It isn't a good pratice to request firmware via relative path, also
might have security issue, so don't do it.

Cc: Takashi Iwai <ti...@suse.de>
Signed-off-by: Ming Lei <ming....@canonical.com>
---
 drivers/base/firmware_class.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 051db83..d381db9 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -356,6 +356,10 @@ static bool fw_get_file_fw_from_paths(const char *paths, 
char *path,
                strncpy(path, &paths[start], len);
                snprintf(&path[len], PATH_MAX - len, "/%s", buf->fw_id);
 
+               /* relative path isn't allowed */
+               if (strstr(path, "../"))
+                       continue;
+
                if (fw_get_file_firmware(path, buf))
                        return true;
        } while (pos && end < strlen(paths) - 1);
@@ -1031,6 +1035,13 @@ _request_firmware_prepare(struct firmware **firmware_p, 
const char *name,
                return 0; /* assigned */
        }
 
+       /* relative path isn't allowed */
+       if (strstr(name, "../")) {
+               dev_err(device, "%s: relative path isn't allowed\n",
+                       name);
+               return -EINVAL;
+       }
+
        ret = fw_lookup_and_allocate_buf(name, &fw_cache, &buf);
 
        /*
-- 
1.7.9.5

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