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-rw-r--r--fs/cifs/asn1.c612
1 files changed, 612 insertions, 0 deletions
diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
new file mode 100644
index 000000000..3150c19cd
--- /dev/null
+++ b/fs/cifs/asn1.c
@@ -0,0 +1,612 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in
+ * turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich
+ *
+ * Copyright (c) 2000 RP Internet (www.rpi.net.au).
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include "cifspdu.h"
+#include "cifsglob.h"
+#include "cifs_debug.h"
+#include "cifsproto.h"
+
+/*****************************************************************************
+ *
+ * Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse)
+ *
+ *****************************************************************************/
+
+/* Class */
+#define ASN1_UNI 0 /* Universal */
+#define ASN1_APL 1 /* Application */
+#define ASN1_CTX 2 /* Context */
+#define ASN1_PRV 3 /* Private */
+
+/* Tag */
+#define ASN1_EOC 0 /* End Of Contents or N/A */
+#define ASN1_BOL 1 /* Boolean */
+#define ASN1_INT 2 /* Integer */
+#define ASN1_BTS 3 /* Bit String */
+#define ASN1_OTS 4 /* Octet String */
+#define ASN1_NUL 5 /* Null */
+#define ASN1_OJI 6 /* Object Identifier */
+#define ASN1_OJD 7 /* Object Description */
+#define ASN1_EXT 8 /* External */
+#define ASN1_ENUM 10 /* Enumerated */
+#define ASN1_SEQ 16 /* Sequence */
+#define ASN1_SET 17 /* Set */
+#define ASN1_NUMSTR 18 /* Numerical String */
+#define ASN1_PRNSTR 19 /* Printable String */
+#define ASN1_TEXSTR 20 /* Teletext String */
+#define ASN1_VIDSTR 21 /* Video String */
+#define ASN1_IA5STR 22 /* IA5 String */
+#define ASN1_UNITIM 23 /* Universal Time */
+#define ASN1_GENTIM 24 /* General Time */
+#define ASN1_GRASTR 25 /* Graphical String */
+#define ASN1_VISSTR 26 /* Visible String */
+#define ASN1_GENSTR 27 /* General String */
+
+/* Primitive / Constructed methods*/
+#define ASN1_PRI 0 /* Primitive */
+#define ASN1_CON 1 /* Constructed */
+
+/*
+ * Error codes.
+ */
+#define ASN1_ERR_NOERROR 0
+#define ASN1_ERR_DEC_EMPTY 2
+#define ASN1_ERR_DEC_EOC_MISMATCH 3
+#define ASN1_ERR_DEC_LENGTH_MISMATCH 4
+#define ASN1_ERR_DEC_BADVALUE 5
+
+#define SPNEGO_OID_LEN 7
+#define NTLMSSP_OID_LEN 10
+#define KRB5_OID_LEN 7
+#define KRB5U2U_OID_LEN 8
+#define MSKRB5_OID_LEN 7
+static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
+static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
+static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
+static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
+static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
+
+/*
+ * ASN.1 context.
