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confluent/confluent_osdeploy/utils/sha-256.h
Jarrod Johnson 2d5a016ad4 Tweak various issues for static analysis.
For autocons, though it's copying from a static source, use strncpy anyway,
despite the length being hardcoded already.  This makes static analysis happier.

Terminate the buff with a NULL.  This is superfluous as the strcpies that preceed
are guaranteed to null terminate, or exit the program.

In clortho, free(tmps), which is a valid leak, though clortho isn't long running.
Also, explicitly return 0, which is ultimately returned by main().

Static analysis could not figure out that padneeded implies that keylen is short of
chunk size, so change the check to be expressly the scenario that static analysis
was worried about directly, rather than indirectly.

Hint to static analysis that we don't care about the time as a time value by masking the
lower 32 bit explicitly.  This was already happening, but static analysis was afraid
that we wanted this as time instead of just some mutating value.
2022-12-06 15:35:49 -05:00

105 lines
4.2 KiB
C

#ifndef SHA_256_H
#define SHA_256_H
#include <stdint.h>
#include <string.h>
#ifdef __cplusplus
extern "C" {
#endif
/*
* @brief Size of the SHA-256 sum. This times eight is 256 bits.
*/
#define SIZE_OF_SHA_256_HASH 32
/*
* @brief Size of the chunks used for the calculations.
*
* @note This should mostly be ignored by the user, although when using the streaming API, it has an impact for
* performance. Add chunks whose size is a multiple of this, and you will avoid a lot of superfluous copying in RAM!
*/
#define SIZE_OF_SHA_256_CHUNK 64
/*
* @brief The opaque SHA-256 type, that should be instantiated when using the streaming API.
*
* @note Although the details are exposed here, in order to make instantiation easy, you should refrain from directly
* accessing the fields, as they may change in the future.
*/
struct Sha_256 {
uint8_t *hash;
uint8_t chunk[SIZE_OF_SHA_256_CHUNK];
uint8_t *chunk_pos;
size_t space_left;
size_t total_len;
uint32_t h[8];
};
/*
* @brief The simple SHA-256 calculation function.
* @param hash Hash array, where the result is delivered.
* @param input Pointer to the data the hash shall be calculated on.
* @param len Length of the input data, in byte.
*
* @note If all of the data you are calculating the hash value on is available in a contiguous buffer in memory, this is
* the function you should use.
*
* @note If either of the passed pointers is NULL, the results are unpredictable.
*/
void calc_sha_256(uint8_t hash[SIZE_OF_SHA_256_HASH], const void *input, size_t len);
/*
* @brief Initialize a SHA-256 streaming calculation.
* @param sha_256 A pointer to a SHA-256 structure.
* @param hash Hash array, where the result will be delivered.
*
* @note If all of the data you are calculating the hash value on is not available in a contiguous buffer in memory, this is
* where you should start. Instantiate a SHA-256 structure, for instance by simply declaring it locally, make your hash
* buffer available, and invoke this function. Once a SHA-256 hash has been calculated (see further below) a SHA-256
* structure can be initialized again for the next calculation.
*
* @note If either of the passed pointers is NULL, the results are unpredictable.
*/
void hmac_sha256(uint8_t* hmac, char* msg, int msglen, char* key, unsigned int keylen);
void sha_256_init(struct Sha_256 *sha_256, uint8_t hash[SIZE_OF_SHA_256_HASH]);
/*
* @brief Stream more input data for an on-going SHA-256 calculation.
* @param sha_256 A pointer to a previously initialized SHA-256 structure.
* @param data Pointer to the data to be added to the calculation.
* @param len Length of the data to add, in byte.
*
* @note This function may be invoked an arbitrary number of times between initialization and closing, but the maximum
* data length is limited by the SHA-256 algorithm: the total number of bits (i.e. the total number of bytes times
* eight) must be representable by a 64-bit unsigned integer. While that is not a practical limitation, the results are
* unpredictable if that limit is exceeded.
*
* @note This function may be invoked on empty data (zero length), although that obviously will not add any data.
*
* @note If either of the passed pointers is NULL, the results are unpredictable.
*/
void sha_256_write(struct Sha_256 *sha_256, const void *data, size_t len);
/*
* @brief Conclude a SHA-256 streaming calculation, making the hash value available.
* @param sha_256 A pointer to a previously initialized SHA-256 structure.
* @return Pointer to the hash array, where the result is delivered.
*
* @note After this function has been invoked, the result is available in the hash buffer that initially was provided. A
* pointer to the hash value is returned for convenience, but you should feel free to ignore it: it is simply a pointer
* to the first byte of your initially provided hash array.
*
* @note If the passed pointer is NULL, the results are unpredictable.
*
* @note Invoking this function for a calculation with no data (the writing function has never been invoked, or it only
* has been invoked with empty data) is legal. It will calculate the SHA-256 value of the empty string.
*/
uint8_t *sha_256_close(struct Sha_256 *sha_256);
#ifdef __cplusplus
}
#endif
#endif