From f3b93547b91ad849b58eb5ab2dd070950ad7beb3 Mon Sep 17 00:00:00 2001 From: Thorsten Leemhuis Date: Wed, 16 Oct 2024 16:18:41 +0200 Subject: module: sign with sha512 instead of sha1 by default Switch away from using sha1 for module signing by default and use the more modern sha512 instead, which is what among others Arch, Fedora, RHEL, and Ubuntu are currently using for their kernels. Sha1 has not been considered secure against well-funded opponents since 2005[1]; since 2011 the NIST and other organizations furthermore recommended its replacement[2]. This is why OpenSSL on RHEL9, Fedora Linux 41+[3], and likely some other current and future distributions reject the creation of sha1 signatures, which leads to a build error of allmodconfig configurations: 80A20474797F0000:error:03000098:digital envelope routines:do_sigver_init:invalid digest:crypto/evp/m_sigver.c:342: make[4]: *** [.../certs/Makefile:53: certs/signing_key.pem] Error 1 make[4]: *** Deleting file 'certs/signing_key.pem' make[4]: *** Waiting for unfinished jobs.... make[3]: *** [.../scripts/Makefile.build:478: certs] Error 2 make[2]: *** [.../Makefile:1936: .] Error 2 make[1]: *** [.../Makefile:224: __sub-make] Error 2 make[1]: Leaving directory '...' make: *** [Makefile:224: __sub-make] Error 2 This change makes allmodconfig work again and sets a default that is more appropriate for current and future users, too. Link: https://www.schneier.com/blog/archives/2005/02/cryptanalysis_o.html [1] Link: https://csrc.nist.gov/projects/hash-functions [2] Link: https://fedoraproject.org/wiki/Changes/OpenSSLDistrustsha1SigVer [3] Signed-off-by: Thorsten Leemhuis Reviewed-by: Sami Tolvanen Tested-by: kdevops [0] Link: https://github.com/linux-kdevops/linux-modules-kpd/actions/runs/11420092929/job/31775404330 [0] Link: https://lore.kernel.org/r/52ee32c0c92afc4d3263cea1f8a1cdc809728aff.1729088288.git.linux@leemhuis.info Signed-off-by: Petr Pavlu --- kernel/module/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig index 7b329057997a..74fe976e3b01 100644 --- a/kernel/module/Kconfig +++ b/kernel/module/Kconfig @@ -231,6 +231,7 @@ comment "Do not forget to sign required modules with scripts/sign-file" choice prompt "Hash algorithm to sign modules" depends on MODULE_SIG || IMA_APPRAISE_MODSIG + default MODULE_SIG_SHA512 help This determines which sort of hashing algorithm will be used during signature generation. This algorithm _must_ be built into the kernel -- cgit v1.2.3-59-g8ed1b