Daniel Xu 6fa6d28051 lib/strncpy_from_user.c: Mask out bytes after NUL terminator. ... do_strncpy_from_user() may copy some extra bytes after the NUL terminator into the destination buffer. This usually does not matter for normal string operations. However, when BPF programs key BPF maps with strings, this matters a lot. A BPF program may read strings from user memory by calling the bpf_probe_read_user_str() helper which eventually calls do_strncpy_from_user(). The program can then key a map with the destination buffer. BPF map keys are fixed-width and string-agnostic, meaning that map keys are treated as a set of bytes. The issue is when do_strncpy_from_user() overcopies bytes after the NUL terminator, it can result in seemingly identical strings occupying multiple slots in a BPF map. This behavior is subtle and totally unexpected by the user. This commit masks out the bytes following the NUL while preserving long-sized stride in the fast path. Fixes: 6ae08ae3de ("bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers") Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/21efc982b3e9f2f7b0379eed642294caaa0c27a7.1605642949.git.dxu@dxuuu.xyz		2020-11-19 11:56:16 -08:00
..
blktrace.c	block: add a bdget_part helper	2020-10-05 10:38:33 -06:00
bpf_trace.c	lib/strncpy_from_user.c: Mask out bytes after NUL terminator.	2020-11-19 11:56:16 -08:00
bpf_trace.h	bpf: Use dedicated bpf_trace_printk event instead of trace_printk()	2020-07-13 16:55:49 -07:00
fgraph.c	fgraph: Convert ret_stack tasklist scanning to rcu	2020-09-21 21:06:02 -04:00
ftrace.c	Updates for tracing and bootconfig:	2020-10-15 15:51:28 -07:00
ftrace_internal.h	x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up	2020-05-12 18:24:34 -04:00
Kconfig	Tracing updates for 5.8:	2020-06-09 10:06:18 -07:00
kprobe_event_gen_test.c	tracing: Add kprobe event command generation test module	2020-01-30 09:46:28 -05:00
Makefile	Kbuild updates for v5.9	2020-08-09 14:10:26 -07:00
power-traces.c
preemptirq_delay_test.c	tracing: Wait for preempt irq delay thread to execute	2020-05-11 17:00:34 -04:00
ring_buffer.c	ring-buffer: Fix recursion protection transitions between interrupt context	2020-11-02 15:58:32 -05:00
ring_buffer_benchmark.c	sched,tracing: Convert to sched_set_fifo()	2020-07-29 11:43:53 +02:00
rpm-traces.c
synth_event_gen_test.c	tracing: Add support for dynamic strings to synthetic events	2020-10-05 19:32:18 -04:00
trace.c	tracing: Fix the checking of stackidx in __ftrace_trace_stack	2020-11-02 11:21:40 -05:00
trace.h	ftrace: Handle tracing when switching between context	2020-11-02 08:52:18 -05:00
trace_benchmark.c	trace: Use pr_warn instead of pr_warning	2019-10-18 15:01:57 +02:00
trace_benchmark.h	tracing: Fix SPDX format headers to use C++ style comments	2018-08-16 19:08:06 -04:00
trace_boot.c	tracing/boot: Add ftrace.instance.*.alloc_snapshot option	2020-10-15 12:01:13 -04:00
trace_branch.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
trace_clock.c	tracing: Add SPDX License format tags to tracing files	2018-08-16 19:08:06 -04:00
trace_dynevent.c	tracing: Delete repeated words in comments	2020-09-21 21:06:02 -04:00
trace_dynevent.h	tracing: Remove check_arg() callbacks from dynevent args	2020-02-01 13:09:23 -05:00
trace_entries.h	tracing: Make ftrace packed events have align of 1	2020-06-16 21:21:02 -04:00
trace_event_perf.c	Merge branch 'perf/urgent' into perf/core, to pick up fixes	2019-10-28 12:38:26 +01:00
trace_events.c	Tracing: Fix mismatch section of adding early trace events	2020-10-16 14:56:52 -07:00
trace_events_filter.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
trace_events_filter_test.h	tracing: Fix SPDX format headers to use C++ style comments	2018-08-16 19:08:06 -04:00
trace_events_hist.c	tracing: Check return value of __create_val_fields() before using its result	2020-10-15 12:00:59 -04:00
trace_events_inject.c	tracing: Initialize val to zero in parse_entry of inject code	2020-01-02 19:04:57 -05:00
trace_events_synth.c	tracing: Make -ENOMEM the default error for parse_synth_field()	2020-11-02 15:58:32 -05:00
trace_events_trigger.c	tracing: Fix event trigger to accept redundant spaces	2020-06-23 21:51:40 -04:00
trace_export.c	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
trace_functions.c	tracing: Enable creating new instance early boot	2020-09-21 21:06:04 -04:00
trace_functions_graph.c	tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer	2020-09-18 22:17:14 -04:00
trace_hwlat.c	tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer	2020-09-18 22:17:14 -04:00
trace_irqsoff.c	tracing: Rename trace_buffer to array_buffer	2020-01-13 13:19:38 -05:00
trace_kdb.c	tracing: Rename trace_buffer to array_buffer	2020-01-13 13:19:38 -05:00
trace_kprobe.c	kprobes: Use module_name() macro	2020-09-24 15:55:49 +02:00
trace_kprobe_selftest.c	selftest/ftrace: Move kprobe selftest function to separate compile unit	2018-07-30 18:41:04 -04:00
trace_kprobe_selftest.h	tracing: Fix SPDX format headers to use C++ style comments	2018-08-16 19:08:06 -04:00
trace_mmiotrace.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
trace_nop.c
trace_output.c	tracing: Make the space reserved for the pid wider	2020-09-18 12:42:11 -04:00
trace_output.h	tracing: Fix SPDX format headers to use C++ style comments	2018-08-16 19:08:06 -04:00
trace_preemptirq.c	lockdep: fix order in trace_hardirqs_off_caller()	2020-09-14 10:08:07 +02:00
trace_printk.c	Updates for tracing and bootconfig:	2020-10-15 15:51:28 -07:00
trace_probe.c	tracing/probe: Fix memleak in fetch_op_data operations	2020-06-16 21:21:02 -04:00
trace_probe.h	tracing: Move is_good_name() from trace_probe.h to trace.h	2020-10-15 12:01:13 -04:00
trace_probe_tmpl.h	tracing/probe: Support user-space dereference	2019-05-25 23:04:42 -04:00
trace_sched_switch.c	tracing: Fix sched switch start/stop refcount racy updates	2020-01-30 09:46:10 -05:00
trace_sched_wakeup.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
trace_selftest.c	ftrace: Handle tracing when switching between context	2020-11-02 08:52:18 -05:00
trace_selftest_dynamic.c
trace_seq.c	tracing: Remove unused TRACE_SEQ_BUF_USED	2020-01-21 18:39:54 -05:00
trace_stack.c	tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer	2020-09-18 22:17:14 -04:00
trace_stat.c	tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer	2020-09-18 22:17:14 -04:00
trace_stat.h	tracing: Use generic type for comparator function	2019-11-14 13:15:11 -05:00
trace_synth.h	tracing: Add support for dynamic strings to synthetic events	2020-10-05 19:32:18 -04:00
trace_syscalls.c	Tracing updates:	2020-02-06 07:12:11 +00:00
trace_uprobe.c	tracing/uprobes: Support perf-style return probe	2020-09-21 21:06:03 -04:00
tracing_map.c	tracing: Delete repeated words in comments	2020-09-21 21:06:02 -04:00
tracing_map.h	tracing: Fix SPDX format headers to use C++ style comments	2018-08-16 19:08:06 -04:00