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https://git.tartarus.org/simon/putty.git
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840043f06e
This provides a convenient hook to be called between SSH messages, for the crypto components to do any per-message processing like incrementing a sequence number.
112 lines
4.8 KiB
C
112 lines
4.8 KiB
C
/*
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* Definitions likely to be helpful to multiple AES implementations.
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*/
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/*
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* The 'extra' structure used by AES implementations is used to
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* include information about how to check if a given implementation is
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* available at run time, and whether we've already checked.
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*/
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struct aes_extra_mutable;
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struct aes_extra {
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/* Function to check availability. Might be expensive, so we don't
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* want to call it more than once. */
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bool (*check_available)(void);
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/* Point to a writable substructure. */
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struct aes_extra_mutable *mut;
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};
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struct aes_extra_mutable {
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bool checked_availability;
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bool is_available;
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};
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static inline bool check_availability(const struct aes_extra *extra)
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{
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if (!extra->mut->checked_availability) {
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extra->mut->is_available = extra->check_available();
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extra->mut->checked_availability = true;
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}
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return extra->mut->is_available;
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}
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/*
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* Macros to define vtables for AES variants. There are a lot of
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* these, because of the cross product between cipher modes, key
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* sizes, and assorted HW/SW implementations, so it's worth spending
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* some effort here to reduce the boilerplate in the sub-files.
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*/
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#define AES_EXTRA(impl_c) \
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static struct aes_extra_mutable aes ## impl_c ## _extra_mut; \
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static const struct aes_extra aes ## impl_c ## _extra = { \
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.check_available = aes ## impl_c ## _available, \
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.mut = &aes ## impl_c ## _extra_mut, \
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}
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#define AES_CBC_VTABLE(impl_c, impl_display, bits) \
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const ssh_cipheralg ssh_aes ## bits ## _cbc ## impl_c = { \
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.new = aes ## impl_c ## _new, \
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.free = aes ## impl_c ## _free, \
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.setiv = aes ## impl_c ## _setiv_cbc, \
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.setkey = aes ## impl_c ## _setkey, \
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.encrypt = aes ## bits ## impl_c ## _cbc_encrypt, \
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.decrypt = aes ## bits ## impl_c ## _cbc_decrypt, \
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.next_message = nullcipher_next_message, \
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.ssh2_id = "aes" #bits "-cbc", \
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.blksize = 16, \
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.real_keybits = bits, \
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.padded_keybytes = bits/8, \
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.flags = SSH_CIPHER_IS_CBC, \
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.text_name = "AES-" #bits " CBC (" impl_display ")", \
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.extra = &aes ## impl_c ## _extra, \
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}
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#define AES_SDCTR_VTABLE(impl_c, impl_display, bits) \
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const ssh_cipheralg ssh_aes ## bits ## _sdctr ## impl_c = { \
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.new = aes ## impl_c ## _new, \
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.free = aes ## impl_c ## _free, \
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.setiv = aes ## impl_c ## _setiv_sdctr, \
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.setkey = aes ## impl_c ## _setkey, \
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.encrypt = aes ## bits ## impl_c ## _sdctr, \
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.decrypt = aes ## bits ## impl_c ## _sdctr, \
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.next_message = nullcipher_next_message, \
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.ssh2_id = "aes" #bits "-ctr", \
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.blksize = 16, \
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.real_keybits = bits, \
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.padded_keybytes = bits/8, \
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.flags = 0, \
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.text_name = "AES-" #bits " SDCTR (" impl_display ")", \
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.extra = &aes ## impl_c ## _extra, \
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}
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#define AES_ALL_VTABLES(impl_c, impl_display) \
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AES_CBC_VTABLE(impl_c, impl_display, 128); \
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AES_CBC_VTABLE(impl_c, impl_display, 192); \
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AES_CBC_VTABLE(impl_c, impl_display, 256); \
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AES_SDCTR_VTABLE(impl_c, impl_display, 128); \
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AES_SDCTR_VTABLE(impl_c, impl_display, 192); \
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AES_SDCTR_VTABLE(impl_c, impl_display, 256)
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/*
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* Macros to repeat a piece of code particular numbers of times that
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* correspond to 1 fewer than the number of AES rounds. (Because the
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* last round is different.)
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*/
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#define REP2(x) x x
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#define REP4(x) REP2(REP2(x))
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#define REP8(x) REP2(REP4(x))
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#define REP9(x) REP8(x) x
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#define REP11(x) REP8(x) REP2(x) x
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#define REP13(x) REP8(x) REP4(x) x
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/*
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* The round constants used in key schedule expansion.
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*/
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extern const uint8_t aes_key_setup_round_constants[10];
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/*
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* The largest number of round keys ever needed.
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*/
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#define MAXROUNDKEYS 15
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