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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>
This commit is contained in:
Maninder Singh 2023-06-08 09:01:18 +05:30 committed by Luis Chamberlain
parent 4f521bab5b
commit b06e9318bf
3 changed files with 46 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/Makefile
View File

@ -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

35
kernel/kallsyms.c
View File

@ -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)
{
/*

45
kernel/ksyms_common.c Normal file
View File

@ -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