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 --- lib/crypto/arc4.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 lib/crypto/arc4.c (limited to 'lib/crypto/arc4.c') diff --git a/lib/crypto/arc4.c b/lib/crypto/arc4.c new file mode 100644 index 000000000..4e950e1e6 --- /dev/null +++ b/lib/crypto/arc4.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cryptographic API + * + * ARC4 Cipher Algorithm + * + * Jon Oberheide + */ + +#include +#include +#include + +int arc4_setkey(struct arc4_ctx *ctx, const u8 *in_key, unsigned int key_len) +{ + int i, j = 0, k = 0; + + ctx->x = 1; + ctx->y = 0; + + for (i = 0; i < 256; i++) + ctx->S[i] = i; + + for (i = 0; i < 256; i++) { + u32 a = ctx->S[i]; + + j = (j + in_key[k] + a) & 0xff; + ctx->S[i] = ctx->S[j]; + ctx->S[j] = a; + if (++k >= key_len) + k = 0; + } + + return 0; +} +EXPORT_SYMBOL(arc4_setkey); + +void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in, unsigned int len) +{ + u32 *const S = ctx->S; + u32 x, y, a, b; + u32 ty, ta, tb; + + if (len == 0) + return; + + x = ctx->x; + y = ctx->y; + + a = S[x]; + y = (y + a) & 0xff; + b = S[y]; + + do { + S[y] = a; + a = (a + b) & 0xff; + S[x] = b; + x = (x + 1) & 0xff; + ta = S[x]; + ty = (y + ta) & 0xff; + tb = S[ty]; + *out++ = *in++ ^ S[a]; + if (--len == 0) + break; + y = ty; + a = ta; + b = tb; + } while (true); + + ctx->x = x; + ctx->y = y; +} +EXPORT_SYMBOL(arc4_crypt); + +MODULE_DESCRIPTION("ARC4 Cipher Algorithm"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1