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 knosyms.c. With this patch code is just moved to new file and no functional change. Next patch will enable defination of function for all cases. Co-developed-by: Onkarnath <onkarnath.1@xxxxxxxxxxx> Signed-off-by: Onkarnath <onkarnath.1@xxxxxxxxxxx> Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx> --- earlier conversations:(then it has dependancy on other change, but that was stashed from linux-next, now it can be pushed) https://lkml.org/lkml/2022/5/11/212 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 kernel/Makefile | 2 +- kernel/kallsyms.c | 35 ---------------------------------- kernel/knosyms.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 49 insertions(+), 36 deletions(-) create mode 100644 kernel/knosyms.c diff --git a/kernel/Makefile b/kernel/Makefile index f9e3fd9195d9..918d3e9b14bc 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 knosyms.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/knosyms.c b/kernel/knosyms.c new file mode 100644 index 000000000000..9e2c72a89ea5 --- /dev/null +++ b/kernel/knosyms.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2023 Samsung Electronics Co., Ltd + * + * A split of kernel/kallsyms.c + * It will contain 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
