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redict/src/acl.c

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/*
* Copyright (c) 2018, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "server.h"
/* =============================================================================
* Global state for ACLs
* ==========================================================================*/
rax *Users; /* Table mapping usernames to user structures. */
user *DefaultUser; /* Global reference to the default user.
Every new connection is associated to it, if no
AUTH or HELLO is used to authenticate with a
different user. */
struct ACLCategoryItem {
const char *name;
uint64_t flag;
} ACLCommandCategories[] = {
{"keyspace", CMD_CATEGORY_KEYSPACE},
{"read", CMD_CATEGORY_READ},
{"write", CMD_CATEGORY_WRITE},
{"set", CMD_CATEGORY_SET},
{"sortedset", CMD_CATEGORY_SORTEDSET},
{"list", CMD_CATEGORY_LIST},
{"hash", CMD_CATEGORY_HASH},
{"string", CMD_CATEGORY_STRING},
{"bitmap", CMD_CATEGORY_BITMAP},
{"hyperloglog", CMD_CATEGORY_HYPERLOGLOG},
{"geo", CMD_CATEGORY_GEO},
{"stream", CMD_CATEGORY_STREAM},
{"pubsub", CMD_CATEGORY_PUBSUB},
{"admin", CMD_CATEGORY_ADMIN},
{"fast", CMD_CATEGORY_FAST},
{"slow", CMD_CATEGORY_SLOW},
{"blocking", CMD_CATEGORY_BLOCKING},
{"dangerous", CMD_CATEGORY_DANGEROUS},
{"connection", CMD_CATEGORY_CONNECTION},
{"transaction", CMD_CATEGORY_TRANSACTION},
{"scripting", CMD_CATEGORY_SCRIPTING},
{NULL,0} /* Terminator. */
};
struct ACLUserFlag {
const char *name;
uint64_t flag;
} ACLUserFlags[] = {
{"on", USER_FLAG_ENABLED},
{"off", USER_FLAG_DISABLED},
{"allkeys", USER_FLAG_ALLKEYS},
{"allcommands", USER_FLAG_ALLCOMMANDS},
{"nopass", USER_FLAG_NOPASS},
{NULL,0} /* Terminator. */
};
void ACLResetSubcommandsForCommand(user *u, unsigned long id);
/* =============================================================================
* Helper functions for the rest of the ACL implementation
* ==========================================================================*/
/* Return zero if strings are the same, non-zero if they are not.
* The comparison is performed in a way that prevents an attacker to obtain
* information about the nature of the strings just monitoring the execution
* time of the function.
*
* Note that limiting the comparison length to strings up to 512 bytes we
* can avoid leaking any information about the password length and any
* possible branch misprediction related leak.
*/
int time_independent_strcmp(char *a, char *b) {
char bufa[CONFIG_AUTHPASS_MAX_LEN], bufb[CONFIG_AUTHPASS_MAX_LEN];
/* The above two strlen perform len(a) + len(b) operations where either
* a or b are fixed (our password) length, and the difference is only
* relative to the length of the user provided string, so no information
* leak is possible in the following two lines of code. */
unsigned int alen = strlen(a);
unsigned int blen = strlen(b);
unsigned int j;
int diff = 0;
/* We can't compare strings longer than our static buffers.
* Note that this will never pass the first test in practical circumstances
* so there is no info leak. */
if (alen > sizeof(bufa) || blen > sizeof(bufb)) return 1;
memset(bufa,0,sizeof(bufa)); /* Constant time. */
memset(bufb,0,sizeof(bufb)); /* Constant time. */
/* Again the time of the following two copies is proportional to
* len(a) + len(b) so no info is leaked. */
memcpy(bufa,a,alen);
memcpy(bufb,b,blen);
/* Always compare all the chars in the two buffers without
* conditional expressions. */
for (j = 0; j < sizeof(bufa); j++) {
diff |= (bufa[j] ^ bufb[j]);
}
/* Length must be equal as well. */
diff |= alen ^ blen;
return diff; /* If zero strings are the same. */
}
/* =============================================================================
* Low level ACL API
* ==========================================================================*/
/* Given the category name the command returns the corresponding flag, or
* zero if there is no match. */
uint64_t ACLGetCommandCategoryFlagByName(const char *name) {
for (int j = 0; ACLCommandCategories[j].flag != 0; j++) {
if (!strcasecmp(name,ACLCommandCategories[j].name)) {
return ACLCommandCategories[j].flag;
}
}
return 0; /* No match. */
}
/* Method for passwords/pattern comparison used for the user->passwords list
* so that we can search for items with listSearchKey(). */
int ACLListMatchSds(void *a, void *b) {
return sdscmp(a,b) == 0;
}
/* Method to free list elements from ACL users password/ptterns lists. */
void ACLListFreeSds(void *item) {
sdsfree(item);
}
/* Create a new user with the specified name, store it in the list
* of users (the Users global radix tree), and returns a reference to
* the structure representing the user.
