[PATCH 1/5] Add ucs2 -> utf8 helper functions

[PATCH 1/5] Add ucs2 -> utf8 helper functions

[Peter Jones]

This adds ucs2_utf8size(), which tells us how big our ucs2 string is in
bytes, and ucs2_as_utf8, which translates from ucs2 to utf8..
---
 include/linux/ucs2_string.h |  4 +++
 lib/ucs2_string.c           | 62 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/include/linux/ucs2_string.h b/include/linux/ucs2_string.h
index cbb20af..bb679b4 100644
--- a/include/linux/ucs2_string.h
+++ b/include/linux/ucs2_string.h
@@ -11,4 +11,8 @@ unsigned long ucs2_strlen(const ucs2_char_t *s);
 unsigned long ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength);
 int ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len);
 
+unsigned long ucs2_utf8size(const ucs2_char_t *src);
+unsigned long ucs2_as_utf8(u8 *dest, const ucs2_char_t *src,
+			   unsigned long maxlength);
+
 #endif /* _LINUX_UCS2_STRING_H_ */
diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c
index 6f500ef..17dd74e 100644
--- a/lib/ucs2_string.c
+++ b/lib/ucs2_string.c
@@ -49,3 +49,65 @@ ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
         }
 }
 EXPORT_SYMBOL(ucs2_strncmp);
+
+unsigned long
+ucs2_utf8size(const ucs2_char_t *src)
+{
+	unsigned long i;
+	unsigned long j = 0;
+
+	for (i = 0; i < ucs2_strlen(src); i++) {
+		u16 c = src[i];
+
+		if (c > 0x800)
+			j += 3;
+		else if (c > 0x80)
+			j += 2;
+		else
+			j += 1;
+	}
+
+	return j;
+}
+EXPORT_SYMBOL(ucs2_utf8size);
+
+/*
+ * copy at most maxlength bytes of whole utf8 characters to dest from the
+ * ucs2 string src.
+ *
+ * The return value is the number of characters copied, not including the
+ * final NUL character.
+ */
+unsigned long
+ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength)
+{
+	unsigned int i;
+	unsigned long j = 0;
+	unsigned long limit = ucs2_strnlen(src, maxlength);
+
+	for (i = 0; maxlength && i < limit; i++) {
+		u16 c = src[i];
+
+		if (c > 0x800) {
+			if (maxlength < 3)
+				break;
+			maxlength -= 3;
+			dest[j++] = 0xe0 | (c & 0xf000) >> 12;
+			dest[j++] = 0x80 | (c & 0x0fc0) >> 8;
+			dest[j++] = 0x80 | (c & 0x003f);
+		} else if (c > 0x80) {
+			if (maxlength < 2)
+				break;
+			maxlength -= 2;
+			dest[j++] = 0xc0 | (c & 0xfe0) >> 5;
+			dest[j++] = 0x80 | (c & 0x01f);
+		} else {
+			maxlength -= 1;
+			dest[j++] = c & 0x7f;
+		}
+	}
+	if (maxlength)
+		dest[j] = '\0';
+	return j;
+}
+EXPORT_SYMBOL(ucs2_as_utf8);
-- 
2.5.0

[PATCH 2/5] efi: use ucs2_as_utf8 in efivarfs instead of open coding a bad version

[Peter Jones]

Translate EFI's UCS-2 variable names to UTF-8 instead of just assuming
all variable names fit in ASCII.

Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/firmware/efi/efivars.c | 13 ++++---------
 fs/efivarfs/super.c            |  7 +++----
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index 756eca8..eef6331 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -540,7 +540,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 static int
 efivar_create_sysfs_entry(struct efivar_entry *new_var)
 {
-	int i, short_name_size;
+	int short_name_size;
 	char *short_name;
 	unsigned long variable_name_size;
 	efi_char16_t *variable_name;
@@ -553,22 +553,17 @@ efivar_create_sysfs_entry(struct efivar_entry *new_var)
 	 * Length of the variable bytes in ASCII, plus the '-' separator,
 	 * plus the GUID, plus trailing NUL
 	 */
-	short_name_size = variable_name_size / sizeof(efi_char16_t)
-				+ 1 + EFI_VARIABLE_GUID_LEN + 1;
+	short_name_size = ucs2_utf8size(new_var->var.VariableName) + 1;
 
 	short_name = kzalloc(short_name_size, GFP_KERNEL);
 
 	if (!short_name)
 		return -ENOMEM;
 
