On 2023/6/6 12:28, Maninder Singh wrote: > 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@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://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. > > 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..e776f12f0f5a > --- /dev/null > +++ b/kernel/ksyms_common.c > @@ -0,0 +1,45 @@ > +// SPDX-License-Identifier: GPL-2.0 Keep it the same as kernel/kallsyms.c. GPL-2.0-only Sorry, I didn't think of that last time. Otherwise, Reviewed-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> > +/* > + * 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 > -- Regards, Zhen Lei