*
* If the user with such name already exists NULL is returned. */
user *ACLCreateUser(const char *name, size_t namelen) {
if (raxFind(Users,(unsigned char*)name,namelen) != raxNotFound) return NULL;
user *u = zmalloc(sizeof(*u));
u->name = sdsnewlen(name,namelen);
u->flags = USER_FLAG_DISABLED;
u->allowed_subcommands = NULL;
u->passwords = listCreate();
u->patterns = listCreate();
listSetMatchMethod(u->passwords,ACLListMatchSds);
listSetFreeMethod(u->passwords,ACLListFreeSds);
listSetMatchMethod(u->patterns,ACLListMatchSds);
listSetFreeMethod(u->patterns,ACLListFreeSds);
memset(u->allowed_commands,0,sizeof(u->allowed_commands));
raxInsert(Users,(unsigned char*)name,namelen,u,NULL);
return u;
}
/* Given a command ID, this function set by reference 'word' and 'bit'
* so that user->allowed_commands[word] will address the right word
* where the corresponding bit for the provided ID is stored, and
* so that user->allowed_commands[word]&bit will identify that specific
* bit. The function returns C_ERR in case the specified ID overflows
* the bitmap in the user representation. */
int ACLGetCommandBitCoordinates(uint64_t id, uint64_t *word, uint64_t *bit) {
if (id >= USER_COMMAND_BITS_COUNT) return C_ERR;
*word = id / sizeof(uint64_t) / 8;
*bit = 1ULL << (id % (sizeof(uint64_t) * 8));
return C_OK;
}
/* Check if the specified command bit is set for the specified user.
* The function returns 1 is the bit is set or 0 if it is not.
* Note that this function does not check the ALLCOMMANDS flag of the user
* but just the lowlevel bitmask.
*
* If the bit overflows the user internal represetation, zero is returned
* in order to disallow the execution of the command in such edge case. */
int ACLGetUserCommandBit(user *u, unsigned long id) {
uint64_t word, bit;
if (ACLGetCommandBitCoordinates(id,&word,&bit) == C_ERR) return 0;
return (u->allowed_commands[word] & bit) != 0;
}
/* When +@all or allcommands is given, we set a reserved bit as well that we
* can later test, to see if the user has the right to execute "future commands",
* that is, commands loaded later via modules. */
int ACLUserCanExecuteFutureCommands(user *u) {
return ACLGetUserCommandBit(u,USER_COMMAND_BITS_COUNT-1);
}
/* Set the specified command bit for the specified user to 'value' (0 or 1).
* If the bit overflows the user internal represetation, no operation
* is performed. As a side effect of calling this function with a value of
* zero, the user flag ALLCOMMANDS is cleared since it is no longer possible
* to skip the command bit explicit test. */
void ACLSetUserCommandBit(user *u, unsigned long id, int value) {
uint64_t word, bit;
if (value == 0) u->flags &= ~USER_FLAG_ALLCOMMANDS;
if (ACLGetCommandBitCoordinates(id,&word,&bit) == C_ERR) return;
if (value)
u->allowed_commands[word] |= bit;
else
u->allowed_commands[word] &= ~bit;
}
/* This is like ACLSetUserCommandBit(), but instead of setting the specified
* ID, it will check all the commands in the category specified as argument,
* and will set all the bits corresponding to such commands to the specified
* value. Since the category passed by the user may be non existing, the
* function returns C_ERR if the category was not found, or C_OK if it was
* found and the operation was performed. */
int ACLSetUserCommandBitsForCategory(user *u, const char *category, int value) {
uint64_t cflag = ACLGetCommandCategoryFlagByName(category);
if (!cflag) return C_ERR;
dictIterator *di = dictGetIterator(server.orig_commands);
dictEntry *de;
while ((de = dictNext(di)) != NULL) {
struct redisCommand *cmd = dictGetVal(de);
if (cmd->flags & cflag) {
ACLSetUserCommandBit(u,cmd->id,value);
ACLResetSubcommandsForCommand(u,cmd->id);
}
}
dictReleaseIterator(di);
return C_OK;
}
/* Return the number of commands allowed (on) and denied (off) for the user 'u'
* in the subset of commands flagged with the specified category name.
