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bpf: fs/xattr: don't assume the inode is locked in path_unlink/path_rmdir

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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: 5646729279 ("bpf: fs/xattr: Add BPF kfuncs to set and remove xattrs")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://patch.msgid.link/20260922145530.369775-1-parri.andrea@gmail.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Andrea Parri 2026-09-22 16:55:30 +02:00 committed by Christian Brauner
parent aa5e44b29f
commit 35d442ed1f
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1 changed files with 0 additions and 4 deletions
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4
fs/bpf_fs_kfuncs.c
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@ -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)