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Better handling of invalid key files.

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Passing an invalid public key to libssh2_userauth_publickey_fromfile_ex
triggered an assertion.  Replaced this with a runtime check that rejects
obviously invalid key data.
This commit is contained in:
Alexander Lamaison 2010-06-10 12:01:43 +01:00
parent ab8ee8abf3
commit c87a48ae4c
1 changed files with 18 additions and 2 deletions
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20
src/userauth.c
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@ -876,6 +876,15 @@ _libssh2_userauth_publickey(LIBSSH2_SESSION *session,
unsigned char *s;
if (session->userauth_pblc_state == libssh2_NB_state_idle) {
/*
* The call to _libssh2_ntohu32 later relies on pubkeydata having at
* least 4 valid bytes containing the length of the method name.
*/
if (pubkeydata_len < 4)
return _libssh2_error(session, LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED,
"Invalid public key, too short");
/* Zero the whole thing out */
memset(&session->userauth_pblc_packet_requirev_state, 0,
sizeof(session->userauth_pblc_packet_requirev_state));
@ -898,8 +907,15 @@ _libssh2_userauth_publickey(LIBSSH2_SESSION *session,
memcpy(session->userauth_pblc_method, pubkeydata + 4,
session->userauth_pblc_method_len);
}
assert( /* preallocated method len should match what we expect */
session->userauth_pblc_method_len == _libssh2_ntohu32(pubkeydata));
/*
* The length of the method name read from plaintext prefix in the
* file must match length embedded in the key.
* TODO: The data should match too but we don't check that. Should we?
*/
else if (session->userauth_pblc_method_len !=
_libssh2_ntohu32(pubkeydata))
return _libssh2_error(session, LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED,
"Invalid public key");
/*
* 45 = packet_type(1) + username_len(4) + servicename_len(4) +