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uinput: fix race condition in uinput syspath check

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In theory, the device could change between stat() call and open(), resulting
in us opening the new device. Change to open() first, then fstat() on the fd.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
This commit is contained in:
Peter Hutterer 2015-12-22 09:02:46 +10:00
parent 3c85fcb62f
commit 006f10cfcb
1 changed files with 8 additions and 8 deletions
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16
libevdev/libevdev-uinput.c
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@ -225,19 +225,19 @@ fetch_syspath_and_devnode(struct libevdev_uinput *uinput_dev)
continue;
}
if (stat(buf, &st) == -1)
continue;
/* created before UI_DEV_CREATE, or after it finished */
if (st.st_ctime < uinput_dev->ctime[0] ||
st.st_ctime > uinput_dev->ctime[1])
continue;
/* created within time frame */
fd = open(buf, O_RDONLY);
if (fd < 0)
continue;
/* created before UI_DEV_CREATE, or after it finished */
if (fstat(fd, &st) == -1 ||
st.st_ctime < uinput_dev->ctime[0] ||
st.st_ctime > uinput_dev->ctime[1]) {
close(fd);
continue;
}
len = read(fd, buf, sizeof(buf));
close(fd);
if (len <= 0)