view src/core/ngx_md5.c @ 8018:5119c8150478

Fixed runtime handling of systems without EPOLLRDHUP support. In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP support in the kernel (but with EPOLLRDHUP in headers) was broken. Before the change, rev->available was never set to 0 unless ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP introduced in 6536:f7849bfb6d21 succeeded). After the change, rev->available might reach 0 on systems without runtime EPOLLRDHUP support, stopping further reading in ngx_readv_chain() and ngx_unix_recv(). And, if EOF happened to be already reported along with the last event, it is not reported again by epoll_wait(), leading to connection hangs and timeouts on such systems. This affects Linux kernels before 2.6.17 if nginx was compiled with newer headers, and, more importantly, emulation layers, such as DigitalOcean's App Platform's / gVisor's epoll emulation layer. Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author Marcus Ball <marcus.ball@live.com>
date Mon, 30 May 2022 02:38:07 +0300
parents 9eefb38f0005
children
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/*
 * An internal implementation, based on Alexander Peslyak's
 * public domain implementation:
 * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_md5.h>


static const u_char *ngx_md5_body(ngx_md5_t *ctx, const u_char *data,
    size_t size);


void
ngx_md5_init(ngx_md5_t *ctx)
{
    ctx->a = 0x67452301;
    ctx->b = 0xefcdab89;
    ctx->c = 0x98badcfe;
    ctx->d = 0x10325476;

    ctx->bytes = 0;
}


void
ngx_md5_update(ngx_md5_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_md5_body(ctx, ctx->buffer, 64);
    }

    if (size >= 64) {
        data = ngx_md5_body(ctx, data, size & ~(size_t) 0x3f);
        size &= 0x3f;
    }

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


void
ngx_md5_final(u_char result[16], ngx_md5_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_md5_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;
    ctx->buffer[57] = (u_char) (ctx->bytes >> 8);
    ctx->buffer[58] = (u_char) (ctx->bytes >> 16);
    ctx->buffer[59] = (u_char) (ctx->bytes >> 24);
    ctx->buffer[60] = (u_char) (ctx->bytes >> 32);
    ctx->buffer[61] = (u_char) (ctx->bytes >> 40);
    ctx->buffer[62] = (u_char) (ctx->bytes >> 48);
    ctx->buffer[63] = (u_char) (ctx->bytes >> 56);

    (void) ngx_md5_body(ctx, ctx->buffer, 64);

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

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


/*
 * The basic MD5 functions.
 *
 * F and G are optimized compared to their RFC 1321 definitions for
 * architectures that lack an AND-NOT instruction, just like in
 * Colin Plumb's implementation.
 */

#define F(x, y, z)  ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z)  ((y) ^ ((z) & ((x) ^ (y))))
#define H(x, y, z)  ((x) ^ (y) ^ (z))
#define I(x, y, z)  ((y) ^ ((x) | ~(z)))

/*
 * The MD5 transformation for all four rounds.
 */

#define STEP(f, a, b, c, d, x, t, s)                                          \
    (a) += f((b), (c), (d)) + (x) + (t);                                      \
    (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s))));                \
    (a) += (b)

/*
 * SET() reads 4 input bytes in little-endian byte order and stores them
 * in a properly aligned word in host byte order.
 *
 * The check for little-endian architectures that tolerate unaligned
 * memory accesses is just an optimization.  Nothing will break if it
 * does not work.
 */

#if (NGX_HAVE_LITTLE_ENDIAN && NGX_HAVE_NONALIGNED)

#define SET(n)      (*(uint32_t *) &p[n * 4])
#define GET(n)      (*(uint32_t *) &p[n * 4])

#else

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

#define GET(n)      block[n]

#endif


/*
 * 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_md5_body(ngx_md5_t *ctx, const u_char *data, size_t size)
{
    uint32_t       a, b, c, d;
    uint32_t       saved_a, saved_b, saved_c, saved_d;
    const u_char  *p;
#if !(NGX_HAVE_LITTLE_ENDIAN && NGX_HAVE_NONALIGNED)
    uint32_t       block[16];
#endif

    p = data;

