dr.-ing. jaseg on Nostr: I've written up a short blog post on tracking down the memcpy SIMD register leakage ...
I've written up a short blog post on tracking down the memcpy SIMD register leakage path I observed earlier this week.
The takeaway is, glibc memcpy on secrets can leak data into kernel memory even long after the original buffers are zeroed. -fzero-call-used-regs and the corresponding attribute plug this hole. The option comes at a performance cost, while the attribute is difficult to target.
https://jaseg.de/blog/simd-register-leakage/#security #arm64 #linux
Published at
2026-08-12 17:11:59 UTCEvent JSON
{
"id": "0fefa215e4f8e91b2480991760cbb32812ae9d9b5bba37bab1c5bad6c640bab3",
"pubkey": "c2756be6b1216a7f8d6d0f9d48359f79d60ff5eaf7d20e67e45ec8cd6b11abb4",
"created_at": 1786554719,
"kind": 1,
"tags": [
[
"t",
"security"
],
[
"t",
"arm64"
],
[
"t",
"linux"
],
[
"proxy",
"https://chaos.social/users/jaseg/statuses/117083650093594154",
"activitypub"
],
[
"client",
"Mostr",
"31990:6be38f8c63df7dbf84db7ec4a6e6fbbd8d19dca3b980efad18585c46f04b26f9:mostr",
"wss://relay.ditto.pub"
]
],
"content": "\n\nI've written up a short blog post on tracking down the memcpy SIMD register leakage path I observed earlier this week.\n\nThe takeaway is, glibc memcpy on secrets can leak data into kernel memory even long after the original buffers are zeroed. -fzero-call-used-regs and the corresponding attribute plug this hole. The option comes at a performance cost, while the attribute is difficult to target.\n\nhttps://jaseg.de/blog/simd-register-leakage/\n\n#security #arm64 #linux",
"sig": "ddc53d9370e207e1408dc1babba7af24c8363b5b8b58cd36fed39694a712ac953cd6d18a3b79c74f5bcf45e8809ad5c30141def59ab50b30a177bb0b3e4d9db9"
}
