From: Kees Cook <keesc...@chromium.org>
commit c307459b9d1fcb8bbf3ea5a4162979532322ef77 upstream.
FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs
that are interested in filtering between types of things. The "how"
should be an internal detail made uninteresting to the LSMs.
Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer")
Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures
(pre-allocated buffer)")
Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware
(pre-allocated buffer)")
Signed-off-by: Kees Cook <keesc...@chromium.org>
Reviewed-by: Mimi Zohar <zo...@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcg...@kernel.org>
Acked-by: Scott Branden <scott.bran...@broadcom.com>
Cc: sta...@vger.kernel.org
Link: https://lore.kernel.org/r/20201002173828.2099543-2-keesc...@chromium.org
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/base/firmware_loader/main.c | 5 ++---
fs/exec.c | 7 ++++---
include/linux/fs.h | 1 -
kernel/module.c | 2 +-
security/integrity/digsig.c | 2 +-
security/integrity/ima/ima_fs.c | 2 +-
security/integrity/ima/ima_main.c | 6 ++----
7 files changed, 11 insertions(+), 14 deletions(-)
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -470,14 +470,12 @@ fw_get_filesystem_firmware(struct device
int i, len;
int rc = -ENOENT;
char *path;
- enum kernel_read_file_id id = READING_FIRMWARE;
size_t msize = INT_MAX;
void *buffer = NULL;
/* Already populated data member means we're loading into a buffer */
if (!decompress && fw_priv->data) {
buffer = fw_priv->data;
- id = READING_FIRMWARE_PREALLOC_BUFFER;
msize = fw_priv->allocated_size;
}
@@ -501,7 +499,8 @@ fw_get_filesystem_firmware(struct device
/* load firmware files from the mount namespace of init */
rc = kernel_read_file_from_path_initns(path, &buffer,
- &size, msize, id);
+ &size, msize,
+ READING_FIRMWARE);
if (rc) {
if (rc != -ENOENT)
dev_warn(device, "loading %s failed with error
%d\n",
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -955,6 +955,7 @@ int kernel_read_file(struct file *file,
{
loff_t i_size, pos;
ssize_t bytes = 0;
+ void *allocated = NULL;
int ret;
if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
@@ -978,8 +979,8 @@ int kernel_read_file(struct file *file,
goto out;
}
- if (id != READING_FIRMWARE_PREALLOC_BUFFER)
- *buf = vmalloc(i_size);
+ if (!*buf)
+ *buf = allocated = vmalloc(i_size);
if (!*buf) {
ret = -ENOMEM;
goto out;
@@ -1008,7 +1009,7 @@ int kernel_read_file(struct file *file,
out_free:
if (ret < 0) {
- if (id != READING_FIRMWARE_PREALLOC_BUFFER) {
+ if (allocated) {
vfree(*buf);
*buf = NULL;
}
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2861,7 +2861,6 @@ extern int do_pipe_flags(int *, int);
#define __kernel_read_file_id(id) \
id(UNKNOWN, unknown) \
id(FIRMWARE, firmware) \
- id(FIRMWARE_PREALLOC_BUFFER, firmware) \
id(MODULE, kernel-module) \
id(KEXEC_IMAGE, kexec-image) \
id(KEXEC_INITRAMFS, kexec-initramfs) \
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4028,7 +4028,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, c
{
struct load_info info = { };
loff_t size;
- void *hdr;
+ void *hdr = NULL;
int err;
err = may_init_module();
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -169,7 +169,7 @@ int __init integrity_add_key(const unsig
int __init integrity_load_x509(const unsigned int id, const char *path)
{
- void *data;
+ void *data = NULL;
loff_t size;
int rc;
key_perm_t perm;
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -272,7 +272,7 @@ static const struct file_operations ima_
static ssize_t ima_read_policy(char *path)
{
- void *data;
+ void *data = NULL;
char *datap;
loff_t size;
int rc, pathlen = strlen(path);
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -621,19 +621,17 @@ void ima_post_path_mknod(struct dentry *
int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
{
/*
- * READING_FIRMWARE_PREALLOC_BUFFER
- *
* Do devices using pre-allocated memory run the risk of the
* firmware being accessible to the device prior to the completion
* of IMA's signature verification any more than when using two
- * buffers?
+ * buffers? It may be desirable to include the buffer address
+ * in this API and walk all the dma_map_single() mappings to check.
*/
return 0;
}
const int read_idmap[READING_MAX_ID] = {
[READING_FIRMWARE] = FIRMWARE_CHECK,
- [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
[READING_MODULE] = MODULE_CHECK,
[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