+ */
+struct asn1_ctx {
+ int error; /* Error condition */
+ unsigned char *pointer; /* Octet just to be decoded */
+ unsigned char *begin; /* First octet */
+ unsigned char *end; /* Octet after last octet */
+};
+
+/*
+ * Octet string (not null terminated)
+ */
+struct asn1_octstr {
+ unsigned char *data;
+ unsigned int len;
+};
+
+static void
+asn1_open(struct asn1_ctx *ctx, unsigned char *buf, unsigned int len)
+{
+ ctx->begin = buf;
+ ctx->end = buf + len;
+ ctx->pointer = buf;
+ ctx->error = ASN1_ERR_NOERROR;
+}
+
+static unsigned char
+asn1_octet_decode(struct asn1_ctx *ctx, unsigned char *ch)
+{
+ if (ctx->pointer >= ctx->end) {
+ ctx->error = ASN1_ERR_DEC_EMPTY;
+ return 0;
+ }
+ *ch = *(ctx->pointer)++;
+ return 1;
+}
+
+#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
+static unsigned char
+asn1_enum_decode(struct asn1_ctx *ctx, __le32 *val)
+{
+ unsigned char ch;
+
+ if (ctx->pointer >= ctx->end) {
+ ctx->error = ASN1_ERR_DEC_EMPTY;
+ return 0;
+ }
+
+ ch = *(ctx->pointer)++; /* ch has 0xa, ptr points to length octet */
+ if ((ch) == ASN1_ENUM) /* if ch value is ENUM, 0xa */
+ *val = *(++(ctx->pointer)); /* value has enum value */
+ else
+ return 0;
+
+ ctx->pointer++;
+ return 1;
+}
+#endif
+
+static unsigned char
+asn1_tag_decode(struct asn1_ctx *ctx, unsigned int *tag)
+{
+ unsigned char ch;
+
+ *tag = 0;
+
+ do {
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+ *tag <<= 7;
+ *tag |= ch & 0x7F;
+ } while ((ch & 0x80) == 0x80);
+ return 1;
+}
+
+static unsigned char
+asn1_id_decode(struct asn1_ctx *ctx,
+ unsigned int *cls, unsigned int *con, unsigned int *tag)
+{
+ unsigned char ch;
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *cls = (ch & 0xC0) >> 6;
+ *con = (ch & 0x20) >> 5;
+ *tag = (ch & 0x1F);
+
+ if (*tag == 0x1F) {
+ if (!asn1_tag_decode(ctx, tag))
+ return 0;
+ }
+ return 1;
+}
+
+static unsigned char
+asn1_length_decode(struct asn1_ctx *ctx, unsigned int *def, unsigned int *len)
+{
+ unsigned char ch, cnt;
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ if (ch == 0x80)
+ *def = 0;
+ else {
+ *def = 1;
+
+ if (ch < 0x80)
+ *len = ch;
+ else {
+ cnt = (unsigned char) (ch & 0x7F);
+ *len = 0;
+
+ while (cnt > 0) {
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+ *len <<= 8;
+ *len |= ch;
+ cnt--;
+ }
+ }
+ }
+
+ /* don't trust len bigger than ctx buffer */
+ if (*len > ctx->end - ctx->pointer)
+ return 0;
+
+ return 1;
+}
+
+static unsigned char
+asn1_header_decode(struct asn1_ctx *ctx,
+ unsigned char **eoc,
+ unsigned int *cls, unsigned int *con, unsigned int *tag)
+{
+ unsigned int def = 0;
+ unsigned int len = 0;
+
+ if (!asn1_id_decode(ctx, cls, con, tag))
+ return 0;
+
+ if (!asn1_length_decode(ctx, &def, &len))
+ return 0;
+
+ /* primitive shall be definite, indefinite shall be constructed */
+ if (*con == ASN1_PRI && !def)
+ return 0;
+
+ if (def)
+ *eoc = ctx->pointer + len;
+ else
+ *eoc = NULL;
+ return 1;
+}
+
+static unsigned char
+asn1_eoc_decode(struct asn1_ctx *ctx, unsigned char *eoc)
+{
+ unsigned char ch;
+
+ if (eoc == NULL) {
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ if (ch != 0x00) {
+ ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
+ return 0;
+ }
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ if (ch != 0x00) {
+ ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
+ return 0;
+ }
+ return 1;
+ } else {
+ if (ctx->pointer != eoc) {
+ ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH;
+ return 0;
+ }
+ return 1;
+ }
+}
+
+/* static unsigned char asn1_null_decode(struct asn1_ctx *ctx,
+ unsigned char *eoc)
+{
+ ctx->pointer = eoc;
+ return 1;
+}
+
