Merge remote-tracking branch 'restricted/pr/418' into mbedtls-1.3-restricted

* restricted/pr/418:
  RSA PSS: remove redundant check; changelog
  RSA PSS: fix first byte check for keys of size 8N+1
  RSA PSS: fix minimum length check for keys of size 8N+1
  RSA: Fix another buffer overflow in PSS signature verification
  RSA: Fix buffer overflow in PSS signature verification

ChangeLog

@@ -2,6 +2,13 @@ mbed TLS ChangeLog (Sorted per branch, date)
 
 = mbed TLS 1.3.22 branch released 2017-xx-xx
 
+Security
+   * Fix buffer overflow in RSA-PSS verification when the hash is too
+     large for the key size. Found by Seth Terashima, Qualcomm Product
+     Security Initiative, Qualcomm Technologies Inc.
+   * Fix buffer overflow in RSA-PSS verification when the unmasked
+     data is all zeros.
+
 Bugfix
    * Fix memory leak in ssl_set_hostname() when called multiple times.
      Found by projectgus and jethrogb, #836.
@@ -14,6 +21,8 @@ Bugfix
    * Fix leap year calculation in x509_date_is_valid() to ensure that invalid
      dates on leap years with 100 and 400 intervals are handled correctly. Found
      by Nicholas Wilson. #694
+   * Fix some invalid RSA-PSS signatures with keys of size 8N+1 that were
+     accepted. Generating these signatures required the private key.
 
 = mbed TLS 1.3.21 branch released 2017-08-10
 

library/rsa.c

@@ -1325,10 +1325,11 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
     size_t siglen;
     unsigned char *p;
     unsigned char buf[POLARSSL_MPI_MAX_SIZE];
+    unsigned char *hash_start;
     unsigned char result[POLARSSL_MD_MAX_SIZE];
     unsigned char zeros[8];
     unsigned int hlen;
-    size_t slen, msb;
+    size_t observed_salt_len, msb;
     const md_info_t *md_info;
     md_context_t md_ctx;
 
@@ -1368,7 +1369,6 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
         return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
 
     hlen = md_get_size( md_info );
-    slen = siglen - hlen - 1; /* Currently length of salt + padding */
 
     memset( zeros, 0, 8 );
 
@@ -1376,6 +1376,9 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
     //
     msb = mpi_msb( &ctx->N ) - 1;
 
+    if( buf[0] >> ( 8 - siglen * 8 + msb ) )
+        return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
+
     // Compensate for boundary condition when applying mask
     //
     if( msb % 8 == 0 )
@@ -1383,8 +1386,10 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
         p++;
         siglen -= 1;
     }
-    if( buf[0] >> ( 8 - siglen * 8 + msb ) )
+
+    if( siglen < hlen + 2 )
         return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
+    hash_start = p + siglen - hlen - 1;
 
     md_init( &md_ctx );
     if( ( ret = md_init_ctx( &md_ctx, md_info ) ) != 0 )
@@ -1393,25 +1398,23 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
         return( ret );
     }
 
-    mgf_mask( p, siglen - hlen - 1, p + siglen - hlen - 1, hlen, &md_ctx );
+    mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx );
 
     buf[0] &= 0xFF >> ( siglen * 8 - msb );
 
-    while( p < buf + siglen && *p == 0 )
+    while( p < hash_start - 1 && *p == 0 )
         p++;
 
-    if( p == buf + siglen ||
+    if( *p++ != 0x01 )
-        *p++ != 0x01 )
     {
         md_free( &md_ctx );
         return( POLARSSL_ERR_RSA_INVALID_PADDING );
     }
 
-    /* Actual salt len */
+    observed_salt_len = hash_start - p;
-    slen -= p - buf;
 
     if( expected_salt_len != RSA_SALT_LEN_ANY &&
-        slen != (size_t) expected_salt_len )
+        observed_salt_len != (size_t) expected_salt_len )
     {
         md_free( &md_ctx );
         return( POLARSSL_ERR_RSA_INVALID_PADDING );
@@ -1422,12 +1425,12 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
     md_starts( &md_ctx );
     md_update( &md_ctx, zeros, 8 );
     md_update( &md_ctx, hash, hashlen );
-    md_update( &md_ctx, p, slen );
+    md_update( &md_ctx, p, observed_salt_len );
     md_finish( &md_ctx, result );
 
     md_free( &md_ctx );
 
