Fix two issues in boot menu input parsing:
1. ebcdic_strtoul returns unsigned long but the value was stored in an int.
2. ebcdic_strtoul could overflow if @value exceeds ULONG_MAX.
Both problems are easy to trigger by entering an excessively large value
in the boot menu, which can lead to unsigned long overflow and memory
corruption.
Use a checked addition to prevent overflow and change menu_read() return
type to unsigned long.
Suggested-by: Eduard Shishkin <edward6@linux.ibm.com>
Reviewed-by: Eduard Shishkin <edward6@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
a2663ec8d3