OpenBSD manual page server

Manual Page Search Parameters

EVP_MD_CTX_CTRL(3) Library Functions Manual EVP_MD_CTX_CTRL(3)

EVP_MD_CTX_ctrl, EVP_MD_CTX_set_flags, EVP_MD_CTX_clear_flags, EVP_MD_CTX_test_flags, EVP_MD_CTX_pkey_ctx, EVP_MD_CTX_set_pkey_ctx, EVP_MD_CTX_md_dataconfigure EVP message digest contexts

#include <openssl/evp.h>

EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int command, int p1, void* p2);

EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);

EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags);

EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags);

EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx);

EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);

void *
EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);

() performs the digest-specific control command with the command-specific arguments p1 and p2 on ctx, which needs to already be set up with EVP_DigestInit_ex(3) before calling this function. Other restrictions may apply depending on the control command and digest implementation.

If the command is EVP_MD_CTRL_MICALG, p1 is ignored and p2 is an output argument of the type char **p2. A string specifying the digest Message Integrity Check algorithm is allocated and a pointer to this string is returned in *p2. It is the responsibility of the caller to free(3) *p2 when it is no longer needed. This command is used by SMIME_write_ASN1(3) when creating S/MIME multipart/signed messages as specified in RFC 3851.

() sets and () clears all the flag bits in ctx that are set in the flags argument. () tests which of the flag bits that are set in the flags argument are also set in ctx. Possible flag bits are:

Instruct EVP_DigestInit_ex(3) and functions calling it not to initialise the internal data that is specific to the digest method and its implementation.
Instruct the digest to optimize for one update only, if possible. For digest algorithms built into the library, this flag usually has no effect.

() returns the EVP_PKEY_CTX assigned to ctx. The returned pointer should not be freed by the caller.

() assigns pctx to ctx. This is normally used to provide a customized EVP_PKEY_CTX to EVP_DigestSignInit(3) or EVP_DigestVerifyInit(3). The caller retains ownership of the pctx passed to this function and is responsible for freeing it when it is no longer needed.

If the ctx already contains a EVP_PKEY_CTX when this function is called, that old EVP_PKEY_CTX is freed if it was created internally, but if it was also installed with (), the pointer to the old EVP_PKEY_CTX is merely replaced by the new pointer and ownership of the old EVP_PKEY_CTX remains with the previous caller.

Passing a NULL pointer for the pctx argument is also allowed. In that case, any EVP_PKEY_CTX already assigned to ctx is dissociated from it as described above, but no new EVP_PKEY_CTX is assigned.

() returns the digest method private data of ctx. The space was allocated and its size set with EVP_MD_meth_set_app_datasize(3).

EVP_MD_CTX_ctrl() returns 1 for success or 0 for failure.

EVP_MD_CTX_test_flags() returns the bitwise OR of the flags argument and the flags set in ctx.

EVP_MD_CTX_pkey_ctx() and EVP_MD_CTX_md_data() return pointers to storage owned by ctx.

evp(3), EVP_DigestInit(3), EVP_MD_meth_new(3), EVP_MD_nid(3)

EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), and EVP_MD_CTX_test_flags(), first appeared in OpenSSL 0.9.7 and have been available since OpenBSD 3.2.

EVP_MD_CTX_ctrl() first appeared in OpenSSL 1.1.0 and has been available since OpenBSD 5.7.

EVP_MD_CTX_pkey_ctx() and EVP_MD_CTX_md_data() first appeared in OpenSSL 1.1.0 and EVP_MD_CTX_set_pkey_ctx() in OpenSSL 1.1.1. These functions have been available since OpenBSD 7.1.

September 7, 2023 OpenBSD-current