-	/* Convert Unicode to normal chars (assume top bits are 0),
-	   ala UTF-8 */
-	for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
-		short_name[i] = variable_name[i] & 0xFF;
-	}
+	ucs2_as_utf8(short_name, variable_name, short_name_size);
+
 	/* This is ugly, but necessary to separate one vendor's
 	   private variables from another's.         */
-
 	*(short_name + strlen(short_name)) = '-';
 	efi_guid_to_str(&new_var->var.VendorGuid,
 			 short_name + strlen(short_name));
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index b8a564f..8651ac2 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -118,7 +118,7 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 	struct dentry *dentry, *root = sb->s_root;
 	unsigned long size = 0;
 	char *name;
-	int len, i;
+	int len;
 	int err = -ENOMEM;
 
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
@@ -128,15 +128,14 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 	memcpy(entry->var.VariableName, name16, name_size);
 	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
 
-	len = ucs2_strlen(entry->var.VariableName);
+	len = ucs2_utf8size(entry->var.VariableName);
 
 	/* name, plus '-', plus GUID, plus NUL*/
 	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
 	if (!name)
 		goto fail;
 
-	for (i = 0; i < len; i++)
-		name[i] = entry->var.VariableName[i] & 0xFF;
+	ucs2_as_utf8(name, entry->var.VariableName, len);
 
 	name[len] = '-';
 
-- 
2.5.0

[PATCH 3/5] efi: do variable name validation tests in utf8

[Peter Jones]

Actually translate from ucs2 to utf8 before doing the test, and then
test against our other utf8 data, instead of fudging it.

Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/firmware/efi/vars.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 70a0fb1..36c5a6e 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -192,7 +192,15 @@ bool
 efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long len)
 {
 	int i;
-	u16 *unicode_name = var_name;
+	unsigned long utf8_size;
+	u8 *utf8_name;
+
+	utf8_size = ucs2_utf8size(var_name);
+	utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL);
+	if (!utf8_name)
+		return false;
+
+	ucs2_as_utf8(utf8_name, var_name, len);
 
 	for (i = 0; variable_validate[i].validate != NULL; i++) {
 		const char *name = variable_validate[i].name;
@@ -200,28 +208,29 @@ efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long len)
 
 		for (match = 0; ; match++) {
 			char c = name[match];
-			u16 u = unicode_name[match];
-
-			/* All special variables are plain ascii */
-			if (u > 127)
-				return true;
+			char u = utf8_name[match];
 
 			/* Wildcard in the matching name means we've matched */
-			if (c == '*')
+			if (c == '*') {
+				kfree(utf8_name);
 				return variable_validate[i].validate(var_name,
 							     match, data, len);
+			}
 
 			/* Case sensitive match */
 			if (c != u)
 				break;
 
 			/* Reached the end of the string while matching */
-			if (!c)
+			if (!c) {
+				kfree(utf8_name);
 				return variable_validate[i].validate(var_name,
 							     match, data, len);
+			}
 		}
 	}
 
+	kfree(utf8_name);
 	return true;
 }
 EXPORT_SYMBOL_GPL(efivar_validate);
-- 
2.5.0

[PATCH 4/5] efi: make our variable validation list include the guid (v2)

[Peter Jones]

v2 correctly checks the guid for validation *as well as* attribute
whitelisting.

Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/firmware/efi/efivars.c |  5 +++--
 drivers/firmware/efi/vars.c    | 43 +++++++++++++++++++++++-------------------
 include/linux/efi.h            |  3 ++-
 3 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index eef6331..707b0fd 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -221,7 +221,7 @@ sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
 	}
 
 	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
-	    efivar_validate(name, data, size) == false) {
+	    efivar_validate(vendor, name, data, size) == false) {
 		printk(KERN_ERR "efivars: Malformed variable content\n");
 		return -EINVAL;
 	}
@@ -447,7 +447,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 	}
 
 	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
-	    efivar_validate(name, data, size) == false) {
+	    efivar_validate(new_var->var.VendorGuid, name, data,
+			    size) == false) {
 		printk(KERN_ERR "efivars: Malformed variable content\n");
 		return -EINVAL;
 	}
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 36c5a6e..5a88ce0 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -165,31 +165,33 @@ validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer,
 }
 
 struct variable_validate {
+	efi_guid_t vendor;
 	char *name;
 	bool (*validate)(efi_char16_t *var_name, int match, u8 *data,
 			 unsigned long len);
 };
 
