Commit b06e9318 authored by Maninder Singh's avatar Maninder Singh Committed by Luis Chamberlain
Browse files

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: default avatarOnkarnath <onkarnath.1@samsung.com>
Signed-off-by: default avatarOnkarnath <onkarnath.1@samsung.com>
Signed-off-by: default avatarManinder Singh <maninder1.s@samsung.com>
Reviewed-by: default avatarZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
parent 4f521bab

kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

kernel/kallsyms.c

+0 −35
Original line number Diff line number Diff line
@@ -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)

{

	/*

kernel/ksyms_common.c

0 → 100644
+45 −0
Original line number Diff line number Diff line 
// 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