* If the categoty name is not valid, C_ERR is returend, otherwise C_OK is
* returned and on and off are populated by reference. */
int ACLCountCategoryBitsForUser(user *u, unsigned long *on, unsigned long *off,
const char *category)
{
uint64_t cflag = ACLGetCommandCategoryFlagByName(category);
if (!cflag) return C_ERR;
*on = *off = 0;
dictIterator *di = dictGetIterator(server.orig_commands);
dictEntry *de;
while ((de = dictNext(di)) != NULL) {
struct redisCommand *cmd = dictGetVal(de);
if (cmd->flags & cflag) {
if (ACLGetUserCommandBit(u,cmd->id))
(*on)++;
else
(*off)++;
}
}
dictReleaseIterator(di);
return C_OK;
}
/* This function returns an SDS string representing the specified user ACL
* rules related to command execution, in the same format you could set them
* back using ACL SETUSER. The function will return just the set of rules needed
* to recreate the user commands bitmap, without including other user flags such
* as on/off, passwords and so forth. The returned string always starts with
* the +@all or -@all rule, depending on the user bitmap, and is followed, if
* needed, by the other rules needed to narrow or extend what the user can do. */
sds ACLDescribeUserCommandRules(user *u) {
sds rules = sdsempty();
int additive; /* If true we start from -@all and add, otherwise if
false we start from +@all and remove. */
/* This code is based on a trick: as we generate the rules, we apply
* them to a fake user, so that as we go we still know what are the
* bit differences we should try to address by emitting more rules. */
user fu = {0};
user *fakeuser = &fu;
/* Here we want to understand if we should start with +@all and remove
* the commands corresponding to the bits that are not set in the user
* commands bitmap, or the contrary. Note that semantically the two are
* different. For instance starting with +@all and subtracting, the user
* will be able to execute future commands, while -@all and adding will just
* allow the user the run the selected commands and/or categories.
* How do we test for that? We use the trick of a reserved command ID bit
* that is set only by +@all (and its alias "allcommands"). */
if (ACLUserCanExecuteFutureCommands(u)) {
additive = 0;
rules = sdscat(rules,"+@all ");
ACLSetUser(fakeuser,"+@all",-1);
} else {
additive = 1;
rules = sdscat(rules,"-@all ");
ACLSetUser(fakeuser,"-@all",-1);
}
/* Try to add or subtract each category one after the other. Often a
* single category will not perfectly match the set of commands into
* it, so at the end we do a final pass adding/removing the single commands
* needed to make the bitmap exactly match. */
for (int j = 0; ACLCommandCategories[j].flag != 0; j++) {
unsigned long on, off;
ACLCountCategoryBitsForUser(u,&on,&off,ACLCommandCategories[j].name);
if ((additive && on > off) || (!additive && off > on)) {
sds op = sdsnewlen(additive ? "+@" : "-@", 2);
op = sdscat(op,ACLCommandCategories[j].name);
ACLSetUser(fakeuser,op,-1);
rules = sdscatsds(rules,op);
rules = sdscatlen(rules," ",1);
sdsfree(op);
}
}
/* Fix the final ACLs with single commands differences. */
dictIterator *di = dictGetIterator(server.orig_commands);
dictEntry *de;
while ((de = dictNext(di)) != NULL) {
struct redisCommand *cmd = dictGetVal(de);
int userbit = ACLGetUserCommandBit(u,cmd->id);
int fakebit = ACLGetUserCommandBit(fakeuser,cmd->id);
if (userbit != fakebit) {
rules = sdscatlen(rules, userbit ? "+" : "-", 1);
rules = sdscat(rules,cmd->name);
rules = sdscatlen(rules," ",1);
ACLSetUserCommandBit(fakeuser,cmd->id,userbit);
}
/* Emit the subcommands if there are any. */
if (userbit == 0 && u->allowed_subcommands &&
u->allowed_subcommands[cmd->id])
{
for (int j = 0; u->allowed_subcommands[cmd->id][j]; j++) {
rules = sdscatlen(rules,"+",1);
rules = sdscat(rules,cmd->name);
rules = sdscatlen(rules,"|",1);
rules = sdscatsds(rules,u->allowed_subcommands[cmd->id][j]);
rules = sdscatlen(rules," ",1);
}
}
}
dictReleaseIterator(di);
/* Trim the final useless space. */
sdsrange(rules,0,-2);
/* This is technically not needed, but we want to verify that now the
* predicted bitmap is exactly the same as the user bitmap, and abort
* otherwise, because aborting is better than a security risk in this
* code path. */
if (memcmp(fakeuser->allowed_commands,
u->allowed_commands,
sizeof(u->allowed_commands)) != 0)
{
serverLog(LL_WARNING,
"CRITICAL ERROR: User ACLs don't match final bitmap: '%s'",
rules);
