fileio: quote more shell characters in envfiles

Turns out, making strings shell-proof is harder than expected:

    # machinectl set-hostname "foo|poweroff" && . /etc/machine-info

(This could be simplified by quoting *and* escaping all characters,
which is harmless in shell but unnecessary.)

diff --git a/src/shared/fileio.c b/src/shared/fileio.c
index b0ab780d771b63e076cb8dabc159b95c55582bb6..cbb40c237998438fac7ef27234bcb134866c44dc 100644 (file)
--- a/src/shared/fileio.c
+++ b/src/shared/fileio.c
@@ -738,11 +738,11 @@ static void write_env_var(FILE *f, const char *v) {
         p++;
         fwrite(v, 1, p-v, f);
 
         p++;
         fwrite(v, 1, p-v, f);
 

-        if (string_has_cc(p, NULL) || chars_intersect(p, WHITESPACE "\'\"\\`$")) {
+        if (string_has_cc(p, NULL) || chars_intersect(p, WHITESPACE SHELL_NEED_QUOTES)) {

                 fputc('\"', f);
 
                 for (; *p; p++) {
                 fputc('\"', f);
 
                 for (; *p; p++) {

-                        if (strchr("\'\"\\`$", *p))
+                        if (strchr(SHELL_NEED_ESCAPE, *p))

                                 fputc('\\', f);
 
                         fputc(*p, f);
                                 fputc('\\', f);
 
                         fputc(*p, f);

diff --git a/src/shared/util.h b/src/shared/util.h
index c5eadc97c093c091264201c7ef330efb1549849e..b3187a9ea1d708e789b22862d8544c381526bb22 100644 (file)
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -93,6 +93,12 @@
 #define COMMENTS   "#;"
 #define GLOB_CHARS "*?["
 
 #define COMMENTS   "#;"
 #define GLOB_CHARS "*?["
 

+/* What characters are special in the shell? */
+/* must be escaped outside and inside double-quotes */
+#define SHELL_NEED_ESCAPE "\"\\`$"
+/* can be escaped or double-quoted */
+#define SHELL_NEED_QUOTES SHELL_NEED_ESCAPE GLOB_CHARS "'()<>|&;"
+

 #define FORMAT_BYTES_MAX 8
 
 #define ANSI_HIGHLIGHT_ON "\x1B[1;39m"
 #define FORMAT_BYTES_MAX 8
 
 #define ANSI_HIGHLIGHT_ON "\x1B[1;39m"