-    if( memcmp( p + slen, result, hlen ) == 0 )
+    if( memcmp( hash_start, result, hlen ) == 0 )
         return( 0 );
     else
         return( POLARSSL_ERR_RSA_VERIFY_FAILED );

tests/data_files/rsa512.key

@@ -0,0 +1,9 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIBOwIBAAJBALB20jJQgW+aqwIwfkUrl/DK51mDabQWJOivx5caWaE4kvZLB+qm
+7JKMFgstbsj50N1bY8izrAdntPZciS9WwQ8CAwEAAQJAKYfNcIoB7II6PQmsrhrU
+Z5dZW3fSKNANX7X/A1DwR0DlF8uZnpWsWbYcRoXX7QjvepZqc54wryhW55Wlm6yI
+AQIhAOJIaLjSpbHjzzcJQ7mylxn2WGIlbJPPzJ9OaFZCZQvxAiEAx6OEAvl6JKa6
+6a+N2Wvhtcgb4qqR6UHQGJQYGJz5nP8CIAvgoR6ScAAWZRoOcm+c4DGMrLb6H+ji
+T2tNQkzEz2kBAiEAmw34GStU36STpa6RGJ4+tyZN6jWakDVqf7x+HpfFE1cCIQDc
+KzXIxec2taye4OeIa1v4W/MigMmYE9w93Uw/Qi3azA==
+-----END RSA PRIVATE KEY-----

tests/data_files/rsa521.key

@@ -0,0 +1,9 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIBPQIBAAJCATG2mGDzy5v4XqNY/fK9KZDxt3qA1qT9+BekPdiWvffdJq+KwCN/
+Um4NM7EFyXH9vU/6ns6Z/EafMez0Kej1YsHDAgMBAAECQCdoYjwdMSHp4kksL5Aa
+0kDc58ni0chy9IgXo+FHjTVmR9DkaZANrwfVvYMJxqYCZo0im1Dw7ZJBUDJQNXnl
+ZokCIRiSk66I24AWa7XGUFvatVwXWi2ACE4QEKqzWQe1mQ24/wIhDHD1TCKpqucA
+XDI+1N7EHs+fN4CfTSWe8FPGiK6q3VM9AiESrKKLi/q011U4KeS8SfR2blDcL2cg
+XFkuQWqxzzLoGOUCIQmgl5E0+Ypwe0zc7NYZFDarf4+ZjqxKQnXCvk0irMHcGQIh
+EVPli6RQb3Gcx7vXJHltzSTno7NElzBDRMBVUlBmVxAJ
+-----END RSA PRIVATE KEY-----

tests/data_files/rsa522.key

@@ -0,0 +1,9 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIBPgIBAAJCAtMCdT492ij0L02fkshkdCDqb7yXwQ+EmLlmqVPzV2mNZYEGDf4y
+yKuY20vFzirN8MHm5ASnWhMoJVDBqjfTzci/AgMBAAECQU05ffxf7uVg74yC9tKg
+qCa746NpMh3OM+HZrUxiOXv0sJMRXNEPD5HNLtgcNY6MI5NYbUvkOXktnFZpxWYP
+TH7BAiEeFJGs5Z6gRd2v/IbYLMFDHgjqho04INGTOvnyI7lGVKUCIRgJM7moFuoM
+UrKTmJK1uOzauWEykCKgc6BGH6TGZoEWkwIhBzQn2v82qO1ydOYGKRk2w2sa+Yd1
+pH5/kkHqf+m8QjKdAiEQ9eVW+4J30wxD0JyX4b1E/S5UpN5KYNhWX0US+6D3NBsC
+IRxePzdQlutZWg0Cnku3QE1tOLBCFlP7QVVl5FbKcY5H5w==
+-----END RSA PRIVATE KEY-----

tests/data_files/rsa528.key

@@ -0,0 +1,9 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIBRQIBAAJDAOMcJG1GSFmEJh/RdMqz1DVzRGAuzXk8R9vlQlLTe7NQvGNDWbGV
+FVQggORySktnIpG+V8dkj1Finq7yNOhH2ZzGXwIDAQABAkMAsWYyLglQSlwnS4NZ
+L1z4zieTqW3lomWr2+BgxkHbxl2w0Rx4L+Ezp+YK6mhtIQWNkoytPvWJJMS7Jrkg
+agMAHQJBAiIA+F1y5GO0Bv+igsNLXwwtbCqs8hAkavU9W8egt/oDbhzbAiIA6hds
+PZp/s1X7n7dwfmebSs+3vLZFuQfifN8XZLw0CXHNAiEuEzgDQrPdMIN3er96zImI
+rYoUBgabiQ9u/WPFfa4xOU0CIgDDYC089Tfjy72pPgcr2PkpZVhqro5esg/8PI5f
+yxx7TXkCIgCYoE8Y5IxomtL1ub1AQzPe9UyyUGzQB1yWeiloJh6LjxA=
+-----END RSA PRIVATE KEY-----