 static const struct variable_validate variable_validate[] = {
-	{ "BootNext", validate_uint16 },
-	{ "BootOrder", validate_boot_order },
-	{ "DriverOrder", validate_boot_order },
-	{ "Boot*", validate_load_option },
-	{ "Driver*", validate_load_option },
-	{ "ConIn", validate_device_path },
-	{ "ConInDev", validate_device_path },
-	{ "ConOut", validate_device_path },
-	{ "ConOutDev", validate_device_path },
-	{ "ErrOut", validate_device_path },
-	{ "ErrOutDev", validate_device_path },
-	{ "Timeout", validate_uint16 },
-	{ "Lang", validate_ascii_string },
-	{ "PlatformLang", validate_ascii_string },
-	{ "", NULL },
+	{ EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 },
+	{ EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order },
+	{ EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
+	{ EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option },
+	{ EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option },
+	{ EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path },
+	{ EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path },
+	{ EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path },
+	{ EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path },
+	{ EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path },
+	{ EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path },
+	{ EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
+	{ EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string },
+	{ EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string },
+	{ NULL_GUID, "", NULL },
 };
 
 bool
-efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long len)
+efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
+		unsigned long len)
 {
 	int i;
 	unsigned long utf8_size;
@@ -202,9 +204,12 @@ efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long len)
 
 	ucs2_as_utf8(utf8_name, var_name, len);
 
-	for (i = 0; variable_validate[i].validate != NULL; i++) {
+	for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
 		const char *name = variable_validate[i].name;
-		int match;
+		int match = 0;
+
+		if (efi_guidcmp(vendor, variable_validate[i].vendor))
+			continue;
 
 		for (match = 0; ; match++) {
 			char c = name[match];
@@ -861,7 +866,7 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
 
 	*set = false;
 
-	if (efivar_validate(name, data, *size) == false)
+	if (efivar_validate(*vendor, name, data, *size) == false)
 		return -EINVAL;
 
 	/*
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 569b5a8..52444fd 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1199,7 +1199,8 @@ int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
 struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
 				       struct list_head *head, bool remove);
 
-bool efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long len);
+bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
+		     unsigned long len);
 
 extern struct work_struct efivar_work;
 void efivar_run_worker(void);
-- 
2.5.0

Re: [PATCH 4/5] efi: make our variable validation list include the guid (v2)

[joeyli]

Hi Peter, 

On Wed, Feb 03, 2016 at 11:43:53AM -0500, Peter Jones wrote:
> v2 correctly checks the guid for validation *as well as* attribute
> whitelisting.
> 
> Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/firmware/efi/efivars.c |  5 +++--
>  drivers/firmware/efi/vars.c    | 43 +++++++++++++++++++++++-------------------
>  include/linux/efi.h            |  3 ++-
>  3 files changed, 29 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
> index eef6331..707b0fd 100644
> --- a/drivers/firmware/efi/efivars.c
> +++ b/drivers/firmware/efi/efivars.c
> @@ -221,7 +221,7 @@ sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
>  	}
>  
>  	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
> -	    efivar_validate(name, data, size) == false) {
> +	    efivar_validate(vendor, name, data, size) == false) {
>  		printk(KERN_ERR "efivars: Malformed variable content\n");
>  		return -EINVAL;
>  	}
> @@ -447,7 +447,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
>  	}
>  
>  	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
> -	    efivar_validate(name, data, size) == false) {
> +	    efivar_validate(new_var->var.VendorGuid, name, data,
> +			    size) == false) {

I just built fail here:

  CC      drivers/firmware/efi/efivars.o
drivers/firmware/efi/efivars.c: In function ‘efivar_create’:
drivers/firmware/efi/efivars.c:450:29: error: ‘struct efi_variable’ has no member named ‘var’
  efivar_validate(new_var->var.VendorGuid, name, data,
                         ^
scripts/Makefile.build:258: recipe for target 'drivers/firmware/efi/efivars.o' failed


Regards

Joey Lee

Re: [PATCH 4/5] efi: make our variable validation list include the guid (v2)

[Peter Jones]

On Thu, Feb 04, 2016 at 01:51:28AM +0800, joeyli wrote:
> Hi Peter, 
> 
> On Wed, Feb 03, 2016 at 11:43:53AM -0500, Peter Jones wrote:
> > v2 correctly checks the guid for validation *as well as* attribute
> > whitelisting.
> > 
> > Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > ---
> >  drivers/firmware/efi/efivars.c |  5 +++--
> >  drivers/firmware/efi/vars.c    | 43 +++++++++++++++++++++++-------------------
> >  include/linux/efi.h            |  3 ++-
> >  3 files changed, 29 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
> > index eef6331..707b0fd 100644
> > --- a/drivers/firmware/efi/efivars.c
> > +++ b/drivers/firmware/efi/efivars.c
> > @@ -221,7 +221,7 @@ sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
> >  	}
> >  
> >  	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
> > -	    efivar_validate(name, data, size) == false) {
> > +	    efivar_validate(vendor, name, data, size) == false) {
> >  		printk(KERN_ERR "efivars: Malformed variable content\n");
> >  		return -EINVAL;
> >  	}
> > @@ -447,7 +447,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
> >  	}
> >  
> >  	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
> > -	    efivar_validate(name, data, size) == false) {
> > +	    efivar_validate(new_var->var.VendorGuid, name, data,
> > +			    size) == false) {
> 
> I just built fail here:
> 
>   CC      drivers/firmware/efi/efivars.o
> drivers/firmware/efi/efivars.c: In function ‘efivar_create’:
> drivers/firmware/efi/efivars.c:450:29: error: ‘struct efi_variable’ has no member named ‘var’
>   efivar_validate(new_var->var.VendorGuid, name, data,
>                          ^
> scripts/Makefile.build:258: recipe for target 'drivers/firmware/efi/efivars.o' failed

