bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 101 insertions, 0 deletions

diff --git a/crypto/lzo.c b/crypto/lzo.c
new file mode 100644
index 000000000..d43242b24
--- /dev/null
+++ b/crypto/lzo.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Cryptographic API.
+ */
+
+#include <crypto/internal/scompress.h>
+#include <linux/init.h>
+#include <linux/lzo.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+static void *lzo_alloc_ctx(void)
+{
+	void *ctx;
+
+	ctx = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	return ctx;
+}
+
+static void lzo_free_ctx(void *ctx)
+{
+	kvfree(ctx);
+}
+
+static int __lzo_compress(const u8 *src, unsigned int slen,
+			  u8 *dst, unsigned int *dlen, void *ctx)
+{
+	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
+	int err;
+
+	err = lzo1x_1_compress_safe(src, slen, dst, &tmp_len, ctx);
+
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	*dlen = tmp_len;
+	return 0;
+}
+
+static int lzo_scompress(struct crypto_scomp *tfm, const u8 *src,
+			 unsigned int slen, u8 *dst, unsigned int *dlen,
+			 void *ctx)
+{
+	return __lzo_compress(src, slen, dst, dlen, ctx);
+}
+
+static int __lzo_decompress(const u8 *src, unsigned int slen,
+			    u8 *dst, unsigned int *dlen)
+{
+	int err;
+	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
+
+	err = lzo1x_decompress_safe(src, slen, dst, &tmp_len);
+
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	*dlen = tmp_len;
+	return 0;
+}
+
+static int lzo_sdecompress(struct crypto_scomp *tfm, const u8 *src,
+			   unsigned int slen, u8 *dst, unsigned int *dlen,
+			   void *ctx)
+{
+	return __lzo_decompress(src, slen, dst, dlen);
+}
+
+static struct scomp_alg scomp = {
+	.streams		= {
+		.alloc_ctx	= lzo_alloc_ctx,
+		.free_ctx	= lzo_free_ctx,
+	},
+	.compress		= lzo_scompress,
+	.decompress		= lzo_sdecompress,
+	.base			= {
+		.cra_name	= "lzo",
+		.cra_driver_name = "lzo-scomp",
+		.cra_module	 = THIS_MODULE,
+	}
+};
+
+static int __init lzo_mod_init(void)
+{
+	return crypto_register_scomp(&scomp);
+}
+
+static void __exit lzo_mod_fini(void)
+{
+	crypto_unregister_scomp(&scomp);
+}
+
+module_init(lzo_mod_init);
+module_exit(lzo_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO Compression Algorithm");
+MODULE_ALIAS_CRYPTO("lzo");