- 10 Apr, 2017 3 commits
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antirez authored
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Salvatore Sanfilippo authored
fixed free of blocked client before refering to it
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antirez authored
If a thread unblocks a client blocked in a module command, by using the RedisMdoule_UnblockClient() API, the event loop may not be awaken until the next timeout of the multiplexing API or the next unrelated I/O operation on other clients. We actually want the client to be served ASAP, so a mechanism is needed in order for the unblocking API to inform Redis that there is a client to serve ASAP. This commit fixes the issue using the old trick of the pipe: when a client needs to be unblocked, a byte is written in a pipe. When we run the list of clients blocked in modules, we consume all the bytes written in the pipe. Writes and reads are performed inside the context of the mutex, so no race is possible in which we consume the bytes that are actually related to an awake request for a client that should still be put into the list of clients to unblock. It was verified that after the fix the server handles the blocked clients with the expected short delay. Thanks to @dvirsky for understanding there was such a problem and reporting it.
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- 08 Apr, 2017 1 commit
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antirez authored
Important bugs fixed.
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- 07 Apr, 2017 1 commit
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antirez authored
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- 27 Mar, 2017 1 commit
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antirez authored
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- 15 Mar, 2017 2 commits
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Salvatore Sanfilippo authored
add LFU policies to the test suite, just for coverage
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Oran Agra authored
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- 09 Mar, 2017 1 commit
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antirez authored
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- 01 Mar, 2017 1 commit
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Dvir Volk authored
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- 23 Feb, 2017 4 commits
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Salvatore Sanfilippo authored
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Salvatore Sanfilippo authored
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Salvatore Sanfilippo authored
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- 22 Feb, 2017 3 commits
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antirez authored
Testing with Solaris C compiler (SunOS 5.11 11.2 sun4v sparc sun4v) there were issues compiling due to atomicvar.h and running the tests also failed because of "tail" usage not conform with Solaris tail implementation. This commit fixes both the issues.
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antirez authored
Slow systems like the original Raspberry PI need more time than 5 seconds to start the script and detect writes. After fixing the Raspberry PI can pass the unit without issues.
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antirez authored
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- 21 Feb, 2017 4 commits
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antirez authored
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antirez authored
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antirez authored
For performance reasons we use a reduced rounds variant of SipHash. This should still provide enough protection and the effects in the hash table distribution are non existing. If some real world attack on SipHash 1-2 will be found we can trivially switch to something more secure. Anyway it is a big step forward from Murmurhash, for which it is trivial to generate *seed independent* colliding keys... The speed penatly introduced by SipHash 2-4, around 4%, was a too big price to pay compared to the effectiveness of the HashDoS attack against SipHash 1-2, and considering so far in the Redis history, no such an incident ever happened even while using trivially to collide hash functions.
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antirez authored
1. Refactor memory overhead computation into a function. 2. Every 10 keys evicted, check if memory usage already reached the target value directly, since we otherwise don't count all the memory reclaimed by the background thread right now.
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- 20 Feb, 2017 5 commits
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antirez authored
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antirez authored
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antirez authored
This change attempts to switch to an hash function which mitigates the effects of the HashDoS attack (denial of service attack trying to force data structures to worst case behavior) while at the same time providing Redis with an hash function that does not expect the input data to be word aligned, a condition no longer true now that sds.c strings have a varialbe length header. Note that it is possible sometimes that even using an hash function for which collisions cannot be generated without knowing the seed, special implementation details or the exposure of the seed in an indirect way (for example the ability to add elements to a Set and check the return in which Redis returns them with SMEMBERS) may make the attacker's life simpler in the process of trying to guess the correct seed, however the next step would be to switch to a log(N) data structure when too many items in a single bucket are detected: this seems like an overkill in the case of Redis. SPEED REGRESION TESTS: In order to verify that switching from MurmurHash to SipHash had no impact on speed, a set of benchmarks involving fast insertion of 5 million of keys were performed. The result shows Redis with SipHash in high pipelining conditions to be about 4% slower compared to using the previous hash function. However this could partially be related to the fact that the current implementation does not attempt to hash whole words at a time but reads single bytes, in order to have an output which is endian-netural and at the same time working on systems where unaligned memory accesses are a problem. Further X86 specific optimizations should be tested, the function may easily get at the same level of MurMurHash2 if a few optimizations are performed.