Thanks for this - I've got a couple more fixes mfleming wanted and then
I'll send out a new version once I've built and tested the whole
patchset again.

-- 
        Peter

[PATCH 5/5] efi: Make efivarfs entries immutable by default. (v3)

[Peter Jones]

"rm -rf" is bricking some peoples' laptops because of variables being
used to store non-reinitializable firmware driver data that's required
to POST the hardware.

These are 100% bugs, and they need to be fixed, but in the mean time it
shouldn't be easy to *accidentally* brick machines.

We have to have delete working, and picking which variables do and don't
work for deletion is quite intractable, so instead make everything
immutable by default (except for a whitelist), and make tools that
aren't quite so broad-spectrum unset the immutable flag.

v2: adds Timeout to our whitelist.
v3:
 - takes the extra Timeout out of the whitelist
 - fixes whitelist matching to actually work
 - inverts the flag on efivarfs_get_inode() and calls it is_removable
 - adds documentation and test cases

Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 Documentation/filesystems/efivarfs.txt         |  7 ++
 drivers/firmware/efi/vars.c                    | 97 ++++++++++++++++++++------
 fs/efivarfs/file.c                             | 69 ++++++++++++++++++
 fs/efivarfs/inode.c                            | 31 +++++---
 fs/efivarfs/internal.h                         |  3 +-
 fs/efivarfs/super.c                            |  9 ++-
 include/linux/efi.h                            |  2 +
 tools/testing/selftests/efivarfs/efivarfs.sh   | 19 ++++-
 tools/testing/selftests/efivarfs/open-unlink.c | 72 ++++++++++++++++++-
 9 files changed, 268 insertions(+), 41 deletions(-)

diff --git a/Documentation/filesystems/efivarfs.txt b/Documentation/filesystems/efivarfs.txt
index c477af0..686a64b 100644
--- a/Documentation/filesystems/efivarfs.txt
+++ b/Documentation/filesystems/efivarfs.txt
@@ -14,3 +14,10 @@ filesystem.
 efivarfs is typically mounted like this,
 
 	mount -t efivarfs none /sys/firmware/efi/efivars
+
+Due to the presence of numerous firmware bugs where removing non-standard
+UEFI variables causes the system firmware to fail to POST, efivarfs
+files that are not well-known standardized variables are created
+as immutable files.  This doesn't prevent removal - "chattr -i" will work -
+but it does prevent this kind of failure from being accomplished
+accidentally.
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 5a88ce0..490cd60 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -171,11 +171,21 @@ struct variable_validate {
 			 unsigned long len);
 };
 
+/*
+ * This list is an list of variables we need to validate, as well as the
+ * whitelist for what we think is safe not to default to immutable.
+ *
+ * If it has a validate() method that's not NULL, it'll go into the
+ * validation routine.  If not, it'll just be used for whitelisting.
+ *
+ * Note that it's sorted by {vendor,name}, but globbed names must come after
+ * any other name with the same prefix.
+ */
 static const struct variable_validate variable_validate[] = {
 	{ EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 },
 	{ EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order },
-	{ EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
 	{ EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option },
+	{ EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
 	{ EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option },
 	{ EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path },
 	{ EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path },
@@ -183,12 +193,38 @@ static const struct variable_validate variable_validate[] = {
 	{ EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path },
 	{ EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path },
 	{ EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path },
-	{ EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
 	{ EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string },
+	{ EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
 	{ EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string },
+	{ EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL },
 	{ NULL_GUID, "", NULL },
 };
 