serverPanic("No bitmap match in ACLDescribeUserCommandRules()");
}
return rules;
}
/* This is similar to ACLDescribeUserCommandRules(), however instead of
* describing just the user command rules, everything is described: user
* flags, keys, passwords and finally the command rules obtained via
* the ACLDescribeUserCommandRules() function. This is the function we call
* when we want to rewrite the configuration files describing ACLs and
* in order to show users with ACL LIST. */
sds ACLDescribeUser(user *u) {
sds res = sdsempty();
/* Flags. */
for (int j = 0; ACLUserFlags[j].flag; j++) {
/* Skip the allcommands and allkeys flags because they'll be emitted
* later as ~* and +@all. */
if (ACLUserFlags[j].flag == USER_FLAG_ALLKEYS ||
ACLUserFlags[j].flag == USER_FLAG_ALLCOMMANDS) continue;
if (u->flags & ACLUserFlags[j].flag) {
res = sdscat(res,ACLUserFlags[j].name);
res = sdscatlen(res," ",1);
}
}
/* Passwords. */
listIter li;
listNode *ln;
listRewind(u->passwords,&li);
while((ln = listNext(&li))) {
sds thispass = listNodeValue(ln);
res = sdscatlen(res,">",1);
res = sdscatsds(res,thispass);
res = sdscatlen(res," ",1);
}
/* Key patterns. */
if (u->flags & USER_FLAG_ALLKEYS) {
res = sdscatlen(res,"~* ",3);
} else {
listRewind(u->patterns,&li);
while((ln = listNext(&li))) {
sds thispat = listNodeValue(ln);
res = sdscatlen(res,"~",1);
res = sdscatsds(res,thispat);
res = sdscatlen(res," ",1);
}
}
/* Command rules. */
sds rules = ACLDescribeUserCommandRules(u);
res = sdscatsds(res,rules);
sdsfree(rules);
return res;
}
/* Get a command from the original command table, that is not affected
* by the command renaming operations: we base all the ACL work from that
* table, so that ACLs are valid regardless of command renaming. */
struct redisCommand *ACLLookupCommand(const char *name) {
struct redisCommand *cmd;
sds sdsname = sdsnew(name);
cmd = dictFetchValue(server.orig_commands, sdsname);
sdsfree(sdsname);
return cmd;
}
/* Flush the array of allowed subcommands for the specified user
* and command ID. */
void ACLResetSubcommandsForCommand(user *u, unsigned long id) {
if (u->allowed_subcommands && u->allowed_subcommands[id]) {
zfree(u->allowed_subcommands[id]);
u->allowed_subcommands[id] = NULL;
}
}
/* Flush the entire table of subcommands. This is useful on +@all, -@all
* or similar to return back to the minimal memory usage (and checks to do)
* for the user. */
void ACLResetSubcommands(user *u) {
if (u->allowed_subcommands == NULL) return;
for (int j = 0; j < USER_COMMAND_BITS_COUNT; j++) {
if (u->allowed_subcommands[j]) {
for (int i = 0; u->allowed_subcommands[j][i]; i++)
sdsfree(u->allowed_subcommands[j][i]);
zfree(u->allowed_subcommands[j]);
}
}
zfree(u->allowed_subcommands);
u->allowed_subcommands = NULL;
}
/* Add a subcommand to the list of subcommands for the user 'u' and
* the command id specified. */
void ACLAddAllowedSubcommand(user *u, unsigned long id, const char *sub) {
/* If this is the first subcommand to be configured for
* this user, we have to allocate the subcommands array. */
if (u->allowed_subcommands == NULL) {
u->allowed_subcommands = zcalloc(USER_COMMAND_BITS_COUNT *
sizeof(sds*));
}
/* We also need to enlarge the allocation pointing to the
* null terminated SDS array, to make space for this one.
* To start check the current size, and while we are here
* make sure the subcommand is not already specified inside. */
long items = 0;
if (u->allowed_subcommands[id]) {
while(u->allowed_subcommands[id][items]) {
/* If it's already here do not add it again. */
if (!strcasecmp(u->allowed_subcommands[id][items],sub)) return;
items++;
}
}
/* Now we can make space for the new item (and the null term). */
items += 2;
u->allowed_subcommands[id] = zrealloc(u->allowed_subcommands[id],
sizeof(sds)*items);
u->allowed_subcommands[id][items-2] = sdsnew(sub);
u->allowed_subcommands[id][items-1] = NULL;
}
/* Set user properties according to the string "op". The following
* is a description of what different strings will do:
*
* on Enable the user: it is possible to authenticate as this user.
* off Disable the user: it's no longer possible to authenticate
* with this user, however the already authenticated connections
* will still work.
* +<command> Allow the execution of that command
* -<command> Disallow the execution of that command
* +@<category> Allow the execution of all the commands in such category
* with valid categories are like @admin, @set, @sortedset, ...
