X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=c084258e007961a52ee8e5794f39a01bf93dd9bd;hp=ccca9624121e5beb370d30748b63a8cf96e7cee3;hb=d364e4a9e3a18a144b35c47ce213e09087978d1b;hpb=ef8f45b98b5c4db398321cd36d052ccbb9c3784a diff --git a/src/security.c b/src/security.c index ccca9624..c084258e 100644 --- a/src/security.c +++ b/src/security.c @@ -1,8 +1,9 @@ /* * 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. */ /* @@ -11,24 +12,47 @@ * This file is part of wimlib, a library for working with WIM files. * * wimlib 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) + * 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. * * 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 Lesser General Public License for more + * 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 + * 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 "buffer_io.h" #include "security.h" -/* +/* + * 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 this ensures that that the security descriptors pass + * the validation in libntfs-3g. + */ +static void empty_sacl_fixup(u8 *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 = cpu_to_le32(0); + *size_p -= sizeof(ACL); + } + } +} + +/* * Reads the security data from the metadata resource. * * @metadata_resource: An array that contains the uncompressed metadata @@ -50,6 +74,11 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, int ret; u64 total_len; + /* + * Sorry this function is excessively complicated--- I'm just being + * extremely careful about integer overflows. + */ + sd = MALLOC(sizeof(struct wim_security_data)); if (!sd) { ERROR("Out of memory"); @@ -61,7 +90,17 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, p = metadata_resource; p = get_u32(p, &sd->total_length); - p = get_u32(p, &sd->num_entries); + p = get_u32(p, (u32*)&sd->num_entries); + + /* The security_id field of each dentry is a signed 32-bit integer, so + * the possible indices into the security descriptors table are 0 + * through 0x7fffffff. Which means 0x80000000 security descriptors + * maximum. Not like you should ever have anywhere close to that many + * security descriptors! */ + if (sd->num_entries > 0x80000000) { + ERROR("Security data has too many entries!"); + goto out_invalid_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 @@ -75,17 +114,21 @@ int read_security_data(const u8 metadata_resource[], u64 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_RESOURCE_SIZE; - goto out_free_sd; + goto out_invalid_sd; } DEBUG("Reading security data: %u entries, length = %u", sd->num_entries, sd->total_length); if (sd->num_entries == 0) { - /* No security data. */ - total_len = 8; - goto out; + /* No security descriptors. */ + if (sd->total_length != 0 && sd->total_length != 8) { + ERROR("Invalid security data length (%u): expected 0 or 8", + sd->total_length); + goto out_invalid_sd; + } + sd->total_length = 8; + goto out_return_sd; } u64 sizes_size = (u64)sd->num_entries * sizeof(u64); @@ -94,8 +137,11 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, 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_RESOURCE_SIZE; - goto out_free_sd; + goto out_invalid_sd; + } + if (sizeof(size_t) < 8 && sizes_size > 0xffffffff) { + ERROR("Too many security descriptors!"); + goto out_invalid_sd; } sd->sizes = MALLOC(sizes_size); if (!sd->sizes) { @@ -105,7 +151,7 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, /* Copy the sizes array in from the file data. */ p = get_bytes(p, sizes_size, sd->sizes); - array_to_le64(sd->sizes, sd->num_entries); + array_le64_to_cpu(sd->sizes, sd->num_entries); /* Allocate the array of pointers to descriptors, and read them in. */ sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*)); @@ -125,16 +171,18 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, "(current total length = %"PRIu64", security " "descriptor size = %"PRIu64")", total_len, sd->sizes[i]); - ret = WIMLIB_ERR_INVALID_SECURITY_DATA; - goto out_free_sd; + goto out_invalid_sd; } total_len += sd->sizes[i]; + /* This check assures that the descriptor size fits in a 32 bit + * integer. Because if it didn't, the total length would come + * out bigger than sd->total_length, which is a 32 bit integer. + * */ 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_RESOURCE_SIZE; - goto