From patchwork Wed Jul 24 22:52:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 13741420 X-Patchwork-Delegate: bpf@iogearbox.net 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 C7A0513C683 for ; Wed, 24 Jul 2024 22:52:23 +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=1721861543; cv=none; b=NM3JjjB0bSftr12emCF4fBxlGVt56gOnhM/ONDIN4bcqDx83iMvq3NfU+6eImwOQUu5HZ7UDQFNMS0WdPxJ+UcK0HwCDIY3H6/YM3KHhmwmafeAMg+bIHZFf64gJXCtSVD5CrgmNw36nwdGH98C+/V/Ot7QT2P9NrYioxOSi51s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721861543; c=relaxed/simple; bh=azpAbr+6SOKGRgY4Eh1WfByGTMRsHGb35RAVJRMiCV8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VQpY9JhQSPdNe/rKRJcAZug0q9OU/wpUjotO9fhvz4Q2VV1RdNVMihWg+OoIk013f5gqWoGPlEDpdz/1kLW9iHH7XMBGlJqvpymNTlsXKrXw2/31GzEAbAEJounHBTX3iC2IwC/s4hZTEznKDyG4vsxKWZgiDhox22x1t/CG3fc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UjGKrOEr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UjGKrOEr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 826EAC32781; Wed, 24 Jul 2024 22:52:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1721861543; bh=azpAbr+6SOKGRgY4Eh1WfByGTMRsHGb35RAVJRMiCV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UjGKrOEr8SUACvJMfJ7sDCw9seYAgaMF3ZMxmmZpq4vj4qMYa9xiqeAmuuKoohnBo 7+duYW6MfOp2gbqM7OlYLUwOZZASzT+SMf6Ho3xL2Pi2VfeWd1EAN9VDOf7BXja1lc mjCGPgBTNySMRJpVrFk0vOteGjmcj5j3cRTooKuOIj5POsidfNKxtbMTM+Jf0ZOcGK dq7xrFoHuU8iDX8rQmcWNNDNH7M7TsroTDYTF5aHNuwhOLmlgW/kXUn8YE2RQAG4sh m957If7WczlcdFQOpAXnRrOnl7eSXxJbNVc0s21u2tDNru3WMztTenxeZuJSV+UdDp RQQWSQ+iWStvA== From: Andrii Nakryiko To: bpf@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, adobriyan@gmail.com, shakeel.butt@linux.dev, hannes@cmpxchg.org, ak@linux.intel.com, osandov@osandov.com, song@kernel.org, Andrii Nakryiko Subject: [PATCH v2 bpf-next 03/10] lib/buildid: remove single-page limit for PHDR search Date: Wed, 24 Jul 2024 15:52:03 -0700 Message-ID: <20240724225210.545423-4-andrii@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240724225210.545423-1-andrii@kernel.org> References: <20240724225210.545423-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Now that freader allows to access multiple pages transparently, there is no need to limit program headers to the very first ELF file page. Remove this limitation, but still put some sane limit on amount of program headers that we are willing to iterate over (set arbitrarily to 256). Signed-off-by: Andrii Nakryiko --- lib/buildid.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/lib/buildid.c b/lib/buildid.c index ce48ffab4111..49fcb9a549bf 100644 --- a/lib/buildid.c +++ b/lib/buildid.c @@ -8,6 +8,8 @@ #define BUILD_ID 3 +#define MAX_PHDR_CNT 256 + struct freader { void *buf; u32 buf_sz; @@ -216,9 +218,9 @@ static int get_build_id_32(struct freader *r, unsigned char *build_id, __u32 *si phnum = ehdr->e_phnum; phoff = READ_ONCE(ehdr->e_phoff); - /* only supports phdr that fits in one page */ - if (phnum > (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)) - return -EINVAL; + /* set upper bound on amount of segments (phdrs) we iterate */ + if (phnum > MAX_PHDR_CNT) + phnum = MAX_PHDR_CNT; for (i = 0; i < phnum; ++i) { phdr = freader_fetch(r, phoff + i * sizeof(Elf32_Phdr), sizeof(Elf32_Phdr)); @@ -248,9 +250,9 @@ static int get_build_id_64(struct freader *r, unsigned char *build_id, __u32 *si phnum = ehdr->e_phnum; phoff = READ_ONCE(ehdr->e_phoff); - /* only supports phdr that fits in one page */ - if (phnum > (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr)) - return -EINVAL; + /* set upper bound on amount of segments (phdrs) we iterate */ + if (phnum > MAX_PHDR_CNT) + phnum = MAX_PHDR_CNT; for (i = 0; i < phnum; ++i) { phdr = freader_fetch(r, phoff + i * sizeof(Elf64_Phdr), sizeof(Elf64_Phdr));