* and so forth, see the full list in the server.c file where
* the Redis command table is described and defined.
* The special category @all means all the commands, but currently
* present in the server, and that will be loaded in the future
* via modules.
* +<command>|subcommand Allow a specific subcommand of an otherwise
* disabled command. Note that this form is not
* allowed as negative like -DEBUG|SEGFAULT, but
* only additive starting with "+".
* allcommands Alias for +@all. Note that it implies the ability to execute
* all the future commands loaded via the modules system.
* nocommands Alias for -@all.
* ~<pattern> Add a pattern of keys that can be mentioned as part of
* commands. For instance ~* allows all the keys. The pattern
* is a glob-style pattern like the one of KEYS.
* It is possible to specify multiple patterns.
* allkeys Alias for ~*
* resetkeys Flush the list of allowed keys patterns.
* ><password> Add this passowrd to the list of valid password for the user.
* For example >mypass will add "mypass" to the list.
* This directive clears the "nopass" flag (see later).
* <<password> Remove this password from the list of valid passwords.
* nopass All the set passwords of the user are removed, and the user
* is flagged as requiring no password: it means that every
* password will work against this user. If this directive is
* used for the default user, every new connection will be
* immediately authenticated with the default user without
* any explicit AUTH command required. Note that the "resetpass"
* directive will clear this condition.
* resetpass Flush the list of allowed passwords. Moreover removes the
* "nopass" status. After "resetpass" the user has no associated
* passwords and there is no way to authenticate without adding
* some password (or setting it as "nopass" later).
* reset Performs the following actions: resetpass, resetkeys, off,
* -@all. The user returns to the same state it has immediately
* after its creation.
*
* The 'op' string must be null terminated. The 'oplen' argument should
* specify the length of the 'op' string in case the caller requires to pass
* binary data (for instance the >password form may use a binary password).
* Otherwise the field can be set to -1 and the function will use strlen()
* to determine the length.
*
* The function returns C_OK if the action to perform was understood because
* the 'op' string made sense. Otherwise C_ERR is returned if the operation
* is unknown or has some syntax error.
*
* When an error is returned, errno is set to the following values:
*
* EINVAL: The specified opcode is not understood.
* ENOENT: The command name or command category provided with + or - is not
* known.
* EBUSY: The subcommand you want to add is about a command that is currently
* fully added.
* EEXIST: You are adding a key pattern after "*" was already added. This is
* almost surely an error on the user side.
*/
int ACLSetUser(user *u, const char *op, ssize_t oplen) {
if (oplen == -1) oplen = strlen(op);
if (!strcasecmp(op,"on")) {
u->flags |= USER_FLAG_ENABLED;
u->flags &= ~USER_FLAG_DISABLED;
} else if (!strcasecmp(op,"off")) {
u->flags |= USER_FLAG_DISABLED;
u->flags &= ~USER_FLAG_ENABLED;
} else if (!strcasecmp(op,"allkeys") ||
!strcasecmp(op,"~*"))
{
u->flags |= USER_FLAG_ALLKEYS;
listEmpty(u->patterns);
} else if (!strcasecmp(op,"resetkeys")) {
u->flags &= ~USER_FLAG_ALLKEYS;
listEmpty(u->patterns);
} else if (!strcasecmp(op,"allcommands") ||
!strcasecmp(op,"+@all"))
{
memset(u->allowed_commands,255,sizeof(u->allowed_commands));
u->flags |= USER_FLAG_ALLCOMMANDS;
ACLResetSubcommands(u);
} else if (!strcasecmp(op,"nocommands") ||
!strcasecmp(op,"-@all"))
{
memset(u->allowed_commands,0,sizeof(u->allowed_commands));
u->flags &= ~USER_FLAG_ALLCOMMANDS;
ACLResetSubcommands(u);
} else if (!strcasecmp(op,"nopass")) {
u->flags |= USER_FLAG_NOPASS;
listEmpty(u->passwords);
} else if (!strcasecmp(op,"resetpass")) {
u->flags &= ~USER_FLAG_NOPASS;
listEmpty(u->passwords);
} else if (op[0] == '>') {
sds newpass = sdsnewlen(op+1,oplen-1);
listNode *ln = listSearchKey(u->passwords,newpass);
/* Avoid re-adding the same password multiple times. */