+static bool
+variable_matches(const char *var_name, size_t len, const char *match_name,
+		 int *match)
+{
+	for (*match = 0; ; (*match)++) {
+		char c = match_name[*match];
+		char u = var_name[*match];
+
+		/* Wildcard in the matching name means we've matched */
+		if (c == '*')
+			return true;
+
+		/* Case sensitive match */
+		if (!c && *match == len)
+			return true;
+
+		if (c != u)
+			return false;
+
+		if (!c)
+			return true;
+	}
+	return true;
+}
+
 bool
 efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
 		unsigned long len)
@@ -211,35 +247,50 @@ efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
 		if (efi_guidcmp(vendor, variable_validate[i].vendor))
 			continue;
 
-		for (match = 0; ; match++) {
-			char c = name[match];
-			char u = utf8_name[match];
-
-			/* Wildcard in the matching name means we've matched */
-			if (c == '*') {
-				kfree(utf8_name);
-				return variable_validate[i].validate(var_name,
-							     match, data, len);
-			}
-
-			/* Case sensitive match */
-			if (c != u)
+		if (variable_matches(utf8_name, utf8_size+1, name, &match)) {
+			kfree(utf8_name);
+			if (variable_validate[i].validate == NULL)
 				break;
-
-			/* Reached the end of the string while matching */
-			if (!c) {
-				kfree(utf8_name);
-				return variable_validate[i].validate(var_name,
-							     match, data, len);
-			}
+			return variable_validate[i].validate(var_name, match,
+							     data, len);
 		}
-	}
 
+	}
 	kfree(utf8_name);
 	return true;
 }
 EXPORT_SYMBOL_GPL(efivar_validate);
 
+bool
+efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
+			     size_t len)
+{
+	int i;
+	bool found = false;
+	int match = 0;
+
+	/*
+	 * Now check the validated variables list and then the whitelist -
+	 * both are whitelists
+	 */
+	for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
+		if (efi_guidcmp(variable_validate[i].vendor, vendor))
+			continue;
+
+		if (variable_matches(var_name, len,
+				     variable_validate[i].name, &match)) {
+			found = true;
+			break;
+		}
+	}
+
+	/*
+	 * If we found it in our list, it /isn't/ one of our protected names.
+	 */
+	return found;
+}
+EXPORT_SYMBOL_GPL(efivar_variable_is_removable);
+
 static efi_status_t
 check_var_size(u32 attributes, unsigned long size)
 {
diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index c424e48..b793c85 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -10,6 +10,7 @@
 #include <linux/efi.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
+#include <linux/mount.h>
 
 #include "internal.h"
 
@@ -103,9 +104,77 @@ out_free:
 	return size;
 }
 
+static int
+efivarfs_ioc_getxflags(struct file *file,
+		       void __user *arg)
+{
+	struct inode *inode = file->f_mapping->host;
+	unsigned int iflags;
+	unsigned int flags = 0;
+
+	iflags = inode->i_flags;
+	if (iflags & S_IMMUTABLE)
+		flags |= FS_IMMUTABLE_FL;
+
+	if (copy_to_user(arg, &flags, sizeof(flags)))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+efivarfs_ioc_setxflags(struct file *file,
+		       void __user *arg)
+{
+	struct inode *inode = file->f_mapping->host;
+	unsigned int flags;
+	int error;
+
+	if (!inode_owner_or_capable(inode))
+		return -EACCES;
+
+	if (copy_from_user(&flags, arg, sizeof(flags)))
+		return -EFAULT;
+
+	if (flags & ~FS_IMMUTABLE_FL)
+		return -EOPNOTSUPP;
+
+	if (!capable(CAP_LINUX_IMMUTABLE))
+		return -EPERM;
+
+	error = mnt_want_write_file(file);
+	if (error)
+		return error;
+
+	if (flags & FS_IMMUTABLE_FL)
+		inode->i_flags |= S_IMMUTABLE;
+	else
+		inode->i_flags &= ~S_IMMUTABLE;
+
+	return 0;
+}
+
+long
+efivarfs_file_ioctl(
+		    struct file *file,
+		    unsigned int cmd,
+		    unsigned long p)
+{
+	void __user *arg = (void __user *)p;
+
+	switch (cmd) {
+	case FS_IOC_GETFLAGS:
+		return efivarfs_ioc_getxflags(file, arg);
+	case FS_IOC_SETFLAGS:
+		return efivarfs_ioc_setxflags(file, arg);
+	}
+
+	return -ENOTTY;
+}
+
 const struct file_operations efivarfs_file_operations = {
 	.open	= simple_open,
 	.read	= efivarfs_file_read,
 	.write	= efivarfs_file_write,
 	.llseek	= no_llseek,
+	.unlocked_ioctl = efivarfs_file_ioctl,
 };
diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 3381b9d..88242a3 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -15,7 +15,8 @@
 #include "internal.h"
 
 struct inode *efivarfs_get_inode(struct super_block *sb,
-				const struct inode *dir, int mode, dev_t dev)
+				const struct inode *dir, int mode,
+				dev_t dev, bool is_removable)
 {
 	struct inode *inode = new_inode(sb);
 