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

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

        /* Round 1 */

        STEP(F, a, b, c, d, SET(0),  0xd76aa478, 7);
        STEP(F, d, a, b, c, SET(1),  0xe8c7b756, 12);
        STEP(F, c, d, a, b, SET(2),  0x242070db, 17);
        STEP(F, b, c, d, a, SET(3),  0xc1bdceee, 22);
        STEP(F, a, b, c, d, SET(4),  0xf57c0faf, 7);
        STEP(F, d, a, b, c, SET(5),  0x4787c62a, 12);
        STEP(F, c, d, a, b, SET(6),  0xa8304613, 17);
        STEP(F, b, c, d, a, SET(7),  0xfd469501, 22);
        STEP(F, a, b, c, d, SET(8),  0x698098d8, 7);
        STEP(F, d, a, b, c, SET(9),  0x8b44f7af, 12);
        STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17);
        STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22);
        STEP(F, a, b, c, d, SET(12), 0x6b901122, 7);
        STEP(F, d, a, b, c, SET(13), 0xfd987193, 12);
        STEP(F, c, d, a, b, SET(14), 0xa679438e, 17);
        STEP(F, b, c, d, a, SET(15), 0x49b40821, 22);

        /* Round 2 */

        STEP(G, a, b, c, d, GET(1),  0xf61e2562, 5);
        STEP(G, d, a, b, c, GET(6),  0xc040b340, 9);
        STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14);
        STEP(G, b, c, d, a, GET(0),  0xe9b6c7aa, 20);
        STEP(G, a, b, c, d, GET(5),  0xd62f105d, 5);
        STEP(G, d, a, b, c, GET(10), 0x02441453, 9);
        STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14);
        STEP(G, b, c, d, a, GET(4),  0xe7d3fbc8, 20);
        STEP(G, a, b, c, d, GET(9),  0x21e1cde6, 5);
        STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9);
        STEP(G, c, d, a, b, GET(3),  0xf4d50d87, 14);
        STEP(G, b, c, d, a, GET(8),  0x455a14ed, 20);
        STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5);
        STEP(G, d, a, b, c, GET(2),  0xfcefa3f8, 9);
        STEP(G, c, d, a, b, GET(7),  0x676f02d9, 14);
        STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20);

        /* Round 3 */

        STEP(H, a, b, c, d, GET(5),  0xfffa3942, 4);
        STEP(H, d, a, b, c, GET(8),  0x8771f681, 11);
        STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16);
        STEP(H, b, c, d, a, GET(14), 0xfde5380c, 23);
        STEP(H, a, b, c, d, GET(1),  0xa4beea44, 4);
        STEP(H, d, a, b, c, GET(4),  0x4bdecfa9, 11);
        STEP(H, c, d, a, b, GET(7),  0xf6bb4b60, 16);
        STEP(H, b, c, d, a, GET(10), 0xbebfbc70, 23);
        STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4);
        STEP(H, d, a, b, c, GET(0),  0xeaa127fa, 11);
        STEP(H, c, d, a, b, GET(3),  0xd4ef3085, 16);
        STEP(H, b, c, d, a, GET(6),  0x04881d05, 23);
        STEP(H, a, b, c, d, GET(9),  0xd9d4d039, 4);
        STEP(H, d, a, b, c, GET(12), 0xe6db99e5, 11);
        STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16);
        STEP(H, b, c, d, a, GET(2),  0xc4ac5665, 23);

        /* Round 4 */

        STEP(I, a, b, c, d, GET(0),  0xf4292244, 6);
        STEP(I, d, a, b, c, GET(7),  0x432aff97, 10);
        STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15);
        STEP(I, b, c, d, a, GET(5),  0xfc93a039, 21);
        STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6);
        STEP(I, d, a, b, c, GET(3),  0x8f0ccc92, 10);
        STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15);
        STEP(I, b, c, d, a, GET(1),  0x85845dd1, 21);
        STEP(I, a, b, c, d, GET(8),  0x6fa87e4f, 6);
        STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10);
        STEP(I, c, d, a, b, GET(6),  0xa3014314, 15);
        STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21);
        STEP(I, a, b, c, d, GET(4),  0xf7537e82, 6);
        STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10);
        STEP(I, c, d, a, b, GET(2),  0x2ad7d2bb, 15);
        STEP(I, b, c, d, a, GET(9),  0xeb86d391, 21);

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

        p += 64;

    } while (size -= 64);

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

    return p;
}