[PATCH 18/19] smack: smack_inode_setsecurity(): find label instead of import

[Konstantin Andreev]

smack_inode_setsecurity() is called
for label-containing xattrs either
after smack_inode_setxattr():

    fs/xattr.c:

    ...
    ` __vfs_setxattr_locked
      ` security_inode_setxattr
      ` __vfs_setxattr_noperm
        ` security_inode_setsecurity
or
    ...
    ` smack_inode_notifysecctx
      ` smack_inode_setsecurity

In both cases - via security_inode_setxattr()
or smack_inode_notifysecctx() -
the label is imported in advance.

There is no need to validate and import
the input value again; looking it up is sufficient.

Signed-off-by: Konstantin Andreev <andreev at swemel.ru>
---
 security/smack/smack_lsm.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 5d3d72162444..6c529de00584 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2996,17 +2996,16 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	))
 		return -EOPNOTSUPP;
 
-	if (value == NULL || size > SMK_LONGLABEL || size == 0)
-		return -EINVAL;
-
 	if (strcmp(name, XATTR_SMACK_TRANSMUTE) == 0) {
 		nsp->smk_flags |= SMK_INODE_TRANSMUTE;
 		return 0;
 	}
 
-	skp = smk_import_entry(value, size);
-	if (IS_ERR(skp))
-		return PTR_ERR(skp);
+	if (strcmp(name, XATTR_SMACK_EXEC) == 0 ||
+	    strcmp(name, XATTR_SMACK_MMAP) == 0)
+		return -ENODATA;
+
+	skp = smk_find_label(value, size);
 
 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
 		nsp->smk_inode = skp;
@@ -3014,9 +3013,6 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 		return 0;
 	}
 
-	if (strcmp(name, XATTR_SMACK_EXEC) == 0 ||
-	    strcmp(name, XATTR_SMACK_MMAP) == 0)
-		return -ENODATA;
 	/*
 	 * The rest of the Smack xattrs are only on sockets.
 	 * smack_inode_setxattr() has checked that inode is sockfs
-- 
2.43.0