@@ -23,6 +24,7 @@ struct inode *efivarfs_get_inode(struct super_block *sb,
 		inode->i_ino = get_next_ino();
 		inode->i_mode = mode;
 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
 		switch (mode & S_IFMT) {
 		case S_IFREG:
 			inode->i_fop = &efivarfs_file_operations;
@@ -102,22 +104,17 @@ static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 			  umode_t mode, bool excl)
 {
-	struct inode *inode;
+	struct inode *inode = NULL;
 	struct efivar_entry *var;
 	int namelen, i = 0, err = 0;
+	bool is_removable = false;
 
 	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
 		return -EINVAL;
 
-	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
-	if (!inode)
-		return -ENOMEM;
-
 	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
-	if (!var) {
-		err = -ENOMEM;
-		goto out;
-	}
+	if (!var)
+		return -ENOMEM;
 
 	/* length of the variable name itself: remove GUID and separator */
 	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
@@ -125,6 +122,17 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 	efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
 			&var->var.VendorGuid);
 
+	if (efivar_variable_is_removable(var->var.VendorGuid,
+					 dentry->d_name.name,
+					 dentry->d_name.len))
+		is_removable = true;
+
+	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
+	if (!inode) {
+		err = -ENOMEM;
+		goto out;
+	}
+
 	for (i = 0; i < namelen; i++)
 		var->var.VariableName[i] = dentry->d_name.name[i];
 
@@ -138,7 +146,8 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 out:
 	if (err) {
 		kfree(var);
-		iput(inode);
+		if (inode)
+			iput(inode);
 	}
 	return err;
 }
diff --git a/fs/efivarfs/internal.h b/fs/efivarfs/internal.h
index b5ff16a..b450518 100644
--- a/fs/efivarfs/internal.h
+++ b/fs/efivarfs/internal.h
@@ -15,7 +15,8 @@ extern const struct file_operations efivarfs_file_operations;
 extern const struct inode_operations efivarfs_dir_inode_operations;
 extern bool efivarfs_valid_name(const char *str, int len);
 extern struct inode *efivarfs_get_inode(struct super_block *sb,
-			const struct inode *dir, int mode, dev_t dev);
+			const struct inode *dir, int mode, dev_t dev,
+			bool is_removable);
 
 extern struct list_head efivarfs_list;
 
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 8651ac2..dd029d1 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -120,6 +120,7 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 	char *name;
 	int len;
 	int err = -ENOMEM;
+	bool is_removable = false;
 
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry)
@@ -137,13 +138,17 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 
 	ucs2_as_utf8(name, entry->var.VariableName, len);
 
+	if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
+		is_removable = true;
+
 	name[len] = '-';
 
 	efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
 
 	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
 
-	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0);
+	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
+				   is_removable);
 	if (!inode)
 		goto fail_name;
 
@@ -199,7 +204,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_d_op		= &efivarfs_d_ops;
 	sb->s_time_gran         = 1;
 
-	inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
+	inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true);
 	if (!inode)
 		return -ENOMEM;
 	inode->i_op = &efivarfs_dir_inode_operations;
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 52444fd..1869d5c 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1201,6 +1201,8 @@ struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
 
 bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
 		     unsigned long len);
+bool efivar_variable_is_removable(efi_guid_t vendor, const char *name,
+				  size_t len);
 
 extern struct work_struct efivar_work;
 void efivar_run_worker(void);
diff --git a/tools/testing/selftests/efivarfs/efivarfs.sh b/tools/testing/selftests/efivarfs/efivarfs.sh
index 77edcdc..0572784 100755
--- a/tools/testing/selftests/efivarfs/efivarfs.sh
+++ b/tools/testing/selftests/efivarfs/efivarfs.sh
@@ -88,7 +88,11 @@ test_delete()
 		exit 1
 	fi
 
-	rm $file
+	rm $file 2>/dev/null
+	if [ $? -ne 0 ]; then
+		chattr -i $file
+		rm $file
+	fi
 
 	if [ -e $file ]; then
 		echo "$file couldn't be deleted" >&2
@@ -111,6 +115,7 @@ test_zero_size_delete()
 		exit 1
 	fi
 
+	chattr -i $file
 	printf "$attrs" > $file
 
 	if [ -e $file ]; then
@@ -141,7 +146,11 @@ test_valid_filenames()
 			echo "$file could not be created" >&2
 			ret=1
 		else
-			rm $file
+			rm $file 2>/dev/null
+			if [ $? -ne 0 ]; then
+				chattr -i $file
+				rm $file
+			fi
 		fi
 	done
 
