printf: protect against bogus format specifiers. Hopefully closes bug 4184
diff --git a/coreutils/printf.c b/coreutils/printf.c
index a14306f..d877e05 100644
--- a/coreutils/printf.c
+++ b/coreutils/printf.c
@@ -33,7 +33,8 @@
The 'format' argument is re-used as many times as necessary
to convert all of the given arguments.
- David MacKenzie <djm@gnu.ai.mit.edu> */
+ David MacKenzie <djm@gnu.ai.mit.edu>
+*/
// 19990508 Busy Boxed! Dave Cinege
@@ -251,10 +252,12 @@
++f;
++direc_length;
}
- /*
- if (!strchr ("diouxXfeEgGcs", *f))
- fprintf(stderr, "%%%c: invalid directive", *f);
- */
+ /* needed - try "printf %" without it */
+ if (!strchr("diouxXfeEgGcs", *f)) {
+ bb_error_msg("invalid directive '%s'", direc_start);
+ /* causes main() to exit with error */
+ return saved_argv - 1;
+ }
++direc_length;
if (*argv) {
print_direc(direc_start, direc_length, field_width,
@@ -285,7 +288,8 @@
char **argv2;
/* We must check that stdout is not closed.
- * The reason for this is highly non-obvious. printf_main is used from shell.
+ * The reason for this is highly non-obvious.
+ * printf_main is used from shell.
* Shell must correctly handle 'printf "%s" foo'
* if stdout is closed. With stdio, output gets shoveled into
* stdout buffer, and even fflush cannot clear it out. It seems that
@@ -298,7 +302,7 @@
/* bash builtin errors out on "printf '-%s-\n' foo",
* coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
* We will mimic coreutils. */
- if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && argv[1][2] == '\0')
+ if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && !argv[1][2])
argv++;
if (!argv[1])
bb_show_usage();
@@ -309,12 +313,12 @@
do {
argv = argv2;
argv2 = print_formatted(format, argv);
- } while (argv2 != argv && *argv2);
+ } while (argv2 > argv && *argv2);
/* coreutils compat (bash doesn't do this):
if (*argv)
fprintf(stderr, "excess args ignored");
*/
- return EXIT_SUCCESS;
+ return (argv2 < argv); /* if true, print_formatted errored out */
}
