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tty: hvc: replace BUG_ON() with negative return value

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commit e679004dec upstream.

Xen frontends shouldn't BUG() in case of illegal data received from
their backends. So replace the BUG_ON()s when reading illegal data from
the ring page with negative return values.

Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210707091045.460-1-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Juergen Gross 2021-07-07 11:10:45 +02:00 committed by Greg Kroah-Hartman
parent 1c5f722a8f
commit a94e4a7b77
1 changed files with 14 additions and 3 deletions
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15
drivers/tty/hvc/hvc_xen.c
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@ -86,7 +86,11 @@ static int __write_console(struct xencons_info *xencons,
cons = intf->out_cons; cons = intf->out_cons;
prod = intf->out_prod; prod = intf->out_prod;
mb(); /* update queue values before going on */ mb(); /* update queue values before going on */
BUG_ON((prod - cons) > sizeof(intf->out));
if ((prod - cons) > sizeof(intf->out)) {
pr_err_once("xencons: Illegal ring page indices");
return -EINVAL;
}
while ((sent < len) && ((prod - cons) < sizeof(intf->out))) while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
@ -115,6 +119,9 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
while (len) { while (len) {
int sent = __write_console(cons, data, len); int sent = __write_console(cons, data, len);
if (sent < 0)
return sent;
data += sent; data += sent;
len -= sent; len -= sent;
@ -138,7 +145,11 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
cons = intf->in_cons; cons = intf->in_cons;
prod = intf->in_prod; prod = intf->in_prod;
mb(); /* get pointers before reading ring */ mb(); /* get pointers before reading ring */
BUG_ON((prod - cons) > sizeof(intf->in));
if ((prod - cons) > sizeof(intf->in)) {
pr_err_once("xencons: Illegal ring page indices");
return -EINVAL;
}
while (cons != prod && recv < len) while (cons != prod && recv < len)
buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)]; buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];