X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=7efc542b1e1de80a58dde1b8cf688cc170798782;hp=ca75ac0bf442ffb490ad8c9912a131e7fcf088d2;hb=34c830edf813567274416e84816947d3383a6ac5;hpb=2a36f3ccb3773c33f0be7e8bc1e9e552ecf9fae0 diff --git a/src/security.c b/src/security.c index ca75ac0b..7efc542b 100644 --- a/src/security.c +++ b/src/security.c @@ -1,13 +1,11 @@ /* * security.c * - * 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. + * Read and write the per-WIM-image table of security descriptors. */ /* - * Copyright (C) 2012 Eric Biggers + * Copyright (C) 2012, 2013 Eric Biggers * * This file is part of wimlib, a library for working with WIM files. * @@ -26,10 +24,104 @@ */ #include "wimlib_internal.h" -#include "io.h" +#include "buffer_io.h" #include "security.h" -/* +/* At the start of each type of access control entry. */ +typedef struct { + /* enum ace_type, specifies what type of ACE this is. */ + u8 type; + + /* bitwise OR of the inherit ACE flags #defined above */ + u8 flags; + + /* Size of the access control entry. */ + u8 size; +} ACEHeader; + +/* Grants rights to a user or group */ +typedef struct { + ACEHeader hdr; + u32 mask; + u32 sid_start; +} AccessAllowedACE; + +/* Denies rights to a user or group */ +typedef struct { + ACEHeader hdr; + u32 mask; + u32 sid_start; +} AccessDeniedACE; + +typedef struct { + ACEHeader hdr; + u32 mask; + u32 sid_start; +} SystemAuditACE; + + +/* Header of an access control list. */ +typedef struct { + /* ACL_REVISION or ACL_REVISION_DS */ + u8 revision; + + /* padding */ + u8 sbz1; + + /* Total size of the ACL, including all access control entries */ + u16 acl_size; + + /* Number of access control entry structures that follow the ACL + * structure. */ + u16 ace_count; + + /* padding */ + u16 sbz2; +} ACL; + +/* A structure used to identify users or groups. */ +typedef struct { + + /* example: 0x1 */ + u8 revision; + u8 sub_authority_count; + + /* Identifies the authority that issued the SID. Can be, but does not + * have to be, one of enum sid_authority_value */ + u8 identifier_authority[6]; + + u32 sub_authority[0]; +} SID; + + +typedef struct { + /* Example: 0x1 */ + u8 revision; + /* Example: 0x0 */ + u8 sbz1; + /* Example: 0x4149 */ + u16 security_descriptor_control; + + /* Offset of a SID structure in the security descriptor. */ + /* Example: 0x14 */ + u32 owner_offset; + + /* Offset of a SID structure in the security descriptor. */ + /* Example: 0x24 */ + u32 group_offset; + + /* Offset of an ACL structure in the security descriptor. */ + /* System ACL. */ + /* Example: 0x00 */ + u32 sacl_offset; + + /* Offset of an ACL structure in the security descriptor. */ + /* Discretionary ACL. */ + /* Example: 0x34 */ + u32 dacl_offset; +} SecurityDescriptor; + +/* * 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 @@ -37,27 +129,32 @@ * 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 + * entries anyway; however this ensures that that the security descriptors pass * the validation in libntfs-3g. */ -static void empty_sacl_fixup(char *descr, u64 *size_p) +static void +empty_sacl_fixup(u8 *descr, u64 *size_p) { + /* No-op if no NTFS-3g support, or if NTFS-3g is version 2013 or later + * */ +#if defined(WITH_NTFS_3G) && !defined(HAVE_NTFS_MNT_RDONLY) 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); + sd->sacl_offset = cpu_to_le32(0); *size_p -= sizeof(ACL); } } +#endif } -/* +/* * 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. It MUST be at + * @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 @@ -66,14 +163,22 @@ static void empty_sacl_fixup(char *descr, u64 *size_p) * 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; int ret; u64 total_len; + wimlib_assert(metadata_resource_len >= 8); + + /* + * 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"); @@ -87,10 +192,14 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, p = get_u32(p, &sd->total_length); p = get_u32(p, (u32*)&sd->num_entries); - if (sd->num_entries > 0x7fffffff) { + /* 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!"); - ret = WIMLIB_ERR_INVALID_SECURITY_DATA; - goto out_free_sd; + goto out_invalid_sd; } /* Verify the listed total length of the security data is big enough to @@ -105,28 +214,34 @@ 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_SECURITY_DATA; - 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. We