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 51A7E1F866C; Tue, 17 Dec 2024 17:14:18 +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=1734455658; cv=none; b=CFZdavUOoNgm41CJGJ0uCSCfR98J5rbfkx+czWZvdlwA5ULJLDOc2QIkrGL1IFFrk74v9WMJ4J+mfSCCBuN5ulLN5zuinWyMZy3j8NFWCevv8I9yaz0QddOAG0e5xsT3G1knaCai5YF21hXwr5pA6oX23yhxVRoIizf5vAA5gbg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734455658; c=relaxed/simple; bh=Xju3wOKtVoDNagCLfQbI+cyrDYtfq6pKVK/Mq/pUu0U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rVVADOMgbtBqd3ON/4eHmxl5ARb+ShvILYABGLRj88vojJ5tPVIf9PNnWNpyRdOpvVAPOmcQitVAuu14FyMUfiKcHQC7jJ7v2xa5zYCLSJp+Ez5qkhGQsZjzqwLRBxbr1gzQVFoEdllA0MGGSfeOODC1bSq5E4F5470/ma8vrio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AHjCg6oU; 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="AHjCg6oU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BAEE8C4CED3; Tue, 17 Dec 2024 17:14:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734455658; bh=Xju3wOKtVoDNagCLfQbI+cyrDYtfq6pKVK/Mq/pUu0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AHjCg6oU6aUVBl9QJiezZ7pwtBN1QSG2fru/EG9mj593kLDth8Ug9gReyhkVdZkxM 2ZSgRz+vFDyaN1FzG/y4R85gyPiYvT8pxcj65PDfB1Nim0SWcpNt5qfQHPrjXy9uXB MS5nPBletsfyjRraqTGhUQ7Qz9pGlTO4525rukE0= 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 , Shung-Hsi Yu Subject: [PATCH 5.15 40/51] bpf: sync_linked_regs() must preserve subreg_def Date: Tue, 17 Dec 2024 18:07:33 +0100 Message-ID: <20241217170522.120712077@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241217170520.301972474@linuxfoundation.org> References: <20241217170520.301972474@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eduard Zingerman commit e9bd9c498cb0f5843996dbe5cbce7a1836a83c70 upstream. 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 [ shung-hsi.yu: sync_linked_regs() was called find_equal_scalars() before commit 4bf79f9be434 ("bpf: Track equal scalars history on per-instruction level"), and modification is done because there is only a single call to copy_register_state() before commit 98d7ca374ba4 ("bpf: Track delta between "linked" registers."). ] Signed-off-by: Shung-Hsi Yu Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9223,8 +9223,11 @@ static void find_equal_scalars(struct bp struct bpf_reg_state *reg; bpf_for_each_reg_in_vstate(vstate, state, reg, ({ - if (reg->type == SCALAR_VALUE && reg->id == known_reg->id) + if (reg->type == SCALAR_VALUE && reg->id == known_reg->id) { + s32 saved_subreg_def = reg->subreg_def; copy_register_state(reg, known_reg); + reg->subreg_def = saved_subreg_def; + } })); }