@@ -174,7 +183,11 @@ test_invalid_filenames()
 
 		if [ -e $file ]; then
 			echo "Creating $file should have failed" >&2
-			rm $file
+			rm $file 2>/dev/null
+			if [ $? -ne 0 ]; then
+				chattr -i $file
+				rm $file
+			fi
 			ret=1
 		fi
 	done
diff --git a/tools/testing/selftests/efivarfs/open-unlink.c b/tools/testing/selftests/efivarfs/open-unlink.c
index 8c07644..4af74f7 100644
--- a/tools/testing/selftests/efivarfs/open-unlink.c
+++ b/tools/testing/selftests/efivarfs/open-unlink.c
@@ -1,10 +1,68 @@
+#include <errno.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sys/ioctl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <linux/fs.h>
+
+static int set_immutable(const char *path, int immutable)
+{
+	unsigned int flags;
+	int fd;
+	int rc;
+	int error;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return fd;
+
+	rc = ioctl(fd, FS_IOC_GETFLAGS, &flags);
+	if (rc < 0) {
+		error = errno;
+		close(fd);
+		errno = error;
+		return rc;
+	}
+
+	if (immutable)
+		flags |= FS_IMMUTABLE_FL;
+	else
+		flags &= ~FS_IMMUTABLE_FL;
+
+	rc = ioctl(fd, FS_IOC_SETFLAGS, &flags);
+	error = errno;
+	close(fd);
+	errno = error;
+	return rc;
+}
+
+static int get_immutable(const char *path)
+{
+	unsigned int flags;
+	int fd;
+	int rc;
+	int error;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return fd;
+
+	rc = ioctl(fd, FS_IOC_GETFLAGS, &flags);
+	if (rc < 0) {
+		error = errno;
+		close(fd);
+		errno = error;
+		return rc;
+	}
+	close(fd);
+	if (flags & FS_IMMUTABLE_FL)
+		return 1;
+	return 0;
+}
 
 int main(int argc, char **argv)
 {
@@ -27,7 +85,7 @@ int main(int argc, char **argv)
 	buf[4] = 0;
 
 	/* create a test variable */
-	fd = open(path, O_WRONLY | O_CREAT);
+	fd = open(path, O_WRONLY | O_CREAT, 0600);
 	if (fd < 0) {
 		perror("open(O_WRONLY)");
 		return EXIT_FAILURE;
@@ -41,6 +99,18 @@ int main(int argc, char **argv)
 
 	close(fd);
 
+	rc = get_immutable(path);
+	if (rc < 0) {
+		perror("ioctl(FS_IOC_GETFLAGS)");
+		return EXIT_FAILURE;
+	} else if (rc) {
+		rc = set_immutable(path, 0);
+		if (rc < 0) {
+			perror("ioctl(FS_IOC_SETFLAGS)");
+			return EXIT_FAILURE;
+		}
+	}
+
 	fd = open(path, O_RDONLY);
 	if (fd < 0) {
 		perror("open");
-- 
2.5.0

Re: [PATCH 5/5] efi: Make efivarfs entries immutable by default. (v3)

[joeyli]

On Wed, Feb 03, 2016 at 11:43:54AM -0500, Peter Jones wrote:
> "rm -rf" is bricking some peoples' laptops because of variables being
> used to store non-reinitializable firmware driver data that's required
> to POST the hardware.
> 
> These are 100% bugs, and they need to be fixed, but in the mean time it
> shouldn't be easy to *accidentally* brick machines.
> 
> We have to have delete working, and picking which variables do and don't
> work for deletion is quite intractable, so instead make everything
> immutable by default (except for a whitelist), and make tools that
> aren't quite so broad-spectrum unset the immutable flag.
> 
> v2: adds Timeout to our whitelist.
> v3:
>  - takes the extra Timeout out of the whitelist
>  - fixes whitelist matching to actually work
>  - inverts the flag on efivarfs_get_inode() and calls it is_removable
>  - adds documentation and test cases
> 
> Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Tested-by: Lee, Chun-Yi <jlee-IBi9RG/b67k@public.gmane.org>

