Module Name: src Committed By: rillig Date: Tue Dec 22 06:48:33 UTC 2020
Modified Files: src/usr.bin/make: parse.c Log Message: make(1): prevent undefined behavior in loadfile_mmap Reading a file without a trailing newline had resulted in an out-of-bounds write, in the common case where the file is loaded via mmap. To generate a diff of this commit: cvs rdiff -u -r1.509 -r1.510 src/usr.bin/make/parse.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/usr.bin/make/parse.c diff -u src/usr.bin/make/parse.c:1.509 src/usr.bin/make/parse.c:1.510 --- src/usr.bin/make/parse.c:1.509 Mon Dec 21 02:09:34 2020 +++ src/usr.bin/make/parse.c Tue Dec 22 06:48:33 2020 @@ -1,4 +1,4 @@ -/* $NetBSD: parse.c,v 1.509 2020/12/21 02:09:34 rillig Exp $ */ +/* $NetBSD: parse.c,v 1.510 2020/12/22 06:48:33 rillig Exp $ */ /* * Copyright (c) 1988, 1989, 1990, 1993 @@ -117,7 +117,7 @@ #include "pathnames.h" /* "@(#)parse.c 8.3 (Berkeley) 3/19/94" */ -MAKE_RCSID("$NetBSD: parse.c,v 1.509 2020/12/21 02:09:34 rillig Exp $"); +MAKE_RCSID("$NetBSD: parse.c,v 1.510 2020/12/22 06:48:33 rillig Exp $"); /* types and constants */ @@ -2687,10 +2687,22 @@ ParseRawLine(IFile *curFile, char **out_ if (ch == '\\') { if (firstBackslash == NULL) firstBackslash = p; + /* + * FIXME: In opt-file.mk, this command succeeds: + * printf '%s' 'V=v\' | make -r -f - + * Using an intermediate file fails though: + * printf '%s' 'V=v\' > backslash + * make -r -f backslash + * + * In loadedfile_mmap, the trailing newline is not + * added in every case, only if the file ends at a + * page boundary. + */ if (p[1] == '\n') curFile->lineno++; p += 2; line_end = p; + assert(p <= curFile->buf_end); continue; } @@ -2831,6 +2843,12 @@ ParseGetLine(GetLineMode mode) } /* We now have a line of data */ + /* + * FIXME: undefined behavior since line_end points right + * after the allocated buffer. This becomes apparent when + * using a strict malloc implementation that adds canaries + * before and after the allocated space. + */ *line_end = '\0'; if (mode == GLM_FOR_BODY)