libreboot-utils: unified max path lengths

just use PATH_MAX like a normal person

with additional safety

Signed-off-by: Leah Rowe <leah@libreboot.org>

7 files changed, 26 insertions, 78 deletions

diff --git a/util/libreboot-utils/include/common.h b/util/libreboot-utils/include/common.h
index 8276d6da..12c6c486 100644
--- a/util/libreboot-utils/include/common.h
+++ b/util/libreboot-utils/include/common.h
@@ -65,8 +65,10 @@ int fchmod(int fd, mode_t mode);
 
 #define MAX_CMD_LEN 50
 
-#ifndef PATH_LEN
-#define PATH_LEN 4096
+#ifndef PATH_MAX
+#error PATH_MAX_undefined
+#elif ((PATH_MAX) < 1024)
+#error PATH_MAX_too_low
 #endif
 
 #define OFF_ERR 0
@@ -613,7 +615,7 @@ typedef char assert_read[(IO_READ==0)?1:-1];
 typedef char assert_write[(IO_WRITE==1)?1:-1];
 typedef char assert_pread[(IO_PREAD==2)?1:-1];
 typedef char assert_pwrite[(IO_PWRITE==3)?1:-1];
-typedef char assert_pathlen[(PATH_LEN>=256)?1:-1];
+typedef char assert_pathlen[(PATH_MAX>=1024)?1:-1];
 /* commands */
 typedef char assert_cmd_dump[(CMD_DUMP==0)?1:-1];
 typedef char assert_cmd_setmac[(CMD_SETMAC==1)?1:-1];
diff --git a/util/libreboot-utils/lib/file.c b/util/libreboot-utils/lib/file.c
index b9d31ad7..1d2de9b8 100644
--- a/util/libreboot-utils/lib/file.c
+++ b/util/libreboot-utils/lib/file.c
@@ -71,7 +71,6 @@ fsync_dir(const char *path)
 	int saved_errno = errno;
 
 	size_t pathlen = 0;
-	size_t maxlen = 0;
 
 	char *dirbuf = NULL;
 	int dirfd = -1;
@@ -81,14 +80,7 @@ fsync_dir(const char *path)
 
 	int close_errno;
 
-#if defined(PATH_LEN) && \
-    (PATH_LEN) >= 256
-	maxlen = PATH_LEN;
-#else
-	maxlen = 4096;
-#endif
-
-	if (if_err(slen(path, maxlen, &pathlen) == 0, EINVAL))
+	if (if_err(slen(path, PATH_MAX, &pathlen) == 0, EINVAL))
 		goto err_fsync_dir;
 
 	memcpy(smalloc(&dirbuf, pathlen + 1),
@@ -677,7 +669,7 @@ rootfs(void)
  * TODO:
 	missing length bound check.
 	potential CPU DoS on very long paths, spammed repeatedly.
-	perhaps cap at PATH_LEN?
+	perhaps cap at MAX_PATH?
  */
 int
 fs_resolve_at(int dirfd, const char *path, int flags)
@@ -685,12 +677,7 @@ fs_resolve_at(int dirfd, const char *path, int flags)
 	int nextfd = -1;
 	int curfd;
 	const char *p;
-#if defined(PATH_LEN) && \
-    ((PATH_LEN) >= 256)
-	char name[PATH_LEN];
-#else
-	char name[4096];
-#endif
+	char name[PATH_MAX];
 	int saved_errno = errno;
 	int r;
 	int is_last;
@@ -756,12 +743,6 @@ fs_next_component(const char **p,
 {
 	const char *s = *p;
 	size_t len = 0;
-#if defined(PATH_LEN) && \
-(PATH_LEN) >= 256
-	size_t maxlen = PATH_LEN;
-#else
-	size_t maxlen = 4096;
-#endif
 
 	while (*s == '/')
 		s++;
@@ -775,7 +756,7 @@ fs_next_component(const char **p,
 		len++;
 
 	if (len == 0 || len >= namesz ||
-	    len >= maxlen) {
+	    len >= PATH_MAX) {
 		errno = ENAMETOOLONG;
 		return -1;
 	}
@@ -831,17 +812,11 @@ fs_dirname_basename(const char *path,
 	char *slash;
 	size_t len;
 	int rval;
-#if defined(PATH_LEN) && \
-(PATH_LEN) >= 256
-	size_t maxlen = PATH_LEN;
-#else
-	size_t maxlen = 4096;
-#endif
 
 	if (if_err(path == NULL || dir == NULL || base == NULL, EFAULT))
 		return -1;
 
