X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=ca75ac0bf442ffb490ad8c9912a131e7fcf088d2;hp=cfc6fbd1874f3f20126d8f0121266533d8dc1237;hb=2a36f3ccb3773c33f0be7e8bc1e9e552ecf9fae0;hpb=8e4a9a0129dabaddef33ee0a99f7f8b221bdf483 diff --git a/src/security.c b/src/security.c index cfc6fbd1..ca75ac0b 100644 --- a/src/security.c +++ b/src/security.c @@ -1,95 +1,136 @@ /* * security.c * - * Read the security data from the WIM. Doing anything with the security data - * is not yet implemented other than printing some information about it. - * + * Read and write the WIM security data. The security data is a table of + * security descriptors. Each WIM image has its own security data, but it's + * possible that an image's security data have no security descriptors. + */ + +/* * Copyright (C) 2012 Eric Biggers * - * wimlib - Library for working with WIM files + * This file is part of wimlib, a library for working with WIM files. * - * This library is free software; you can redistribute it and/or modify it under - * the terms of the GNU Lesser General Public License as published by the Free - * Software Foundation; either version 2.1 of the License, or (at your option) any - * later version. + * wimlib is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License as published by the Free + * Software Foundation; either version 3 of the License, or (at your option) + * any later version. * - * This library is distributed in the hope that it will be useful, but WITHOUT ANY - * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A - * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. + * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + * A PARTICULAR PURPOSE. See the GNU General Public License for more + * details. * - * You should have received a copy of the GNU Lesser General Public License along - * with this library; if not, write to the Free Software Foundation, Inc., 59 - * Temple Place, Suite 330, Boston, MA 02111-1307 USA + * You should have received a copy of the GNU General Public License + * along with wimlib; if not, see http://www.gnu.org/licenses/. */ #include "wimlib_internal.h" #include "io.h" #include "security.h" -#ifdef ENABLE_SECURITY_DATA +/* + * This is a hack to work around a problem in libntfs-3g. libntfs-3g validates + * security descriptors with a function named ntfs_valid_descr(). + * ntfs_valid_descr() considers a security descriptor that ends in a SACL + * (Sysetm Access Control List) with no ACE's (Access Control Entries) to be + * invalid. However, a security descriptor like this exists in the Windows 7 + * install.wim. Here, security descriptors matching this pattern are modified + * to have no SACL. This should make no difference since the SACL had no + * entries anyway; however his ensures that that the security descriptors pass + * the validation in libntfs-3g. + */ +static void empty_sacl_fixup(char *descr, u64 *size_p) +{ + if (*size_p >= sizeof(SecurityDescriptor)) { + SecurityDescriptor *sd = (SecurityDescriptor*)descr; + u32 sacl_offset = le32_to_cpu(sd->sacl_offset); + if (sacl_offset == *size_p - sizeof(ACL)) { + sd->sacl_offset = to_le32(0); + *size_p -= sizeof(ACL); + } + } +} /* * Reads the security data from the metadata resource. * * @metadata_resource: An array that contains the uncompressed metadata * resource for the WIM file. - * @metadata_resource_len: The length of @metadata_resource. - * @sd_p: A pointer to a pointer wim_security_data structure that will be filled - * in with a pointer to a new wim_security_data structure on success. + * @metadata_resource_len: The length of @metadata_resource. It MUST be at + * least 8 bytes. + * @sd_p: A pointer to a pointer to a wim_security_data structure that + * will be filled in with a pointer to a new wim_security_data + * structure on success. * * Note: There is no `offset' argument because the security data is located at * the beginning of the metadata resource. */ -int read_security_data(const u8 metadata_resource[], - u64 metadata_resource_len, struct wim_security_data **sd_p) +int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, + struct wim_security_data **sd_p) { struct wim_security_data *sd; const u8 *p; - u64 sizes_size; + int ret; + u64 total_len; - if (metadata_resource_len < 8) { - ERROR("Not enough space in %"PRIu64"-byte file resource for " - "security data!