forked from luck/tmp_suning_uos_patched
modpost: fix potential mmap'ed file overrun in get_src_version()
I do not know how reliably this function works, but it looks dangerous to me. strchr(sources, '\n'); ... continues searching until it finds '\n' or it reaches the '\0' terminator. In other words, 'sources' should be a null-terminated string. However, grab_file() just mmaps a file, so 'sources' is not terminated with null byte. If the file does not contain '\n' at all, strchr() will go beyond the mmap'ed memory. Use read_text_file(), which loads the file content into a malloc'ed buffer, appending null byte. Here we are interested only in the first line of *.mod files. Use get_line() helper to get the first line. This also makes missing *.mod file a fatal error. Commit4be40e2223
("kbuild: do not emit src version warning for non-modules") ignored missing *.mod files. I do not fully understand what that commit addressed, but commit91341d4b2c
("kbuild: introduce new option to enhance section mismatch analysis") introduced partial section checks by using modpost. built-in.o was parsed by modpost. Even modules had a problem because *.mod files were created after the modpost check. Commitb7dca6dd1e
("kbuild: create *.mod with full directory path and remove MODVERDIR") stopped doing that. Now that modpost is only invoked after the directory descend, *.mod files should always exist at the modpost stage. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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parent
ac5100f543
commit
f531c1b5de
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@ -392,40 +392,34 @@ static int parse_source_files(const char *objfile, struct md4_ctx *md)
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/* Calc and record src checksum. */
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void get_src_version(const char *modname, char sum[], unsigned sumlen)
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{
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void *file;
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unsigned long len;
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char *buf, *pos, *firstline;
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struct md4_ctx md;
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char *sources, *end, *fname;
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char *fname;
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char filelist[PATH_MAX + 1];
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/* objects for a module are listed in the first line of *.mod file. */
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snprintf(filelist, sizeof(filelist), "%.*smod",
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(int)strlen(modname) - 1, modname);
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file = grab_file(filelist, &len);
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if (!file)
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/* not a module or .mod file missing - ignore */
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return;
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buf = read_text_file(filelist);
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sources = file;
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end = strchr(sources, '\n');
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if (!end) {
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pos = buf;
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firstline = get_line(&pos);
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if (!firstline) {
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warn("bad ending versions file for %s\n", modname);
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goto release;
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goto free;
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}
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*end = '\0';
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md4_init(&md);
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while ((fname = strsep(&sources, " ")) != NULL) {
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while ((fname = strsep(&firstline, " "))) {
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if (!*fname)
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continue;
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if (!(is_static_library(fname)) &&
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!parse_source_files(fname, &md))
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goto release;
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goto free;
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}
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md4_final_ascii(&md, sum, sumlen);
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release:
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release_file(file, len);
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free:
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free(buf);
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}
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