-	slen(path, maxlen, &len);
+	slen(path, PATH_MAX, &len);
 	memcpy(smalloc(&buf, len + 1),
 	    path, len + 1);
 
@@ -863,7 +838,7 @@ fs_dirname_basename(const char *path,
 		}
 	} else if (allow_relative) {
 
-		sdup(".", maxlen, dir);
+		sdup(".", PATH_MAX, dir);
 		*base = buf;
 	} else {
 		errno = EINVAL;
diff --git a/util/libreboot-utils/lib/mkhtemp.c b/util/libreboot-utils/lib/mkhtemp.c
index 0560da47..7a73befb 100644
--- a/util/libreboot-utils/lib/mkhtemp.c
+++ b/util/libreboot-utils/lib/mkhtemp.c
@@ -55,12 +55,6 @@ int
 new_tmp_common(int *fd, char **path, int type,
     char *tmpdir, const char *template)
 {
-#if defined(PATH_LEN) && \
-    (PATH_LEN) >= 256
-	size_t maxlen = PATH_LEN;
-#else
-	size_t maxlen = 4096;
-#endif
 	struct stat st;
 
 	const char *templatestr;
@@ -131,11 +125,11 @@ new_tmp_common(int *fd, char **path, int type,
 		templatestr = "tmp.XXXXXXXXXX";
 
 	/* may as well calculate in advance */
-	destlen = slen(tmpdir, maxlen, &dirlen) + 1
-	    + slen(templatestr, maxlen, &templatestr_len);
+	destlen = slen(tmpdir, PATH_MAX, &dirlen) + 1
+	    + slen(templatestr, PATH_MAX, &templatestr_len);
 	/* full path: */
 	dest = scatn(3, (const char *[]) { tmpdir, "/", templatestr },
-	    maxlen, &dest);
+	    PATH_MAX, &dest);
 
 	fname = dest + dirlen + 1;
 
@@ -298,19 +292,12 @@ same_dir(const char *a, const char *b)
 	int saved_errno = errno;
 	int rval_scmp;
 
-#if defined(PATH_LEN) && \
-    (PATH_LEN) >= 256
-	size_t maxlen = (PATH_LEN);
-#else
-	size_t maxlen = 4096;
-#endif
-
 	/* optimisation: if both dirs
 	   are the same, we don't need
 	   to check anything. sehr schnell!
 	 */
 	/* bonus: scmp checks null for us */
-	if (!scmp(a, b, maxlen, &rval_scmp))
+	if (!scmp(a, b, PATH_MAX, &rval_scmp))
 		goto success_same_dir;
 
 	fd_a = fs_open(a, O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
@@ -531,12 +518,6 @@ mkhtemp(int *fd,
 	int close_errno;
 	int saved_errno = errno;
 
-#if defined(PATH_LEN) && \
-    (PATH_LEN) >= 256
-	size_t max_len = PATH_LEN;
-#else
-	size_t max_len = 4096;
-#endif
 	int r;
 	char *end;
 
@@ -547,10 +528,10 @@ mkhtemp(int *fd,
 		return -1;
 
 	/* count X */
-	for (end = template + slen(template, max_len, &template_len);
+	for (end = template + slen(template, PATH_MAX, &template_len);
 	    end > template && *--end == 'X'; xc++);
 
