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 D04F11C15 for ; Wed, 28 Dec 2022 16:39:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EC32C433D2; Wed, 28 Dec 2022 16:39:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245582; bh=H5nfNj6i2aBjx1sIE6dF/39prsVVVi+kb+2ZnFvZ8IU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R4PEMujYIzMVo/qju4qHxaesLSsCE//Vr/E3WWZXTObVBCSHF8pbjfrRF18cXnNo9 qbiVQlal2RU3n4QKJXTUH70wDyxCJN08JO9d+uKiltVgMKyuZ45QBNfreRep8jYg9J QpUJE6tisX+/bMZbuYZTOJk8tEXvbg34i+GtHxTQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nicholas Piggin , Michael Ellerman , Sasha Levin Subject: [PATCH 6.1 0857/1146] powerpc/perf: callchain validate kernel stack pointer bounds Date: Wed, 28 Dec 2022 15:39:56 +0100 Message-Id: <20221228144353.433111218@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144330.180012208@linuxfoundation.org> References: <20221228144330.180012208@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: Nicholas Piggin [ Upstream commit 32c5209214bd8d4f8c4e9d9b630ef4c671f58e79 ] The interrupt frame detection and loads from the hypothetical pt_regs are not bounds-checked. The next-frame validation only bounds-checks STACK_FRAME_OVERHEAD, which does not include the pt_regs. Add another test for this. The user could set r1 to be equal to the address matching the first interrupt frame - STACK_INT_FRAME_SIZE, which is in the previous page due to the kernel redzone, and induce the kernel to load the marker from there. Possibly this could cause a crash at least. If the user could induce the previous page to contain a valid marker, then it might be able to direct perf to read specific memory addresses in a way that could be transmitted back to the user in the perf data. Fixes: 20002ded4d93 ("perf_counter: powerpc: Add callchain support") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221127124942.1665522-4-npiggin@gmail.com Signed-off-by: Sasha Levin --- arch/powerpc/perf/callchain.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index 082f6d0308a4..8718289c051d 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -61,6 +61,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re next_sp = fp[0]; if (next_sp == sp + STACK_INT_FRAME_SIZE && + validate_sp(sp, current, STACK_INT_FRAME_SIZE) && fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { /* * This looks like an interrupt frame for an -- 2.35.1