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Diffstat (limited to '')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1687653 | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1687653 b/results/scraper/launchpad-without-comments/1687653 new file mode 100644 index 00000000..b8f2e25b --- /dev/null +++ b/results/scraper/launchpad-without-comments/1687653 @@ -0,0 +1,65 @@ +QEMU-KVM / detect_zeroes causes KVM to start unlimited number of threads on Guest-Sided High-IO with big Blocksize + +QEMU-KVM in combination with "detect_zeroes=on" makes a Guest able to DoS the Host. This is possible if the Host itself has "detect_zeroes" enabled and the Guest writes a large Chunk of data with a huge blocksize onto the drive. + +E.g.: dd if=/dev/zero of=/tmp/DoS bs=1G count=1 oflag=direct + +All QEMU-Versions after implementation of detect_zeroes are affected. Prior are unaffected. This is absolutely critical, please fix this ASAP! + +##### + +Provided by Dominik Csapak: + +source , bs , count , O_DIRECT, behaviour + +urandom , bs 1M, count 1024, O_DIRECT: OK +file , bs 1M, count 1024, O_DIRECT: OK +/dev/zero , bs 1M, count 1024, O_DIRECT: OK +zero file , bs 1M, count 1024, O_DIRECT: OK +/dev/zero , bs 1G, count 1, O_DIRECT: NOT OK +zero file , bs 1G, count 1, O_DIRECT: NOT OK +zero file , bs 1G, count 1, no O_DIRECT: NOT OK +rand file , bs 1G, count 1, O_DIRECT: OK +rand file , bs 1G, count 1, no O_DIRECT: OK + +discard on: + +urandom , bs 1M, count 1024, O_DIRECT: OK +rand file , bs 1M, count 1024, O_DIRECT: OK +/dev/zero , bs 1M, count 1024, O_DIRECT: OK +zero file , bs 1M, count 1024, O_DIRECT: OK +/dev/zero , bs 1G, count 1, O_DIRECT: NOT OK +zero file , bs 1G, count 1, O_DIRECT: NOT OK +zero file , bs 1G, count 1, no O_DIRECT: NOT OK +rand file , bs 1G, count 1, O_DIRECT: OK +rand file , bs 1G, count 1, no O_DIRECT: OK + +detect_zeros off: + +urandom , bs 1M, count 1024, O_DIRECT: OK +rand file , bs 1M, count 1024, O_DIRECT: OK +/dev/zero , bs 1M, count 1024, O_DIRECT: OK +zero file , bs 1M, count 1024, O_DIRECT: OK +/dev/zero , bs 1G, count 1, O_DIRECT: OK +zero file , bs 1G, count 1, O_DIRECT: OK +zero file , bs 1G, count 1, no O_DIRECT: OK +rand file , bs 1G, count 1, O_DIRECT: OK +rand file , bs 1G, count 1, no O_DIRECT: OK + +##### + +Provided by Florian Strankowski + +bs - count - io-threads + +512K - 2048 - 2 +1M - 1024 - 2 +2M - 512 - 4 +4M - 256 - 6 +8M - 128 - 10 +16M - 64 - 18 +32M - 32 - uncountable + +Please refer to further information here: + +https://bugzilla.proxmox.com/show_bug.cgi?id=1368
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