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efi: NUL terminate strings read with efivar_get()

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let's be more careful and NUL terminate everything we read from EFI
variables, in case it isn't already.
This commit is contained in:
Lennart Poettering 2018-10-23 13:44:23 +02:00
parent 996daf2fa9
commit 3b42f34910
1 changed files with 17 additions and 2 deletions
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19
src/boot/efi/util.c
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@ -105,18 +105,33 @@ EFI_STATUS efivar_set_int(CHAR16 *name, UINTN i, BOOLEAN persistent) {
EFI_STATUS efivar_get(const CHAR16 *name, CHAR16 **value) {
_cleanup_freepool_ CHAR8 *buf = NULL;
EFI_STATUS err;
CHAR16 *val;
UINTN size;
EFI_STATUS err;
err = efivar_get_raw(&loader_guid, name, &buf, &size);
if (EFI_ERROR(err))
return err;
val = StrDuplicate((CHAR16 *)buf);
/* Make sure there are no incomplete characters in the buffer */
if ((size % 2) != 0)
return EFI_INVALID_PARAMETER;
/* Return buffer directly if it happens to be NUL terminated already */
if (size >= 2 && buf[size-2] == 0 && buf[size-1] == 0) {
*value = (CHAR16*) buf;
buf = NULL;
return EFI_SUCCESS;
}
/* Make sure a terminating NUL is available at the end */
val = AllocatePool(size + 2);
if (!val)
return EFI_OUT_OF_RESOURCES;
CopyMem(val, buf, size);
val[size/2] = 0; /* NUL terminate */
*value = val;
return EFI_SUCCESS;
}