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2016.Június 2.(Cs) 02:31 időpontban Max R.D. Parmer ezt írta: |
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> On Wed, Jun 1, 2016, at 15:49, Tóth Attila wrote: |
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>> I've just had an unsuccessful attempt to upgrade to systemd-230-r1. It |
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>> segfaults and slows the system down. The symptoms are better compared to |
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>> -229, but still significant. |
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>> |
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>> https://forums.grsecurity.net/viewtopic.php?f=3&t=4485 |
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>> |
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>> Some relevant log entries: |
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>> grsec: denied resource overstep by requesting 8392704 for RLIMIT_STACK |
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>> against limit 8388608 for /usr/lib64/systemd/systemd[systemd:2735] |
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>> uid/euid:0/0 gid/egid:0/0, parent /usr/lib64/systemd/systemd[systemd:1] |
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>> uid/euid:0/0 gid/egid:0/0 |
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>> systemd[2735]: segfault at 39f8d01cf00 ip 00000368d4caa2e4 sp |
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>> 0000039f8d01cf00 error 6 in libc-2.23.so[368d4c62000+19a000] |
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>> grsec: Segmentation fault occurred at 0000039f8d01cf00 in |
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>> /usr/lib64/systemd/systemd[systemd:2735] uid/euid:0/0 gid/egid:0/0, |
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>> parent |
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>> /usr/lib64/systemd/systemd[systemd:1] uid/euid:0/0 gid/egid:0/0 |
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>> grsec: bruteforce prevention initiated for the next 30 minutes or until |
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>> service restarted, stalling each fork 30 seconds. Please investigate |
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>> the |
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>> crash report for /usr/lib64/systemd/systemd[systemd:2735] uid/euid:0/0 |
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>> gid/egid:0/0, parent /usr/lib64/systemd/systemd[systemd:1] uid/euid:0/0 |
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>> gid/egid:0/0 |
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>> |
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>> systemd-coredump[2747]: Process 2735 (systemd) of user 0 dumped core. |
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>> |
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>> Stack trace of thread |
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>> 2735: |
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>> #0 |
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>> 0x00000368d4caa2e4 |
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>> _IO_vfprintf |
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>> (libc.so.6) |
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>> #1 |
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>> 0x00000368d4d5e852 |
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>> __vsnprintf_chk |
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>> (libc.so.6) |
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>> #2 |
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>> 0x00000368d4d5e7a4 |
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>> __snprintf_chk |
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>> (libc.so.6) |
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>> #3 |
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>> 0x00000000df8db344 |
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>> n/a (systemd) |
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>> #4 |
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>> 0x00000000df8db9aa |
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>> n/a (systemd) |
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> |
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> Not necessarily the ideal solution, but have you tried twiddling with |
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> the stack size in limits.conf? |
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|
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I checked an the system-wide defaults apply to systemd, which is: 8M soft |
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limit and _unlimited_ hard limit for stack size. So after exceeding soft |
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limit systemd segfaults and tries to dump core. |
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|
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cat /proc/1/limits |
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Limit Soft Limit Hard Limit Units |
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Max stack size 8388608 unlimited bytes |
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|
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I expect any process to handle a situation of trying to exceed soft limit |
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with unlimited hard limit in another way than segfaulting and attempting |
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to dump core... |
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|
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> If I read this right, grsec limits the size of the stack, which causes |
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> the process to segfault. |
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|
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I think grsec does not enforce any stack limits here, it just reports the |
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issue and makes it more visible. |
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|
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BR: Dw. |
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-- |
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dr Tóth Attila, Radiológus, 06-20-825-8057 |
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Attila Toth MD, Radiologist, +36-20-825-8057 |
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