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From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: Jessica Yu <jeyu@kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 06/29] modpost: avoid false-positive file open error
Date: Sun, 17 May 2020 18:48:36 +0900	[thread overview]
Message-ID: <20200517094859.2376211-7-masahiroy@kernel.org> (raw)
In-Reply-To: <20200517094859.2376211-1-masahiroy@kernel.org>

One problem of grab_file() is that it cannot distinguish the following
two cases:

 - I cannot read the file (the file does not exist, or read permission
   is not set)

 - It can read the file, but the file size is zero

This is because grab_file() calls mmap(), which requires the mapped
length is greater than 0. Hence, grab_file() fails for both cases.

If an empty header file were included from a module that requires checksum
calculation, the following warning would be printed:

  WARNING: modpost: could not open ...: Invalid argument

An empty file is a valid source file, so it should not fail.

Use read_text_file() instead. It can read a zero-length file.
Then, parse_file() will succeed with doing nothing.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/mod/sumversion.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index f9df0b1863f1..a1c7b0f4cd5a 100644
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -258,10 +258,12 @@ static int parse_file(const char *fname, struct md4_ctx *md)
 	char *file;
 	unsigned long i, len;
 
-	file = grab_file(fname, &len);
+	file = read_text_file(fname);
 	if (!file)
 		return 0;
 
+	len = strlen(file);
+
 	for (i = 0; i < len; i++) {
 		/* Collapse and ignore \ and CR. */
 		if (file[i] == '\\' && (i+1 < len) && file[i+1] == '\n') {
@@ -287,7 +289,7 @@ static int parse_file(const char *fname, struct md4_ctx *md)
 
 		add_char(file[i], md);
 	}
-	release_file(file, len);
+	free(file);
 	return 1;
 }
 /* Check whether the file is a static library or not */
-- 
2.25.1


  parent reply	other threads:[~2020-05-17  9:49 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-17  9:48 [PATCH 00/29] modpost: various fixes, cleanups, optimizations Masahiro Yamada
2020-05-17  9:48 ` [PATCH 01/29] modpost: drop RCS/CVS $Revision handling in MODULE_VERSION() Masahiro Yamada
2020-05-17  9:48 ` [PATCH 02/29] modpost: do not call get_modinfo() for vmlinux Masahiro Yamada
2020-05-17  9:48 ` [PATCH 03/29] modpost: add read_text_file() and get_line() helpers Masahiro Yamada
2020-05-19 10:21   ` Peter Zijlstra
2020-05-20 12:17     ` Masahiro Yamada
2020-05-20 12:29       ` Peter Zijlstra
2020-05-23  4:18         ` Masahiro Yamada
2020-05-17  9:48 ` [PATCH 04/29] modpost: fix potential mmap'ed file overrun in get_src_version() Masahiro Yamada
2020-05-17  9:48 ` [PATCH 05/29] modpost: re-add warning about missing *.mod file Masahiro Yamada
2020-05-17  9:48 ` Masahiro Yamada [this message]
2020-05-17  9:48 ` [PATCH 07/29] modpost: use read_text_file() and get_line() for reading text files Masahiro Yamada
2020-05-17  9:48 ` [PATCH 08/29] modpost: remove get_next_text() and make {grab,release_}file static Masahiro Yamada
2020-05-17  9:48 ` [PATCH 09/29] kbuild: disallow multi-word in M= or KBUILD_EXTMOD Masahiro Yamada
2020-05-17 12:33   ` David Laight
2020-05-21  3:57     ` Masahiro Yamada
2020-05-17  9:48 ` [PATCH 10/29] modpost: move -T option close to the modpost command Masahiro Yamada
2020-05-17  9:48 ` [PATCH 11/29] modpost: pass -N option only for modules modpost Masahiro Yamada
2020-05-17  9:48 ` [PATCH 12/29] modpost: move external module options Masahiro Yamada
2020-05-17  9:48 ` [PATCH 13/29] modpost: load KBUILD_EXTRA_SYMBOLS files in order Masahiro Yamada
2020-05-17  9:48 ` [PATCH 14/29] modpost: track if the symbol origin is a dump file or ELF object Masahiro Yamada
2020-05-17  9:48 ` [PATCH 15/29] modpost: allow to pass -i option multiple times remove -e option Masahiro Yamada
2020-05-17  9:48 ` [PATCH 16/29] modpost: rename ext_sym_list to dump_list Masahiro Yamada
2020-05-17  9:48 ` [PATCH 17/29] modpost: re-add -e to set external_module flag Masahiro Yamada
2020-05-17  9:48 ` [PATCH 18/29] modpost: show warning if vmlinux is not found when processing modules Masahiro Yamada
2020-05-17  9:48 ` [PATCH 19/29] modpost: show warning if it fails to read symbol dump file Masahiro Yamada
2020-05-17  9:48 ` [PATCH 20/29] modpost: generate vmlinux.symvers and reuse it for the second modpost Masahiro Yamada
2020-05-17  9:48 ` [PATCH 21/29] modpost: remove -s option Masahiro Yamada
2020-05-17  9:48 ` [PATCH 22/29] modpost: remove mod->is_dot_o struct member Masahiro Yamada
2020-05-17  9:48 ` [PATCH 23/29] modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}() Masahiro Yamada
2020-05-17  9:48 ` [PATCH 24/29] modpost: add mod->is_vmlinux struct member Masahiro Yamada
2020-05-17  9:48 ` [PATCH 25/29] modpost: remove mod->skip " Masahiro Yamada
2020-05-17  9:48 ` [PATCH 26/29] modpost: set have_vmlinux in new_module() Masahiro Yamada
2020-05-17  9:48 ` [PATCH 27/29] modpost: strip .o from modname before calling new_module() Masahiro Yamada
2020-05-17  9:48 ` [PATCH 28/29] modpost: remove is_vmlinux() helper Masahiro Yamada
2020-05-17  9:48 ` [PATCH 29/29] modpost: change elf_info->size to size_t Masahiro Yamada

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