Commit 8db50d6d authored by Andy Polyakov's avatar Andy Polyakov Committed by Matt Caswell
Browse files

err/err.c: add err_clear_last_constant_time. 



Expected usage pattern is to unconditionally set error and then
wipe it if there was no actual error.

Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(cherry picked from commit f658a3b6)

Resolved conflicts:
	crypto/err/err.c
	crypto/constant_time_locl.h

(Merged from https://github.com/openssl/openssl/pull/7737)
parent 02354431

crypto/constant_time_locl.h

+6 −0
Original line number Diff line number Diff line
@@ -204,6 +204,12 @@ static inline int constant_time_select_int(unsigned int mask, int a, int b) 
    return (int)(constant_time_select(mask, (unsigned)(a), (unsigned)(b)));

}



/*

 * Expected usage pattern is to unconditionally set error and then

 * wipe it if there was no actual error. |clear| is 1 or 0.

 */

void err_clear_last_constant_time(int clear);



#ifdef __cplusplus

}

#endif

crypto/err/err.c

+38 −0
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ 
#include <openssl/buffer.h>

#include <openssl/bio.h>

#include <openssl/err.h>

#include "constant_time_locl.h"



DECLARE_LHASH_OF(ERR_STRING_DATA);

DECLARE_LHASH_OF(ERR_STATE);
@@ -1156,3 +1157,40 @@ int ERR_pop_to_mark(void) 
    es->err_flags[es->top] &= ~ERR_FLAG_MARK;

    return 1;

}



#ifdef UINTPTR_T

# undef UINTPTR_T

#endif

/*

 * uintptr_t is the answer, but unformtunately we can't assume that all

 * compilers supported by 1.0.2 have it :-(

 */

#if defined(OPENSSL_SYS_VMS) && __INITIAL_POINTER_SIZE==64

/*

 * But we can't use size_t on VMS, because it adheres to sizeof(size_t)==4

 * even in 64-bit builds, which means that it won't work as mask.

 */

# define UINTPTR_T unsigned long long

#else

# define UINTPTR_T size_t

#endif



void err_clear_last_constant_time(int clear)

{

    ERR_STATE *es;

    int top;



    es = ERR_get_state();

    if (es == NULL)

        return;



    top = es->top;



    es->err_flags[top] &= ~(0 - clear);

    es->err_buffer[top] &= ~(0UL - clear);

    es->err_file[top] = (const char *)((UINTPTR_T)es->err_file[top] &

                                       ~((UINTPTR_T)0 - clear));

    es->err_line[top] |= 0 - clear;



    es->top = (top + ERR_NUM_ERRORS - clear) % ERR_NUM_ERRORS;

}