Mercurial > hg > nginx
view src/core/ngx_crypt.c @ 7054:e02555553d0b
Range filter: protect from total size overflows.
The overflow can be used to circumvent the restriction on total size of
ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow
allows producing ranges with negative start (such ranges can be created
by using a suffix, "bytes=-100"; normally this results in 200 due to
the total size check). These can result in the following errors in logs:
[crit] ... pread() ... failed (22: Invalid argument)
[alert] ... sendfile() failed (22: Invalid argument)
When using cache, it can be also used to reveal cache file header.
It is believed that there are no other negative effects, at least with
standard nginx modules.
In theory, this can also result in memory disclosure and/or segmentation
faults if multiple ranges are allowed, and the response is returned in a
single in-memory buffer. This never happens with standard nginx modules
though, as well as known 3rd party modules.
Fix is to properly protect from possible overflow when incrementing size.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 11 Jul 2017 16:06:23 +0300 |
parents | 1064ea81ed3a |
children |
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/* * Copyright (C) Maxim Dounin */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_crypt.h> #include <ngx_md5.h> #include <ngx_sha1.h> #if (NGX_CRYPT) static ngx_int_t ngx_crypt_apr1(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted); static ngx_int_t ngx_crypt_plain(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted); static ngx_int_t ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted); static ngx_int_t ngx_crypt_sha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted); static u_char *ngx_crypt_to64(u_char *p, uint32_t v, size_t n); ngx_int_t ngx_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted) { if (ngx_strncmp(salt, "$apr1$", sizeof("$apr1$") - 1) == 0) { return ngx_crypt_apr1(pool, key, salt, encrypted); } else if (ngx_strncmp(salt, "{PLAIN}", sizeof("{PLAIN}") - 1) == 0) { return ngx_crypt_plain(pool, key, salt, encrypted); } else if (ngx_strncmp(salt, "{SSHA}", sizeof("{SSHA}") - 1) == 0) { return ngx_crypt_ssha(pool, key, salt, encrypted); } else if (ngx_strncmp(salt, "{SHA}", sizeof("{SHA}") - 1) == 0) { return ngx_crypt_sha(pool, key, salt, encrypted); } /* fallback to libc crypt() */ return ngx_libc_crypt(pool, key, salt, encrypted); } static ngx_int_t ngx_crypt_apr1(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted) { ngx_int_t n; ngx_uint_t i; u_char *p, *last, final[16]; size_t saltlen, keylen; ngx_md5_t md5, ctx1; /* Apache's apr1 crypt is Poul-Henning Kamp's md5 crypt with $apr1$ magic */ keylen = ngx_strlen(key); /* true salt: no magic, max 8 chars, stop at first $ */ salt += sizeof("$apr1$") - 1; last = salt + 8; for (p = salt; *p && *p != '$' && p < last; p++) { /* void */ } saltlen = p - salt; /* hash key and salt */ ngx_md5_init(&md5); ngx_md5_update(&md5, key, keylen); ngx_md5_update(&md5, (u_char *) "$apr1$", sizeof("$apr1$") - 1); ngx_md5_update(&md5, salt, saltlen); ngx_md5_init(&ctx1); ngx_md5_update(&ctx1, key, keylen); ngx_md5_update(&ctx1, salt, saltlen); ngx_md5_update(&ctx1, key, keylen); ngx_md5_final(final, &ctx1); for (n = keylen; n > 0; n -= 16) { ngx_md5_update(&md5, final, n > 16 ? 