diff options
Diffstat (limited to 'krb5-1.12-CVE-2014-4341_4342.patch')
| -rw-r--r-- | krb5-1.12-CVE-2014-4341_4342.patch | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/krb5-1.12-CVE-2014-4341_4342.patch b/krb5-1.12-CVE-2014-4341_4342.patch new file mode 100644 index 0000000..c7719d2 --- /dev/null +++ b/krb5-1.12-CVE-2014-4341_4342.patch @@ -0,0 +1,163 @@ +commit e6ae703ae597d798e310368d52b8f38ee11c6a73 +Author: Greg Hudson <ghudson@mit.edu> +Date: Thu Jun 19 13:49:16 2014 -0400 + + Handle invalid RFC 1964 tokens [CVE-2014-4341...] + + Detect the following cases which would otherwise cause invalid memory + accesses and/or integer underflow: + + * An RFC 1964 token being processed by an RFC 4121-only context + [CVE-2014-4342] + + * A header with fewer than 22 bytes after the token ID or an + incomplete checksum [CVE-2014-4341 CVE-2014-4342] + + * A ciphertext shorter than the confounder [CVE-2014-4341] + + * A declared padding length longer than the plaintext [CVE-2014-4341] + + If we detect a bad pad byte, continue on to compute the checksum to + avoid creating a padding oracle, but treat the checksum as invalid + even if it compares equal. + + CVE-2014-4341: + + In MIT krb5, an unauthenticated remote attacker with the ability to + inject packets into a legitimately established GSSAPI application + session can cause a program crash due to invalid memory references + when attempting to read beyond the end of a buffer. + + CVSSv2 Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C + + CVE-2014-4342: + + In MIT krb5 releases krb5-1.7 and later, an unauthenticated remote + attacker with the ability to inject packets into a legitimately + established GSSAPI application session can cause a program crash due + to invalid memory references when reading beyond the end of a buffer + or by causing a null pointer dereference. + + CVSSv2 Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C + + [tlyu@mit.edu: CVE summaries, CVSS] + + (cherry picked from commit fb99962cbd063ac04c9a9d2cc7c75eab73f3533d) + + ticket: 7949 + version_fixed: 1.12.2 + status: resolved + +diff --git a/src/lib/gssapi/krb5/k5unseal.c b/src/lib/gssapi/krb5/k5unseal.c +index ca21d43..b65c83c 100644 +--- a/src/lib/gssapi/krb5/k5unseal.c ++++ b/src/lib/gssapi/krb5/k5unseal.c +@@ -74,6 +74,7 @@ kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer, + int conflen = 0; + int signalg; + int sealalg; ++ int bad_pad = 0; + gss_buffer_desc token; + krb5_checksum cksum; + krb5_checksum md5cksum; +@@ -86,6 +87,7 @@ kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer, + krb5_ui_4 seqnum; + OM_uint32 retval; + size_t sumlen; ++ size_t padlen; + krb5_keyusage sign_usage = KG_USAGE_SIGN; + + if (toktype == KG_TOK_SEAL_MSG) { +@@ -93,18 +95,23 @@ kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer, + message_buffer->value = NULL; + } + +- /* get the sign and seal algorithms */ +- +- signalg = ptr[0] + (ptr[1]<<8); +- sealalg = ptr[2] + (ptr[3]<<8); +- + /* Sanity checks */ + +- if ((ptr[4] != 0xff) || (ptr[5] != 0xff)) { ++ if (ctx->seq == NULL) { ++ /* ctx was established using a newer enctype, and cannot process RFC ++ * 1964 tokens. */ ++ *minor_status = 0; ++ return GSS_S_DEFECTIVE_TOKEN; ++ } ++ ++ if ((bodysize < 22) || (ptr[4] != 0xff) || (ptr[5] != 0xff)) { + *minor_status = 0; + return GSS_S_DEFECTIVE_TOKEN; + } + ++ signalg = ptr[0] + (ptr[1]<<8); ++ sealalg = ptr[2] + (ptr[3]<<8); ++ + if ((toktype != KG_TOK_SEAL_MSG) && + (sealalg != 0xffff)) { + *minor_status = 0; +@@ -153,6 +160,11 @@ kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer, + return GSS_S_DEFECTIVE_TOKEN; + } + ++ if ((size_t)bodysize < 14 + cksum_len) { ++ *minor_status = 0; ++ return GSS_S_DEFECTIVE_TOKEN; ++ } ++ + /* get the token parameters */ + + if ((code = kg_get_seq_num(context, ctx->seq, ptr+14, ptr+6, &direction, +@@ -207,7 +219,20 @@ kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer, + plainlen = tmsglen; + + conflen = kg_confounder_size(context, ctx->enc->keyblock.enctype); +- token.length = tmsglen - conflen - plain[tmsglen-1]; ++ if (tmsglen < conflen) { ++ if (sealalg != 0xffff) ++ xfree(plain); ++ *minor_status = 0; ++ return(GSS_S_DEFECTIVE_TOKEN); ++ } ++ padlen = plain[tmsglen - 1]; ++ if (tmsglen - conflen < padlen) { ++ /* Don't error out yet, to avoid padding oracle attacks. We will ++ * treat this as a checksum failure later on. */ ++ padlen = 0; ++ bad_pad = 1; ++ } ++ token.length = tmsglen - conflen - padlen; + + if (token.length) { + if ((token.value = (void *) gssalloc_malloc(token.length)) == NULL) { +@@ -403,7 +428,7 @@ kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer, + + /* compare the computed checksum against the transmitted checksum */ + +- if (code) { ++ if (code || bad_pad) { + if (toktype == KG_TOK_SEAL_MSG) + gssalloc_free(token.value); + *minor_status = 0; +diff --git a/src/lib/gssapi/krb5/k5unsealiov.c b/src/lib/gssapi/krb5/k5unsealiov.c +index e34bda4..8d6a2da 100644 +--- a/src/lib/gssapi/krb5/k5unsealiov.c ++++ b/src/lib/gssapi/krb5/k5unsealiov.c +@@ -69,7 +69,14 @@ kg_unseal_v1_iov(krb5_context context, + return GSS_S_DEFECTIVE_TOKEN; + } + +- if (header->buffer.length < token_wrapper_len + 14) { ++ if (ctx->seq == NULL) { ++ /* ctx was established using a newer enctype, and cannot process RFC ++ * 1964 tokens. */ ++ *minor_status = 0; ++ return GSS_S_DEFECTIVE_TOKEN; ++ } ++ ++ if (header->buffer.length < token_wrapper_len + 22) { + *minor_status = 0; + return GSS_S_DEFECTIVE_TOKEN; + } |