsym changes in2 patches, non functional and
functional change
v3 -> v4: patch order changed, file name changed form knosyms -> ksyms_common
and copyright header modified.
v4 -> v5: license changed to kallsyms.c file, and bpf changes are
dropped as confirmed from BPF side:
https://lore.kernel.org/lkml/CAEf4Bzb4B9FxMnf3t81D22FWkciLOvwDPLY0BbEPGGe7R5QPrg@mail.gmail.com/T/
kernel/Makefile | 2 +-
kernel/kallsyms.c | 35 ---------------------------------
kernel/ksyms_common.c | 45 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 46 insertions(+), 36 deletions(-)
create mode 100644 kernel/ksyms_common.c
diff --git a/kernel/Makefile b/kernel/Makefile
index f9e3fd9195d9..3947122d618b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -10,7 +10,7 @@ obj-y = fork.o exec_domain.o panic.o \
extable.o params.o \
kthread.o sys_ni.o nsproxy.o \
notifier.o ksysfs.o cred.o reboot.o \
- async.o range.o smpboot.o ucount.o regset.o
+ async.o range.o smpboot.o ucount.o regset.o ksyms_common.o
obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o
obj-$(CONFIG_MULTIUSER) += groups.o
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 8193e947aa10..0f82c3d5a57d 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -907,41 +907,6 @@ late_initcall(bpf_ksym_iter_register);
#endif /* CONFIG_BPF_SYSCALL */
-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;
- }
-}
-
static int kallsyms_open(struct inode *inode, struct file *file)
{
/*
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
--
2.17.1
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