The redis-cli command line tool and redis-sentinel service may be vulnerable
to integer overflow when parsing specially crafted large multi-bulk network
replies. This is a result of a vulnerability in the underlying hiredis
library which does not perform an overflow check before calling the calloc()
heap allocation function.
This issue only impacts systems with heap allocators that do not perform their
own overflow checks. Most modern systems do and are therefore not likely to
be affected. Furthermore, by default redis-sentinel uses the jemalloc allocator
which is also not vulnerable.
Redis-cli handles the debugger "eval" command in a special way since
sdssplitargs() would not be ok: we need to send the Redis debugger the
whole Lua script without any parsing. However in order to later free the
argument vector inside redis-cli using just sdsfreesplitres(), we need
to allocate the array of SDS pointers using the same allocator SDS is
using, that may differ to what Redis is using.
So now a newer version of SDS exports sds_malloc() and other allocator
functions to give access, to the program it is linked to, the allocator
used internally by SDS.
This fixes issue #2535, that was actually an hiredis library bug (I
submitted an issue and fix to the redis/hiredis repo as well).
When an asynchronous hiredis connection subscribes to a Pub/Sub channel
and gets an error, and in other related conditions, the function
redisProcessCallbacks() enters a code path where the link is
disconnected, however the function returns before freeing the allocated
reply object. This causes a memory leak. The memory leak was trivial to
trigger in Redis Sentinel, which uses hiredis, every time we tried to
subscribe to an instance that required a password, in case the Sentinel
was configured either with the wrong password or without password at
all. In this case, the -AUTH error caused the leaking code path to be
executed.
It was verified with Valgrind that after this change the leak no longer
happens in Sentinel with a misconfigured authentication password.
This is hiredis f225c276be7fd0646019b51023e3f41566633dfe
This update includes all changes that diverged inside of Redis since
the last update. This version also allows optional source address
binding for connections which we need for some Sentinel deployments.
This version of hiredis merges modifications of the Redis fork with
latest changes in the hiredis repository.
The same version was pushed on the hiredis repository and will probably
merged into the master branch in short time.
