From 28f6c37a2910f565b4f5960df52b2eccae28c891 Mon Sep 17 00:00:00 2001 From: Chen Zhongjin Date: Mon, 1 Aug 2022 11:37:19 +0800 Subject: [PATCH 1/5] kprobes: Forbid probing on trampoline and BPF code areas kernel_text_address() treats ftrace_trampoline, kprobe_insn_slot and bpf_text_address as valid kprobe addresses - which is not ideal. These text areas are removable and changeable without any notification to kprobes, and probing on them can trigger unexpected behavior: https://lkml.org/lkml/2022/7/26/1148 Considering that jump_label and static_call text are already forbiden to probe, kernel_text_address() should be replaced with core_kernel_text() and is_module_text_address() to check other text areas which are unsafe to kprobe. [ mingo: Rewrote the changelog. ] Fixes: 5b485629ba0d ("kprobes, extable: Identify kprobes trampolines as kernel text area") Fixes: 74451e66d516 ("bpf: make jited programs visible in traces") Signed-off-by: Chen Zhongjin Signed-off-by: Ingo Molnar Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20220801033719.228248-1-chenzhongjin@huawei.com --- kernel/kprobes.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index f214f8c088ed..80697e5e03e4 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1560,7 +1560,8 @@ static int check_kprobe_address_safe(struct kprobe *p, preempt_disable(); /* Ensure it is not in reserved area nor out of text */ - if (!kernel_text_address((unsigned long) p->addr) || + if (!(core_kernel_text((unsigned long) p->addr) || + is_module_text_address((unsigned long) p->addr)) || within_kprobe_blacklist((unsigned long) p->addr) || jump_label_text_reserved(p->addr, p->addr) || static_call_text_reserved(p->addr, p->addr) || From dec8784c9088b131a1523f582c2194cfc8107dc0 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 2 Aug 2022 15:04:16 +0900 Subject: [PATCH 2/5] x86/kprobes: Update kcb status flag after singlestepping MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix kprobes to update kcb (kprobes control block) status flag to KPROBE_HIT_SSDONE even if the kp->post_handler is not set. This bug may cause a kernel panic if another INT3 user runs right after kprobes because kprobe_int3_handler() misunderstands the INT3 is kprobe's single stepping INT3. Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Reported-by: Daniel Müller Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Ingo Molnar Tested-by: Daniel Müller Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20220727210136.jjgc3lpqeq42yr3m@muellerd-fedora-PC2BDTX9 Link: https://lore.kernel.org/r/165942025658.342061.12452378391879093249.stgit@devnote2 --- arch/x86/kernel/kprobes/core.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 7c4ab8870da4..74167dc5f55e 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -814,16 +814,20 @@ set_current_kprobe(struct kprobe *p, struct pt_regs *regs, static void kprobe_post_process(struct kprobe *cur, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { - if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { - kcb->kprobe_status = KPROBE_HIT_SSDONE; - cur->post_handler(cur, regs, 0); - } - /* Restore back the original saved kprobes variables and continue. */ - if (kcb->kprobe_status == KPROBE_REENTER) + if (kcb->kprobe_status == KPROBE_REENTER) { + /* This will restore both kcb and current_kprobe */ restore_previous_kprobe(kcb); - else + } else { + /* + * Always update the kcb status because + * reset_curent_kprobe() doesn't update kcb. + */ + kcb->kprobe_status = KPROBE_HIT_SSDONE; + if (cur->post_handler) + cur->post_handler(cur, regs, 0); reset_current_kprobe(); + } } NOKPROBE_SYMBOL(kprobe_post_process); From b6a5068854cfe372da7dee3224dcf023ed5b00cb Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 21 Jul 2022 11:01:23 -0700 Subject: [PATCH 3/5] scripts/faddr2line: Fix vmlinux detection on arm64 Since commit dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel"), faddr2line is completely broken on arm64. For some reason, on arm64, the vmlinux ELF object file type is ET_DYN rather than ET_EXEC. Check for both when determining whether the object is vmlinux. Modules and vmlinux.o have type ET_REL on all arches. Fixes: dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel") Reported-by: John Garry Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Tested-by: John Garry Link: https://lore.kernel.org/r/dad1999737471b06d6188ce4cdb11329aa41682c.1658426357.git.jpoimboe@kernel.org --- scripts/faddr2line | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/scripts/faddr2line b/scripts/faddr2line index 94ed98dd899f..57099687e5e1 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -112,7 +112,9 @@ __faddr2line() { # section offsets. local file_type=$(${READELF} --file-header $objfile | ${AWK} '$1 == "Type:" { print $2; exit }') - [[ $file_type = "EXEC" ]] && is_vmlinux=1 + if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then + is_vmlinux=1 + fi # Go through each of the object's symbols which match the func name. # In rare cases there might be duplicates, in which case we print all From a41a2e2e34a907bd8979a53c58f44287630616e8 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 21 Jul 2022 11:01:24 -0700 Subject: [PATCH 4/5] scripts/faddr2line: Add CONFIG_DEBUG_INFO check Otherwise without DWARF it spits out gibberish and gives no indication of what the problem is. Suggested-by: John Garry Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Tested-by: John Garry Link: https://lore.kernel.org/r/ffa7734c929445caa374bf9e68078300174f09b4.1658426357.git.jpoimboe@kernel.org --- scripts/faddr2line | 3 +++ 1 file changed, 3 insertions(+) diff --git a/scripts/faddr2line b/scripts/faddr2line index 57099687e5e1..5514c23f45c2 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -61,6 +61,7 @@ die() { READELF="${CROSS_COMPILE:-}readelf" ADDR2LINE="${CROSS_COMPILE:-}addr2line" AWK="awk" +GREP="grep" command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed" command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed" @@ -271,6 +272,8 @@ LIST=0 [[ ! -f $objfile ]] && die "can't find objfile $objfile" shift +${READELF} --section-headers --wide $objfile | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled" + DIR_PREFIX=supercalifragilisticexpialidocious find_dir_prefix $objfile From 99643bab36b642be10bf09cd3285c37c9e5b597f Mon Sep 17 00:00:00 2001 From: Slark Xiao Date: Wed, 20 Jul 2022 17:12:20 +0800 Subject: [PATCH 5/5] perf/core: Fix ';;' typo Remove double ';;'. Signed-off-by: Slark Xiao Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20220720091220.14200-1-slark_xiao@163.com --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index c9d32d4d2e20..bd23f3e9bdae 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4457,7 +4457,7 @@ int perf_event_read_local(struct perf_event *event, u64 *value, *value = local64_read(&event->count); if (enabled || running) { - u64 __enabled, __running, __now;; + u64 __enabled, __running, __now; calc_timer_values(event, &__now, &__enabled, &__running); if (enabled)