8d3b7dce86
%s specifier makes bpf program and kernel debugging easier.
To make sure that trace_printk won't crash the unsafe string
is copied into stack and unsafe pointer is substituted.
The following C program:
#include <linux/fs.h>
int foo(struct pt_regs *ctx, struct filename *filename)
{
void *name = 0;
bpf_probe_read(&name, sizeof(name), &filename->name);
bpf_trace_printk("executed %s\n", name);
return 0;
}
when attached to kprobe do_execve()
will produce output in /sys/kernel/debug/tracing/trace_pipe :
make-13492 [002] d..1 3250.997277: : executed /bin/sh
sh-13493 [004] d..1 3250.998716: : executed /usr/bin/gcc
gcc-13494 [002] d..1 3250.999822: : executed /usr/lib/gcc/x86_64-linux-gnu/4.7/cc1
gcc-13495 [002] d..1 3251.006731: : executed /usr/bin/as
gcc-13496 [002] d..1 3251.011831: : executed /usr/lib/gcc/x86_64-linux-gnu/4.7/collect2
collect2-13497 [000] d..1 3251.012941: : executed /usr/bin/ld
Suggested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
|---|---|---|
| .. | ||
| bpf | ||
| configs | ||
| debug | ||
| events | ||
| gcov | ||
| irq | ||
| livepatch | ||
| locking | ||
| power | ||
| printk | ||
| rcu | ||
| sched | ||
| time | ||
| trace | ||
| .gitignore | ||
| acct.c | ||
| async.c | ||
| audit_tree.c | ||
| audit_watch.c | ||
| audit.c | ||
| audit.h | ||
| auditfilter.c | ||
| auditsc.c | ||
| backtracetest.c | ||
| bounds.c | ||
| capability.c | ||
| cgroup_freezer.c | ||
| cgroup.c | ||
| compat.c | ||
| configs.c | ||
| context_tracking.c | ||
| cpu_pm.c | ||
| cpu.c | ||
| cpuset.c | ||
| crash_dump.c | ||
| cred.c | ||
| delayacct.c | ||
| dma.c | ||
| elfcore.c | ||
| exec_domain.c | ||
| exit.c | ||
| extable.c | ||
| fork.c | ||
| freezer.c | ||
| futex_compat.c | ||
| futex.c | ||
| groups.c | ||
| hung_task.c | ||
| irq_work.c | ||
| jump_label.c | ||
| kallsyms.c | ||
| kcmp.c | ||
| Kconfig.freezer | ||
| Kconfig.hz | ||
| Kconfig.locks | ||
| Kconfig.preempt | ||
| kexec.c | ||
| kmod.c | ||
| kprobes.c | ||
| ksysfs.c | ||
| kthread.c | ||
| latencytop.c | ||
| Makefile | ||
| module_signing.c | ||
| module-internal.h | ||
| module.c | ||
| notifier.c | ||
| nsproxy.c | ||
| padata.c | ||
| panic.c | ||
| params.c | ||
| pid_namespace.c | ||
| pid.c | ||
| profile.c | ||
| ptrace.c | ||
| range.c | ||
| reboot.c | ||
| relay.c | ||
| resource.c | ||
| seccomp.c | ||
| signal.c | ||
| smp.c | ||
| smpboot.c | ||
| smpboot.h | ||
| softirq.c | ||
| stacktrace.c | ||
| stop_machine.c | ||
| sys_ni.c | ||
| sys.c | ||
| sysctl_binary.c | ||
| sysctl.c | ||
| system_certificates.S | ||
| system_keyring.c | ||
| task_work.c | ||
| taskstats.c | ||
| test_kprobes.c | ||
| torture.c | ||
| tracepoint.c | ||
| tsacct.c | ||
| uid16.c | ||
| up.c | ||
| user_namespace.c | ||
| user-return-notifier.c | ||
| user.c | ||
| utsname_sysctl.c | ||
| utsname.c | ||
| watchdog.c | ||
| workqueue_internal.h | ||
| workqueue.c | ||