+static unsigned char asn1_long_decode(struct asn1_ctx *ctx,
+ unsigned char *eoc, long *integer)
+{
+ unsigned char ch;
+ unsigned int len;
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *integer = (signed char) ch;
+ len = 1;
+
+ while (ctx->pointer < eoc) {
+ if (++len > sizeof(long)) {
+ ctx->error = ASN1_ERR_DEC_BADVALUE;
+ return 0;
+ }
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *integer <<= 8;
+ *integer |= ch;
+ }
+ return 1;
+}
+
+static unsigned char asn1_uint_decode(struct asn1_ctx *ctx,
+ unsigned char *eoc,
+ unsigned int *integer)
+{
+ unsigned char ch;
+ unsigned int len;
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *integer = ch;
+ if (ch == 0)
+ len = 0;
+ else
+ len = 1;
+
+ while (ctx->pointer < eoc) {
+ if (++len > sizeof(unsigned int)) {
+ ctx->error = ASN1_ERR_DEC_BADVALUE;
+ return 0;
+ }
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *integer <<= 8;
+ *integer |= ch;
+ }
+ return 1;
+}
+
+static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx,
+ unsigned char *eoc,
+ unsigned long *integer)
+{
+ unsigned char ch;
+ unsigned int len;
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *integer = ch;
+ if (ch == 0)
+ len = 0;
+ else
+ len = 1;
+
+ while (ctx->pointer < eoc) {
+ if (++len > sizeof(unsigned long)) {
+ ctx->error = ASN1_ERR_DEC_BADVALUE;
+ return 0;
+ }
+
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *integer <<= 8;
+ *integer |= ch;
+ }
+ return 1;
+}
+
+static unsigned char
+asn1_octets_decode(struct asn1_ctx *ctx,
+ unsigned char *eoc,
+ unsigned char **octets, unsigned int *len)
+{
+ unsigned char *ptr;
+
+ *len = 0;
+
+ *octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC);
+ if (*octets == NULL) {
+ return 0;
+ }
+
+ ptr = *octets;
+ while (ctx->pointer < eoc) {
+ if (!asn1_octet_decode(ctx, (unsigned char *) ptr++)) {
+ kfree(*octets);
+ *octets = NULL;
+ return 0;
+ }
+ (*len)++;
+ }
+ return 1;
+} */
+
+static unsigned char
+asn1_subid_decode(struct asn1_ctx *ctx, unsigned long *subid)
+{
+ unsigned char ch;
+
+ *subid = 0;
+
+ do {
+ if (!asn1_octet_decode(ctx, &ch))
+ return 0;
+
+ *subid <<= 7;
+ *subid |= ch & 0x7F;
+ } while ((ch & 0x80) == 0x80);
+ return 1;
+}
+
+static int
+asn1_oid_decode(struct asn1_ctx *ctx,
+ unsigned char *eoc, unsigned long **oid, unsigned int *len)
+{
+ unsigned long subid;
+ unsigned int size;
+ unsigned long *optr;
+
+ size = eoc - ctx->pointer + 1;
+
+ /* first subid actually encodes first two subids */
+ if (size < 2 || size > UINT_MAX/sizeof(unsigned long))
+ return 0;
+
+ *oid = kmalloc_array(size, sizeof(unsigned long), GFP_ATOMIC);
+ if (*oid == NULL)
+ return 0;
+
+ optr = *oid;
+
+ if (!asn1_subid_decode(ctx, &subid)) {
+ kfree(*oid);
+ *oid = NULL;
+ return 0;
+ }
+
+ if (subid < 40) {
+ optr[0] = 0;
+ optr[1] = subid;
+ } else if (subid < 80) {
+ optr[0] = 1;
+ optr[1] = subid - 40;
+ } else {
+ optr[0] = 2;
+ optr[1] = subid - 80;
+ }
+
+ *len = 2;
+ optr += 2;
+
+ while (ctx->pointer < eoc) {
+ if (++(*len) > size) {
+ ctx->error = ASN1_ERR_DEC_BADVALUE;
+ kfree(*oid);
+ *oid = NULL;
+ return 0;
+ }
+
+ if (!asn1_subid_decode(ctx, optr++)) {
+ kfree(*oid);
+ *oid = NULL;
+ return 0;
+ }
+ }
+ return 1;
+}
+
+static int
+compare_oid(unsigned long *oid1, unsigned int oid1len,
+ unsigned long *oid2, unsigned int oid2len)
+{
+ unsigned int i;
+
+ if (oid1len != oid2len)
+ return 0;
+ else {
+ for (i = 0; i < oid1len; i++) {
+ if (oid1[i] != oid2[i])
+ return 0;
+ }
+ return 1;
+ }
+}
+
+ /* BB check for endian conversion issues here */
+
+int
+decode_negTokenInit(unsigned char *security_blob, int length,
+ struct TCP_Server_Info *server)
+{
