Move the helper from the firmware specific code to a header so we can
reuse it for coredump sockets.
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
drivers/base/firmware_loader/main.c | 31 +++++++++++--------------------
include/linux/fs.h | 16 ++++++++++++++++
2 files changed, 27 insertions(+), 20 deletions(-)
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 44486b2c7172..6942c62fa59d 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -822,26 +822,6 @@ static void fw_log_firmware_info(const struct firmware *fw, const char *name,
{}
#endif
-/*
- * Reject firmware file names with ".." path components.
- * There are drivers that construct firmware file names from device-supplied
- * strings, and we don't want some device to be able to tell us "I would like to
- * be sent my firmware from ../../../etc/shadow, please".
- *
- * Search for ".." surrounded by either '/' or start/end of string.
- *
- * This intentionally only looks at the firmware name, not at the firmware base
- * directory or at symlink contents.
- */
-static bool name_contains_dotdot(const char *name)
-{
- size_t name_len = strlen(name);
-
- return strcmp(name, "..") == 0 || strncmp(name, "../", 3) == 0 ||
- strstr(name, "/../") != NULL ||
- (name_len >= 3 && strcmp(name+name_len-3, "/..") == 0);
-}
-
/* called from request_firmware() and request_firmware_work_func() */
static int
_request_firmware(const struct firmware **firmware_p, const char *name,
@@ -862,6 +842,17 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
goto out;
}
+
+ /*
+ * Reject firmware file names with ".." path components.
+ * There are drivers that construct firmware file names from
+ * device-supplied strings, and we don't want some device to be
+ * able to tell us "I would like to be sent my firmware from
+ * ../../../etc/shadow, please".
+ *
+ * This intentionally only looks at the firmware name, not at
+ * the firmware base directory or at symlink contents.
+ */
if (name_contains_dotdot(name)) {
dev_warn(device,
"Firmware load for '%s' refused, path contains '..' component\n",
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 96c7925a6551..18fdbd184eea 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3264,6 +3264,22 @@ static inline bool is_dot_dotdot(const char *name, size_t len)
(len == 1 || (len == 2 && name[1] == '.'));
}
+/**
+ * name_contains_dotdot - check if a file name contains ".." path components
+ *
+ * Search for ".." surrounded by either '/' or start/end of string.
+ */
+static inline bool name_contains_dotdot(const char *name)
+{
+ size_t name_len;
+
+ name_len = strlen(name);
+ return strcmp(name, "..") == 0 ||
+ strncmp(name, "../", 3) == 0 ||
+ strstr(name, "/../") != NULL ||
+ (name_len >= 3 && strcmp(name + name_len - 3, "/..") == 0);
+}
+
#include <linux/err.h>
/* needed for stackable file system support */
--
2.47.2
