The Samba-Bugzilla – Attachment 17565 Details for
Bug 15203
CVE-2022-42898 [SECURITY] krb5_pac_parse() buffer parsing vulnerability
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[patch]
proposed patch for master v1
CVE-2022-42898-pac-parse-overflow-v1-master.patch (text/plain), 17.56 KB, created by
Jo Sutton
on 2022-10-17 07:34:24 UTC
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Description:
proposed patch for master v1
Filename:
MIME Type:
Creator:
Jo Sutton
Created:
2022-10-17 07:34:24 UTC
Size:
17.56 KB
patch
obsolete
>From d689d1bf8e149095a90e8ae019238a8a11725dda Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Fri, 14 Oct 2022 16:45:37 +1300 >Subject: [PATCH 1/8] CVE-2022-42898 third_party/heimdal: Avoid potential > overflows in krb5_pac_add_buffer() > >Catch overflows that result from adding PAC_INFO_BUFFER_SIZE. > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index c8f355c8179..d4a0719daf2 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -394,9 +394,21 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > > p->pac = ptr; > >- for (i = 0; i < len; i++) >- p->pac->buffers[i].offset_lo += PAC_INFO_BUFFER_SIZE; >+ for (i = 0; i < len; i++) { >+ if (p->pac->buffers[i].offset_lo > UINT32_MAX - PAC_INFO_BUFFER_SIZE) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ return ret; >+ } > >+ p->pac->buffers[i].offset_lo += PAC_INFO_BUFFER_SIZE; >+ } >+ >+ if (p->data.length > UINT32_MAX - PAC_INFO_BUFFER_SIZE) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ return ret; >+ } > offset = p->data.length + PAC_INFO_BUFFER_SIZE; > > p->pac->buffers[len].type = type; >-- >2.35.0 > > >From 7bad60f68c18f3e880424a214510396dac872f77 Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 19:07:42 +1300 >Subject: [PATCH 2/8] CVE-2022-42898 third_party/heimdal: Resize offset and > size variables > >We don't support PACs with offsets larger than 32 bits (4 GiB). This can >be made clearer by restricting ourselves to 32-bit types. > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index d4a0719daf2..a62e396d99b 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -380,7 +380,7 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > { > krb5_error_code ret; > void *ptr; >- size_t len, offset, header_end, old_end; >+ uint32_t len, offset, header_end, old_end; > uint32_t i; > > assert(data->data != NULL); >@@ -477,8 +477,8 @@ krb5_pac_get_buffer(krb5_context context, krb5_const_pac p, > uint32_t i; > > for (i = 0; i < p->pac->numbuffers; i++) { >- const size_t len = p->pac->buffers[i].buffersize; >- const size_t offset = p->pac->buffers[i].offset_lo; >+ const uint32_t len = p->pac->buffers[i].buffersize; >+ const uint32_t offset = p->pac->buffers[i].offset_lo; > > if (p->pac->buffers[i].type != type) > continue; >-- >2.35.0 > > >From ca0487e60f9797557303f70bc167b9705ea91300 Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 19:05:15 +1300 >Subject: [PATCH 3/8] CVE-2022-42898 third_party/heimdal: Avoid integer > overflow when calculating PAC header size > >On 32-bit systems, or after converting integer types to uint32_t, the >multiplication of buffer count by size can overflow. Introduce a helper >function that prevents this from occurring. > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 58 +++++++++++++++++++++++++----- > 1 file changed, 50 insertions(+), 8 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index a62e396d99b..4e227911a59 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -133,6 +133,34 @@ struct heim_type_data pac_object = { > NULL > }; > >+static krb5_error_code pac_header_size(krb5_context context, >+ uint32_t num_buffers, >+ uint32_t *result) >+{ >+ krb5_error_code ret; >+ uint32_t header_size; >+ >+ /* Guard against integer overflow on 32-bit systems. */ >+ if (num_buffers > UINT32_MAX / PAC_INFO_BUFFER_SIZE) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "PAC has too many buffers"); >+ return ret; >+ } >+ header_size = PAC_INFO_BUFFER_SIZE * num_buffers; >+ >+ /* Guard against integer overflow on 32-bit systems. */ >+ if (header_size > UINT32_MAX - PACTYPE_SIZE) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "PAC has too many buffers"); >+ return ret; >+ } >+ header_size += PACTYPE_SIZE; >+ >+ *result = header_size; >+ >+ return 0; >+} >+ > /* > * HMAC-MD5 checksum over any key (needed for the PAC routines) > */ >@@ -217,8 +245,12 @@ krb5_pac_parse(krb5_context context, const void *ptr, size_t len, > goto out; > } > >- p->pac = calloc(1, >- sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (tmp - 1))); >+ ret = pac_header_size(context, tmp, &header_end); >+ if (ret) { >+ return ret; >+ } >+ >+ p->pac = calloc(1, header_end); > if (p->pac == NULL) { > ret = krb5_enomem(context); > goto out; >@@ -227,7 +259,6 @@ krb5_pac_parse(krb5_context context, const void *ptr, size_t len, > p->pac->numbuffers = tmp; > p->pac->version = tmp2; > >- header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers); > if (header_end > len) { > ret = EINVAL; > goto out; >@@ -387,8 +418,12 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > > len = p->pac->numbuffers; > >- ptr = realloc(p->pac, >- sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * len)); >+ ret = pac_header_size(context, len + 1, &header_end); >+ if (ret) { >+ return ret; >+ } >+ >+ ptr = realloc(p->pac, header_end); > if (ptr == NULL) > return krb5_enomem(context); > >@@ -435,7 +470,7 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > /* > * make place for new PAC INFO BUFFER header > */ >- header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers); >+ header_end -= PAC_INFO_BUFFER_SIZE; > memmove((unsigned char *)p->data.data + header_end + PAC_INFO_BUFFER_SIZE, > (unsigned char *)p->data.data + header_end , > old_end - header_end); >@@ -1377,8 +1412,13 @@ _krb5_pac_sign(krb5_context context, > > if (num) { > void *ptr; >+ uint32_t len; > >- ptr = realloc(p->pac, sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (p->pac->numbuffers + num - 1))); >+ ret = pac_header_size(context, p->pac->numbuffers + num, &len); >+ if (ret) >+ goto out; >+ >+ ptr = realloc(p->pac, len); > if (ptr == NULL) { > ret = krb5_enomem(context); > goto out; >@@ -1440,7 +1480,9 @@ _krb5_pac_sign(krb5_context context, > CHECK(ret, krb5_store_uint32(sp, p->pac->numbuffers), out); > CHECK(ret, krb5_store_uint32(sp, p->pac->version), out); > >- end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers); >+ ret = pac_header_size(context, p->pac->numbuffers, &end); >+ if (ret) >+ goto out; > > for (i = 0; i < p->pac->numbuffers; i++) { > uint32_t len; >-- >2.35.0 > > >From 4eb087e0368fd1769953183f87e898ffda9e0461 Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 19:04:04 +1300 >Subject: [PATCH 4/8] CVE-2022-42898 third_party/heimdal: Limit PAC buffers to > (2^32) - 1 bytes in length > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 6 ++++++ > 1 file changed, 6 insertions(+) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index 4e227911a59..b35874742d2 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -416,6 +416,12 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > > assert(data->data != NULL); > >+ if (data->length > UINT32_MAX) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ return ret; >+ } >+ > len = p->pac->numbuffers; > > ret = pac_header_size(context, len + 1, &header_end); >-- >2.35.0 > > >From 39dff5d908192738b27672cc5287e7a90bd3ccc9 Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 18:40:12 +1300 >Subject: [PATCH 5/8] CVE-2022-42898 third_party/heimdal: Avoid integer > overflows in _krb5_pac_sign() > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 49 ++++++++++++++++++++++++++++-- > 1 file changed, 47 insertions(+), 2 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index b35874742d2..0bdd2997494 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -1498,26 +1498,66 @@ _krb5_pac_sign(krb5_context context, > /* store data */ > > if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) { >+ if (server_size > UINT32_MAX - 4) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > len = server_size + 4; >+ if (end > UINT32_MAX - 4) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > server_offset = end + 4; > CHECK(ret, krb5_store_uint32(spdata, server_cksumtype), out); > CHECK(ret, fill_zeros(context, spdata, server_size), out); > } else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) { >+ if (priv_size > UINT32_MAX - 4) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > len = priv_size + 4; >+ if (end > UINT32_MAX - 4) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > priv_offset = end + 4; > CHECK(ret, krb5_store_uint32(spdata, priv_cksumtype), out); > CHECK(ret, fill_zeros(context, spdata, priv_size), out); > if (rodc_id != 0) { >+ if (len > UINT32_MAX - sizeof(rodc_id)) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > len += sizeof(rodc_id); > CHECK(ret, fill_zeros(context, spdata, sizeof(rodc_id)), out); > } > } else if (p->ticket_sign_data.length != 0 && > p->pac->buffers[i].type == PAC_TICKET_CHECKSUM) { >+ if (priv_size > UINT32_MAX - 4) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > len = priv_size + 4; >+ if (end > UINT32_MAX - 4) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > ticket_offset = end + 4; > CHECK(ret, krb5_store_uint32(spdata, priv_cksumtype), out); > CHECK(ret, fill_zeros(context, spdata, priv_size), out); > if (rodc_id != 0) { >+ if (len > UINT32_MAX - sizeof(rodc_id)) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > len += sizeof(rodc_id); > CHECK(ret, krb5_store_uint16(spdata, rodc_id), out); > } >@@ -1547,11 +1587,16 @@ _krb5_pac_sign(krb5_context context, > > /* advance data endpointer and align */ > { >- int32_t e; >+ uint32_t e; > >+ if (end > UINT32_MAX - len) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ goto out; >+ } > end += len; > e = ((end + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT; >- if ((int32_t)end != e) { >+ if (end != e) { > CHECK(ret, fill_zeros(context, spdata, e - end), out); > } > end = e; >-- >2.35.0 > > >From c7ab9911f2b669cb623eb953fe7fbe7c1bcd0331 Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 18:43:47 +1300 >Subject: [PATCH 6/8] CVE-2022-42898 third_party/heimdal: Avoid integer > overflow when aligning PAC buffers > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 37 +++++++++++++++++++++++++----- > 1 file changed, 31 insertions(+), 6 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index 0bdd2997494..67d259510ce 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -161,6 +161,28 @@ static krb5_error_code pac_header_size(krb5_context context, > return 0; > } > >+static krb5_error_code pac_aligned_size(krb5_context context, >+ uint32_t size, >+ uint32_t *aligned_size) >+{ >+ krb5_error_code ret; >+ >+ /* Guard against integer overflow on 32-bit systems. */ >+ if (size > UINT32_MAX - (PAC_ALIGNMENT - 1)) { >+ ret = EINVAL; >+ krb5_set_error_message(context, ret, "integer overrun"); >+ return ret; >+ } >+ size += PAC_ALIGNMENT - 1; >+ >+ /* align to PAC_ALIGNMENT */ >+ size = (size / PAC_ALIGNMENT) * PAC_ALIGNMENT; >+ >+ *aligned_size = size; >+ >+ return 0; >+} >+ > /* > * HMAC-MD5 checksum over any key (needed for the PAC routines) > */ >@@ -458,14 +480,13 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > p->pac->buffers[len].offset_hi = 0; > > old_end = p->data.length; >- len = p->data.length + data->length + PAC_INFO_BUFFER_SIZE; >- if (len < p->data.length) { >+ if (offset > UINT32_MAX - data->length) { > krb5_set_error_message(context, EINVAL, "integer overrun"); > return EINVAL; > } >- >- /* align to PAC_ALIGNMENT */ >- len = ((len + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT; >+ ret = pac_aligned_size(context, offset + data->length, &len); >+ if (ret) >+ return ret; > > ret = krb5_data_realloc(&p->data, len); > if (ret) { >@@ -1595,7 +1616,11 @@ _krb5_pac_sign(krb5_context context, > goto out; > } > end += len; >- e = ((end + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT; >+ >+ ret = pac_aligned_size(context, end, &e); >+ if (ret) >+ goto out; >+ > if (end != e) { > CHECK(ret, fill_zeros(context, spdata, e - end), out); > } >-- >2.35.0 > > >From a3b0e2ef206ed0f12f65f63e7ab41a2c31ccaa65 Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 18:27:16 +1300 >Subject: [PATCH 7/8] CVE-2022-42898 third_party/heimdal: Introduce > unaligned_len variable > >This is intended to clarify the code. > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index 67d259510ce..767d8566f46 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -435,6 +435,7 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > void *ptr; > uint32_t len, offset, header_end, old_end; > uint32_t i; >+ uint32_t unaligned_len; > > assert(data->data != NULL); > >@@ -484,7 +485,9 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > krb5_set_error_message(context, EINVAL, "integer overrun"); > return EINVAL; > } >- ret = pac_aligned_size(context, offset + data->length, &len); >+ unaligned_len = offset + data->length; >+ >+ ret = pac_aligned_size(context, unaligned_len, &len); > if (ret) > return ret; > >@@ -510,7 +513,7 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > memcpy((unsigned char *)p->data.data + offset, > data->data, data->length); > memset((unsigned char *)p->data.data + offset + data->length, >- 0, p->data.length - offset - data->length); >+ 0, p->data.length - unaligned_len); > > p->pac->numbuffers += 1; > >-- >2.35.0 > > >From f08fa4fa3a4194e4b4997edfbbe116b495a6142e Mon Sep 17 00:00:00 2001 >From: Joseph Sutton <josephsutton@catalyst.net.nz> >Date: Mon, 17 Oct 2022 18:23:38 +1300 >Subject: [PATCH 8/8] CVE-2022-42898 third_party/heimdal: Introduce num_buffers > variable > >Reusing 'len' for two unrelated quantities is confusing. > >BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203 > >Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz> >--- > third_party/heimdal/lib/krb5/pac.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > >diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c >index 767d8566f46..38bc59dc939 100644 >--- a/third_party/heimdal/lib/krb5/pac.c >+++ b/third_party/heimdal/lib/krb5/pac.c >@@ -436,6 +436,7 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > uint32_t len, offset, header_end, old_end; > uint32_t i; > uint32_t unaligned_len; >+ uint32_t num_buffers; > > assert(data->data != NULL); > >@@ -445,9 +446,9 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > return ret; > } > >- len = p->pac->numbuffers; >+ num_buffers = p->pac->numbuffers; > >- ret = pac_header_size(context, len + 1, &header_end); >+ ret = pac_header_size(context, num_buffers + 1, &header_end); > if (ret) { > return ret; > } >@@ -458,7 +459,7 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > > p->pac = ptr; > >- for (i = 0; i < len; i++) { >+ for (i = 0; i < num_buffers; i++) { > if (p->pac->buffers[i].offset_lo > UINT32_MAX - PAC_INFO_BUFFER_SIZE) { > ret = EINVAL; > krb5_set_error_message(context, ret, "integer overrun"); >@@ -475,10 +476,10 @@ krb5_pac_add_buffer(krb5_context context, krb5_pac p, > } > offset = p->data.length + PAC_INFO_BUFFER_SIZE; > >- p->pac->buffers[len].type = type; >- p->pac->buffers[len].buffersize = data->length; >- p->pac->buffers[len].offset_lo = offset; >- p->pac->buffers[len].offset_hi = 0; >+ p->pac->buffers[num_buffers].type = type; >+ p->pac->buffers[num_buffers].buffersize = data->length; >+ p->pac->buffers[num_buffers].offset_lo = offset; >+ p->pac->buffers[num_buffers].offset_hi = 0; > > old_end = p->data.length; > if (offset > UINT32_MAX - data->length) { >-- >2.35.0 >
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