linux-kernel - [GIT pull] efi/urgent for 5.6-rc6

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Date:   Sun, 15 Mar 2020 15:14:38 -0000
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org
Subject: [GIT pull] efi/urgent for 5.6-rc6

Linus,

please pull the latest efi/urgent branch from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git efi-urgent-2020-03-15

up to:  d6c066fda90d: efi: Add a sanity check to efivar_store_raw()

Two EFI fixes:

 - Prevent a race and buffer overflow in the sysfs efivars interface which
   causes kernel memory corruption.

 - Add the missing NULL pointer checks in efivar_store_raw()

Thanks,

	tglx

------------------>
Vladis Dronov (2):
      efi: Fix a race and a buffer overflow while reading efivars via sysfs
      efi: Add a sanity check to efivar_store_raw()


 drivers/firmware/efi/efivars.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index 7576450c8254..aff3dfb4d7ba 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -83,13 +83,16 @@ static ssize_t
 efivar_attr_read(struct efivar_entry *entry, char *buf)
 {
 	struct efi_variable *var = &entry->var;
+	unsigned long size = sizeof(var->Data);
 	char *str = buf;
+	int ret;
 
 	if (!entry || !buf)
 		return -EINVAL;
 
-	var->DataSize = 1024;
-	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
+	ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data);
+	var->DataSize = size;
+	if (ret)
 		return -EIO;
 
 	if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
@@ -116,13 +119,16 @@ static ssize_t
 efivar_size_read(struct efivar_entry *entry, char *buf)
 {
 	struct efi_variable *var = &entry->var;
+	unsigned long size = sizeof(var->Data);
 	char *str = buf;
+	int ret;
 
 	if (!entry || !buf)
 		return -EINVAL;
 
-	var->DataSize = 1024;
-	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
+	ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data);
+	var->DataSize = size;
+	if (ret)
 		return -EIO;
 
 	str += sprintf(str, "0x%lx\n", var->DataSize);
@@ -133,12 +139,15 @@ static ssize_t
 efivar_data_read(struct efivar_entry *entry, char *buf)
 {
 	struct efi_variable *var = &entry->var;
+	unsigned long size = sizeof(var->Data);
+	int ret;
 
 	if (!entry || !buf)
 		return -EINVAL;
 
-	var->DataSize = 1024;
-	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
+	ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data);
+	var->DataSize = size;
+	if (ret)
 		return -EIO;
 
 	memcpy(buf, var->Data, var->DataSize);
@@ -199,6 +208,9 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 	u8 *data;
 	int err;
 
+	if (!entry || !buf)
+		return -EINVAL;
+
 	if (in_compat_syscall()) {
 		struct compat_efi_variable *compat;
 
@@ -250,14 +262,16 @@ efivar_show_raw(struct efivar_entry *entry, char *buf)
 {
 	struct efi_variable *var = &entry->var;
 	struct compat_efi_variable *compat;
+	unsigned long datasize = sizeof(var->Data);
 	size_t size;
+	int ret;
 
 	if (!entry || !buf)
 		return 0;
 
-	var->DataSize = 1024;
-	if (efivar_entry_get(entry, &entry->var.Attributes,
-			     &entry->var.DataSize, entry->var.Data))
+	ret = efivar_entry_get(entry, &var->Attributes, &datasize, var->Data);
+	var->DataSize = datasize;
+	if (ret)
 		return -EIO;
 
 	if (in_compat_syscall()) {