16 : n); } ngx_memzero(final, sizeof(final)); for (i = keylen; i; i >>= 1) { if (i & 1) { ngx_md5_update(&md5, final, 1); } else { ngx_md5_update(&md5, key, 1); } } ngx_md5_final(final, &md5); for (i = 0; i < 1000; i++) { ngx_md5_init(&ctx1); if (i & 1) { ngx_md5_update(&ctx1, key, keylen); } else { ngx_md5_update(&ctx1, final, 16); } if (i % 3) { ngx_md5_update(&ctx1, salt, saltlen); } if (i % 7) { ngx_md5_update(&ctx1, key, keylen); } if (i & 1) { ngx_md5_update(&ctx1, final, 16); } else { ngx_md5_update(&ctx1, key, keylen); } ngx_md5_final(final, &ctx1); } /* output */ *encrypted = ngx_pnalloc(pool, sizeof("$apr1$") - 1 + saltlen + 1 + 22 + 1); if (*encrypted == NULL) { return NGX_ERROR; } p = ngx_cpymem(*encrypted, "$apr1$", sizeof("$apr1$") - 1); p = ngx_copy(p, salt, saltlen); *p++ = '$'; p = ngx_crypt_to64(p, (final[ 0]<<16) | (final[ 6]<<8) | final[12], 4); p = ngx_crypt_to64(p, (final[ 1]<<16) | (final[ 7]<<8) | final[13], 4); p = ngx_crypt_to64(p, (final[ 2]<<16) | (final[ 8]<<8) | final[14], 4); p = ngx_crypt_to64(p, (final[ 3]<<16) | (final[ 9]<<8) | final[15], 4); p = ngx_crypt_to64(p, (final[ 4]<<16) | (final[10]<<8) | final[ 5], 4); p = ngx_crypt_to64(p, final[11], 2); *p = '\0'; return NGX_OK; } static u_char * ngx_crypt_to64(u_char *p, uint32_t v, size_t n) { static u_char itoa64[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; while (n--) { *p++ = itoa64[v & 0x3f]; v >>= 6; } return p; } static ngx_int_t ngx_crypt_plain(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted) { size_t len; u_char *p; len = ngx_strlen(key); *encrypted = ngx_pnalloc(pool, sizeof("{PLAIN}") - 1 + len + 1); if (*encrypted == NULL) { return NGX_ERROR; } p = ngx_cpymem(*encrypted, "{PLAIN}", sizeof("{PLAIN}") - 1); ngx_memcpy(p, key, len + 1); return NGX_OK; } static ngx_int_t ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted) { size_t len; ngx_int_t rc; ngx_str_t encoded, decoded; ngx_sha1_t sha1; /* "{SSHA}" base64(SHA1(key salt) salt) */ /* decode base64 salt to find out true salt */ encoded.data = salt + sizeof("{SSHA}") - 1; encoded.len = ngx_strlen(encoded.data); len = ngx_max(ngx_base64_decoded_length(encoded.len), 20); decoded.data = ngx_pnalloc(pool, len); if (decoded.data == NULL) { return NGX_ERROR; } rc = ngx_decode_base64(&decoded, &encoded); if (rc != NGX_OK || decoded.len < 20) { decoded.len = 20; } /* update SHA1 from key and salt */ ngx_sha1_init(&sha1); ngx_sha1_update(&sha1, key, ngx_strlen(key)); ngx_sha1_update(&sha1, decoded.data + 20, decoded.len - 20); ngx_sha1_final(decoded.data, &sha1); /* encode it back to base64 */ len = sizeof("{SSHA}") - 1 + ngx_base64_encoded_length(decoded.len) + 1; *encrypted = ngx_pnalloc(pool, len); if (*encrypted == NULL) { return NGX_ERROR; } encoded.data = ngx_cpymem(*encrypted, "{SSHA}", sizeof("{SSHA}") - 1); ngx_encode_base64(&encoded, &decoded); encoded.data[encoded.len] = '\0'; return NGX_OK; } static ngx_int_t ngx_crypt_sha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted) { size_t len; ngx_str_t encoded, decoded; ngx_sha1_t sha1; u_char digest[20]; /* "{SHA}" base64(SHA1(key)) */ decoded.len = sizeof(digest); decoded.data = digest; ngx_sha1_init(&sha1); ngx_sha1_update(&sha1, key, ngx_strlen(key)); ngx_sha1_final(digest, &sha1); len = sizeof("{SHA}") - 1 + ngx_base64_encoded_length(decoded.len) + 1; *encrypted = ngx_pnalloc(pool, len); if (*encrypted == NULL) { return NGX_ERROR; } encoded.data = ngx_cpymem(*encrypted, "{SHA}", sizeof("{SHA}") - 1); ngx_encode_base64(&encoded, &decoded); encoded.data[encoded.len] = '\0'; return NGX_OK; } #endif /* NGX_CRYPT */