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authorJiri Slaby <jslaby@suse.cz>2020-10-19 10:55:16 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-10-28 13:41:02 +0100
commit6ca03f90527e499dd5e32d6522909e2ad390896b (patch)
tree8e8e540c9d6383a80b8ebfca3ad2fe07af47bf83
parentc97f2a6fb3dfbfbbc88edc8ea62ef2b944e18849 (diff)
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vt: keyboard, simplify vt_kdgkbsent
Use 'strlen' of the string, add one for NUL terminator and simply do 'copy_to_user' instead of the explicit 'for' loop. This makes the KDGKBSENT case more compact. The only thing we need to take care about is NULL 'func_table[i]'. Use an empty string in that case. The original check for overflow could never trigger as the func_buf strings are always shorter or equal to 'struct kbsentry's. Cc: <stable@vger.kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20201019085517.10176-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/vt/keyboard.c28
1 files changed, 9 insertions, 19 deletions
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index 0db53b5b3acf..7bfa95c3252c 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -1995,9 +1995,7 @@ out:
int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
{
struct kbsentry *kbs;
- char *p;
u_char *q;
- u_char __user *up;
int sz, fnw_sz;
int delta;
char *first_free, *fj, *fnw;
@@ -2023,23 +2021,15 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
i = array_index_nospec(kbs->kb_func, MAX_NR_FUNC);
switch (cmd) {
- case KDGKBSENT:
- sz = sizeof(kbs->kb_string) - 1; /* sz should have been
- a struct member */
- up = user_kdgkb->kb_string;
- p = func_table[i];
- if(p)
- for ( ; *p && sz; p++, sz--)
- if (put_user(*p, up++)) {
- ret = -EFAULT;
- goto reterr;
- }
- if (put_user('\0', up)) {
- ret = -EFAULT;
- goto reterr;
- }
- kfree(kbs);
- return ((p && *p) ? -EOVERFLOW : 0);
+ case KDGKBSENT: {
+ /* size should have been a struct member */
+ unsigned char *from = func_table[i] ? : "";
+
+ ret = copy_to_user(user_kdgkb->kb_string, from,
+ strlen(from) + 1) ? -EFAULT : 0;
+
+ goto reterr;
+ }
case KDSKBSENT:
if (!perm) {
ret = -EPERM;