mirror of
https://git.tartarus.org/simon/putty.git
synced 2025-01-09 09:27:59 +00:00
fca13a17b1
This applies to all of AES, SHA-1, SHA-256 and SHA-512. All those source files previously contained multiple implementations of the algorithm, enabled or disabled by ifdefs detecting whether they would work on a given compiler. And in order to get advanced machine instructions like AES-NI or NEON crypto into the output file when the compile flags hadn't enabled them, we had to do nasty stuff with compiler-specific pragmas or attributes. Now we can do the detection at cmake time, and enable advanced instructions in the more sensible way, by compile-time flags. So I've broken up each of these modules into lots of sub-pieces: a file called (e.g.) 'foo-common.c' containing common definitions across all implementations (such as round constants), one called 'foo-select.c' containing the top-level vtable(s), and a separate file for each implementation exporting just the vtable(s) for that implementation. One advantage of this is that it depends a lot less on compiler- specific bodgery. My particular least favourite part of the previous setup was the part where I had to _manually_ define some Arm ACLE feature macros before including <arm_neon.h>, so that it would define the intrinsics I wanted. Now I'm enabling interesting architecture features in the normal way, on the compiler command line, there's no need for that kind of trick: the right feature macros are already defined and <arm_neon.h> does the right thing. Another change in this reorganisation is that I've stopped assuming there's just one hardware implementation per platform. Previously, the accelerated vtables were called things like sha256_hw, and varied between FOO-NI and NEON depending on platform; and the selection code would simply ask 'is hw available? if so, use hw, else sw'. Now, each HW acceleration strategy names its vtable its own way, and the selection vtable has a whole list of possibilities to iterate over looking for a supported one. So if someone feels like writing a second accelerated implementation of something for a given platform - for example, I've heard you can use plain NEON to speed up AES somewhat even without the crypto extension - then it will now have somewhere to drop in alongside the existing ones.
110 lines
4.6 KiB
C
110 lines
4.6 KiB
C
/*
|
|
* Definitions likely to be helpful to multiple AES implementations.
|
|
*/
|
|
|
|
/*
|
|
* The 'extra' structure used by AES implementations is used to
|
|
* include information about how to check if a given implementation is
|
|
* available at run time, and whether we've already checked.
|
|
*/
|
|
struct aes_extra_mutable;
|
|
struct aes_extra {
|
|
/* Function to check availability. Might be expensive, so we don't
|
|
* want to call it more than once. */
|
|
bool (*check_available)(void);
|
|
|
|
/* Point to a writable substructure. */
|
|
struct aes_extra_mutable *mut;
|
|
};
|
|
struct aes_extra_mutable {
|
|
bool checked_availability;
|
|
bool is_available;
|
|
};
|
|
static inline bool check_availability(const struct aes_extra *extra)
|
|
{
|
|
if (!extra->mut->checked_availability) {
|
|
extra->mut->is_available = extra->check_available();
|
|
extra->mut->checked_availability = true;
|
|
}
|
|
|
|
return extra->mut->is_available;
|
|
}
|
|
|
|
/*
|
|
* Macros to define vtables for AES variants. There are a lot of
|
|
* these, because of the cross product between cipher modes, key
|
|
* sizes, and assorted HW/SW implementations, so it's worth spending
|
|
* some effort here to reduce the boilerplate in the sub-files.
|
|
*/
|
|
|
|
#define AES_EXTRA(impl_c) \
|
|
static struct aes_extra_mutable aes ## impl_c ## _extra_mut; \
|
|
static const struct aes_extra aes ## impl_c ## _extra = { \
|
|
.check_available = aes ## impl_c ## _available, \
|
|
.mut = &aes ## impl_c ## _extra_mut, \
|
|
}
|
|
|
|
#define AES_CBC_VTABLE(impl_c, impl_display, bits) \
|
|
const ssh_cipheralg ssh_aes ## bits ## _cbc ## impl_c = { \
|
|
.new = aes ## impl_c ## _new, \
|
|
.free = aes ## impl_c ## _free, \
|
|
.setiv = aes ## impl_c ## _setiv_cbc, \
|
|
.setkey = aes ## impl_c ## _setkey, \
|
|
.encrypt = aes ## bits ## impl_c ## _cbc_encrypt, \
|
|
.decrypt = aes ## bits ## impl_c ## _cbc_decrypt, \
|
|
.ssh2_id = "aes" #bits "-cbc", \
|
|
.blksize = 16, \
|
|
.real_keybits = bits, \
|
|
.padded_keybytes = bits/8, \
|
|
.flags = SSH_CIPHER_IS_CBC, \
|
|
.text_name = "AES-" #bits " CBC (" impl_display ")", \
|
|
.extra = &aes ## impl_c ## _extra, \
|
|
}
|
|
|
|
#define AES_SDCTR_VTABLE(impl_c, impl_display, bits) \
|
|
const ssh_cipheralg ssh_aes ## bits ## _sdctr ## impl_c = { \
|
|
.new = aes ## impl_c ## _new, \
|
|
.free = aes ## impl_c ## _free, \
|
|
.setiv = aes ## impl_c ## _setiv_sdctr, \
|
|
.setkey = aes ## impl_c ## _setkey, \
|
|
.encrypt = aes ## bits ## impl_c ## _sdctr, \
|
|
.decrypt = aes ## bits ## impl_c ## _sdctr, \
|
|
.ssh2_id = "aes" #bits "-ctr", \
|
|
.blksize = 16, \
|
|
.real_keybits = bits, \
|
|
.padded_keybytes = bits/8, \
|
|
.flags = 0, \
|
|
.text_name = "AES-" #bits " SDCTR (" impl_display ")", \
|
|
.extra = &aes ## impl_c ## _extra, \
|
|
}
|
|
|
|
#define AES_ALL_VTABLES(impl_c, impl_display) \
|
|
AES_CBC_VTABLE(impl_c, impl_display, 128); \
|
|
AES_CBC_VTABLE(impl_c, impl_display, 192); \
|
|
AES_CBC_VTABLE(impl_c, impl_display, 256); \
|
|
AES_SDCTR_VTABLE(impl_c, impl_display, 128); \
|
|
AES_SDCTR_VTABLE(impl_c, impl_display, 192); \
|
|
AES_SDCTR_VTABLE(impl_c, impl_display, 256)
|
|
|
|
/*
|
|
* Macros to repeat a piece of code particular numbers of times that
|
|
* correspond to 1 fewer than the number of AES rounds. (Because the
|
|
* last round is different.)
|
|
*/
|
|
#define REP2(x) x x
|
|
#define REP4(x) REP2(REP2(x))
|
|
#define REP8(x) REP2(REP4(x))
|
|
#define REP9(x) REP8(x) x
|
|
#define REP11(x) REP8(x) REP2(x) x
|
|
#define REP13(x) REP8(x) REP4(x) x
|
|
|
|
/*
|
|
* The round constants used in key schedule expansion.
|
|
*/
|
|
extern const uint8_t aes_key_setup_round_constants[10];
|
|
|
|
/*
|
|
* The largest number of round keys ever needed.
|
|
*/
|
|
#define MAXROUNDKEYS 15
|