if (ln == NULL) listAddNodeTail(u->passwords,newpass);
u->flags &= ~USER_FLAG_NOPASS;
} else if (op[0] == '<') {
sds delpass = sdsnewlen(op+1,oplen-1);
listNode *ln = listSearchKey(u->passwords,delpass);
if (ln) listDelNode(u->passwords,ln);
sdsfree(delpass);
} else if (op[0] == '~') {
if (u->flags & USER_FLAG_ALLKEYS) {
errno = EEXIST;
return C_ERR;
}
sds newpat = sdsnewlen(op+1,oplen-1);
listNode *ln = listSearchKey(u->patterns,newpat);
/* Avoid re-adding the same pattern multiple times. */
if (ln == NULL) listAddNodeTail(u->patterns,newpat);
u->flags &= ~USER_FLAG_ALLKEYS;
} else if (op[0] == '+' && op[1] != '@') {
if (strchr(op,'|') == NULL) {
if (ACLLookupCommand(op+1) == NULL) {
errno = ENOENT;
return C_ERR;
}
unsigned long id = ACLGetCommandID(op+1);
ACLSetUserCommandBit(u,id,1);
ACLResetSubcommandsForCommand(u,id);
} else {
/* Split the command and subcommand parts. */
char *copy = zstrdup(op+1);
char *sub = strchr(copy,'|');
sub[0] = '\0';
sub++;
/* Check if the command exists. We can't check the
* subcommand to see if it is valid. */
if (ACLLookupCommand(copy) == NULL) {
zfree(copy);
errno = ENOENT;
return C_ERR;
}
unsigned long id = ACLGetCommandID(copy);
/* The subcommand cannot be empty, so things like DEBUG|
* are syntax errors of course. */
if (strlen(sub) == 0) {
zfree(copy);
errno = EINVAL;
return C_ERR;
}
/* The command should not be set right now in the command
* bitmap, because adding a subcommand of a fully added
* command is probably an error on the user side. */
if (ACLGetUserCommandBit(u,id) == 1) {
zfree(copy);
errno = EBUSY;
return C_ERR;
}
/* Add the subcommand to the list of valid ones. */
ACLAddAllowedSubcommand(u,id,sub);
/* We have to clear the command bit so that we force the
* subcommand check. */
ACLSetUserCommandBit(u,id,0);
zfree(copy);
}
} else if (op[0] == '-' && op[1] != '@') {
if (ACLLookupCommand(op+1) == NULL) {
errno = ENOENT;
return C_ERR;
}
unsigned long id = ACLGetCommandID(op+1);
ACLSetUserCommandBit(u,id,0);
ACLResetSubcommandsForCommand(u,id);
} else if ((op[0] == '+' || op[0] == '-') && op[1] == '@') {
int bitval = op[0] == '+' ? 1 : 0;
if (ACLSetUserCommandBitsForCategory(u,op+2,bitval) == C_ERR) {
errno = ENOENT;
return C_ERR;
}
} else if (!strcasecmp(op,"reset")) {
serverAssert(ACLSetUser(u,"resetpass",-1) == C_OK);
serverAssert(ACLSetUser(u,"resetkeys",-1) == C_OK);
serverAssert(ACLSetUser(u,"off",-1) == C_OK);
serverAssert(ACLSetUser(u,"-@all",-1) == C_OK);
} else {
errno = EINVAL;
return C_ERR;
}
return C_OK;
}
/* Return a description of the error that occurred in ACLSetUser() according to
* the errno value set by the function on error. */
char *ACLSetUserStringError(void) {
char *errmsg = "Wrong format";
if (errno == ENOENT)
errmsg = "Unknown command or category name in ACL";
else if (errno == EINVAL)
errmsg = "Syntax error";
else if (errno == EBUSY)
errmsg = "Adding a subcommand of a command already fully "
"added is not allowed. Remove the command to start. "
"Example: -DEBUG +DEBUG|DIGEST";
else if (errno == EEXIST)
errmsg = "Adding a pattern after the * pattern (or the "
"'allkeys' flag) is not valid and does not have any "
"effect. Try 'resetkeys' to start with an empty "
"list of patterns";
return errmsg;
}
/* Return the first password of the default user or NULL.
* This function is needed for backward compatibility with the old
* directive "requirepass" when Redis supported a single global
* password. */
sds ACLDefaultUserFirstPassword(void) {
if (listLength(DefaultUser->passwords) == 0) return NULL;
listNode *first = listFirst(DefaultUser->passwords);
return listNodeValue(first);
}
/* Initialization of the ACL subsystem. */
void ACLInit(void) {
Users = raxNew();
DefaultUser = ACLCreateUser("default",7);
ACLSetUser(DefaultUser,"+@all",-1);
ACLSetUser(DefaultUser,"~*",-1);
ACLSetUser(DefaultUser,"on",-1);
ACLSetUser(DefaultUser,"nopass",-1);
}
/* Check the username and password pair and return C_OK if they are valid,
* otherwise C_ERR is returned and errno is set to:
*
* EINVAL: if the username-password do not match.
* ENONENT: if the specified user does not exist at all.