-	fname_len = slen(fname, max_len, &fname_len);
+	fname_len = slen(fname, PATH_MAX, &fname_len);
 	if (if_err(strrchr(fname, '/') != NULL, EINVAL))
 		return -1;
 
diff --git a/util/libreboot-utils/lib/state.c b/util/libreboot-utils/lib/state.c
index f0be5656..f32d4078 100644
--- a/util/libreboot-utils/lib/state.c
+++ b/util/libreboot-utils/lib/state.c
@@ -22,12 +22,6 @@
 struct xstate *
 xstart(int argc, char *argv[])
 {
-#if defined(PATH_LEN) && \
-    ((PATH_LEN) >= 256)
-	static size_t maxlen = PATH_LEN;
-#else
-	static size_t maxlen = 4096;
-#endif
 	static int first_run = 1;
 	static char *dir = NULL;
 	static char *base = NULL;
@@ -119,7 +113,7 @@ xstart(int argc, char *argv[])
 		err_exit(errno, "xstart: don't know CWD of %s",
 		    us.f.fname);
 
-	sdup(base, maxlen, &us.f.base);
+	sdup(base, PATH_MAX, &us.f.base);
 
 	us.f.dirfd = fs_open(dir,
 	    O_RDONLY | O_DIRECTORY);
@@ -133,7 +127,7 @@ xstart(int argc, char *argv[])
 	    &tmpdir, &tmpbase_local, 0) < 0)
 		err_exit(errno, "tmp basename");
 
-	sdup(tmpbase_local, maxlen, &us.f.tmpbase);
+	sdup(tmpbase_local, PATH_MAX, &us.f.tmpbase);
 
 	free_and_set_null(&tmpdir);
 
diff --git a/util/libreboot-utils/lib/string.c b/util/libreboot-utils/lib/string.c
index c083bd6d..ad11d29d 100644
--- a/util/libreboot-utils/lib/string.c
+++ b/util/libreboot-utils/lib/string.c
@@ -601,7 +601,7 @@ lbsetprogname(char *argv0)
 	if (!set) {
 		if (argv0 == NULL)
 			return "libreboot-utils";
-		(void) sdup(argv0, 4096, &progname);
+		(void) sdup(argv0, PATH_MAX, &progname);
 		set = 1;
 	}
 
diff --git a/util/libreboot-utils/lottery.c b/util/libreboot-utils/lottery.c
index 7370de1b..9906ed11 100644
--- a/util/libreboot-utils/lottery.c
+++ b/util/libreboot-utils/lottery.c
@@ -36,6 +36,8 @@ main(int argc, char **argv)
 	free_and_set_null(&buf);
 
 	fprintf(stderr, "\n%s\n", same ? "You win!" : "You lose!");
+
+	printf("%lu\n", PATH_MAX);
 	return same ? EXIT_SUCCESS : EXIT_FAILURE;
 }
 
diff --git a/util/libreboot-utils/mkhtemp.c b/util/libreboot-utils/mkhtemp.c
index f4c2b646..f7480ed6 100644
--- a/util/libreboot-utils/mkhtemp.c
+++ b/util/libreboot-utils/mkhtemp.c
@@ -40,12 +40,6 @@ exit_cleanup(void);
 int
 main(int argc, char *argv[])
 {
-#if defined (PATH_LEN) && \
-    (PATH_LEN) >= 256
-	size_t maxlen = PATH_LEN;
-#else
-	size_t maxlen = 4096;
-#endif
 	size_t len;
 	size_t tlen;
 	size_t xc = 0;
@@ -55,7 +49,7 @@ main(int argc, char *argv[])
 	char *p;
 	char *s = NULL;
 	char *rp;
-	char resolved[maxlen];
+	char resolved[PATH_MAX];
 	char c;
 
 	int fd = -1;
@@ -95,7 +89,7 @@ main(int argc, char *argv[])
 
 	/* custom template e.g. foo.XXXXXXXXXXXXXXXXXXXXX */
 	if (template != NULL) {	
-		for (p = template + slen(template, maxlen, &tlen);
+		for (p = template + slen(template, PATH_MAX, &tlen);
 		    p > template && *--p == 'X'; xc++);
 
 		if (xc < 3) /* the gnu mktemp errs on less than 3 */
@@ -129,8 +123,8 @@ main(int argc, char *argv[])
 	if (*s == '\0')
 		err_exit(EFAULT, "empty string initialisation");
 
-	slen(s, maxlen, &len); /* Nullterminierung prüfen */
-	/* for good measure */
+	slen(s, PATH_MAX, &len); /* Nullterminierung prüfen */
+	/* for good measure. (bonus: also re-checks length overflow) */
 
 	printf("%s\n", s);