view src/core/ngx_sha1.c @ 7667:1ece2ac2555a

OCSP: fixed use-after-free on error. When validating second and further certificates, ssl callback could be called twice to report the error. After the first call client connection is terminated and its memory is released. Prior to the second call and in it released connection memory is accessed. Errors triggering this behavior: - failure to create the request - failure to start resolving OCSP responder name - failure to start connecting to the OCSP responder The fix is to rearrange the code to eliminate the second call.
author Roman Arutyunyan <arut@nginx.com>
date Mon, 15 Jun 2020 20:17:16 +0300
parents 9eefb38f0005
children
line wrap: on
line source


/*
 * Copyright (C) Maxim Dounin
 * Copyright (C) Nginx, Inc.
 *
 * An internal SHA1 implementation.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_sha1.h>


static const u_char *ngx_sha1_body(ngx_sha1_t *ctx, const u_char *data,
    size_t size);


void
ngx_sha1_init(ngx_sha1_t *ctx)
{
    ctx->a = 0x67452301;
    ctx->b = 0xefcdab89;
    ctx->c = 0x98badcfe;
    ctx->d = 0x10325476;
    ctx->e = 0xc3d2e1f0;

    ctx->bytes = 0;
}


void
ngx_sha1_update(ngx_sha1_t *ctx, const void *data, size_t size)
{
    size_t  used, free;

    used = (size_t) (ctx->bytes & 0x3f);
    ctx->bytes += size;

    if (used) {
        free = 64 - used;

        if (size < free) {
            ngx_memcpy(&ctx->buffer[used], data, size);
            return;
        }

        ngx_memcpy(&ctx->buffer[used], data, free);
        data = (u_char *) data + free;
        size -= free;
        (void) ngx_sha1_body(ctx, ctx->buffer, 64);
    }

    if (size >= 64) {
        data = ngx_sha1_body(ctx, data, size & ~(size_t) 0x3f);
        size &= 0x3f;
    }

    ngx_memcpy(ctx->buffer, data, size);
}


void
ngx_sha1_final(u_char result[20], ngx_sha1_t *ctx)
{
    size_t  used, free;

    used = (size_t) (ctx->bytes & 0x3f);

    ctx->buffer[used++] = 0x80;

    free = 64 - used;

    if (free < 8) {
        ngx_memzero(&ctx->buffer[used], free);
        (void) ngx_sha1_body(ctx, ctx->buffer, 64);
        used = 0;
        free = 64;
    }

    ngx_memzero(&ctx->buffer[used], free - 8);

    ctx->bytes <<= 3;
    ctx->buffer[56] = (u_char) (ctx->bytes >> 56);
    ctx->buffer[57] = (u_char) (ctx->bytes >> 48);
    ctx->buffer[58] = (u_char) (ctx->bytes >> 40);
    ctx->buffer[59] = (u_char) (ctx->bytes >> 32);
    ctx->buffer[60] = (u_char) (ctx->bytes >> 24);
    ctx->buffer[61] = (u_char) (ctx->bytes >> 16);
    ctx->buffer[62] = (u_char) (ctx->bytes >> 8);
    ctx->buffer[63] = (u_char) ctx->bytes;

    (void) ngx_sha1_body(ctx, ctx->buffer, 64);

    result[0] = (u_char) (ctx->a >> 24);
    result[1] = (u_char) (ctx->a >> 16);
    result[2] = (u_char) (ctx->a >> 8);
    result[3] = (u_char) ctx->a;
    result[4] = (u_char) (ctx->b >> 24);
    result[5] = (u_char) (ctx->b >> 16);
    result[6] = (u_char) (ctx->b >> 8);
    result[7] = (u_char) ctx->b;
    result[8] = (u_char) (ctx->c >> 24);
    result[9] = (u_char) (ctx->c >> 16);
    result[10] = (u_char) (ctx->c >> 8);
    result[11] = (u_char) ctx->c;
    result[12] = (u_char) (ctx->d >> 24);
    result[13] = (u_char) (ctx->d >> 16);
    result[14] = (u_char) (ctx->d >> 8);
    result[15] = (u_char) ctx->d;
    result[16] = (u_char) (ctx->e >> 24);
    result[17] = (u_char) (ctx->e >> 16);
    result[18] = (u_char) (ctx->e >> 8);
    result[19] = (u_char) ctx->e;

    ngx_memzero(ctx, sizeof(*ctx));
}


/*
 * Helper functions.
 */

#define ROTATE(bits, word)  (((word) << (bits)) | ((word) >> (32 - (bits))))

