From 1537ad15c9c59ce852748578eb5633139053e86b Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Wed, 3 Apr 2019 09:29:41 +0200 Subject: kernfs: fix xattr name handling in LSM helpers The implementation of kernfs_security_xattr_*() helpers reuses the kernfs_node_xattr_*() functions, which take the suffix of the xattr name and extract full xattr name from it using xattr_full_name(). However, this function relies on the fact that the suffix passed to xattr handlers from VFS is always constructed from the full name by just incerementing the pointer. This doesn't necessarily hold for the callers of kernfs_security_xattr_*(), so their usage will easily lead to out-of-bounds access. Fix this by moving the xattr name reconstruction to the VFS xattr handlers and replacing the kernfs_security_xattr_*() helpers with more general kernfs_xattr_*() helpers that take full xattr name and allow accessing all kernfs node's xattrs. Reported-by: kernel test robot Fixes: b230d5aba2d1 ("LSM: add new hook for kernfs node initialization") Fixes: ec882da5cda9 ("selinux: implement the kernfs_init_security hook") Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore --- security/selinux/hooks.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'security') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index b6e61524d68d..d5fdcb0d26fe 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3394,7 +3394,7 @@ static int selinux_kernfs_init_security(struct kernfs_node *kn_dir, int rc; char *context; - rc = kernfs_security_xattr_get(kn_dir, XATTR_SELINUX_SUFFIX, NULL, 0); + rc = kernfs_xattr_get(kn_dir, XATTR_NAME_SELINUX, NULL, 0); if (rc == -ENODATA) return 0; else if (rc < 0) @@ -3405,8 +3405,7 @@ static int selinux_kernfs_init_security(struct kernfs_node *kn_dir, if (!context) return -ENOMEM; - rc = kernfs_security_xattr_get(kn_dir, XATTR_SELINUX_SUFFIX, context, - clen); + rc = kernfs_xattr_get(kn_dir, XATTR_NAME_SELINUX, context, clen); if (rc < 0) { kfree(context); return rc; @@ -3439,8 +3438,8 @@ static int selinux_kernfs_init_security(struct kernfs_node *kn_dir, if (rc) return rc; - rc = kernfs_security_xattr_set(kn, XATTR_SELINUX_SUFFIX, context, clen, - XATTR_CREATE); + rc = kernfs_xattr_set(kn, XATTR_NAME_SELINUX, context, clen, + XATTR_CREATE); kfree(context); return rc; } -- cgit