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authorNick Kralevich <nnk@google.com>2018-10-22 10:18:14 -0500
committerRob Landley <rob@landley.net>2018-10-22 10:18:14 -0500
commitad1f2685eb2768dbc2b52a9962d6279aa90a343d (patch)
tree4aa04d07fb311fedd81dae4725ea1adbe0c6c66e /lib
parente13985bf81681373fe4337d03382e3c0201912ba (diff)
downloadtoybox-ad1f2685eb2768dbc2b52a9962d6279aa90a343d.tar.gz
Don't call TIOCGWINSZ on non-ttys
Prior to calling TIOCGWINSZ on stdin/stdout/stderr, check to see if the file descriptor is a tty. Calling TIOCGWINSZ on a non-tty doesn't make any sense. Calling TIOCGWINSZ on a non-tty is mildly problematic for systems like Android where strict ioctl filtering is in place, and generates SELinux audit noise. Strict ioctl filtering for non-filesystem fifo_files (eg pipe() or pipe2() generated pipes) was enabled in Android in commit https://android-review.googlesource.com/c/platform/system/sepolicy/+/792599
Diffstat (limited to 'lib')
-rw-r--r--lib/interestingtimes.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/interestingtimes.c b/lib/interestingtimes.c
index 9cf84041..a1aa2b67 100644
--- a/lib/interestingtimes.c
+++ b/lib/interestingtimes.c
@@ -27,7 +27,7 @@ int terminal_size(unsigned *xx, unsigned *yy)
// stdin, stdout, stderr
for (i=0; i<3; i++) {
memset(&ws, 0, sizeof(ws));
- if (!ioctl(i, TIOCGWINSZ, &ws)) {
+ if (isatty(i) && !ioctl(i, TIOCGWINSZ, &ws)) {
if (ws.ws_col) x = ws.ws_col;
if (ws.ws_row) y = ws.ws_row;