X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=62b6e8e9eb42cd1693544ad22d593c34988881e9;hp=5b0e81b3363f1b0372f741e4a56aedc52d6c06f4;hb=4d9794d1f1a6044c261faae0968af1b2c0480f4b;hpb=f3ab01445d6184f7c5ffd0251667de7ef7437f9a diff --git a/src/security.c b/src/security.c index 5b0e81b3..62b6e8e9 100644 --- a/src/security.c +++ b/src/security.c @@ -43,21 +43,21 @@ typedef struct _ACE_HEADER { u8 flags; /* Size of the access control entry. */ - u16 size; + le16 size; } _packed_attribute ACE_HEADER; /* Grants rights to a user or group */ typedef struct _ACCESS_ALLOWED_ACE { ACE_HEADER hdr; - u32 mask; - u32 sid_start; + le32 mask; + le32 sid_start; } _packed_attribute ACCESS_ALLOWED_ACE; /* Denies rights to a user or group */ typedef struct _ACCESS_DENIED_ACE { ACE_HEADER hdr; - u32 mask; - u32 sid_start; + le32 mask; + le32 sid_start; } _packed_attribute ACCESS_DENIED_ACE; typedef struct _SYSTEM_AUDIT_ACE { @@ -97,10 +97,9 @@ typedef struct _SID { * have to be, one of enum sid_authority_value */ u8 identifier_authority[6]; - u32 sub_authority[0]; + u32 sub_authority[]; } _packed_attribute SID; - typedef struct _SECURITY_DESCRIPTOR_RELATIVE { /* Example: 0x1 */ u8 revision; @@ -128,6 +127,12 @@ typedef struct _SECURITY_DESCRIPTOR_RELATIVE { u32 dacl_offset; } _packed_attribute SECURITY_DESCRIPTOR_RELATIVE; +struct wim_security_data_disk { + u32 total_length; + u32 num_entries; + u64 sizes[]; +} _packed_attribute; + /* * This is a hack to work around a problem in libntfs-3g. libntfs-3g validates * security descriptors with a function named ntfs_valid_descr(). @@ -140,16 +145,15 @@ typedef struct _SECURITY_DESCRIPTOR_RELATIVE { * the validation in libntfs-3g. */ static void -empty_sacl_fixup(u8 *descr, u64 *size_p) +empty_sacl_fixup(SECURITY_DESCRIPTOR_RELATIVE *descr, size_t *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(SECURITY_DESCRIPTOR_RELATIVE)) { - SECURITY_DESCRIPTOR_RELATIVE *sd = (SECURITY_DESCRIPTOR_RELATIVE*)descr; - u32 sacl_offset = le32_to_cpu(sd->sacl_offset); + u32 sacl_offset = le32_to_cpu(descr->sacl_offset); if (sacl_offset == *size_p - sizeof(ACL)) { - sd->sacl_offset = cpu_to_le32(0); + descr->sacl_offset = cpu_to_le32(0); *size_p -= sizeof(ACL); } } @@ -163,56 +167,60 @@ new_wim_security_data(void) } /* - * Reads the security data from the metadata resource. + * Reads the security data from the metadata resource of a WIM image. * * @metadata_resource: An array that contains the uncompressed metadata - * resource for the WIM file. + * resource for the WIM image. * @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 + * @sd_ret: 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. + * structure containing the security data on success. * * Note: There is no `offset' argument because the security data is located at * the beginning of the metadata resource. + * + * Possible errors include: + * WIMLIB_ERR_NOMEM + * WIMLIB_ERR_INVALID_SECURITY_DATA */ int -read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, - struct wim_security_data **sd_p) +read_wim_security_data(const u8 metadata_resource[], size_t metadata_resource_len, + struct wim_security_data **sd_ret) { struct wim_security_data *sd; - const u8 *p; int ret; u64 total_len; + u64 sizes_size; + u64 size_no_descriptors; + const struct wim_security_data_disk *sd_disk; + const u8 *p; wimlib_assert(metadata_resource_len >= 8); - /* - * Sorry this function is excessively complicated--- I'm just being - * extremely careful about integer overflows. - */ + sd = new_wim_security_data(); + if (!sd) + goto out_of_memory; - sd = MALLOC(sizeof(struct wim_security_data)); - if (!sd) { - ERROR("Out of memory"); - return