From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- fs/ubifs/crypto.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 fs/ubifs/crypto.c (limited to 'fs/ubifs/crypto.c') diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c new file mode 100644 index 000000000..0b14d004a --- /dev/null +++ b/fs/ubifs/crypto.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "ubifs.h" + +static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len) +{ + return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT, + ctx, len); +} + +static int ubifs_crypt_set_context(struct inode *inode, const void *ctx, + size_t len, void *fs_data) +{ + /* + * Creating an encryption context is done unlocked since we + * operate on a new inode which is not visible to other users + * at this point. So, no need to check whether inode is locked. + */ + return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT, + ctx, len, 0, false); +} + +static bool ubifs_crypt_empty_dir(struct inode *inode) +{ + return ubifs_check_dir_empty(inode) == 0; +} + +/** + * ubifs_encrypt - Encrypt data. + * @inode: inode which refers to the data node + * @dn: data node to encrypt + * @in_len: length of data to be compressed + * @out_len: allocated memory size for the data area of @dn + * @block: logical block number of the block + * + * This function encrypt a possibly-compressed data in the data node. + * The encrypted data length will store in @out_len. + */ +int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn, + unsigned int in_len, unsigned int *out_len, int block) +{ + struct ubifs_info *c = inode->i_sb->s_fs_info; + void *p = &dn->data; + unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE); + int err; + + ubifs_assert(c, pad_len <= *out_len); + dn->compr_size = cpu_to_le16(in_len); + + /* pad to full block cipher length */ + if (pad_len != in_len) + memset(p + in_len, 0, pad_len - in_len); + + err = fscrypt_encrypt_block_inplace(inode, virt_to_page(p), pad_len, + offset_in_page(p), block); + if (err) { + ubifs_err(c, "fscrypt_encrypt_block_inplace() failed: %d", err); + return err; + } + *out_len = pad_len; + + return 0; +} + +int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn, + unsigned int *out_len, int block) +{ + struct ubifs_info *c = inode->i_sb->s_fs_info; + int err; + unsigned int clen = le16_to_cpu(dn->compr_size); + unsigned int dlen = *out_len; + + if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) { + ubifs_err(c, "bad compr_size: %i", clen); + return -EINVAL; + } + + ubifs_assert(c, dlen <= UBIFS_BLOCK_SIZE); + err = fscrypt_decrypt_block_inplace(inode, virt_to_page(&dn->data), + dlen, offset_in_page(&dn->data), + block); + if (err) { + ubifs_err(c, "fscrypt_decrypt_block_inplace() failed: %d", err); + return err; + } + *out_len = clen; + + return 0; +} + +const struct fscrypt_operations ubifs_crypt_operations = { + .inode_info_offs = (int)offsetof(struct ubifs_inode, i_crypt_info) - + (int)offsetof(struct ubifs_inode, vfs_inode), + .legacy_key_prefix = "ubifs:", + .get_context = ubifs_crypt_get_context, + .set_context = ubifs_crypt_set_context, + .empty_dir = ubifs_crypt_empty_dir, +}; -- cgit v1.3.1