\n", metadata_resource_len); - return WIMLIB_ERR_INVALID_RESOURCE_SIZE; - } sd = MALLOC(sizeof(struct wim_security_data)); - if (!sd) + if (!sd) { + ERROR("Out of memory"); return WIMLIB_ERR_NOMEM; - p = get_u32(metadata_resource, &sd->total_length); - p = get_u32(p, &sd->num_entries); + } + sd->sizes = NULL; + sd->descriptors = NULL; + sd->refcnt = 1; + + p = metadata_resource; + p = get_u32(p, &sd->total_length); + p = get_u32(p, (u32*)&sd->num_entries); + + if (sd->num_entries > 0x7fffffff) { + ERROR("Security data has too many entries!"); + ret = WIMLIB_ERR_INVALID_SECURITY_DATA; + goto out_free_sd; + } /* Verify the listed total length of the security data is big enough to * include the sizes array, verify that the file data is big enough to - * include it as well, then allocate the array of sizes. */ - sizes_size = sd->num_entries * sizeof(u64); + * include it as well, then allocate the array of sizes. + * + * Note: The total length of the security data must fit in a 32-bit + * integer, even though each security descriptor size is a 64-bit + * integer. This is stupid, and we need to be careful not to actually + * let the security descriptor sizes be over 0xffffffff. */ + if ((u64)sd->total_length > metadata_resource_len) { + ERROR("Security data total length (%u) is bigger than the " + "metadata resource length (%"PRIu64")", + sd->total_length, metadata_resource_len); + ret = WIMLIB_ERR_INVALID_SECURITY_DATA; + goto out_free_sd; + } - DEBUG("Reading security data with %u entries\n", sd->num_entries); + DEBUG("Reading security data: %u entries, length = %u", + sd->num_entries, sd->total_length); if (sd->num_entries == 0) { - FREE(sd); - return 0; + /* No security data. */ + total_len = 8; + goto out; } + u64 sizes_size = (u64)sd->num_entries * sizeof(u64); u64 size_no_descriptors = 8 + sizes_size; - if (size_no_descriptors > sd->total_length) { - ERROR("Security data total length of %"PRIu64" is too short because\n" - "there must be at least %"PRIu64" bytes of security " - "data!\n", sd->total_length, - 8 + sizes_size); - FREE(sd); - return WIMLIB_ERR_INVALID_RESOURCE_SIZE; - } - if (size_no_descriptors > metadata_resource_len) { - ERROR("File resource of %"PRIu64" bytes is not big enough\n" - "to hold security data of at least %"PRIu64" " - "bytes!\n", metadata_resource_len, size_no_descriptors); - FREE(sd); - return WIMLIB_ERR_INVALID_RESOURCE_SIZE; + if (size_no_descriptors > (u64)sd->total_length) { + ERROR("Security data total length of %u is too short because " + "there must be at least %"PRIu64" bytes of security data", + sd->total_length, 8 + sizes_size); + ret = WIMLIB_ERR_INVALID_SECURITY_DATA; + goto out_free_sd; } sd->sizes = MALLOC(sizes_size); if (!sd->sizes) { - FREE(sd); - return WIMLIB_ERR_NOMEM; + ret = WIMLIB_ERR_NOMEM; + goto out_free_sd; } /* Copy the sizes array in from the file data. */ @@ -99,39 +140,49 @@ int read_security_data(const u8 metadata_resource[], /* Allocate the array of pointers to descriptors, and read them in. */ sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*)); if (!sd->descriptors) { - FREE(sd); - FREE(sd->sizes); - return WIMLIB_ERR_NOMEM; + ERROR("Out of memory while allocating security " + "descriptors"); + ret = WIMLIB_ERR_NOMEM; + goto out_free_sd; } - u64 total_len = size_no_descriptors; + total_len = size_no_descriptors; - for (uint i = 0; i < sd->num_entries; i++) { - total_len += sd->sizes[i]; - if (total_len > sd->total_length) { - ERROR("Security data total length of %"PRIu64" is too " - "short because there are at least %"PRIu64" " - "bytes of security data!