From patchwork Tue Aug 6 21:20:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Maurer X-Patchwork-Id: 13755331 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BADD8175D49 for ; Tue, 6 Aug 2024 21:21:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722979284; cv=none; b=pYVLOzxBeElFC14JfXgfEl47o8DPrbaOZqcD0OpJOzHamUhbQdLrctJNGI3Mq4w6QJDA6NGTyF2nb0kQRzCdabn3pVqMEZF3Fk6tTYfZ0GeeBTlICYhLbSBE/tkJDNPCkdabv9aExIXMd8wH8Y5t9bvdZnlRN2LN3s3ntM1+nL0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722979284; c=relaxed/simple; bh=6GqSMULtD4el151RcDItMEF6Lt50YlB/q7Pl2DyHeAM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=cnSrPpsk0tNvqw8PmA4dUnnPyKMGypocdQGIg4j3JmoewZHLp3zJICtAU1Xtc/sH6l1ykc6ehLJNH0iZACP2tDvMnPP5uUb1xA41CdataykrMeErIXirFZtXYIN39KDSG/4InMxdM2IOHn8rCQmZfB/ydUHsBOhle4zhv9MPR/c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--mmaurer.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=D9whd75a; arc=none smtp.client-ip=209.85.128.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--mmaurer.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="D9whd75a" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-664916e5b40so4050917b3.1 for ; Tue, 06 Aug 2024 14:21:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1722979281; x=1723584081; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=eZ3gIDpzvqifWGJTrfh1KRlyB6JYqqa8tRhgZU97bFA=; b=D9whd75amNQnRipHcMezPpPIHAcVKP4b0VeRdclHAcV7uFKuGdScMh9wDpGLiYFiaa zFEWltPpNcd5/Fih+fIFsGqlLa3OJI4alRfJy3XOa/bysydrFOHZpiPSc58GyR7TUxMt HP7N/l0J0IJrjGcfCJCZ46NexHwLJ/Hb02puo1P1GweRxbUWfrIVO2nkEVow2ck7TDKo a4/ws5TzaQhL0T5f3PPm92onlOMktY41pjJuchxrCMQcz+3lywldsnSHpNCGdUVE7JZY KhbBatiZOovw/f94CUYBshamY1CUAf/Fq4CnaY1F+AMCEmlAONhaIf/cJh6Gj+YDy1TQ hJsg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722979281; x=1723584081; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=eZ3gIDpzvqifWGJTrfh1KRlyB6JYqqa8tRhgZU97bFA=; b=XEpdel4b8n8q/AG8XQ4zDEoWk1YSx2dCYfcjy6EXAjUDvm6yrjcexsIxxgTvhr75Rz ZJpATzDyoSZTl23tIGwYfuT8r4V+uf++mfF7gHeeSD9xKCRgJhWKjOgSJkJ2tD19m0k0 xWz8+J4CDH3w2ZpEZYQTtU6o91dVhES4iKELeGERkR0AVNgnm74bta2h2IdKd1Y/7iuK 3Oq7W2/x34dns7sWgf82TJswzvIkHaRwBksnk71tRx2TTh4JRDtGgJPlHqMnhWWKRDRj k4hVfPptEBcC01J/imEwWYE6Zbm1o9xqDvF5MXNl42dP3Jv+QiPB8PqQStEVcYNBeM9Z FvPQ== X-Forwarded-Encrypted: i=1; AJvYcCUKbht5deePWtDrj7E1SeeJZo9aF4EXF62blSqyQ+HdjK0oZ1Y5ymgO9TppK6tExFzpu4EvMP21mzfnYD2ex3Hy8H1esVcSPwdab7pO X-Gm-Message-State: AOJu0YyDDUvLRIyQLjeC3U6rOIW/M5gZPyHAXtBbXxFQAHg6YNOSZq3J c1dz1qd6IR0mYIfGrt+qV9B37Xpkn3XwhNKK0RJqtB7PtbOI6WNkVDnohLRrmSdOfdrxdp5Dmv7 zMZNtjQ== X-Google-Smtp-Source: AGHT+IG4aq7G8KmkD7iN5WibU+xEj88q/B5q5piN0dKYK4ohf6OT5yqQNxgPNSwh7gEkBbs93toGEJAb8w4p X-Received: from anyblade.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:1791]) (user=mmaurer job=sendgmr) by 2002:a0d:f143:0:b0:665:24b0:e936 with SMTP id 00721157ae682-6991404e2b7mr1487b3.4.1722979280882; Tue, 06 Aug 2024 14:21:20 -0700 (PDT) Date: Tue, 6 Aug 2024 21:20:31 +0000 In-Reply-To: <20240806212106.617164-1-mmaurer@google.com> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240806212106.617164-1-mmaurer@google.com> X-Mailer: git-send-email 2.46.0.rc2.264.g509ed76dc8-goog Message-ID: <20240806212106.617164-6-mmaurer@google.com> Subject: [PATCH v3 05/16] module: Factor out elf_validity_cache_index_info From: Matthew Maurer To: masahiroy@kernel.org, ndesaulniers@google.com, ojeda@kernel.org, gary@garyguo.net, mcgrof@kernel.org, Alex Gaynor , Wedson Almeida Filho Cc: Matthew Maurer , rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, neal@gompa.dev, marcan@marcan.st, j@jannau.net, asahi@lists.linux.dev, Boqun Feng , " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " , Benno Lossin , Andreas