From 35d442ed1f86465e49df3119fb898f985186db13 Mon Sep 17 00:00:00 2001 From: Andrea Parri Date: Tue, 22 Sep 2026 16:55:30 +0200 Subject: [PATCH] bpf: fs/xattr: don't assume the inode is locked in path_unlink/path_rmdir bpf_lsm_has_d_inode_locked() makes the verifier rewrite bpf_[set|remove]_dentry_xattr() to the _locked variants, which assume that the caller already holds the inode's i_rwsem. The path_unlink and path_rmdir hooks are listed, but security_path_unlink() and security_path_rmdir() run before vfs_unlink()/vfs_rmdir() take the victim inode's i_rwsem, so a sleepable BPF LSM program attached to either hook mutates the victim's xattrs without the lock held. Drop the two path hooks from d_inode_locked_hooks so that the verifier keeps the locking bpf_[set|remove]_dentry_xattr() variants, which take the lock themselves. Fixes: 56467292794b8 ("bpf: fs/xattr: Add BPF kfuncs to set and remove xattrs") Cc: stable@vger.kernel.org Signed-off-by: Andrea Parri Link: https://patch.msgid.link/20260922145530.369775-1-parri.andrea@gmail.com Signed-off-by: Christian Brauner (Amutable) --- fs/bpf_fs_kfuncs.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/fs/bpf_fs_kfuncs.c b/fs/bpf_fs_kfuncs.c index 6cb877267978..357a379ef92a 100644 --- a/fs/bpf_fs_kfuncs.c +++ b/fs/bpf_fs_kfuncs.c @@ -472,10 +472,6 @@ BTF_ID(func, bpf_lsm_inode_rmdir) BTF_ID(func, bpf_lsm_inode_setattr) BTF_ID(func, bpf_lsm_inode_setxattr) BTF_ID(func, bpf_lsm_inode_unlink) -#ifdef CONFIG_SECURITY_PATH -BTF_ID(func, bpf_lsm_path_unlink) -BTF_ID(func, bpf_lsm_path_rmdir) -#endif /* CONFIG_SECURITY_PATH */ BTF_SET_END(d_inode_locked_hooks) bool bpf_lsm_has_d_inode_locked(const struct bpf_prog *prog)