Regards

Joey Lee

> ---
>  Documentation/filesystems/efivarfs.txt         |  7 ++
>  drivers/firmware/efi/vars.c                    | 97 ++++++++++++++++++++------
>  fs/efivarfs/file.c                             | 69 ++++++++++++++++++
>  fs/efivarfs/inode.c                            | 31 +++++---
>  fs/efivarfs/internal.h                         |  3 +-
>  fs/efivarfs/super.c                            |  9 ++-
>  include/linux/efi.h                            |  2 +
>  tools/testing/selftests/efivarfs/efivarfs.sh   | 19 ++++-
>  tools/testing/selftests/efivarfs/open-unlink.c | 72 ++++++++++++++++++-
>  9 files changed, 268 insertions(+), 41 deletions(-)
> 
> diff --git a/Documentation/filesystems/efivarfs.txt b/Documentation/filesystems/efivarfs.txt
> index c477af0..686a64b 100644
> --- a/Documentation/filesystems/efivarfs.txt
> +++ b/Documentation/filesystems/efivarfs.txt
> @@ -14,3 +14,10 @@ filesystem.
>  efivarfs is typically mounted like this,
> 
[...snip] 
> +static bool
> +variable_matches(const char *var_name, size_t len, const char *match_name,
> +		 int *match)
> +{
> +	for (*match = 0; ; (*match)++) {
> +		char c = match_name[*match];
> +		char u = var_name[*match];
> +
> +		/* Wildcard in the matching name means we've matched */
> +		if (c == '*')
> +			return true;
> +
> +		/* Case sensitive match */
> +		if (!c && *match == len)
> +			return true;
> +
> +		if (c != u)
> +			return false;
> +
> +		if (!c)
> +			return true;
> +	}
> +	return true;
> +}
> +

Yes, this change works on my testing.  

Regards

Joey Lee

Re: [PATCH 5/5] efi: Make efivarfs entries immutable by default. (v3)

[Peter Jones]

On Thu, Feb 04, 2016 at 02:00:16AM +0800, joeyli wrote:
> On Wed, Feb 03, 2016 at 11:43:54AM -0500, Peter Jones wrote:
> > "rm -rf" is bricking some peoples' laptops because of variables being
> > used to store non-reinitializable firmware driver data that's required
> > to POST the hardware.
> > 
> > These are 100% bugs, and they need to be fixed, but in the mean time it
> > shouldn't be easy to *accidentally* brick machines.
> > 
> > We have to have delete working, and picking which variables do and don't
> > work for deletion is quite intractable, so instead make everything
> > immutable by default (except for a whitelist), and make tools that
> > aren't quite so broad-spectrum unset the immutable flag.
> > 
> > v2: adds Timeout to our whitelist.
> > v3:
> >  - takes the extra Timeout out of the whitelist
> >  - fixes whitelist matching to actually work
> >  - inverts the flag on efivarfs_get_inode() and calls it is_removable
> >  - adds documentation and test cases
> > 
> > Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> 
> Tested-by: Lee, Chun-Yi <jlee-IBi9RG/b67k@public.gmane.org>

Is this to say on 4/5 you did s/new_var->var./new_var->/ and then tested
the whole set?

-- 
        Peter

Re: [PATCH 5/5] efi: Make efivarfs entries immutable by default. (v3)

[joeyli]

On Wed, Feb 03, 2016 at 01:18:00PM -0500, Peter Jones wrote:
> On Thu, Feb 04, 2016 at 02:00:16AM +0800, joeyli wrote:
> > On Wed, Feb 03, 2016 at 11:43:54AM -0500, Peter Jones wrote:
> > > "rm -rf" is bricking some peoples' laptops because of variables being
> > > used to store non-reinitializable firmware driver data that's required
> > > to POST the hardware.
> > > 
> > > These are 100% bugs, and they need to be fixed, but in the mean time it
> > > shouldn't be easy to *accidentally* brick machines.
> > > 
> > > We have to have delete working, and picking which variables do and don't
> > > work for deletion is quite intractable, so instead make everything
> > > immutable by default (except for a whitelist), and make tools that
> > > aren't quite so broad-spectrum unset the immutable flag.
> > > 
> > > v2: adds Timeout to our whitelist.
> > > v3:
> > >  - takes the extra Timeout out of the whitelist
> > >  - fixes whitelist matching to actually work
> > >  - inverts the flag on efivarfs_get_inode() and calls it is_removable
> > >  - adds documentation and test cases
> > > 
> > > Signed-off-by: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > 
> > Tested-by: Lee, Chun-Yi <jlee-IBi9RG/b67k@public.gmane.org>
> 
> Is this to say on 4/5 you did s/new_var->var./new_var->/ and then tested
> the whole set?
>

Yes, I changed the code then built whole patch set success. And, I tested
this set on OVMF to remove some variables in whitelist or not. It works to
me to avoid root removes non-whitelist variables.

Actually I tested your last version, it doesn't have compiler problem but
I found there have some whitelist variables that can not be removed because
variable_matches() has issue to compare name. Looks you fixed it in this
version.

So I put Tested-by tag to this set.


Thanks a lot!

Joey Lee