(Cc'ing some other folks that might be interested) On Fri, 2012-10-19 at 15:16 +0800, Jeremy Kerr wrote: > At present, the handling of GUIDs in efivar file names isn't consistent. > We use GUID_LEN in some places, and 38 in others (GUID_LEN plus > separator), and implicitly use the presence of the trailing NUL. > > This change removes the trailing NUL from GUID_LEN, so that we're > explicitly adding it when required. We also replace magic numbers > with GUID_LEN, and clarify the comments where appropriate. > > We also fix the allocation size in efivar_create_sysfs_entry, where > we're allocating one byte too much, due to counting the trailing NUL > twice - once when calculating short_name_size, and once in the kzalloc. > > Signed-off-by: Jeremy Kerr <[email protected]> > > --- > drivers/firmware/efivars.c | 29 +++++++++++++++++++++-------- > 1 file changed, 21 insertions(+), 8 deletions(-) > > diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c > index a86eb55..ce0d6fa 100644 > --- a/drivers/firmware/efivars.c > +++ b/drivers/firmware/efivars.c > @@ -95,7 +95,12 @@ MODULE_LICENSE("GPL"); > MODULE_VERSION(EFIVARS_VERSION); > > #define DUMP_NAME_LEN 52 > -#define GUID_LEN 37 > + > +/* > + * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee")) > + * not including trailing NUL > + */ > +#define GUID_LEN 36 > > /* > * The maximum size of VariableName + Data = 1024 > @@ -876,7 +881,9 @@ static int efivarfs_create(struct inode *dir, struct > dentry *dentry, > struct efivar_entry *var; > int namelen, i = 0, err = 0; > > - if (dentry->d_name.len < 38) > + /* We need a GUID, plus at least one letter for the variable name, > + * plus the '-' separator */ > + if (dentry->d_name.len < GUID_LEN + 2) > return -EINVAL; > > inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0); > @@ -889,7 +896,8 @@ static int efivarfs_create(struct inode *dir, struct > dentry *dentry, > goto out; > } > > - namelen = dentry->d_name.len - GUID_LEN; > + /* length of the variable name itself: remove GUID and separator */ > + namelen = dentry->d_name.len - GUID_LEN - 1; > > efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1, > &var->var.VendorGuid); > @@ -983,8 +991,8 @@ int efivarfs_fill_super(struct super_block *sb, void > *data, int silent) > > len = utf16_strlen(entry->var.VariableName); > > - /* GUID plus trailing NULL */ > - name = kmalloc(len + 38, GFP_ATOMIC); > + /* name, plus '-', plus GUID, plus NUL*/ > + name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC); > if (!name) > goto fail; > > @@ -995,7 +1003,7 @@ int efivarfs_fill_super(struct super_block *sb, void > *data, int silent) > > efi_guid_unparse(&entry->var.VendorGuid, name + len + 1); > > - name[len+GUID_LEN] = '\0'; > + name[len+GUID_LEN+1] = '\0'; > > inode = efivarfs_get_inode(efivarfs_sb, root->d_inode, > S_IFREG | 0644, 0); > @@ -1424,11 +1432,16 @@ efivar_create_sysfs_entry(struct efivars *efivars, > efi_char16_t *variable_name, > efi_guid_t *vendor_guid) > { > - int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38; > + int i, short_name_size; > char *short_name; > struct efivar_entry *new_efivar; > > - short_name = kzalloc(short_name_size + 1, GFP_KERNEL); > + /* Length of the variable bytes in ASCII, plus the '-' separator, > + * plus the GUID, plus trailing NUL */ > + short_name_size = variable_name_size / sizeof(efi_char_16_t) > + + 1 + GUID_LEN + 1; > + > + short_name = kzalloc(short_name_size, GFP_KERNEL); > new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); > > if (!short_name || !new_efivar) {
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