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* [PATCH] selinux: fix inconsistency between inode_getxattr and inode_listsecurity
@ 2020-12-19 10:05 Amir Goldstein
  2021-01-04  9:39 ` Ondrej Mosnacek
  0 siblings, 1 reply; 3+ messages in thread
From: Amir Goldstein @ 2020-12-19 10:05 UTC (permalink / raw)
  To: Paul Moore
  Cc: Michael Labriola, Jonathan Lebon, Stephen Smalley,
	Miklos Szeredi, selinux, linux-security-module, linux-unionfs,
	linux-fsdevel, stable

When inode has no listxattr op of its own (e.g. squashfs) vfs_listxattr
calls the LSM inode_listsecurity hooks to list the xattrs that LSMs will
intercept in inode_getxattr hooks.

When selinux LSM is installed but not initialized, it will list the
security.selinux xattr in inode_listsecurity, but will not intercept it
in inode_getxattr.  This results in -ENODATA for a getxattr call for an
xattr returned by listxattr.

This situation was manifested as overlayfs failure to copy up lower
files from squashfs when selinux is built-in but not initialized,
because ovl_copy_xattr() iterates the lower inode xattrs by
vfs_listxattr() and vfs_getxattr().

Match the logic of inode_listsecurity to that of inode_getxattr and
do not list the security.selinux xattr if selinux is not initialized.

Reported-by: Michael Labriola <>
Tested-by: Michael Labriola <>
Fixes: c8e222616c7e ("selinux: allow reading labels before policy is loaded")
Signed-off-by: Amir Goldstein <>
 security/selinux/hooks.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6b1826fc3658..e132e082a5af 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3406,6 +3406,10 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
 static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
 	const int len = sizeof(XATTR_NAME_SELINUX);
+	if (!selinux_initialized(&selinux_state))
+		return 0;
 	if (buffer && len <= buffer_size)
 		memcpy(buffer, XATTR_NAME_SELINUX, len);
 	return len;

^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-01-05  1:47 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-19 10:05 [PATCH] selinux: fix inconsistency between inode_getxattr and inode_listsecurity Amir Goldstein
2021-01-04  9:39 ` Ondrej Mosnacek
2021-01-05  1:46   ` Paul Moore

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