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FAILED: patch "[PATCH] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Nov 3, 2020

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Stable branch VFS Driver core Security (LSM) +4 more subsystems
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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c307459b9d1fcb8bbf3ea5a4162979532322ef77 Mon Sep 17 00:00:00 2001
From: Kees Cook <[email protected]>
Date: Fri, 2 Oct 2020 10:38:13 -0700
Subject: [PATCH] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum

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 <[email protected]>
Reviewed-by Mimi Zohar <[email protected]>
Reviewed-by Luis Chamberlain <[email protected]>
Acked-by Scott Branden <[email protected]>
Cc [email protected]
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Greg Kroah-Hartman <[email protected]>
drivers/base/firmware_loader/main.c +2 -3
index 63b9714a0154..b0ec2721f55d 100644
@@ -470,14 +470,12 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 	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 *device, struct fw_priv *fw_priv,
 
 		/* 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",
fs/exec.c +4 -3
index a91003e28eaa..9233cd50dc4c 100644
@@ -954,6 +954,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 {
 	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)

@@ -977,8 +978,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 		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;

@@ -1007,7 +1008,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 
 out_free:
 	if (ret < 0) {
-		if (id != READING_FIRMWARE_PREALLOC_BUFFER) {
+		if (allocated) {
 			vfree(*buf);
 			*buf = NULL;
 		}
include/linux/fs.h +1 -1
index 7519ae003a08..7336e22d0c5d 100644
@@ -2858,10 +2858,10 @@ static inline void i_readcount_inc(struct inode *inode)
 #endif
 extern int do_pipe_flags(int *, int);
 
+/* This is a list of *what* is being read, not *how*. */
 #define __kernel_read_file_id(id) \
 	id(UNKNOWN, unknown)		\
 	id(FIRMWARE, firmware)		\
-	id(FIRMWARE_PREALLOC_BUFFER, firmware)	\
 	id(FIRMWARE_EFI_EMBEDDED, firmware)	\
 	id(MODULE, kernel-module)		\
 	id(KEXEC_IMAGE, kexec-image)		\
kernel/module.c +1 -1
index 1c5cff34d9f2..b2808acac46b 100644
@@ -4035,7 +4035,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 {
 	struct load_info info = { };
 	loff_t size;
-	void *hdr;
+	void *hdr = NULL;
 	int err;
 
 	err = may_init_module();
security/integrity/digsig.c +1 -1
index e9cbadade74b..ac02b7632353 100644
@@ -169,7 +169,7 @@ int __init integrity_add_key(const unsigned int id, const void *data,
 
 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;
security/integrity/ima/ima_fs.c +1 -1
index e3fcad871861..15a44c5022f7 100644
@@ -272,7 +272,7 @@ static const struct file_operations ima_ascii_measurements_ops = {
 
 static ssize_t ima_read_policy(char *path)
 {
-	void *data;
+	void *data = NULL;
 	char *datap;
 	loff_t size;
 	int rc, pathlen = strlen(path);
security/integrity/ima/ima_main.c +2 -4
index 8a91711ca79b..2f187784c5bc 100644
@@ -611,19 +611,17 @@ void ima_post_path_mknod(struct dentry *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,