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 433A0A47; Mon, 28 Oct 2024 06:46:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730097967; cv=none; b=BDksa0qCkrvYN0603a4n+DZKfMkScmP9z5J5Hh9SRA1xcLVITf/Yubg8MIwnMOwAn2R/2c6s5fttOg5/fgpH3TVsnIJd8FlJHKIuUUhT0Y3Moos+Mo17O3mHd4lty4AE/D+JEYxlU4wHIjVNSGG3K76Li2EeUyuPpgmWuiFila0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730097967; c=relaxed/simple; bh=pPaJbsg6ylaN8T6/fKBFcluBL8/NboAFsAHyVSwA9KI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G9mE6K7IytTtBN7piErKRvgfbpynbCFajE8KLUMBMmS73PK6TlMo2z2W3Hw16FFJa/foAznVUWJsXwkfuFivuE4JFIsMN9/iwgAchwZA9dxND4UyrEG/T61Hcnhn9D2JoG8UBJyMzUeqBEEQjhYJ0ftrOoDnMPOxvXkMJc9ijLo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hNmJbjFZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hNmJbjFZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D88B1C4CEC3; Mon, 28 Oct 2024 06:46:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730097967; bh=pPaJbsg6ylaN8T6/fKBFcluBL8/NboAFsAHyVSwA9KI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hNmJbjFZM/iIrREHf+meHBrv3INBiTWzX7s5wJtsWCi5pRy1RVGf3BDhAUzNb/WjO hFoqn/Ojb1V3Cy3pqpcQV/npZaRe/WpybRSkXy2n5ljOTRmHvOcNEhqj5afYWw9+rV gb+Me8Sg9X/j/hGTfu6Q2N3K5vNb7YqPTg3ETzmQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lonial Con , Eduard Zingerman , Andrii Nakryiko , Daniel Borkmann , Sasha Levin Subject: [PATCH 6.11 004/261] bpf: sync_linked_regs() must preserve subreg_def Date: Mon, 28 Oct 2024 07:22:26 +0100 Message-ID: <20241028062312.121180262@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241028062312.001273460@linuxfoundation.org> References: <20241028062312.001273460@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eduard Zingerman [ Upstream commit e9bd9c498cb0f5843996dbe5cbce7a1836a83c70 ] Range propagation must not affect subreg_def marks, otherwise the following example is rewritten by verifier incorrectly when BPF_F_TEST_RND_HI32 flag is set: 0: call bpf_ktime_get_ns call bpf_ktime_get_ns 1: r0 &= 0x7fffffff after verifier r0 &= 0x7fffffff 2: w1 = w0 rewrites w1 = w0 3: if w0 < 10 goto +0 --------------> r11 = 0x2f5674a6 (r) 4: r1 >>= 32 r11 <<= 32 (r) 5: r0 = r1 r1 |= r11 (r) 6: exit; if w0 < 0xa goto pc+0 r1 >>= 32 r0 = r1 exit (or zero extension of w1 at (2) is missing for architectures that require zero extension for upper register half). The following happens w/o this patch: - r0 is marked as not a subreg at (0); - w1 is marked as subreg at (2); - w1 subreg_def is overridden at (3) by copy_register_state(); - w1 is read at (5) but mark_insn_zext() does not mark (2) for zero extension, because w1 subreg_def is not set; - because of BPF_F_TEST_RND_HI32 flag verifier inserts random value for hi32 bits of (2) (marked (r)); - this random value is read at (5). Fixes: 75748837b7e5 ("bpf: Propagate scalar ranges through register assignments.") Reported-by: Lonial Con Signed-off-by: Lonial Con Signed-off-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Daniel Borkmann Closes: https://lore.kernel.org/bpf/7e2aa30a62d740db182c170fdd8f81c596df280d.camel@gmail.com Link: https://lore.kernel.org/bpf/20240924210844.1758441-1-eddyz87@gmail.com Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d5215cb1747f1..5c5dea5e137e7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -15140,8 +15140,12 @@ static void find_equal_scalars(struct bpf_verifier_state *vstate, continue; if ((!(reg->id & BPF_ADD_CONST) && !(known_reg->id & BPF_ADD_CONST)) || reg->off == known_reg->off) { + s32 saved_subreg_def = reg->subreg_def; + copy_register_state(reg, known_reg); + reg->subreg_def = saved_subreg_def; } else { + s32 saved_subreg_def = reg->subreg_def; s32 saved_off = reg->off; fake_reg.type = SCALAR_VALUE; @@ -15154,6 +15158,7 @@ static void find_equal_scalars(struct bpf_verifier_state *vstate, * otherwise another find_equal_scalars() will be incorrect. */ reg->off = saved_off; + reg->subreg_def = saved_subreg_def; scalar32_min_max_add(reg, &fake_reg); scalar_min_max_add(reg, &fake_reg); -- 2.43.0