tests/suites/test_suite_pkcs1_v21.data

@@ -787,3 +787,47 @@ RSASSA-PSS Signature verify options #13 (MGF1 alg != MSG hash alg, arg wrong)
 depends_on:POLARSSL_SHA256_C
 pkcs1_rsassa_pss_verify_ext:1024:16:"00dd118a9f99bab068ca2aea3b6a6d5997ed4ec954e40deecea07da01eaae80ec2bb1340db8a128e891324a5c5f5fad8f590d7c8cacbc5fe931dafda1223735279461abaa0572b761631b3a8afe7389b088b63993a0a25ee45d21858bab9931aedd4589a631b37fcf714089f856549f359326dd1e0e86dde52ed66b4a90bda4095":16:"010001":POLARSSL_MD_NONE:POLARSSL_MD_SHA256:POLARSSL_MD_SHA1:RSA_SALT_LEN_ANY:"c0719e9a8d5d838d861dc6f675c899d2b309a3a65bb9fe6b11e5afcbf9a2c0b1":"7fc506d26ca3b22922a1ce39faaedd273161b82d9443c56f1a034f131ae4a18cae1474271cb4b66a17d9707ca58b0bdbd3c406b7e65bbcc9bbbce94dc45de807b4989b23b3e4db74ca29298137837eb90cc83d3219249bc7d480fceaf075203a86e54c4ecfa4e312e39f8f69d76534089a36ed9049ca9cfd5ab1db1fa75fe5c8":0:POLARSSL_ERR_RSA_INVALID_PADDING
 