WIMLIB_ERR_NOMEM; - } - sd->sizes = NULL; - sd->descriptors = NULL; + sd_disk = (const struct wim_security_data_disk*)metadata_resource; + sd->total_length = le32_to_cpu(sd_disk->total_length); + sd->num_entries = le32_to_cpu(sd_disk->num_entries); + + DEBUG("Reading security data: num_entries=%u, total_length=%u", + sd->num_entries, sd->total_length); - p = metadata_resource; - p = get_u32(p, &sd->total_length); - p = get_u32(p, (u32*)&sd->num_entries); + /* Length field of 0 is a special case that really means length + * of 8. */ + if (sd->total_length == 0) + sd->total_length = 8; /* 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!"); + if (sd->num_entries > 0x80000000) 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 @@ -222,167 +230,151 @@ read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, * 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); + if (sd->total_length > metadata_resource_len) goto out_invalid_sd; - } - DEBUG("Reading security data: %u entries, length = %u", - sd->num_entries, sd->total_length); + sizes_size = (u64)sd->num_entries * sizeof(u64); + size_no_descriptors = 8 + sizes_size; + if (size_no_descriptors > sd->total_length) + goto out_invalid_sd; - if (sd->num_entries == 0) { - /* 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; - } + total_len = size_no_descriptors; - 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 seem to be at least %"PRIu64" bytes of security data", - sd->total_length, 8 + sizes_size); - goto out_invalid_sd; - } + /* Return immediately if no security descriptors. */ + if (sd->num_entries == 0) + goto out_align_total_length; + /* Allocate a new buffer for the sizes array */ sd->sizes = MALLOC(sizes_size); - if (!sd->sizes) { - ret = WIMLIB_ERR_NOMEM; - goto out_free_sd; - } + if (!sd->sizes) + goto out_of_memory; - /* Copy the sizes array in from the file data. */ - p = get_bytes(p, sizes_size, sd->sizes); - 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*)); - if (!sd->descriptors) { - ERROR("Out of memory while allocating security " - "descriptors"); - ret = WIMLIB_ERR_NOMEM; - goto out_free_sd; + /* Copy the sizes array into the new buffer */ + for (u32 i = 0; i < sd->num_entries; i++) { + sd->sizes[i] = le64_to_cpu(sd_disk->sizes[i]); + if (sd->sizes[i] > 0xffffffff) + goto out_invalid_sd; } - total_len = size_no_descriptors; + + p = (const u8*)sd_disk + size_no_descriptors; + + /* Allocate the array of pointers to the security descriptors, then read + * them into separate buffers. */ + sd->descriptors = CALLOC(sd->num_entries, sizeof(sd->descriptors[0])); + if (!sd->descriptors) + goto out_of_memory; 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]); - goto out_invalid_sd; - } + if (sd->sizes[i] == 0) + continue; 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 seem to be at least %"PRIu64" " - "bytes of security data", - sd->total_length, total_len); + if (total_len > (u64)sd->total_length) goto out_invalid_sd; - } sd->descriptors[i] = MALLOC(sd->sizes[i]); - if (!sd->descriptors[i]) { - 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]); + if (!sd->descriptors[i]) + goto out_of_memory; + memcpy(sd->descriptors[i], p, sd->sizes[i]); + p += sd->sizes[i]; + empty_sacl_fixup((SECURITY_DESCRIPTOR_RELATIVE*)sd->descriptors[i], + &sd->sizes[i]); } - 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; +out_align_total_length: + total_len = (total_len + 7) & ~7; + sd->total_length = (sd->total_length + 7) & ~7; + if (total_len != sd->total_length) { + WARNING("Expected WIM security data total length of " + "%u bytes, but calculated %u bytes", + sd->total_length, (unsigned)total_len); } - sd->total_length = total_len; out_return_sd: - *sd_p = sd; - return 0; + *sd_ret = sd; + ret = 0; + goto out; out_invalid_sd: + ERROR("WIM security data is invalid!"); ret = WIMLIB_ERR_INVALID_SECURITY_DATA; + goto out_free_sd; +out_of_memory: + ERROR("Out of memory while reading WIM security data!"); + ret = WIMLIB_ERR_NOMEM; out_free_sd: - free_security_data(sd); + free_wim_security_data(sd); +out: return ret; } /* - * Writes security data to an in-memory buffer. + * Writes the security data for a WIM image to an in-memory buffer. */ u8 * -write_security_data(const struct wim_security_data * restrict sd, - u8 * restrict p) +write_wim_security_data(const struct wim_security_data * restrict sd, + u8 * restrict 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, aligned_length); - p = put_u32(p, sd->num_entries); + struct wim_security_data_disk *sd_disk = (struct wim_security_data_disk*)p; + + sd_disk->total_length = cpu_to_le32(sd->total_length); + sd_disk->num_entries = cpu_to_le32(sd->num_entries); for (u32 i = 0; i < sd->num_entries; i++) - p = put_u64(p, sd->sizes[i]); + sd_disk->sizes[i] = cpu_to_le64(sd->sizes[i]); + + p = (u8*)&sd_disk->sizes[sd_disk->num_entries]; for (u32 i = 0; i < sd->num_entries; i++) - p = put_bytes(p, sd->sizes[i], sd->descriptors[i]); + p = mempcpy(p, sd->descriptors[i], sd->sizes[i]); + + while (p - orig_p < sd->total_length) + *p++ = 0; wimlib_assert(p - orig_p == sd->total_length); - p = put_zeroes(p, aligned_length - sd->total_length); DEBUG("Successfully wrote security data."); return p; } static void -print_acl(const void *p, const tchar *type) +print_acl(const ACL *acl, const tchar *type, size_t max_size) { - const ACL *acl = p; + const u8 *p; + + if (max_size < sizeof(ACL)) + return; + u8 revision = acl->revision; 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); + p = (const u8*)acl + sizeof(ACL); for (u16 i = 0; i < ace_count; i++) { - const ACE_HEADER *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); + if (max_size < p + sizeof(ACCESS_ALLOWED_ACE) - (const u8*)acl) + break; const ACCESS_ALLOWED_ACE *aaa = (const ACCESS_ALLOWED_ACE*)p; + tprintf(T(" [ACE]\n")); + tprintf(T(" ACE type = %d\n"), aaa->hdr.type); + tprintf(T(" ACE flags = 0x%x\n"), aaa->hdr.flags); + tprintf(T(" ACE size = %u\n"), le16_to_cpu(aaa->hdr.size)); 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; + p += le16_to_cpu(aaa->hdr.size); } tputchar(T('\n')); } static void -print_sid(const void *p, const tchar *type) +print_sid(const SID *sid, const tchar *type, size_t max_size) { - const SID *sid = p; + if (max_size < sizeof(SID)) + return; + tprintf(T(" [%"TS" SID]\n"), type); tprintf(T(" Revision = %u\n"), sid->revision); tprintf(T(" Subauthority count = %u\n"), sid->sub_authority_count); @@ -390,6 +382,8 @@ print_sid(const void *p, const tchar *type) print_byte_field(sid->identifier_authority, sizeof(sid->identifier_authority), stdout); tputchar(T('\n')); + if (max_size < sizeof(SID) + (size_t)sid->sub_authority_count * sizeof(u32)) + return; for (u8 i = 0; i < sid->sub_authority_count; i++) { tprintf(T(" Subauthority %u = %u\n"), i, le32_to_cpu(sid->sub_authority[i])); @@ -398,38 +392,45 @@ print_sid(const void *p, const tchar *type) } static void -print_security_descriptor(const void *p, u64 size) +print_security_descriptor(const SECURITY_DESCRIPTOR_RELATIVE *descr, + size_t size) { - const SECURITY_DESCRIPTOR_RELATIVE *sd = 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); + u8 revision = descr->revision; + u16 control = le16_to_cpu(descr->security_descriptor_control); + u32 owner_offset = le32_to_cpu(descr->owner_offset); + u32 group_offset = le32_to_cpu(descr->group_offset); + u32 dacl_offset = le32_to_cpu(descr->dacl_offset); + u32 sacl_offset = le32_to_cpu(descr->sacl_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); + tprintf(T("System ACL offset = %u\n"), sacl_offset); + + if (owner_offset != 0 && owner_offset <= size) + print_sid((const SID*)((const u8*)descr + owner_offset), + T("Owner"), size - owner_offset); - if (sd->owner_offset != 0) - print_sid(p + owner_offset, T("Owner")); - if (sd->group_offset != 0) - print_sid(p + group_offset, T("Group")); - if (sd->sacl_offset != 0) - print_acl(p + sacl_offset, T("System")); - if (sd->dacl_offset != 0) - print_acl(p + dacl_offset, T("Discretionary")); + if (group_offset != 0 && group_offset <= size) + print_sid((const SID*)((const u8*)descr + group_offset), + T("Group"), size - group_offset); + + if (dacl_offset != 0 && dacl_offset <= size) + print_acl((const ACL*)((const u8*)descr + dacl_offset), + T("Discretionary"), size - dacl_offset); + + if (sacl_offset != 0 && sacl_offset <= size) + print_acl((const ACL*)((const u8*)descr + sacl_offset), + T("System"), size - sacl_offset); } /* * Prints the security data for a WIM file. */ void -print_security_data(const struct wim_security_data *sd) +print_wim_security_data(const struct wim_security_data *sd) { tputs(T("[SECURITY DATA]")); tprintf(T("Length = %"PRIu32" bytes\n"), sd->total_length); @@ -438,14 +439,15 @@ print_security_data(const struct wim_security_data *sd) for (u32 i = 0; i < sd->num_entries; i++) { tprintf(T("[SECURITY_DESCRIPTOR_RELATIVE %"PRIu32", length = %"PRIu64"]\n"), i, sd->sizes[i]); - print_security_descriptor(sd->descriptors[i], sd->sizes[i]); + print_security_descriptor((const SECURITY_DESCRIPTOR_RELATIVE*)sd->descriptors[i], + sd->sizes[i]); tputchar(T('\n')); } tputchar(T('\n')); } void -free_security_data(struct wim_security_data *sd) +free_wim_security_data(struct wim_security_data *sd) { if (sd) { u8 **descriptors = sd->descriptors; @@ -481,8 +483,10 @@ destroy_sd_set(struct wim_sd_set *sd_set, bool rollback) { if (rollback) { struct wim_security_data *sd = sd_set->sd; - for (s32 i = sd_set->orig_num_entries; i < sd->num_entries; i++) - FREE(sd->descriptors[i]); + u8 **descriptors = sd->descriptors + sd_set->orig_num_entries; + u32 num_entries = sd->num_entries - sd_set->orig_num_entries; + while (num_entries--) + FREE(*descriptors++); sd->num_entries = sd_set->orig_num_entries; } free_sd_tree(sd_set->rb_root.rb_node); @@ -556,9 +560,11 @@ sd_set_add_sd(struct wim_sd_set *sd_set, const char *descriptor, size_t size) security_id = lookup_sd(sd_set, hash); if (security_id >= 0) /* Identical descriptor already exists */ - return security_id; + goto out; /* Need to add a new security descriptor */ + security_id = -1; + new = MALLOC(sizeof(*new)); if (!new) goto out; @@ -588,17 +594,17 @@ sd_set_add_sd(struct wim_sd_set *sd_set, const char *descriptor, size_t size) 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]); + DEBUG("There are now %u security descriptors", sd->num_entries); bret = insert_sd_node(sd_set, new); wimlib_assert(bret); - return new->security_id; + security_id = new->security_id; + goto out; out_free_descr: FREE(descr_copy); out_free_node: FREE(new); out: - return -1; + return security_id; } /* Initialize a `struct sd_set' mapping from SHA1 message digests of security @@ -615,7 +621,7 @@ init_sd_set(struct wim_sd_set *sd_set, struct wim_security_data *sd) /* Remember the original number of security descriptors so that newly * added ones can be rolled back if needed. */ sd_set->orig_num_entries = sd->num_entries; - for (s32 i = 0; i < sd->num_entries; i++) { + for (u32 i = 0; i < sd->num_entries; i++) { struct sd_node *new; new = MALLOC(sizeof(struct sd_node));