*/
int ACLCheckUserCredentials(robj *username, robj *password) {
user *u = ACLGetUserByName(username->ptr,sdslen(username->ptr));
if (u == NULL) {
errno = ENOENT;
return C_ERR;
}
/* Disabled users can't login. */
if (u->flags & USER_FLAG_DISABLED) {
errno = EINVAL;
return C_ERR;
}
/* If the user is configured to don't require any password, we
* are already fine here. */
if (u->flags & USER_FLAG_NOPASS) return C_OK;
/* Check all the user passwords for at least one to match. */
listIter li;
listNode *ln;
listRewind(u->passwords,&li);
while((ln = listNext(&li))) {
sds thispass = listNodeValue(ln);
if (!time_independent_strcmp(password->ptr, thispass))
return C_OK;
}
/* If we reached this point, no password matched. */
errno = EINVAL;
return C_ERR;
}
/* For ACL purposes, every user has a bitmap with the commands that such
* user is allowed to execute. In order to populate the bitmap, every command
* should have an assigned ID (that is used to index the bitmap). This function
* creates such an ID: it uses sequential IDs, reusing the same ID for the same
* command name, so that a command retains the same ID in case of modules that
* are unloaded and later reloaded. */
unsigned long ACLGetCommandID(const char *cmdname) {
static rax *map = NULL;
static unsigned long nextid = 0;
sds lowername = sdsnew(cmdname);
sdstolower(lowername);
if (map == NULL) map = raxNew();
void *id = raxFind(map,(unsigned char*)lowername,sdslen(lowername));
if (id != raxNotFound) {
sdsfree(lowername);
return (unsigned long)id;
}
raxInsert(map,(unsigned char*)lowername,strlen(lowername),
(void*)nextid,NULL);
sdsfree(lowername);
unsigned long thisid = nextid;
nextid++;
/* We never assign the last bit in the user commands bitmap structure,
* this way we can later check if this bit is set, understanding if the
* current ACL for the user was created starting with a +@all to add all
* the possible commands and just subtracting other single commands or
* categories, or if, instead, the ACL was created just adding commands
* and command categories from scratch, not allowing future commands by
* default (loaded via modules). This is useful when rewriting the ACLs
* with ACL SAVE. */
if (nextid == USER_COMMAND_BITS_COUNT-1) nextid++;
return thisid;
}
/* Return an username by its name, or NULL if the user does not exist. */
user *ACLGetUserByName(const char *name, size_t namelen) {
void *myuser = raxFind(Users,(unsigned char*)name,namelen);
if (myuser == raxNotFound) return NULL;
return myuser;
}
/* Check if the command ready to be excuted in the client 'c', and already
* referenced by c->cmd, can be executed by this client according to the
* ACls associated to the client user c->user.
*
* If the user can execute the command ACL_OK is returned, otherwise
* ACL_DENIED_CMD or ACL_DENIED_KEY is returned: the first in case the
* command cannot be executed because the user is not allowed to run such
* command, the second if the command is denied because the user is trying
* to access keys that are not among the specified patterns. */
int ACLCheckCommandPerm(client *c) {
user *u = c->user;
uint64_t id = c->cmd->id;
/* If there is no associated user, the connection can run anything. */
if (u == NULL) return ACL_OK;
/* Check if the user can execute this command. */
if (!(u->flags & USER_FLAG_ALLCOMMANDS) &&
c->cmd->proc != authCommand)
{
/* If the bit is not set we have to check further, in case the
* command is allowed just with that specific subcommand. */
if (ACLGetUserCommandBit(u,id) == 0) {
/* Check if the subcommand matches. */
if (c->argc < 2 ||
u->allowed_subcommands == NULL ||
u->allowed_subcommands[id] == NULL)
{
return ACL_DENIED_CMD;
}
long subid = 0;
while (1) {
if (u->allowed_subcommands[id][subid] == NULL)
return ACL_DENIED_CMD;
if (!strcasecmp(c->argv[1]->ptr,
u->allowed_subcommands[id][subid]))
break; /* Subcommand match found. Stop here. */
subid++;
}
}
}
/* Check if the user can execute commands explicitly touching the keys
* mentioned in the command arguments. */
if (!(c->user->flags & USER_FLAG_ALLKEYS) &&
(c->cmd->getkeys_proc || c->cmd->firstkey))
{
int numkeys;
int *keyidx = getKeysFromCommand(c->cmd,c->argv,c->argc,&numkeys);
for (int j = 0; j < numkeys; j++) {
listIter li;
listNode *ln;
listRewind(u->patterns,&li);
/* Test this key against every pattern. */
int match = 0;
while((ln = listNext(&li))) {
sds pattern = listNodeValue(ln);
size_t plen = sdslen(pattern);
int idx = keyidx[j];
if (stringmatchlen(pattern,plen,c->argv[idx]->ptr,
sdslen(c->argv[idx]->ptr),0))
{
match = 1;
break;
}
}
if (!match) {
getKeysFreeResult(keyidx);
return ACL_DENIED_KEY;
}
}
getKeysFreeResult(keyidx);
}
/* If we survived all the above checks, the user can execute the
* command. */
return ACL_OK;
}
/* =============================================================================
* ACL related commands
* ==========================================================================*/
/* ACL -- show and modify the configuration of ACL users.
