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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-27 16:17:42 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-27 16:17:42 -0800
commite3c4877de8b9d93bd47b6ee88eb594b1c1e10da5 (patch)
tree17ade3a3a13b1e7768abe3561b6808dc4980a5f6 /drivers/firmware
parent18a44a7ff1075ce5157ac07cde573aca6b5e9973 (diff)
parent6b59e366e074d3962e04f01efb8acc10a33c0e1e (diff)
Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/EFI changes from Peter Anvin: - Improve the initrd handling in the EFI boot stub by allowing forward slashes in the pathname - from Chun-Yi Lee. - Cleanup code duplication in the EFI mixed kernel/firmware code - from Satoru Takeuchi. - efivarfs bug fixes for more strict filename validation, with lots of input from Al Viro. * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, efi: remove duplicate code in setup_arch() by using, efi_is_native() efivarfs: guid part of filenames are case-insensitive efivarfs: Validate filenames much more aggressively efivarfs: Use sizeof() instead of magic number x86, efi: Allow slash in file path of initrd
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efivars.c146
1 files changed, 138 insertions, 8 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index fed08b661711..7320bf891706 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -79,6 +79,7 @@
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/pstore.h>
+#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/ramfs.h>
@@ -908,6 +909,48 @@ static struct inode *efivarfs_get_inode(struct super_block *sb,
return inode;
}
+/*
+ * Return true if 'str' is a valid efivarfs filename of the form,
+ *
+ * VariableName-12345678-1234-1234-1234-1234567891bc
+ */
+static bool efivarfs_valid_name(const char *str, int len)
+{
+ static const char dashes[GUID_LEN] = {
+ [8] = 1, [13] = 1, [18] = 1, [23] = 1
+ };
+ const char *s = str + len - GUID_LEN;
+ int i;
+
+ /*
+ * We need a GUID, plus at least one letter for the variable name,
+ * plus the '-' separator
+ */
+ if (len < GUID_LEN + 2)
+ return false;
+
+ /* GUID should be right after the first '-' */
+ if (s - 1 != strchr(str, '-'))
+ return false;
+
+ /*
+ * Validate that 's' is of the correct format, e.g.
+ *
+ * 12345678-1234-1234-1234-123456789abc
+ */
+ for (i = 0; i < GUID_LEN; i++) {
+ if (dashes[i]) {
+ if (*s++ != '-')
+ return false;
+ } else {
+ if (!isxdigit(*s++))
+ return false;
+ }
+ }
+
+ return true;
+}
+
static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
{
guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
@@ -936,11 +979,7 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
struct efivar_entry *var;
int namelen, i = 0, err = 0;
- /*
- * We need a GUID, plus at least one letter for the variable name,
- * plus the '-' separator
- */
- if (dentry->d_name.len < GUID_LEN + 2)
+ if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
return -EINVAL;
inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
@@ -1012,6 +1051,84 @@ static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
return -EINVAL;
};
+/*
+ * Compare two efivarfs file names.
+ *
+ * An efivarfs filename is composed of two parts,
+ *
+ * 1. A case-sensitive variable name
+ * 2. A case-insensitive GUID
+ *
+ * So we need to perform a case-sensitive match on part 1 and a
+ * case-insensitive match on part 2.
+ */
+static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
+ const struct dentry *dentry, const struct inode *inode,
+ unsigned int len, const char *str,
+ const struct qstr *name)
+{
+ int guid = len - GUID_LEN;
+
+ if (name->len != len)
+ return 1;
+
+ /* Case-sensitive compare for the variable name */
+ if (memcmp(str, name->name, guid))
+ return 1;
+
+ /* Case-insensitive compare for the GUID */
+ return strncasecmp(name->name + guid, str + guid, GUID_LEN);
+}
+
+static int efivarfs_d_hash(const struct dentry *dentry,
+ const struct inode *inode, struct qstr *qstr)
+{
+ unsigned long hash = init_name_hash();
+ const unsigned char *s = qstr->name;
+ unsigned int len = qstr->len;
+
+ if (!efivarfs_valid_name(s, len))
+ return -EINVAL;
+
+ while (len-- > GUID_LEN)
+ hash = partial_name_hash(*s++, hash);
+
+ /* GUID is case-insensitive. */
+ while (len--)
+ hash = partial_name_hash(tolower(*s++), hash);
+
+ qstr->hash = end_name_hash(hash);
+ return 0;
+}
+
+/*
+ * Retaining negative dentries for an in-memory filesystem just wastes
+ * memory and lookup time: arrange for them to be deleted immediately.
+ */
+static int efivarfs_delete_dentry(const struct dentry *dentry)
+{
+ return 1;
+}
+
+static struct dentry_operations efivarfs_d_ops = {
+ .d_compare = efivarfs_d_compare,
+ .d_hash = efivarfs_d_hash,
+ .d_delete = efivarfs_delete_dentry,
+};
+
+static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
+{
+ struct qstr q;
+
+ q.name = name;
+ q.len = strlen(name);
+
+ if (efivarfs_d_hash(NULL, NULL, &q))
+ return NULL;
+
+ return d_alloc(parent, &q);
+}
+
static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode = NULL;
@@ -1027,6 +1144,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = EFIVARFS_MAGIC;
sb->s_op = &efivarfs_ops;
+ sb->s_d_op = &efivarfs_d_ops;
sb->s_time_gran = 1;
inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
@@ -1067,7 +1185,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
if (!inode)
goto fail_name;
- dentry = d_alloc_name(root, name);
+ dentry = efivarfs_alloc_dentry(root, name);
if (!dentry)
goto fail_inode;
@@ -1084,7 +1202,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
mutex_lock(&inode->i_mutex);
inode->i_private = entry;
- i_size_write(inode, size+4);
+ i_size_write(inode, size + sizeof(entry->var.Attributes));
mutex_unlock(&inode->i_mutex);
d_add(dentry, inode);
}
@@ -1117,8 +1235,20 @@ static struct file_system_type efivarfs_type = {
.kill_sb = efivarfs_kill_sb,
};
+/*
+ * Handle negative dentry.
+ */
+static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ if (dentry->d_name.len > NAME_MAX)
+ return ERR_PTR(-ENAMETOOLONG);
+ d_add(dentry, NULL);
+ return NULL;
+}
+
static const struct inode_operations efivarfs_dir_inode_operations = {
- .lookup = simple_lookup,
+ .lookup = efivarfs_lookup,
.unlink = efivarfs_unlink,
.create = efivarfs_create,
};

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