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Guard from undefined behaviour in case of an INT_MAX max_pathlen #3192

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merged 1 commit into from
Apr 16, 2020
Merged

Guard from undefined behaviour in case of an INT_MAX max_pathlen #3192

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6 changes: 6 additions & 0 deletions library/x509_crt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -524,6 +524,12 @@ static int x509_get_basic_constraints( unsigned char **p,
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

/* Do not accept max_pathlen equal to INT_MAX to avoid a signed integer
* overflow, which is an undefined behavior. */
if( *max_pathlen == INT_MAX )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_INVALID_LENGTH );

(*max_pathlen)++;

return( 0 );
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20 changes: 20 additions & 0 deletions tests/data_files/server1_pathlen_int_max-1.crt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
-----BEGIN CERTIFICATE-----
MIIDSDCCAjCgAwIBAgIBATANBgkqhkiG9w0BAQUFADA7MQswCQYDVQQGEwJOTDER
MA8GA1UECgwIUG9sYXJTU0wxGTAXBgNVBAMMEFBvbGFyU1NMIFRlc3QgQ0EwHhcN
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BgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAqQIfPUBq1VVTi/027oJlLhVhXom/
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d185fAkER4KwVzlw7aPsFRkeqDMIR8EFQqn9TMO0390GH00QUUBncxMPQPhtgSVf
CrFTxjB+FTms+Vruf5KepgVb5xOXhbUjktnUJAbVCSWJdQfdphqPPwkZvq1lLGTr
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bp7OvViJ4lNZnm5akmXiiD8MlBmj3eXonZUT7Snbq3AS3FrKaxerUoJUsQIDAQAB
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L+nBpz7mO2J6XQ85ip+tLWAGCEHo0omAIQorAoCSqtLiaz47HxOdNK0hnM7V5k8P
05AVhxDa3WqZ9FmMaDc8j8XqmOgKYVMC4/WS0g==
-----END CERTIFICATE-----
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pathlen is 2147483646, OK

20 changes: 20 additions & 0 deletions tests/data_files/server1_pathlen_int_max.crt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
-----BEGIN CERTIFICATE-----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qhkAEPelpaq5ZRM6cYJQoo0Ak64j4svjOZeF0g==
-----END CERTIFICATE-----
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pathlen is 2147483647, OK

8 changes: 8 additions & 0 deletions tests/suites/test_suite_x509parse.data
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Original file line number Diff line number Diff line change
Expand Up @@ -1798,6 +1798,14 @@ X509 CRT ASN1 (TBS, inv extBasicConstraint, no pathlen length)
depends_on:MBEDTLS_RSA_C:MBEDTLS_SHA256_C
x509parse_crt:"3081b030819aa0030201028204deadbeef300d06092a864886f70d01010b0500300c310a30080600130454657374301c170c303930313031303030303030170c303931323331323335393539300c310a30080600130454657374302a300d06092A864886F70D010101050003190030160210ffffffffffffffffffffffffffffffff0202ffffa100a200a314301230100603551d130101010406300402010102300d06092a864886f70d01010b0500030200ff":"":MBEDTLS_ERR_X509_INVALID_EXTENSIONS + MBEDTLS_ERR_ASN1_OUT_OF_DATA

X509 CRT ASN1 (inv extBasicConstraint, pathlen is INT_MAX)
depends_on:MBEDTLS_RSA_C:MBEDTLS_SHA256_C:MBEDTLS_SHA1_C
x509parse_crt_file:"data_files/server1_pathlen_int_max.crt":MBEDTLS_ERR_X509_INVALID_EXTENSIONS + MBEDTLS_ERR_ASN1_INVALID_LENGTH

X509 CRT ASN1 (pathlen is INT_MAX-1)
depends_on:MBEDTLS_RSA_C:MBEDTLS_SHA256_C:MBEDTLS_SHA1_C
x509parse_crt_file:"data_files/server1_pathlen_int_max-1.crt":0

X509 CRT ASN1 (TBS, inv extBasicConstraint, pathlen inv length encoding)
depends_on:MBEDTLS_RSA_C:MBEDTLS_SHA256_C
x509parse_crt:"3081b130819ba0030201028204deadbeef300d06092a864886f70d01010b0500300c310a30080600130454657374301c170c303930313031303030303030170c303931323331323335393539300c310a30080600130454657374302a300d06092A864886F70D010101050003190030160210ffffffffffffffffffffffffffffffff0202ffffa100a200a315301330110603551d13010101040730050201010285300d06092a864886f70d01010b0500030200ff":"":MBEDTLS_ERR_X509_INVALID_EXTENSIONS + MBEDTLS_ERR_ASN1_INVALID_LENGTH
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