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 --- crypto/842.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 crypto/842.c (limited to 'crypto/842.c') diff --git a/crypto/842.c b/crypto/842.c new file mode 100644 index 000000000..4007e87be --- /dev/null +++ b/crypto/842.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cryptographic API for the 842 software compression algorithm. + * + * Copyright (C) IBM Corporation, 2011-2015 + * + * Original Authors: Robert Jennings + * Seth Jennings + * + * Rewrite: Dan Streetman + * + * This is the software implementation of compression and decompression using + * the 842 format. This uses the software 842 library at lib/842/ which is + * only a reference implementation, and is very, very slow as compared to other + * software compressors. You probably do not want to use this software + * compression. If you have access to the PowerPC 842 compression hardware, you + * want to use the 842 hardware compression interface, which is at: + * drivers/crypto/nx/nx-842-crypto.c + */ + +#include +#include +#include +#include + +static void *crypto842_alloc_ctx(void) +{ + void *ctx; + + ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL); + if (!ctx) + return ERR_PTR(-ENOMEM); + + return ctx; +} + +static void crypto842_free_ctx(void *ctx) +{ + kfree(ctx); +} + +static int crypto842_scompress(struct crypto_scomp *tfm, + const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen, void *ctx) +{ + return sw842_compress(src, slen, dst, dlen, ctx); +} + +static int crypto842_sdecompress(struct crypto_scomp *tfm, + const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen, void *ctx) +{ + return sw842_decompress(src, slen, dst, dlen); +} + +static struct scomp_alg scomp = { + .streams = { + .alloc_ctx = crypto842_alloc_ctx, + .free_ctx = crypto842_free_ctx, + }, + .compress = crypto842_scompress, + .decompress = crypto842_sdecompress, + .base = { + .cra_name = "842", + .cra_driver_name = "842-scomp", + .cra_priority = 100, + .cra_module = THIS_MODULE, + } +}; + +static int __init crypto842_mod_init(void) +{ + return crypto_register_scomp(&scomp); +} +module_init(crypto842_mod_init); + +static void __exit crypto842_mod_exit(void) +{ + crypto_unregister_scomp(&scomp); +} +module_exit(crypto842_mod_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("842 Software Compression Algorithm"); +MODULE_ALIAS_CRYPTO("842"); +MODULE_ALIAS_CRYPTO("842-generic"); +MODULE_AUTHOR("Dan Streetman "); -- cgit v1.3.1