6.6-stable review patch. If anyone has any objections, please let me know.
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From: Thorsten Leemhuis linux@leemhuis.info
commit f3b93547b91ad849b58eb5ab2dd070950ad7beb3 upstream.
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 linux@leemhuis.info Reviewed-by: Sami Tolvanen samitolvanen@google.com Tested-by: kdevops kdevops@lists.linux.dev [0] Link: https://github.com/linux-kdevops/linux-modules-kpd/actions/runs/11420092929/... [0] Link: https://lore.kernel.org/r/52ee32c0c92afc4d3263cea1f8a1cdc809728aff.172908828... Signed-off-by: Petr Pavlu petr.pavlu@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/module/Kconfig | 1 + 1 file changed, 1 insertion(+)
--- a/kernel/module/Kconfig +++ b/kernel/module/Kconfig @@ -229,6 +229,7 @@ comment "Do not forget to sign required choice prompt "Which hash algorithm should modules be signed with?" 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