allow the total_length field to + * be either 8 (which is correct, since there are always 2 + * 32-bit integers) or 0. */ + 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); u64 size_no_descriptors = 8 + sizes_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", + "there seem to be at least %"PRIu64" bytes of security data", sd->total_length, 8 + sizes_size); - ret = WIMLIB_ERR_INVALID_SECURITY_DATA; - goto out_free_sd; + goto out_invalid_sd; } + sd->sizes = MALLOC(sizes_size); if (!sd->sizes) { ret = WIMLIB_ERR_NOMEM; @@ -135,7 +250,7 @@ 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*)); @@ -155,16 +270,19 @@ 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 ensures 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_SECURITY_DATA; - goto out_free_sd; + "because there seem to be at least %"PRIu64" " + "bytes of security data", + sd->total_length, total_len); + goto out_invalid_sd; } sd->descriptors[i] = MALLOC(sd->sizes[i]); if (!sd->descriptors[i]) { @@ -176,19 +294,28 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, 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) +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); @@ -212,103 +339,244 @@ u8 *write_security_data(const struct wim_security_data *sd, u8 *p) return p; } -static void print_acl(const u8 *p, const char *type) +static void +print_acl(const void *p, const tchar *type) { - const ACL *acl = (const ACL*)p; + const ACL *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); + u16 acl_size = le16_to_cpu(acl->acl_size); + u16 ace_count = le16_to_cpu(acl->ace_count); + tprintf(T(" [%"TS" ACL]\n"), type); + tprintf(T(" Revision = %u\n"), revision); + tprintf(T(" ACL Size = %u\n"), acl_size); + tprintf(T(" ACE Count = %u\n"), ace_count); p += sizeof(ACL); - for (uint i = 0; i < acl->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); + for (u16 i = 0; i < ace_count; i++) { + const ACEHeader *hdr = p; + tprintf(T(" [ACE]\n")); + tprintf(T(" ACE type = %d\n"), hdr->type); + tprintf(T(" ACE flags = 0x%x\n"), hdr->flags); + tprintf(T(" ACE size = %u\n"), hdr->size); 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)); + tprintf(T(" ACE mask = %x\n"), le32_to_cpu(aaa->mask)); + tprintf(T(" SID start = %u\n"), le32_to_cpu(aaa->sid_start)); p += hdr->size; } - putchar('\n'); + tputchar(T('\n')); } -static void print_sid(const u8 *p, const char *type) +static void +print_sid(const void *p, const tchar *type) { - 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)); - 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'); + const SID *sid = p; + tprintf(T(" [%"TS" SID]\n"), type); + tprintf(T(" Revision = %u\n"), sid->revision); + tprintf(T(" Subauthority count = %u\n"), sid->sub_authority_count); + tprintf(T(" Identifier authority = ")); + print_byte_field(sid->identifier_authority, + sizeof(sid->identifier_authority)); + tputchar(T('\n')); + for (u8 i = 0; i < sid->sub_authority_count; i++) { + tprintf(T(" Subauthority %u = %u\n"), + i, le32_to_cpu(sid->sub_authority[i])); + } + tputchar(T('\n')); } -static void print_security_descriptor(const u8 *p, u64 size) +static void +print_security_descriptor(const void *p, u64 size) { - const SecurityDescriptor *sd = (const SecurityDescriptor*)p; + const SecurityDescriptor *sd = 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); + 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); + tprintf(T("Revision = %u\n"), revision); + tprintf(T("Security Descriptor Control = %#x\n"), control); + tprintf(T("Owner offset = %u\n"), owner_offset); + tprintf(T("Group offset = %u\n"), group_offset); + tprintf(T("System ACL offset = %u\n"), sacl_offset); + tprintf(T("Discretionary ACL offset = %u\n"), dacl_offset); if (sd->owner_offset != 0) - print_sid(p + owner_offset, "Owner"); + print_sid(p + owner_offset, T("Owner")); if (sd->group_offset != 0) - print_sid(p + group_offset, "Group"); + print_sid(p + group_offset, T("Group")); if (sd->sacl_offset != 0) - print_acl(p + sacl_offset, "System"); + print_acl(p + sacl_offset, T("System")); if (sd->dacl_offset != 0) - print_acl(p + dacl_offset, "Discretionary"); + print_acl(p + dacl_offset, T("Discretionary")); } -/* +/* * Prints the security data for a WIM file. */ -void print_security_data(const struct wim_security_data *sd) +void +print_security_data(const