+RSASSA-PSS verify ext, 512-bit key, empty salt, good signature
+depends_on:POLARSSL_SHA256_C
+pkcs1_rsassa_pss_verify_ext:512:16:"00b076d23250816f9aab02307e452b97f0cae7598369b41624e8afc7971a59a13892f64b07eaa6ec928c160b2d6ec8f9d0dd5b63c8b3ac0767b4f65c892f56c10f":16:"010001":POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:0:"":"ace8b03347da1b9a7a5e94a0d76359bb39c819bb170bef38ea84995ed653446c0ae87ede434cdf9d0cb2d7bf164cf427892363e6855a1d24d0ce5dd72acaf246":0:0
+
+RSASSA-PSS verify ext, 512-bit key, empty salt, bad signature
+depends_on:POLARSSL_SHA256_C
+pkcs1_rsassa_pss_verify_ext:512:16:"00b076d23250816f9aab02307e452b97f0cae7598369b41624e8afc7971a59a13892f64b07eaa6ec928c160b2d6ec8f9d0dd5b63c8b3ac0767b4f65c892f56c10f":16:"010001":POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:0:"":"ace8b03347da1b9a7a5e94a0d76359bb39c819bb170bef38ea84995ed653446c0ae87ede434cdf9d0cb2d7bf164cf427892363e6855a1d24d0ce5dd72acaf247":POLARSSL_ERR_RSA_INVALID_PADDING:POLARSSL_ERR_RSA_INVALID_PADDING
+
+RSASSA-PSS verify ext, 522-bit key, SHA-512, empty salt, good signature
+depends_on:POLARSSL_SHA512_C
+pkcs1_rsassa_pss_verify_ext:522:16:"02d302753e3dda28f42f4d9f92c8647420ea6fbc97c10f8498b966a953f357698d6581060dfe32c8ab98db4bc5ce2acdf0c1e6e404a75a13282550c1aa37d3cdc8bf":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:0:"":"016752ae0b5dfbade6bbd3dd37868d48c8d741f92dca41c360aeda553204c2212a117b1a3d77e0d3f48723503c46e16c8a64de00f1dee3e37e478417452630859486":0:0
+
+RSASSA-PSS verify ext, 528-bit key, SHA-512, saltlen=64, good signature with saltlen=0
+depends_on:POLARSSL_SHA512_C
+pkcs1_rsassa_pss_verify_ext:528:16:"00e31c246d46485984261fd174cab3d4357344602ecd793c47dbe54252d37bb350bc634359b19515542080e4724a4b672291be57c7648f51629eaef234e847d99cc65f":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:64:"":"a9ad7994ba3a1071124153486924448cc67a5af3a5d34e9261d53770782cc85f58e2edde5f7004652a645e3e9606530eb57de41df7298ae2be9dec69cc0d613ab629":0:POLARSSL_ERR_RSA_INVALID_PADDING
+
+RSASSA-PSS verify ext, 528-bit key, SHA-512, empty salt, good signature
+depends_on:POLARSSL_SHA512_C
+pkcs1_rsassa_pss_verify_ext:528:16:"00e31c246d46485984261fd174cab3d4357344602ecd793c47dbe54252d37bb350bc634359b19515542080e4724a4b672291be57c7648f51629eaef234e847d99cc65f":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:0:"":"a9ad7994ba3a1071124153486924448cc67a5af3a5d34e9261d53770782cc85f58e2edde5f7004652a645e3e9606530eb57de41df7298ae2be9dec69cc0d613ab629":0:0
+
+RSASSA-PSS verify ext, 528-bit key, SHA-512, saltlen=64, good signature with saltlen=0
+depends_on:POLARSSL_SHA512_C
+pkcs1_rsassa_pss_verify_ext:528:16:"00e31c246d46485984261fd174cab3d4357344602ecd793c47dbe54252d37bb350bc634359b19515542080e4724a4b672291be57c7648f51629eaef234e847d99cc65f":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:64:"":"a9ad7994ba3a1071124153486924448cc67a5af3a5d34e9261d53770782cc85f58e2edde5f7004652a645e3e9606530eb57de41df7298ae2be9dec69cc0d613ab629":0:POLARSSL_ERR_RSA_INVALID_PADDING
+
+RSASSA-PSS verify ext, 512-bit key, SHA-512 (hash too large)
+depends_on:POLARSSL_SHA512_C
+pkcs1_rsassa_pss_verify_ext:512:16:"00b076d23250816f9aab02307e452b97f0cae7598369b41624e8afc7971a59a13892f64b07eaa6ec928c160b2d6ec8f9d0dd5b63c8b3ac0767b4f65c892f56c10f":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:0:"":"ace8b03347da1b9a7a5e94a0d76359bb39c819bb170bef38ea84995ed653446c0ae87ede434cdf9d0cb2d7bf164cf427892363e6855a1d24d0ce5dd72acaf246":POLARSSL_ERR_RSA_BAD_INPUT_DATA:POLARSSL_ERR_RSA_BAD_INPUT_DATA
+
+RSASSA-PSS verify ext, 521-bit key, SHA-512, empty salt, bad signature
+depends_on:POLARSSL_SHA512_C
+pkcs1_rsassa_pss_verify_ext:521:16:"0131b69860f3cb9bf85ea358fdf2bd2990f1b77a80d6a4fdf817a43dd896bdf7dd26af8ac0237f526e0d33b105c971fdbd4ffa9ece99fc469f31ecf429e8f562c1c3":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:0:"":"00471794655837da498cbf27242807b40593a353c707eb22fd2cc5a3259e728ac4f1df676043eeec8e16c1175b3d9ac8cae72ec1d5772dd69de71c5677f19031568e":POLARSSL_ERR_RSA_BAD_INPUT_DATA:POLARSSL_ERR_RSA_BAD_INPUT_DATA
+
+RSASSA-PSS verify ext, 521-bit key, SHA-256, empty salt, good signature
+depends_on:POLARSSL_SHA256_C
+pkcs1_rsassa_pss_verify_ext:521:16:"0131b69860f3cb9bf85ea358fdf2bd2990f1b77a80d6a4fdf817a43dd896bdf7dd26af8ac0237f526e0d33b105c971fdbd4ffa9ece99fc469f31ecf429e8f562c1c3":16:"010001":POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:0:"41":"009c4941157fa36288e467310b198ab0c615c40963d611ffeef03000549ded809235955ecc57adba44782e9497c004f480ba2b3d58db8335fe0b391075c02c843a6d":0:0
+
+RSASSA-PSS verify ext, 521-bit key, SHA-256, empty salt, flipped-highest-bit signature
+depends_on:POLARSSL_SHA256_C
+pkcs1_rsassa_pss_verify_ext:521:16:"0131b69860f3cb9bf85ea358fdf2bd2990f1b77a80d6a4fdf817a43dd896bdf7dd26af8ac0237f526e0d33b105c971fdbd4ffa9ece99fc469f31ecf429e8f562c1c3":16:"010001":POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:0:"41":"00e11a2403df681c44a1f73f014b6c9ad17847d0b673f7c2a801cee208d10ab5792c10cd0cd495a4b331aaa521409fca7cb1b0d978b3a84cd67e28078b98753e9466":POLARSSL_ERR_RSA_BAD_INPUT_DATA:POLARSSL_ERR_RSA_BAD_INPUT_DATA
+
+RSASSA-PSS verify ext, all-zero padding, automatic salt length
+depends_on:POLARSSL_SHA256_C
+pkcs1_rsassa_pss_verify_ext:512:16:"00b076d23250816f9aab02307e452b97f0cae7598369b41624e8afc7971a59a13892f64b07eaa6ec928c160b2d6ec8f9d0dd5b63c8b3ac0767b4f65c892f56c10f":16:"010001":POLARSSL_MD_NONE:POLARSSL_MD_SHA256:POLARSSL_MD_SHA256:RSA_SALT_LEN_ANY:"":"63a35294577c7e593170378175b7df27c293dae583ec2a971426eb2d66f2af483e897bfae5dc20300a9d61a3644e08c3aee61a463690a3498901563c46041056":POLARSSL_ERR_RSA_INVALID_PADDING:POLARSSL_ERR_RSA_INVALID_PADDING
+