On Fri, May 24, 2024 at 08:59:53 -0400, James Bottomley wrote:
> Consumers of the ASN.1 encoder occasionally need to insert OIDs into
> the ASN.1 stream. The existing interface in lib/asn1_encoder.c is
> clunky in that it directly encodes the u32 array form of the OID.
> Instead introduce a function, encode_OID() which takes the OID enum
> and returns the ASN.1 encoding. This is easy because the OID registry
> table already has the binary encoded form for comparison.
>
> Signed-off-by: James Bottomley <[email protected]>
> ---
> include/linux/oid_registry.h | 1 +
> lib/oid_registry.c | 29 +++++++++++++++++++++++++++++
> 2 files changed, 30 insertions(+)
>
> diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
> index 51421fdbb0ba..87a6bcb2f5c0 100644
> --- a/include/linux/oid_registry.h
> +++ b/include/linux/oid_registry.h
> @@ -151,5 +151,6 @@ extern enum OID look_up_OID(const void *data, size_t
> datasize);
> extern int parse_OID(const void *data, size_t datasize, enum OID *oid);
> extern int sprint_oid(const void *, size_t, char *, size_t);
> extern int sprint_OID(enum OID, char *, size_t);
> +extern ssize_t encode_OID(enum OID, u8 *, size_t);
>
> #endif /* _LINUX_OID_REGISTRY_H */
> diff --git a/lib/oid_registry.c b/lib/oid_registry.c
> index fe6705cfd780..adbc287875c1 100644
> --- a/lib/oid_registry.c
> +++ b/lib/oid_registry.c
> @@ -12,6 +12,7 @@
> #include <linux/errno.h>
> #include <linux/bug.h>
> #include <linux/asn1.h>
> +#include <linux/asn1_ber_bytecode.h>
> #include "oid_registry_data.c"
>
> MODULE_DESCRIPTION("OID Registry");
> @@ -196,3 +197,31 @@ int sprint_OID(enum OID oid, char *buffer, size_t
> bufsize)
> return ret;
> }
> EXPORT_SYMBOL_GPL(sprint_OID);
> +
> +/**
> + * encode_OID - embed an ASN.1 encoded OID in the provide buffer
"provided"
--Ben
> + * @oid: The OID to encode
> + * @buffer: The buffer to encode to
> + * @bufsize: the maximum size of the buffer
> + *
> + * Returns: negative error or encoded size in the buffer.
> + */
> +ssize_t encode_OID(enum OID oid, u8 *buffer, size_t bufsize)
> +{
> + int oid_size;
> +
> + BUG_ON(oid >= OID__NR);
> +
> + oid_size = oid_index[oid + 1] - oid_index[oid];
> +
> + if (bufsize < oid_size + 2)
> + return -EINVAL;
> +
> + buffer[0] = _tag(UNIV, PRIM, OID);
> + buffer[1] = oid_size;
> +
> + memcpy(&buffer[2], &oid_data[oid_index[oid]], oid_size);
> +
> + return oid_size + 2;
> +}
> +EXPORT_SYMBOL_GPL(encode_OID);
> --
> 2.35.3
>
>
