Mercurial > hg > nginx-quic
view src/core/ngx_md5.c @ 7629:f47f7d3d1bfa
Mp4: fixed possible chunk offset overflow.
In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming
the "mdat" atom, chunk offsets are casted to off_t values which are typically
64-bit signed integers. A specially crafted mp4 file with huge chunk offsets
may lead to off_t overflow and result in negative trim boundaries.
The consequences of the overflow are:
- Incorrect Content-Length header value in the response.
- Negative left boundary of the response file buffer holding the trimmed "mdat".
This leads to pread()/sendfile() errors followed by closing the client
connection.
On rare systems where off_t is a 32-bit integer, this scenario is also feasible
with the "stco" atom.
The fix is to add checks which make sure data chunks referenced by each track
are within the mp4 file boundaries. Additionally a few more checks are added to
ensure mp4 file consistency and log errors.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 26 Feb 2020 15:10:46 +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; }