+ struct asn1_ctx ctx;
+ unsigned char *end;
+ unsigned char *sequence_end;
+ unsigned long *oid = NULL;
+ unsigned int cls, con, tag, oidlen, rc;
+
+ /* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
+
+ asn1_open(&ctx, security_blob, length);
+
+ /* GSSAPI header */
+ if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
+ cifs_dbg(FYI, "Error decoding negTokenInit header\n");
+ return 0;
+ } else if ((cls != ASN1_APL) || (con != ASN1_CON)
+ || (tag != ASN1_EOC)) {
+ cifs_dbg(FYI, "cls = %d con = %d tag = %d\n", cls, con, tag);
+ return 0;
+ }
+
+ /* Check for SPNEGO OID -- remember to free obj->oid */
+ rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
+ if (rc) {
+ if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
+ (cls == ASN1_UNI)) {
+ rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
+ if (rc) {
+ rc = compare_oid(oid, oidlen, SPNEGO_OID,
+ SPNEGO_OID_LEN);
+ kfree(oid);
+ }
+ } else
+ rc = 0;
+ }
+
+ /* SPNEGO OID not present or garbled -- bail out */
+ if (!rc) {
+ cifs_dbg(FYI, "Error decoding negTokenInit header\n");
+ return 0;
+ }
+
+ /* SPNEGO */
+ if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
+ cifs_dbg(FYI, "Error decoding negTokenInit\n");
+ return 0;
+ } else if ((cls != ASN1_CTX) || (con != ASN1_CON)
+ || (tag != ASN1_EOC)) {
+ cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p exit 0\n",
+ cls, con, tag, end);
+ return 0;
+ }
+
+ /* negTokenInit */
+ if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
+ cifs_dbg(FYI, "Error decoding negTokenInit\n");
+ return 0;
+ } else if ((cls != ASN1_UNI) || (con != ASN1_CON)
+ || (tag != ASN1_SEQ)) {
+ cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p exit 1\n",
+ cls, con, tag, end);
+ return 0;
+ }
+
+ /* sequence */
+ if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
+ cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
+ return 0;
+ } else if ((cls != ASN1_CTX) || (con != ASN1_CON)
+ || (tag != ASN1_EOC)) {
+ cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p exit 0\n",
+ cls, con, tag, end);
+ return 0;
+ }
+
+ /* sequence of */
+ if (asn1_header_decode
+ (&ctx, &sequence_end, &cls, &con, &tag) == 0) {
+ cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
+ return 0;
+ } else if ((cls != ASN1_UNI) || (con != ASN1_CON)
+ || (tag != ASN1_SEQ)) {
+ cifs_dbg(FYI, "cls = %d con = %d tag = %d sequence_end = %p exit 1\n",
+ cls, con, tag, sequence_end);
+ return 0;
+ }
+
+ /* list of security mechanisms */
+ while (!asn1_eoc_decode(&ctx, sequence_end)) {
+ rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
+ if (!rc) {
+ cifs_dbg(FYI, "Error decoding negTokenInit hdr exit2\n");
+ return 0;
+ }
+ if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
+ if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {
+
+ cifs_dbg(FYI, "OID len = %d oid = 0x%lx 0x%lx 0x%lx 0x%lx\n",
+ oidlen, *oid, *(oid + 1), *(oid + 2),
+ *(oid + 3));
+
+ if (compare_oid(oid, oidlen, MSKRB5_OID,
+ MSKRB5_OID_LEN))
+ server->sec_mskerberos = true;
+ else if (compare_oid(oid, oidlen, KRB5U2U_OID,
+ KRB5U2U_OID_LEN))
+ server->sec_kerberosu2u = true;
+ else if (compare_oid(oid, oidlen, KRB5_OID,
+ KRB5_OID_LEN))
+ server->sec_kerberos = true;
+ else if (compare_oid(oid, oidlen, NTLMSSP_OID,
+ NTLMSSP_OID_LEN))
+ server->sec_ntlmssp = true;
+
+ kfree(oid);
+ }
+ } else {
+ cifs_dbg(FYI, "Should be an oid what is going on?\n");
+ }
+ }
+
+ /*
+ * We currently ignore anything at the end of the SPNEGO blob after
+ * the mechTypes have been parsed, since none of that info is
+ * used at the moment.
+ */
+ return 1;
+}
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