Thread (19 messages) 19 messages, 7 authors, 2025-10-08

6.17 crashes in ipv6 code when booted fips=1 [was: [GIT PULL] Crypto Update for 6.17]

From: Jiri Slaby <jirislaby@kernel.org>
Date: 2025-10-02 10:57:15
Also in: linux-crypto, lkml

On 02. 10. 25, 12:13, Jiri Slaby wrote:
On 02. 10. 25, 12:05, Jiri Slaby wrote:
quoted
On 02. 10. 25, 11:30, Herbert Xu wrote:
quoted
On Thu, Oct 02, 2025 at 10:10:41AM +0200, Jiri Slaby wrote:
quoted
On 29. 07. 25, 13:07, Herbert Xu wrote:
quoted
Vegard Nossum (1):
        crypto: testmgr - desupport SHA-1 for FIPS 140
Booting 6.17 with fips=1 crashes with this commit -- see below.

The crash is different being on 6.17 (below) and on the commit --
9d50a25eeb05c45fef46120f4527885a14c84fb2.

6.17 minus that one makes it work again.

Any ideas?
The purpose of the above commit is to remove the SHA1 algorithm
if you boot with fips=1.  As net/ipv6/seg6_hmac.c depends on the
sha1 algorithm, it will obviously fail if SHA1 isn't there.
Ok, but I don't immediately see what is one supposed to do to boot 
6.17 distro (openSUSE) kernel with fips=1 then?
Now I do, in the context you write, I see inet6_init()'s fail path is 
broken. The two backtraces show:
[    2.381371][    T1]  ip6_mr_cleanup+0x43/0x50
[    2.382321][    T1]  inet6_init+0x365/0x3d0

and

[    2.420857][    T1]  proto_unregister+0x93/0x100
[    2.420857][    T1]  inet6_init+0x3a2/0x3d0

I am looking what exactly, but this is rather for netdev@
More functions from the fail path are not ready to unroll and resurrect 
from the failure.

Anyway, cherry-picking this -next commit onto 6.17 works as well (the 
code uses now crypto_lib's sha1, not crypto's):
commit 095928e7d80186c524013a5b5d54889fa2ec1eaa
Author: Eric Biggers [off-list ref]
Date:   Sat Aug 23 21:36:43 2025 -0400

     ipv6: sr: Use HMAC-SHA1 and HMAC-SHA256 library functions


I don't know what to do next -- should it be put into 6.17 stable later 
and we are done?

thanks,
-- 
js
suse labs
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