\n", - sd->total_length, total_len); - free_security_data(sd); - return WIMLIB_ERR_INVALID_RESOURCE_SIZE; + for (u32 i = 0; i < sd->num_entries; i++) { + /* Watch out for huge security descriptor sizes that could + * overflow the total length and wrap it around. */ + if (total_len + sd->sizes[i] < total_len) { + ERROR("Caught overflow in security descriptor lengths " + "(current total length = %"PRIu64", security " + "descriptor size = %"PRIu64")", + total_len, sd->sizes[i]); + ret = WIMLIB_ERR_INVALID_SECURITY_DATA; + goto out_free_sd; } - if (total_len > metadata_resource_len) { - ERROR("File resource of %"PRIu64" bytes is not big enough " - "to hold security data of at least %"PRIu64" " - "bytes!\n", metadata_resource_len, total_len); - free_security_data(sd); - return WIMLIB_ERR_INVALID_RESOURCE_SIZE; + total_len += sd->sizes[i]; + if (total_len > (u64)sd->total_length) { + ERROR("Security data total length of %u is too short " + "because there are at least %"PRIu64" bytes of " + "security data", sd->total_length, total_len); + ret = WIMLIB_ERR_INVALID_SECURITY_DATA; + goto out_free_sd; } sd->descriptors[i] = MALLOC(sd->sizes[i]); if (!sd->descriptors[i]) { - free_security_data(sd); - return WIMLIB_ERR_NOMEM; + ERROR("Out of memory while allocating security " + "descriptors"); + ret = WIMLIB_ERR_NOMEM; + goto out_free_sd; } p = get_bytes(p, sd->sizes[i], sd->descriptors[i]); + empty_sacl_fixup(sd->descriptors[i], &sd->sizes[i]); } - sd->refcnt = 1; +out: + sd->total_length = (u32)total_len; *sd_p = sd; return 0; +out_free_sd: + free_security_data(sd); + return ret; } /* @@ -139,66 +190,58 @@ int read_security_data(const u8 metadata_resource[], */ u8 *write_security_data(const struct wim_security_data *sd, u8 *p) { - if (sd) { - DEBUG("Writing security data (total_length = %u, " - "num_entries = %u)\n", sd->total_length, - sd->num_entries); - u8 *orig_p = p; - p = put_u32(p, sd->total_length); - p = put_u32(p, sd->num_entries); + DEBUG("Writing security data (total_length = %"PRIu32", num_entries " + "= %"PRIu32")", sd->total_length, sd->num_entries); - for (uint i = 0; i < sd->num_entries; i++) - p = put_u64(p, sd->sizes[i]); + u32 aligned_length = (sd->total_length + 7) & ~7; - for (uint i = 0; i < sd->num_entries; i++) - p = put_bytes(p, sd->sizes[i], sd->descriptors[i]); + u8 *orig_p = p; + p = put_u32(p, aligned_length); + p = put_u32(p, sd->num_entries); - wimlib_assert(p - orig_p <= sd->total_length); + for (u32 i = 0; i < sd->num_entries; i++) + p = put_u64(p, sd->sizes[i]); - DEBUG("Successfully wrote security data.\n"); - return orig_p + sd->total_length; - } else { - DEBUG("Writing security data (total_length = 8, " - "num_entries = 0)\n"); - p = put_u32(p, 8); - return put_u32(p, 0); + for (u32 i = 0; i < sd->num_entries; i++) + p = put_bytes(p, sd->sizes[i], sd->descriptors[i]); - } -} + wimlib_assert(p - orig_p == sd->total_length); + p = put_zeroes(p, aligned_length - sd->total_length); -/* XXX We don't actually do anything with the ACL's yet besides being able to - * print a few things. It seems it would be a lot of work to have comprehensive - * support for all the weird flags and stuff, and Windows PE seems to be okay - * running from a WIM file that doesn't have any security data at all... */ + DEBUG("Successfully wrote security data."); + return p; +} -static void print_acl(const u8 *p) +static void print_acl(const u8 *p, const char *type) { - ACL *acl = (ACL*)p; - TO_LE16(acl->acl_size); - TO_LE16(acl->acl_count); - printf(" [ACL]\n"); - printf(" Revision = %u\n", acl->revision); - printf(" ACL Size = %u\n", acl->acl_size); - printf(" ACE Count = %u\n", acl->ace_count); + const ACL *acl = (const ACL*)p; + u8 revision = acl->revision; + u16 acl_size = to_le16(acl->acl_size); + u16 ace_count = to_le16(acl->ace_count); + printf(" [%s ACL]\n", type); + printf(" Revision = %u\n", revision); + printf(" ACL Size = %u\n", acl_size); + printf(" ACE Count = %u\n", ace_count); p += sizeof(ACL); for (uint i = 0; i < acl->ace_count; i++) { - ACEHeader *hdr = (ACEHeader*)p; + const ACEHeader *hdr = (const ACEHeader*)p; printf(" [ACE]\n"); printf(" ACE type = %d\n", hdr->type); printf(" ACE flags = 0x%x\n", hdr->flags); printf(" ACE size = %u\n", hdr->size); - AccessAllowedACE *aaa = (AccessAllowedACE*)hdr; + const AccessAllowedACE *aaa = (const AccessAllowedACE*)hdr; printf(" ACE mask = %x\n", to_le32(aaa->mask)); printf(" SID start = %u\n", to_le32(aaa->sid_start)); p += hdr->size; } + putchar('\n'); } -static void print_sid(const u8 *p) +static void print_sid(const u8 *p, const char *type) { - SID *sid = (SID*)p; - printf(" [SID]\n"); + const SID *sid = (const SID*)p; + printf(" [%s SID]\n", type); printf(" Revision = %u\n", sid->revision); printf(" Subauthority count = %u\n", sid->sub_authority_count); printf(" Identifier authority = "); @@ -206,31 +249,33 @@ static void print_sid(const u8 *p) putchar('\n'); for (uint i = 0; i < sid->sub_authority_count; i++) printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i])); + putchar('\n'); } static void print_security_descriptor(const u8 *p, u64 size) { - SecurityDescriptor *sd = (SecurityDescriptor*)p; - TO_LE16(sd->security_descriptor_control); - TO_LE32(sd->owner_offset); - TO_LE32(sd->group_offset); - TO_LE32(sd->sacl_offset); - TO_LE32(sd->dacl_offset); - printf("Revision = %u\n", sd->revision); - printf("Security Descriptor Control = %u\n", sd->security_descriptor_control); - printf("Owner offset = %u\n", sd->owner_offset); - printf("Group offset = %u\n", sd->group_offset); - printf("System ACL offset = %u\n", sd->sacl_offset); - printf("Discretionary ACL offset = %u\n", sd->dacl_offset); + const SecurityDescriptor *sd = (const SecurityDescriptor*)p; + u8 revision = sd->revision; + u16 control = to_le16(sd->security_descriptor_control); + u32 owner_offset = to_le32(sd->owner_offset); + u32 group_offset = to_le32(sd->group_offset); + u32 sacl_offset = to_le32(sd->sacl_offset); + u32 dacl_offset = to_le32(sd->dacl_offset); + printf("Revision = %u\n", revision); + printf("Security Descriptor Control = %#x\n", control); + printf("Owner offset = %u\n", owner_offset); + printf("Group offset = %u\n", group_offset); + printf("System ACL offset = %u\n", sacl_offset); + printf("Discretionary ACL offset = %u\n", dacl_offset); if (sd->owner_offset != 0) - print_sid(p + sd->owner_offset); + print_sid(p + owner_offset, "Owner"); if (sd->group_offset != 0) - print_sid(p + sd->group_offset); + print_sid(p + group_offset, "Group"); if (sd->sacl_offset != 0) - print_acl(p + sd->sacl_offset); + print_acl(p + sacl_offset, "System"); if (sd->dacl_offset != 0) - print_acl(p + sd->dacl_offset); + print_acl(p + dacl_offset, "Discretionary"); } /* @@ -239,23 +284,14 @@ static void print_security_descriptor(const u8 *p, u64 size) void print_security_data(const struct wim_security_data *sd) { puts("[SECURITY DATA]"); - if (sd) { - printf("Length = %u bytes\n", sd->total_length); - printf("Number of Entries = %u\n", sd->num_entries); + printf("Length = %"PRIu32" bytes\n", sd->total_length); + printf("Number of Entries = %"PRIu32"\n", sd->num_entries); - u64 num_entries = (u64)sd->num_entries; - for (u64 i = 0; i < num_entries; i++) { - printf("[SecurityDescriptor %"PRIu64", " - "length = %"PRIu64"]\n", - i, sd->sizes[i]); - print_security_descriptor(sd->descriptors[i], - sd->sizes[i]); - putchar('\n'); - } - } else { - puts("Length = 8 bytes\n" - "Number of Entries = 0"); - return; + for (u32 i = 0; i < sd->num_entries; i++) { + printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n", + i, sd->sizes[i]); + print_security_descriptor(sd->descriptors[i], sd->sizes[i]); + putchar('\n'); } putchar('\n'); } @@ -264,20 +300,15 @@ void free_security_data(struct wim_security_data *sd) { if (!sd) return; - wimlib_assert(sd->refcnt >= 1); - if (sd->refcnt == 1) { + wimlib_assert(sd->refcnt != 0); + if (--sd->refcnt == 0) { u8 **descriptors = sd->descriptors; - u32 num_entries = sd->num_entries; - + u32 num_entries = sd->num_entries; if (descriptors) while (num_entries--) FREE(*descriptors++); FREE(sd->sizes); FREE(sd->descriptors); FREE(sd); - } else { - sd->refcnt--; } } - -#endif