X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=c084258e007961a52ee8e5794f39a01bf93dd9bd;hp=6f0152eae734f8a150bd48a179c4d9939b978b45;hb=36a737d734cdc6c6eb0ce9da3183a1f8fa4288e6;hpb=60b8f54df8fed44136bdc8ec615ee62703d87b69 diff --git a/src/security.c b/src/security.c index 6f0152ea..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. */ /* @@ -25,10 +26,33 @@ */ #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"); @@ -63,10 +92,14 @@ 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 @@ -81,17 +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_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. */ + 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); @@ -100,8 +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_SECURITY_DATA; - 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) { @@ -111,7 +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*)); @@ -131,16 +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_SECURITY_DATA; - goto out_free_sd; + goto out_invalid_sd; } sd->descriptors[i] = MALLOC(sd->sizes[i]); if (!sd->descriptors[i]) { @@ -150,17 +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) @@ -189,24 +240,25 @@ u8 *write_security_data(const struct wim_security_data *sd, 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); + 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", acl->revision); - printf(" ACL Size = %u\n", acl->acl_size); - printf(" ACE Count = %u\n", acl->ace_count); + 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'); @@ -214,54 +266,59 @@ static void print_acl(const u8 *p, const char *type) static void print_sid(const u8 *p, const char *type) { - SID *sid = (SID*)p; + 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 (uint i = 0; i < sid->sub_authority_count; i++) - printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i])); + 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'); } 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 = %#x\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, "Owner"); + print_sid(p + owner_offset, "Owner"); if (sd->group_offset != 0) - print_sid(p + sd->group_offset, "Group"); + print_sid(p + group_offset, "Group"); if (sd->sacl_offset != 0) - print_acl(p + sd->sacl_offset, "System"); + print_acl(p + sacl_offset, "System"); if (sd->dacl_offset != 0) - print_acl(p + sd->dacl_offset, "Discretionary"); + 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'); @@ -271,17 +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 != 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 (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); + } } }