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John.Koepi authored
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antirez authored
Close #3804.
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- 19 Feb, 2017 4 commits
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Salvatore Sanfilippo authored
GCC will produce certain unaligned multi load-store instructions that will be trapped by the Linux kernel since ARM v6 cannot handle them with unaligned addresses. Better to use the slower but safer implementation instead of generating the exception which should be anyway very slow.
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Salvatore Sanfilippo authored
I'm not sure how much test Jemalloc gets on ARM, moreover compiling Redis with Jemalloc support in not very powerful devices, like most ARMs people will build Redis on, is extremely slow. It is possible to enable Jemalloc build anyway if needed by using "make MALLOC=jemalloc".
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Salvatore Sanfilippo authored
However note that in architectures supporting 64 bit unaligned accesses memcpy(...,...,8) is likely translated to a simple word memory movement anyway.
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Salvatore Sanfilippo authored
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- 09 Feb, 2017 1 commit
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antirez authored
After investigating issue #3796, it was discovered that MIGRATE could call migrateCloseSocket() after the original MIGRATE c->argv was already rewritten as a DEL operation. As a result the host/port passed to migrateCloseSocket() could be anything, often a NULL pointer that gets deferenced crashing the server. Now the socket is closed at an earlier time when there is a socket error in a later stage where no retry will be performed, before we rewrite the argument vector. Moreover a check was added so that later, in the socket_err label, there is no further attempt at closing the socket if the argument was rewritten. This fix should resolve the bug reported in #3796.
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- 01 Feb, 2017 2 commits
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antirez authored
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antirez authored
Ziplists had a bug that was discovered while investigating a different issue, resulting in a corrupted ziplist representation, and a likely segmentation foult and/or data corruption of the last element of the ziplist, once the ziplist is accessed again. The bug happens when a specific set of insertions / deletions is performed so that an entry is encoded to have a "prevlen" field (the length of the previous entry) of 5 bytes but with a count that could be encoded in a "prevlen" field of a since byte. This could happen when the "cascading update" process called by ziplistInsert()/ziplistDelete() in certain contitious forces the prevlen to be bigger than necessary in order to avoid too much data moving around. Once such an entry is generated, inserting a very small entry immediately before it will result in a resizing of the ziplist for a count smaller than the current ziplist length (which is a violation, inserting code expects the ziplist to get bigger actually). So an FF byte is inserted in a misplaced position. Moreover a realloc() is performed with a count smaller than the ziplist current length so the final bytes could be trashed as well. SECURITY IMPLICATIONS: Currently it looks like an attacker can only crash a Redis server by providing specifically choosen commands. However a FF byte is written and there are other memory operations that depend on a wrong count, so even if it is not immediately apparent how to mount an attack in order to execute code remotely, it is not impossible at all that this could be done. Attacks always get better... and we did not spent enough time in order to think how to exploit this issue, but security researchers or malicious attackers could.
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- 30 Jan, 2017 2 commits
- 27 Jan, 2017 2 commits
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Salvatore Sanfilippo authored
Don't divide by zero
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Jan-Erik Rediger authored
Previously Redis crashed on `MEMORY DOCTOR` when it has no slaves attached. Fixes #3783
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- 26 Jan, 2017 2 commits
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Salvatore Sanfilippo authored
Change switch statment to if statment
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miter authored
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- 25 Jan, 2017 1 commit
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Salvatore Sanfilippo authored
Verify pairs are provided after ZADD's subcommands
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