* ACL HELP
* ACL LIST
* ACL SETUSER <username> ... user attribs ...
* ACL DELUSER <username>
* ACL GETUSER <username>
*/
void aclCommand(client *c) {
char *sub = c->argv[1]->ptr;
if (!strcasecmp(sub,"setuser") && c->argc >= 3) {
sds username = c->argv[2]->ptr;
user *u = ACLGetUserByName(username,sdslen(username));
if (!u) u = ACLCreateUser(username,sdslen(username));
serverAssert(u != NULL);
for (int j = 3; j < c->argc; j++) {
if (ACLSetUser(u,c->argv[j]->ptr,sdslen(c->argv[j]->ptr)) != C_OK) {
char *errmsg = ACLSetUserStringError();
addReplyErrorFormat(c,
"Error in ACL SETUSER modifier '%s': %s",
(char*)c->argv[j]->ptr, errmsg);
return;
}
}
addReply(c,shared.ok);
} else if (!strcasecmp(sub,"getuser") && c->argc == 3) {
user *u = ACLGetUserByName(c->argv[2]->ptr,sdslen(c->argv[2]->ptr));
if (u == NULL) {
addReplyNull(c);
return;
}
addReplyMapLen(c,4);
/* Flags */
addReplyBulkCString(c,"flags");
void *deflen = addReplyDeferredLen(c);
int numflags = 0;
for (int j = 0; ACLUserFlags[j].flag; j++) {
if (u->flags & ACLUserFlags[j].flag) {
addReplyBulkCString(c,ACLUserFlags[j].name);
numflags++;
}
}
setDeferredSetLen(c,deflen,numflags);
/* Passwords */
addReplyBulkCString(c,"passwords");
addReplyArrayLen(c,listLength(u->passwords));
listIter li;
listNode *ln;
listRewind(u->passwords,&li);
while((ln = listNext(&li))) {
sds thispass = listNodeValue(ln);
addReplyBulkCBuffer(c,thispass,sdslen(thispass));
}
/* Commands */
addReplyBulkCString(c,"commands");
sds cmddescr = ACLDescribeUserCommandRules(u);
addReplyBulkSds(c,cmddescr);
/* Key patterns */
addReplyBulkCString(c,"keys");
if (u->flags & USER_FLAG_ALLKEYS) {
addReplyArrayLen(c,1);
addReplyBulkCBuffer(c,"*",1);
} else {
addReplyArrayLen(c,listLength(u->patterns));
listIter li;
listNode *ln;
listRewind(u->patterns,&li);
while((ln = listNext(&li))) {
sds thispat = listNodeValue(ln);
addReplyBulkCBuffer(c,thispat,sdslen(thispat));
}
}
} else if (!strcasecmp(sub,"list") || !strcasecmp(sub,"users")) {
int justnames = !strcasecmp(sub,"users");
addReplyArrayLen(c,raxSize(Users));
raxIterator ri;
raxStart(&ri,Users);
raxSeek(&ri,"^",NULL,0);
while(raxNext(&ri)) {
user *u = ri.data;
if (justnames) {
addReplyBulkCBuffer(c,u->name,sdslen(u->name));
} else {
/* Return information in the configuration file format. */
sds config = sdsnew("user ");
config = sdscatsds(config,u->name);
config = sdscatlen(config," ",1);
sds descr = ACLDescribeUser(u);
config = sdscatsds(config,descr);
sdsfree(descr);
addReplyBulkSds(c,config);
}
}
raxStop(&ri);
} else if (!strcasecmp(sub,"whoami")) {
if (c->user != NULL) {
addReplyBulkCBuffer(c,c->user->name,sdslen(c->user->name));
} else {
addReplyNull(c);
}
} else if (!strcasecmp(sub,"help")) {
const char *help[] = {
"LIST -- Show user details in config file format.",
"USERS -- List all the registered usernames.",
"SETUSER <username> [attribs ...] -- Create or modify a user.",
"GETUSER <username> -- Get the user details.",
"DELUSER <username> -- Delete a user.",
"WHOAMI -- Return the current connection username.",
NULL
};
addReplyHelp(c,help);
} else {
addReplySubcommandSyntaxError(c);
}
}
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