Re: [PATCH 06/13] fs/kernel_read_file: Remove redundant size argument

On Tue, Jul 21, 2020 at 02:43:07PM -0700, Scott Branden wrote:

On 2020-07-17 10:43 a.m., Kees Cook wrote:

quoted

In preparation for refactoring kernel_read_file*(), remove the redundant
"size" argument which is not needed: it can be included in the return
code, with callers adjusted. (VFS reads already cannot be larger than
INT_MAX.)

Signed-off-by: Kees Cook <redacted>
---
  drivers/base/firmware_loader/main.c |  8 ++++----
  fs/kernel_read_file.c               | 20 +++++++++-----------
  include/linux/kernel_read_file.h    |  8 ++++----
  kernel/kexec_file.c                 | 13 ++++++-------
  kernel/module.c                     |  7 +++----
  security/integrity/digsig.c         |  5 +++--
  security/integrity/ima/ima_fs.c     |  5 +++--
  7 files changed, 32 insertions(+), 34 deletions(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index d4a413ea48ce..ea419c7d3d34 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c

@@ -462,7 +462,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
  					     size_t in_size,
  					     const void *in_buffer))
  {
-	loff_t size;
+	size_t size;
  	int i, len;
  	int rc = -ENOENT;
  	char *path;

@@ -494,10 +494,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
  		fw_priv->size = 0;
  		/* load firmware files from the mount namespace of init */
-		rc = kernel_read_file_from_path_initns(path, &buffer,
-						       &size, msize,
+		rc = kernel_read_file_from_path_initns(path, &buffer, msize,
  						       READING_FIRMWARE);
-		if (rc) {
+		if (rc < 0) {
  			if (rc != -ENOENT)
  				dev_warn(device, "loading %s failed with error %d\n",
  					 path, rc);

@@ -506,6 +505,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
  					 path);
  			continue;
  		}
+		size = rc;

Change fails to return 0.  Need rc = 0; here.

Oh nice; good catch! I'll fix this.

-- 
Kees Cook