From 8d9353c06213e76c00034883dce83f4ffa3135ca Mon Sep 17 00:00:00 2001 From: "cantab.net!aia21" Date: Thu, 15 Apr 2004 11:10:40 +0000 Subject: [PATCH] Add ntfs_sid_to_mbs_size() and ntfs_sid_to_mbs(). (Logical change 1.368) --- libntfs/security.c | 154 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 150 insertions(+), 4 deletions(-) diff --git a/libntfs/security.c b/libntfs/security.c index 70c441d7..252e3744 100644 --- a/libntfs/security.c +++ b/libntfs/security.c @@ -40,7 +40,7 @@ const GUID *const zero_guid = &__zero_guid; /** * ntfs_guid_is_zero - check if a GUID is zero - * @guid: guid to check + * @guid: [IN] guid to check * * Return TRUE if @guid is a valid pointer to a GUID and it is the zero GUID * and FALSE otherwise. @@ -52,8 +52,8 @@ BOOL ntfs_guid_is_zero(const GUID *guid) /** * ntfs_guid_to_mbs - convert a GUID to a multi byte string - * @guid: guid to convert - * @guid_str: string in which to return the GUID (optional) + * @guid: [IN] guid to convert + * @guid_str: [OUT] string in which to return the GUID (optional) * * Convert the GUID pointed to by @guid to a multi byte string of the form * "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX". Therefore, @guid_str (if not NULL) @@ -83,7 +83,7 @@ char *ntfs_guid_to_mbs(const GUID *guid, char *guid_str) } res = snprintf(_guid_str, 37, "%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x", - le32_to_cpu(guid->data1), + (unsigned int)le32_to_cpu(guid->data1), le16_to_cpu(guid->data2), le16_to_cpu(guid->data3), guid->data4[0], guid->data4[1], guid->data4[2], guid->data4[3], guid->data4[4], @@ -95,3 +95,149 @@ char *ntfs_guid_to_mbs(const GUID *guid, char *guid_str) errno = EINVAL; return NULL; } + +/** + * ntfs_sid_to_mbs_size - determine maximum size for the string of a SID + * @sid: [IN] SID for which to determine the maximum string size + * + * Determine the maximum multi byte string size in bytes which is needed to + * store the standard textual representation of the SID pointed to by @sid. + * See ntfs_sid_to_mbs(), below. + * + * On success return the maximum number of bytes needed to store the multi byte + * string and on failure return -1 with errno set to the error code. + */ +int ntfs_sid_to_mbs_size(const SID *sid) +{ + int size, i; + + if (!ntfs_sid_is_valid(sid)) { + errno = EINVAL; + return -1; + } + /* Start with "S-". */ + size = 2; + /* + * Add the SID_REVISION. Hopefully the compiler will optimize this + * away as SID_REVISION is a constant. + */ + for (i = SID_REVISION; i > 0; i /= 10) + size++; + /* Add the "-". */ + size++; + /* + * Add the identifier authority. If it needs to be in decimal, the + * maximum is 2^32-1 = 4294967295 = 10 characters. If it needs to be + * in hexadecimal, then maximum is 0x665544332211 = 14 characters. + */ + if (!sid->identifier_authority.high_part) + size += 10; + else + size += 14; + /* + * Finally, add the sub authorities. For each we have a "-" followed + * by a decimal which can be up to 2^32-1 = 4294967295 = 10 characters. + */ + size += (1 + 10) * sid->sub_authority_count; + /* We need the zero byte at the end, too. */ + size++; + return size * sizeof(char); +} + +/** + * ntfs_sid_to_mbs - convert a SID to a multi byte string + * @sid: [IN] SID to convert + * @sid_str: [OUT] string in which to return the SID (optional) + * @sid_str_size: [IN] size in bytes of @sid_str + * + * Convert the SID pointed to by @sid to its standard textual representation. + * @sid_str (if not NULL) needs to be able to store at least + * ntfs_sid_to_mbs_size() bytes. @sid_str_size is the size in bytes of + * @sid_str if @sid_str is not NULL. + * + * The standard textual representation of the SID is of the form: + * S-R-I-S-S... + * Where: + * - The first "S" is the literal character 'S' identifying the following + * digits as a SID. + * - R is the revision level of the SID expressed as a sequence of digits + * in decimal. + * - I is the 48-bit identifier_authority, expressed as digits in decimal, + * if I < 2^32, or hexadecimal prefixed by "0x", if I >= 2^32. + * - S... is one or more sub_authority values, expressed as digits in + * decimal. + * + * If @sid_str is not NULL it will contain the converted SUID on return. If it + * is NULL a string will be allocated and this will be returned. The caller is + * responsible for free()ing the string in that case. + * + * On success return the converted string and on failure return NULL with errno + * set to the error code. + */ +char *ntfs_sid_to_mbs(const SID *sid, char *sid_str, size_t sid_str_size) +{ + u64 u; + char *s; + size_t cnt; + int i, j; + + /* + * No need to check @sid if !@sid_str since ntfs_sid_to_mbs_size() will + * check @sid, too. 8 is the minimum SID string size. + */ + if (sid_str && (sid_str_size < 8 || !ntfs_sid_is_valid(sid))) { + errno = EINVAL; + return NULL; + } + /* Allocate string if not provided. */ + if (!sid_str) { + cnt = ntfs_sid_to_mbs_size(sid); + if (cnt < 0) + return NULL; + s = malloc(cnt); + if (!s) + return s; + sid_str = s; + /* So we know we allocated it. */ + sid_str_size = 0; + } else { + s = sid_str; + cnt = sid_str_size; + } + /* Start with "S-R-". */ + i = snprintf(s, cnt, "S-%c-", (char)sid->revision); + if (i < 0 || i >= cnt) + goto err_out; + s += i; + cnt -= i; + /* Add the identifier authority. */ + for (u = i = 0, j = 40; i < 6; i++, j -= 8) + u += (u64)sid->identifier_authority.value[i] << j; + if (!sid->identifier_authority.high_part) + i = snprintf(s, cnt, "%lu", (unsigned long)u); + else + i = snprintf(s, cnt, "0x%llx", (unsigned long long)u); + if (i < 0 || i >= cnt) + goto err_out; + s += i; + cnt -= i; + /* Finally, add the sub authorities. */ + for (i = 0; i < sid->sub_authority_count; i++) { + j = snprintf(s, cnt, "-%u", (unsigned int) + le32_to_cpu(sid->sub_authority[i])); + if (j < 0 || j >= cnt) + goto err_out; + s += j; + cnt -= j; + } + return sid_str; +err_out: + if (i >= cnt) + i = EMSGSIZE; + else + i = errno; + if (!sid_str_size) + free(sid_str); + errno = i; + return NULL; +}