See #5011.

Fix config_set_numerical_field() integer overflow.

The old version could not handle the fact that "STREAMS" is a valid key
name for streams. Now we really try to parse the command like the
command implementation would do.

Related to #5028 and 4857.

Fix core dump when using some commands with wrong arguments.

The loop allocated a buffer for the right number of keys positions, then
overflowed it going past the limit.

Related to #4857 and cause of the memory violation seen in #5028.

Now a MAXLEN of 0 really does what it means: it will create a zero
entries stream. This is useful in order to make sure that the behavior
is identical to XTRIM, that must be able to reduce the stream to zero
elements when MAXLEN is given.

Also now MAXLEN with a count < 0 will return an error.

Critical: Fix server crash and data inconsistency in some cases.

Rdb save incremental fsync

The ability of "SENTINEL SET" to change the reconfiguration script at
runtime is a problem even in the security model of Redis: any client
inside the network may set any executable to be ran once a failover is
triggered.

This option adds protection for this problem: by default the two
SENTINEL SET subcommands modifying scripts paths are denied. However the
user is still able to rever that using the Sentinel configuration file
in order to allow such a feature.

Thanks to @kevinmcgehee for signaling the issue and reasoning about the
consequences and potential fixes.

Issue #5015.

fix geohashEncode bug when step > 30

fix exists command on slave

optimize reply list memory usage

Thanks to Fakhri Zulkifli for reporting it.

The fix switched to dynamic allocation, copying the final prompt in the
static buffer only at the end.

After the first fix to the struct package I found another similar
problem, which is fixed by this patch. It could be reproduced easily by
running the following script:

    return struct.unpack('f', "xxxxxxxxxxxxx",-3)

The above will access bytes before the 'data' pointer.

@soloestoy sent me this additional fixes, after searching for similar
problems to the one reported in mp_pack(). I'm committing the changes
because it was not possible during to make a public PR to protect Redis
users and give Redis providers some time to patch their systems.

During an auditing Apple found that the "struct" Lua package
we ship with Redis (http://www.inf.puc-rio.br/~roberto/struct/) contains
a security problem. A bound-checking statement fails because of integer
overflow. The bug exists since we initially integrated this package with
Lua, when scripting was introduced, so every version of Redis with
EVAL/EVALSHA capabilities exposed is affected.

Instead of just fixing the bug, the library was updated to the latest
version shipped by the author.

During an auditing effort, the Apple Vulnerability Research team discovered
a critical Redis security issue affecting the Lua scripting part of Redis.

-- Description of the problem

Several years ago I merged a pull request including many small changes at
the Lua MsgPack library (that originally I authored myself). The Pull
Request entered Redis in commit 90b6337c, in 2014.
Unfortunately one of the changes included a variadic Lua function that
lacked the check for the available Lua C stack. As a result, calling the
"pack" MsgPack library function with a large number of arguments, results
into pushing into the Lua C stack a number of new values proportional to
the number of arguments the function was called with. The pushed values,
moreover, are controlled by untrusted user input.

This in turn causes stack smashing which we believe to be exploitable,
while not very deterministic, but it is likely that an exploit could be
created targeting specific versions of Redis executables. However at its
minimum the issue results in a DoS, crashing the Redis server.

-- Versions affected

Versions greater or equal to Redis 2.8.18 are affected.

-- Reproducing

Reproduce with this (based on the original reproduction script by
Apple security team):

https://gist.github.com/antirez/82445fcbea6d9b19f97014cc6cc79f8a

-- Verification of the fix

The fix was tested in the following way:

1) I checked that the problem is no longer observable running the trigger.
2) The Lua code was analyzed to understand the stack semantics, and that
actually enough stack is allocated in all the cases of mp_pack() calls.
3) The mp_pack() function was modified in order to show exactly what items
in the stack were being set, to make sure that there is no silent overflow
even after the fix.

-- Credits

Thank you to the Apple team and to the other persons that helped me
checking the patch and coordinating this communication.

This way we let big endian systems to still load old RDB versions.
However newver versions will be saved and loaded in a way that make RDB
expires cross-endian again. Thanks to @oranagra for the reporting and
the discussion about this problem, leading to this fix.

Currently it does not look it's sensible to generate events for streams
consumer groups modification, being them metadata, however at least for
key-level events, like the creation or removal of a consumer group, I
added a few events here and there. Later we can evaluate if it makes
sense to add more. From the POV instead of WAIT (in Redis transaciton)
and signaling the key as modified, it looks like that the transaction
should not fail when a stream is modified, so no calls are made in
consumer groups related functions to signalModifiedKey().

Again thanks to @oranagra. The object idle time does not fit into an int
sometimes: use the native type that the serialization function will get
as argument, which is uint64_t.

Since the introduction of ZPOP makes this needed. Thanks to @oranagra
for reporting.

I'm not sure how this escaped the attention of Redis users for years,
but finally @oranagra reported this issue... Thanks to Oran.

fix active-defrag-threshold value error

The active-defrag-threshold-lower/active-defrag-threshold-upper min/max  value in redis.conf should be consistent with 'config set' command.