Messages in this thread Patch in this message | | | From | Romain Perier <> | Subject | [PATCH 17/20] vt: Manual replacement of the deprecated strlcpy() with return values | Date | Mon, 22 Feb 2021 16:12:28 +0100 |
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The strlcpy() reads the entire source buffer first, it is dangerous if the source buffer lenght is unbounded or possibility non NULL-terminated. It can lead to linear read overflows, crashes, etc...
As recommended in the deprecated interfaces [1], it should be replaced by strscpy.
This commit replaces all calls to strlcpy that handle the return values by the corresponding strscpy calls with new handling of the return values (as it is quite different between the two functions).
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
Signed-off-by: Romain Perier <romain.perier@gmail.com> --- drivers/tty/vt/keyboard.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c index 77638629c562..5e20c6c307e0 100644 --- a/drivers/tty/vt/keyboard.c +++ b/drivers/tty/vt/keyboard.c @@ -2067,9 +2067,12 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) return -ENOMEM; spin_lock_irqsave(&func_buf_lock, flags); - len = strlcpy(kbs, func_table[kb_func] ? : "", len); + len = strscpy(kbs, func_table[kb_func] ? : "", len); spin_unlock_irqrestore(&func_buf_lock, flags); + if (len == -E2BIG) + return -E2BIG; + ret = copy_to_user(user_kdgkb->kb_string, kbs, len + 1) ? -EFAULT : 0;
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