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authorDavid Howells <dhowells@redhat.com>2023-08-08 13:34:20 +0200
committerChristian Brauner <brauner@kernel.org>2023-08-15 08:32:30 +0200
commitd80a8f1b58c2bc8d7c6bfb65401ea4f7ec8cddc2 (patch)
treef20b825962286f47e36e6e4e3d0f0e4a62549f16 /security/security.c
parentfs: unexport d_genocide (diff)
downloadlinux-d80a8f1b58c2bc8d7c6bfb65401ea4f7ec8cddc2.tar.xz
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vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing
When NFS superblocks are created by automounting, their LSM parameters aren't set in the fs_context struct prior to sget_fc() being called, leading to failure to match existing superblocks. This bug leads to messages like the following appearing in dmesg when fscache is enabled: NFS: Cache volume key already in use (nfs,4.2,2,108,106a8c0,1,,,,100000,100000,2ee,3a98,1d4c,3a98,1) Fix this by adding a new LSM hook to load fc->security for submount creation. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/165962680944.3334508.6610023900349142034.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165962729225.3357250.14350728846471527137.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/165970659095.2812394.6868894171102318796.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/166133579016.3678898.6283195019480567275.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/217595.1662033775@warthog.procyon.org.uk/ # v5 Fixes: 9bc61ab18b1d ("vfs: Introduce fs_context, switch vfs_kern_mount() to it.") Fixes: 779df6a5480f ("NFS: Ensure security label is set for root inode") Tested-by: Jeff Layton <jlayton@kernel.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: "Christian Brauner (Microsoft)" <brauner@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230808-master-v9-1-e0ecde888221@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'security/security.c')
-rw-r--r--security/security.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c
index b720424ca37d..549104a447e3 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1139,6 +1139,20 @@ void security_bprm_committed_creds(struct linux_binprm *bprm)
}
/**
+ * security_fs_context_submount() - Initialise fc->security
+ * @fc: new filesystem context
+ * @reference: dentry reference for submount/remount
+ *
+ * Fill out the ->security field for a new fs_context.
+ *
+ * Return: Returns 0 on success or negative error code on failure.
+ */
+int security_fs_context_submount(struct fs_context *fc, struct super_block *reference)
+{
+ return call_int_hook(fs_context_submount, 0, fc, reference);
+}
+
+/**
* security_fs_context_dup() - Duplicate a fs_context LSM blob
* @fc: destination filesystem context
* @src_fc: source filesystem context