Repository files (latest commit first)

Filename	Latest commit message	Latest commit date
Gianluca Borello a5e8c07059 bpf: add bpf_probe_read_str helper ... Provide a simple helper with the same semantics of strncpy_from_unsafe(): int bpf_probe_read_str(void *dst, int size, const void *unsafe_addr) This gives more flexibility to a bpf program. A typical use case is intercepting a file name during sys_open(). The current approach is: SEC("kprobe/sys_open") void bpf_sys_open(struct pt_regs *ctx) { char buf[PATHLEN]; // PATHLEN is defined to 256 bpf_probe_read(buf, sizeof(buf), ctx->di); /* consume buf */ } This is suboptimal because the size of the string needs to be estimated at compile time, causing more memory to be copied than often necessary, and can become more problematic if further processing on buf is done, for example by pushing it to userspace via bpf_perf_event_output(), since the real length of the string is unknown and the entire buffer must be copied (and defining an unrolled strnlen() inside the bpf program is a very inefficient and unfeasible approach). With the new helper, the code can easily operate on the actual string length rather than the buffer size: SEC("kprobe/sys_open") void bpf_sys_open(struct pt_regs *ctx) { char buf[PATHLEN]; // PATHLEN is defined to 256 int res = bpf_probe_read_str(buf, sizeof(buf), ctx->di); /* consume buf, for example push it to userspace via * bpf_perf_event_output(), but this time we can use * res (the string length) as event size, after checking * its boundaries. */ } Another useful use case is when parsing individual process arguments or individual environment variables navigating current->mm->arg_start and current->mm->env_start: using this helper and the return value, one can quickly iterate at the right offset of the memory area. The code changes simply leverage the already existent strncpy_from_unsafe() kernel function, which is safe to be called from a bpf program as it is used in bpf_trace_printk(). Signed-off-by: Gianluca Borello <g.borello@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-01-20 12:08:43 -05:00
..
bpf	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-01-17 15:19:37 -05:00
configs
debug	kdb: call vkdb_printf() from vprintk_default() only when wanted	2016-12-14 16:04:08 -08:00
events	perf/x86/intel: Account interrupts for PEBS errors	2017-01-14 11:06:49 +01:00
gcov
irq	genirq/affinity: Fix node generation from cpumask	2016-12-15 12:32:35 +01:00
livepatch
locking	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
power	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
printk	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
rcu	rcu: Don't kick unless grace period or request	2016-11-14 10:46:31 -08:00
sched	ktime: Cleanup ktime_set() usage	2016-12-25 17:21:22 +01:00
time	nohz: Fix collision between tick and other hrtimers	2017-01-11 10:41:33 +01:00
trace	bpf: add bpf_probe_read_str helper	2017-01-20 12:08:43 -05:00
.gitignore
acct.c
async.c
audit.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-12-17 18:44:00 -08:00
audit.h	audit_log_{name,link_denied}: constify struct path	2016-12-05 19:00:38 -05:00
audit_fsnotify.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-12-17 18:44:00 -08:00
audit_tree.c	Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit	2017-01-05 23:06:06 -08:00
audit_watch.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-12-17 18:44:00 -08:00
auditfilter.c	audit: add support for session ID user filter	2016-11-29 15:10:12 -05:00
auditsc.c	Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit	2016-12-14 14:06:40 -08:00
backtracetest.c
bounds.c
capability.c	capability: export has_capability	2017-01-12 07:01:56 -07:00
cgroup.c	cgroup: add support for eBPF programs	2016-11-25 16:25:52 -05:00
cgroup_freezer.c
cgroup_pids.c
compat.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
configs.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
context_tracking.c
cpu.c	smp/hotplug: Undo tglxs brainfart	2016-12-26 17:30:24 -08:00
cpu_pm.c
cpuset.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
extable.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
fork.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
freezer.c
futex.c	ktime: Get rid of the union	2016-12-25 17:21:22 +01:00
futex_compat.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
groups.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
hung_task.c	hung_task: decrement sysctl_hung_task_warnings only if it is positive	2016-12-12 18:55:09 -08:00
irq_work.c
jump_label.c	jump_labels: API for flushing deferred jump label updates	2017-01-12 14:33:16 +01:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: make kcov work properly with KASLR enabled	2016-12-20 09:48:47 -08:00
kexec.c
kexec_core.c	kexec: add cond_resched into kimage_alloc_crash_control_pages	2016-12-14 16:04:07 -08:00
kexec_file.c	ima: on soft reboot, save the measurement list	2016-12-20 09:48:44 -08:00
kexec_internal.h	kexec_file: Allow arch-specific memory walking for kexec_add_buffer	2016-11-30 23:14:57 +11:00
kmod.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
kprobes.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
ksysfs.c
kthread.c	kthread: add __printf attributes	2016-12-12 18:55:06 -08:00
latencytop.c
Makefile	Merge branch 'akpm' (patches from Andrew)	2016-12-14 17:25:18 -08:00
membarrier.c
memremap.c	mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}	2017-01-10 18:31:54 -08:00
module-internal.h
module.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
module_signing.c
notifier.c
nsproxy.c
padata.c
panic.c	taint/module: Clean up global and module taint flags handling	2016-11-26 11:18:01 -08:00
params.c
pid.c
pid_namespace.c	pid: fix lockdep deadlock warning due to ucount_lock	2017-01-10 13:34:56 +13:00
profile.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
ptrace.c	ptrace: Don't allow accessing an undumpable mm	2016-11-22 12:57:38 -06:00
range.c
reboot.c
relay.c	relay: check array offset before using it	2016-12-14 16:04:08 -08:00
resource.c
seccomp.c	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security	2016-12-14 13:57:44 -08:00
signal.c	signal: protect SIGNAL_UNKILLABLE from unintentional clearing.	2017-01-10 18:31:55 -08:00
smp.c	kernel/smp: Tell the user we're bringing up secondary CPUs	2016-10-26 12:02:35 +02:00
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c	locking/core, stop_machine: Yield the CPU during stop machine()	2016-11-16 10:15:09 +01:00
sys.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
sys_ni.c	move aio compat to fs/aio.c	2016-12-22 22:58:37 -05:00
sysctl.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
sysctl_binary.c	sysctl: add KERN_CONT to deprecated_sysctl_warning()	2016-12-14 16:04:07 -08:00
task_work.c
taskstats.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2016-11-15 10:54:36 -05:00
test_kprobes.c
torture.c
tracepoint.c	tracing: Have the reg function allow to fail	2016-12-09 09:13:30 -05:00
tsacct.c
ucount.c
uid16.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
watchdog.c	kernel/watchdog.c: move hardlockup detector to separate file	2016-12-14 16:04:08 -08:00
watchdog_hld.c	kernel/watchdog.c: move hardlockup detector to separate file	2016-12-14 16:04:08 -08:00
workqueue.c
workqueue_internal.h