Commit 783ee431 authored by Andrzej Zaborowski's avatar Andrzej Zaborowski Committed by Matt Fleming
Browse files

efi-pstore: Fix an overflow on 32-bit builds



In generic_id the long int timestamp is multiplied by 100000 and needs
an explicit cast to u64.

Without that the id in the resulting pstore filename is wrong and
userspace may have problems parsing it, but more importantly files in
pstore can never be deleted and may fill the EFI flash (brick device?).
This happens because when generic pstore code wants to delete a file,
it passes the id to the EFI backend which reinterpretes it and a wrong
variable name is attempted to be deleted.  There's no error message but
after remounting pstore, deleted files would reappear.

Signed-off-by: default avatarAndrew Zaborowski <andrew.zaborowski@intel.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 6fb8cc82
......@@ -40,7 +40,7 @@ struct pstore_read_data {
static inline u64 generic_id(unsigned long timestamp,
unsigned int part, int count)
{
return (timestamp * 100 + part) * 1000 + count;
return ((u64) timestamp * 100 + part) * 1000 + count;
}
static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
......
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