struct wim_security_data *sd) { - puts("[SECURITY DATA]"); - printf("Length = %"PRIu32" bytes\n", sd->total_length); - printf("Number of Entries = %"PRIu32"\n", sd->num_entries); + wimlib_assert(sd != NULL); + + tputs(T("[SECURITY DATA]")); + tprintf(T("Length = %"PRIu32" bytes\n"), sd->total_length); + tprintf(T("Number of Entries = %"PRIu32"\n"), sd->num_entries); for (u32 i = 0; i < sd->num_entries; i++) { - printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n", - i, sd->sizes[i]); + tprintf(T("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n"), + i, sd->sizes[i]); print_security_descriptor(sd->descriptors[i], sd->sizes[i]); - putchar('\n'); + tputchar(T('\n')); + } + tputchar(T('\n')); +} + +void +free_security_data(struct wim_security_data *sd) +{ + 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); + } } - putchar('\n'); } -void free_security_data(struct wim_security_data *sd) +struct sd_node { + int security_id; + u8 hash[SHA1_HASH_SIZE]; + struct rb_node rb_node; +}; + +static void +free_sd_tree(struct rb_node *node) { - if (!sd) - return; - 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); + if (node) { + free_sd_tree(node->rb_left); + free_sd_tree(node->rb_right); + FREE(container_of(node, struct sd_node, rb_node)); } } + +/* Frees a security descriptor index set. */ +void +destroy_sd_set(struct sd_set *sd_set) +{ + free_sd_tree(sd_set->rb_root.rb_node); +} + +/* Inserts a a new node into the security descriptor index tree. */ +static void +insert_sd_node(struct sd_set *set, struct sd_node *new) +{ + struct rb_root *root = &set->rb_root; + struct rb_node **p = &(root->rb_node); + struct rb_node *rb_parent = NULL; + + while (*p) { + struct sd_node *this = container_of(*p, struct sd_node, rb_node); + int cmp = hashes_cmp(new->hash, this->hash); + + rb_parent = *p; + if (cmp < 0) + p = &((*p)->rb_left); + else if (cmp > 0) + p = &((*p)->rb_right); + else + wimlib_assert(0); /* Duplicate SHA1 message digest */ + } + rb_link_node(&new->rb_node, rb_parent, p); + rb_insert_color(&new->rb_node, root); +} + +/* Returns the index of the security descriptor having a SHA1 message digest of + * @hash. If not found, return -1. */ +int +lookup_sd(struct sd_set *set, const u8 hash[SHA1_HASH_SIZE]) +{ + struct rb_node *node = set->rb_root.rb_node; + + while (node) { + struct sd_node *sd_node = container_of(node, struct sd_node, rb_node); + int cmp = hashes_cmp(hash, sd_node->hash); + if (cmp < 0) + node = node->rb_left; + else if (cmp > 0) + node = node->rb_right; + else + return sd_node->security_id; + } + return -1; +} + +/* + * Adds a security descriptor to the indexed security descriptor set as well as + * the corresponding `struct wim_security_data', and returns the new security + * ID; or, if there is an existing security descriptor that is the same, return + * the security ID for it. If a new security descriptor cannot be allocated, + * return -1. + */ +int +sd_set_add_sd(struct sd_set *sd_set, const char descriptor[], size_t size) +{ + u8 hash[SHA1_HASH_SIZE]; + int security_id; + struct sd_node *new; + u8 **descriptors; + u64 *sizes; + u8 *descr_copy; + struct wim_security_data *sd; + + sha1_buffer((const u8*)descriptor, size, hash); + + security_id = lookup_sd(sd_set, hash); + if (security_id >= 0) /* Identical descriptor already exists */ + return security_id; + + /* Need to add a new security descriptor */ + new = MALLOC(sizeof(*new)); + if (!new) + goto out; + descr_copy = MALLOC(size); + if (!descr_copy) + goto out_free_node; + + sd = sd_set->sd; + + memcpy(descr_copy, descriptor, size); + new->security_id = sd->num_entries; + copy_hash(new->hash, hash); + + descriptors = REALLOC(sd->descriptors, + (sd->num_entries + 1) * sizeof(sd->descriptors[0])); + if (!descriptors) + goto out_free_descr; + sd->descriptors = descriptors; + sizes = REALLOC(sd->sizes, + (sd->num_entries + 1) * sizeof(sd->sizes[0])); + if (!sizes) + goto out_free_descr; + sd->sizes = sizes; + sd->descriptors[sd->num_entries] = descr_copy; + sd->sizes[sd->num_entries] = size; + sd->num_entries++; + DEBUG("There are now %d security descriptors", sd->num_entries); + sd->total_length += size + sizeof(sd->sizes[0]); + insert_sd_node(sd_set, new); + return new->security_id; +out_free_descr: + FREE(descr_copy); +out_free_node: + FREE(new); +out: + return -1; +}