From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 49A9D17AA6 for ; Wed, 9 Aug 2023 11:40:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCE5AC433C8; Wed, 9 Aug 2023 11:40:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691581224; bh=fZAj6kHqRhjylCF05G6BmiRfN2FDZ4H8z8vbS0p/zR4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bVHLrU49cLPvg17tzw8l2qE5/hXyH6BXwXe7/Elu5HX1ZzEFL7EQj2Tn6H2sIM9Ol HG/pS1SsJnpnfb0IVA7L/mCe0snCgQXM2Jn54x9gBgzmUptujfBAMa8RD3CVqwY7Nu No1/01SLbSBBG73FXX7MxGrSsnzmgJKQBWWuuPA8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Daniel=20M=C3=BCller?= , "Masami Hiramatsu (Google)" , Ingo Molnar , Li Huafei Subject: [PATCH 5.10 120/201] x86/kprobes: Update kcb status flag after singlestepping Date: Wed, 9 Aug 2023 12:42:02 +0200 Message-ID: <20230809103647.778302502@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103643.799166053@linuxfoundation.org> References: <20230809103643.799166053@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: "Masami Hiramatsu (Google)" [ Upstream commit dec8784c9088b131a1523f582c2194cfc8107dc0 ] 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 Signed-off-by: Li Huafei Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/kprobes/core.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -826,16 +826,20 @@ NOKPROBE_SYMBOL(arch_prepare_kretprobe); 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);