#define F1(b, c, d)  (((b) & (c)) | ((~(b)) & (d)))
#define F2(b, c, d)  ((b) ^ (c) ^ (d))
#define F3(b, c, d)  (((b) & (c)) | ((b) & (d)) | ((c) & (d)))

#define STEP(f, a, b, c, d, e, w, t)                                          \
    temp = ROTATE(5, (a)) + f((b), (c), (d)) + (e) + (w) + (t);               \
    (e) = (d);                                                                \
    (d) = (c);                                                                \
    (c) = ROTATE(30, (b));                                                    \
    (b) = (a);                                                                \
    (a) = temp;


/*
 * GET() reads 4 input bytes in big-endian byte order and returns
 * them as uint32_t.
 */

#define GET(n)                                                                \
    ((uint32_t) p[n * 4 + 3] |                                                \
    ((uint32_t) p[n * 4 + 2] << 8) |                                          \
    ((uint32_t) p[n * 4 + 1] << 16) |                                         \
    ((uint32_t) p[n * 4] << 24))


/*
 * This processes one or more 64-byte data blocks, but does not update
 * the bit counters.  There are no alignment requirements.
 */

static const u_char *
ngx_sha1_body(ngx_sha1_t *ctx, const u_char *data, size_t size)
{
    uint32_t       a, b, c, d, e, temp;
    uint32_t       saved_a, saved_b, saved_c, saved_d, saved_e;
    uint32_t       words[80];
    ngx_uint_t     i;
    const u_char  *p;

    p = data;

    a = ctx->a;
    b = ctx->b;
    c = ctx->c;
    d = ctx->d;
    e = ctx->e;

    do {
        saved_a = a;
        saved_b = b;
        saved_c = c;
        saved_d = d;
        saved_e = e;

        /* Load data block into the words array */

        for (i = 0; i < 16; i++) {
            words[i] = GET(i);
        }

        for (i = 16; i < 80; i++) {
            words[i] = ROTATE(1, words[i - 3] ^ words[i - 8] ^ words[i - 14]
                                 ^ words[i - 16]);
        }

        /* Transformations */

        STEP(F1, a, b, c, d, e, words[0],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[1],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[2],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[3],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[4],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[5],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[6],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[7],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[8],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[9],  0x5a827999);
        STEP(F1, a, b, c, d, e, words[10], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[11], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[12], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[13], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[14], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[15], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[16], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[17], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[18], 0x5a827999);
        STEP(F1, a, b, c, d, e, words[19], 0x5a827999);

        STEP(F2, a, b, c, d, e, words[20], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[21], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[22], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[23], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[24], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[25], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[26], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[27], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[28], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[29], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[30], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[31], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[32], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[33], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[34], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[35], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[36], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[37], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[38], 0x6ed9eba1);
        STEP(F2, a, b, c, d, e, words[39], 0x6ed9eba1);

        STEP(F3, a, b, c, d, e, words[40], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[41], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[42], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[43], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[44], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[45], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[46], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[47], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[48], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[49], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[50], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[51], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[52], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[53], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[54], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[55], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[56], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[57], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[58], 0x8f1bbcdc);
        STEP(F3, a, b, c, d, e, words[59], 0x8f1bbcdc);

        STEP(F2, a, b, c, d, e, words[60], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[61], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[62], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[63], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[64], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[65], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[66], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[67], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[68], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[69], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[70], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[71], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[72], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[73], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[74], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[75], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[76], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[77], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[78], 0xca62c1d6);
        STEP(F2, a, b, c, d, e, words[79], 0xca62c1d6);

        a += saved_a;
        b += saved_b;
        c += saved_c;
        d += saved_d;
        e += saved_e;

        p += 64;

    } while (size -= 64);

    ctx->a = a;
    ctx->b = b;
    ctx->c = c;
    ctx->d = d;
    ctx->e = e;

    return p;
}