Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into efi/urgent
Pull EFI fix from Matt Fleming:
* Avoid out-of-bounds access in the efivars code when performing
string matching on converted EFI variable names (Laszlo Ersek)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 0ac594c..34b7419 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -202,29 +202,44 @@
{ NULL_GUID, "", NULL },
};
+/*
+ * Check if @var_name matches the pattern given in @match_name.
+ *
+ * @var_name: an array of @len non-NUL characters.
+ * @match_name: a NUL-terminated pattern string, optionally ending in "*". A
+ * final "*" character matches any trailing characters @var_name,
+ * including the case when there are none left in @var_name.
+ * @match: on output, the number of non-wildcard characters in @match_name
+ * that @var_name matches, regardless of the return value.
+ * @return: whether @var_name fully matches @match_name.
+ */
static bool
variable_matches(const char *var_name, size_t len, const char *match_name,
int *match)
{
for (*match = 0; ; (*match)++) {
char c = match_name[*match];
- char u = var_name[*match];
- /* Wildcard in the matching name means we've matched */
- if (c == '*')
+ switch (c) {
+ case '*':
+ /* Wildcard in @match_name means we've matched. */
return true;
- /* Case sensitive match */
- if (!c && *match == len)
- return true;
+ case '\0':
+ /* @match_name has ended. Has @var_name too? */
+ return (*match == len);
- if (c != u)
+ default:
+ /*
+ * We've reached a non-wildcard char in @match_name.
+ * Continue only if there's an identical character in
+ * @var_name.
+ */
+ if (*match < len && c == var_name[*match])
+ continue;
return false;
-
- if (!c)
- return true;
+ }
}
- return true;
}
bool