Hindborg , Alice Ryhl , linux-modules@vger.kernel.org Centralize .modinfo detection and property validation. Signed-off-by: Matthew Maurer --- kernel/module/main.c | 82 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 68 insertions(+), 14 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index 252cfa9eee67..61325a767645 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -195,6 +195,38 @@ static unsigned int find_sec(const struct load_info *info, const char *name) return 0; } +/** + * find_any_unique_sec() - Find a unique section index by name + * @info: Load info for the module to scan + * @name: Name of the section we're looking for + * + * Locates a unique section by name. Ignores SHF_ALLOC. + * + * Return: Section index if found uniquely, zero if absent, negative count + * of total instances if multiple were found. + */ +static int find_any_unique_sec(const struct load_info *info, const char *name) +{ + unsigned int idx; + unsigned int count = 0; + int i; + + for (i = 1; i < info->hdr->e_shnum; i++) { + if (strcmp(info->secstrings + info->sechdrs[i].sh_name, + name) == 0) { + count++; + idx = i; + } + } + if (count == 1) { + return idx; + } else if (count == 0) { + return 0; + } else { + return -count; + } +} + /* Find a module section, or NULL. */ static void *section_addr(const struct load_info *info, const char *name) { @@ -1854,6 +1886,39 @@ static int elf_validity_cache_secstrings(struct load_info *info) return 0; } +/** + * elf_validity_cache_index_info() - Validate and cache modinfo section + * @info: Load info to populate the modinfo index on. + * Must have &load_info->sechdrs and &load_info->secstrings populated + * + * Checks that if there is a .modinfo section, it is unique. + * Then, it caches its index in &load_info->index.info. + * Finally, it tries to populate the name to improve error messages. + * + * Return: %0 if valid, %-ENOEXEC if multiple modinfo sections were found. + */ +static int elf_validity_cache_index_info(struct load_info *info) +{ + int info_idx; + + info_idx = find_any_unique_sec(info, ".modinfo"); + + if (info_idx == 0) + /* Early return, no .modinfo */ + return 0; + + if (info_idx < 0) { + pr_err("Only one .modinfo section must exist.\n"); + return -ENOEXEC; + } + + info->index.info = info_idx; + /* Try to find a name early so we can log errors with a module name */ + info->name = get_modinfo(info, "name"); + + return 0; +} + /* * Check userspace passed ELF module against our expectations, and cache * useful variables for further processing as we go. @@ -1880,13 +1945,15 @@ static int elf_validity_cache_copy(struct load_info *info, int flags) Elf_Shdr *shdr; int err; unsigned int num_mod_secs = 0, mod_idx; - unsigned int num_info_secs = 0, info_idx; unsigned int num_sym_secs = 0, sym_idx; err = elf_validity_cache_sechdrs(info); if (err < 0) return err; err = elf_validity_cache_secstrings(info); + if (err < 0) + return err; + err = elf_validity_cache_index_info(info); if (err < 0) return err; @@ -1912,24 +1979,11 @@ static int elf_validity_cache_copy(struct load_info *info, int flags) ".gnu.linkonce.this_module") == 0) { num_mod_secs++; mod_idx = i; - } else if (strcmp(info->secstrings + shdr->sh_name, - ".modinfo") == 0) { - num_info_secs++; - info_idx = i; } break; } } - if (num_info_secs > 1) { - pr_err("Only one .modinfo section must exist.\n"); - goto no_exec; - } else if (num_info_secs == 1) { - /* Try to find a name early so we can log errors with a module name */ - info->index.info = info_idx; - info->name = get_modinfo(info, "name"); - } - if (num_sym_secs != 1) { pr_warn("%s: module has no symbols (stripped?)\n", info->name ?: "(missing .modinfo section or name field)");