out_free_sd; + goto out_invalid_sd; } sd->descriptors[i] = MALLOC(sd->sizes[i]); if (!sd->descriptors[i]) { @@ -144,17 +192,26 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, goto out_free_sd; } p = get_bytes(p, sd->sizes[i], sd->descriptors[i]); + empty_sacl_fixup(sd->descriptors[i], &sd->sizes[i]); } -out: - sd->total_length = (u32)total_len; + wimlib_assert(total_len <= 0xffffffff); + if (((total_len + 7) & ~7) != ((sd->total_length + 7) & ~7)) { + ERROR("Expected security data total length = %u, but " + "calculated %u", sd->total_length, (unsigned)total_len); + goto out_invalid_sd; + } + sd->total_length = total_len; +out_return_sd: *sd_p = sd; return 0; +out_invalid_sd: + ret = WIMLIB_ERR_INVALID_SECURITY_DATA; out_free_sd: free_security_data(sd); return ret; } -/* +/* * Writes security data to an in-memory buffer. */ u8 *write_security_data(const struct wim_security_data *sd, u8 *p) @@ -162,8 +219,10 @@ u8 *write_security_data(const struct wim_security_data *sd, u8 *p) DEBUG("Writing security data (total_length = %"PRIu32", num_entries " "= %"PRIu32")", sd->total_length, sd->num_entries); + u32 aligned_length = (sd->total_length + 7) & ~7; + u8 *orig_p = p; - p = put_u32(p, sd->total_length); + p = put_u32(p, aligned_length); p = put_u32(p, sd->num_entries); for (u32 i = 0; i < sd->num_entries; i++) @@ -173,89 +232,93 @@ u8 *write_security_data(const struct wim_security_data *sd, u8 *p) 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); DEBUG("Successfully wrote security data."); return p; } -/* 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... */ - -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 = le16_to_cpu(acl->acl_size); + u16 ace_count = le16_to_cpu(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; + for (u16 i = 0; i < ace_count; i++) { + 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; - printf(" ACE mask = %x\n", to_le32(aaa->mask)); - printf(" SID start = %u\n", to_le32(aaa->sid_start)); + const AccessAllowedACE *aaa = (const AccessAllowedACE*)hdr; + printf(" ACE mask = %x\n", le32_to_cpu(aaa->mask)); + printf(" SID start = %u\n", le32_to_cpu(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 = "); - print_byte_field(sid->identifier_authority, sizeof(sid->identifier_authority)); + print_byte_field(sid->identifier_authority, + sizeof(sid->identifier_authority)); + putchar('\n'); + for (u8 i = 0; i < sid->sub_authority_count; i++) + printf(" Subauthority %u = %u\n", + i, le32_to_cpu(sid->sub_authority[i])); putchar('\n'); - for (uint i = 0; i < sid->sub_authority_count; i++) - printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i])); } 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 = le16_to_cpu(sd->security_descriptor_control); + u32 owner_offset = le32_to_cpu(sd->owner_offset); + u32 group_offset = le32_to_cpu(sd->group_offset); + u32 sacl_offset = le32_to_cpu(sd->sacl_offset); + u32 dacl_offset = le32_to_cpu(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"); } -/* +/* * Prints the security data for a WIM file. */ void print_security_data(const struct wim_security_data *sd) { + wimlib_assert(sd != NULL); + puts("[SECURITY DATA]"); printf("Length = %"PRIu32" bytes\n", sd->total_length); printf("Number of Entries = %"PRIu32"\n", sd->num_entries); for (u32 i = 0; i < sd->num_entries; i++) { - printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n", + printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n", i, sd->sizes[i]); print_security_descriptor(sd->descriptors[i], sd->sizes[i]); putchar('\n'); @@ -265,19 +328,17 @@ void print_security_data(const struct wim_security_data *sd) void free_security_data(struct wim_security_data *sd) { - if (!sd) - return; - wimlib_assert(sd->refcnt >= 1); - if (sd->refcnt == 1) { - u8 **descriptors = sd->descriptors; - u32 num_entries = sd->num_entries; - if (descriptors) - while (num_entries--) - FREE(*descriptors++); - FREE(sd->sizes); - FREE(sd->descriptors); - FREE(sd); - } else { - sd->refcnt--; + if (sd) { + wimlib_assert(sd->refcnt != 0); + if (--sd->refcnt == 0) { + u8 **descriptors = sd->descriptors; + u32 num_entries = sd->num_entries; + if (descriptors) + while (num_entries--) + FREE(*descriptors++); + FREE(sd->sizes); + FREE(sd->descriptors); + FREE(sd); + } } }