From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: <093e06b77d7e44af8b9597f1a3701fa7@citrus.nl> References: <093e06b77d7e44af8b9597f1a3701fa7@citrus.nl> Date: Wed, 31 Jan 2018 09:39:39 -0800 Message-ID: Subject: Re: modinfo shows md4 signature instead of sha256 From: Lucas De Marchi To: Ferry van Steen Cc: "jcm@jonmasters.org" , David Howells , linux-modules Content-Type: text/plain; charset="UTF-8" List-ID: Hi Ferry, CC'ing mailing list and Yauheni who worked on fixing modinfo output in the last release. On Wed, Jan 31, 2018 at 1:23 AM, Ferry van Steen wrote: > Hi, > > > sorry, not sure where to file this. There seems to be a bug in either the > kernel signing modules with a wrong signature algorithm, or modinfo is > reporting it incorrectly. I presume it's the latter. > > > More details are here: https://bugzilla.redhat.com/show_bug.cgi?id=3D1490= 975 Not showing the output on older versions is a known issue: support for PKCS#7 sig type was only added to kmod in v23. Now for the incorrect info, the problem appears to be in the kernel implementation: it appends a PKCS#7, but doens't fill out the struct module_signature correctly. So in F27 I get this from, e.g. soundcore.ko: $ xxd -c 8 -g 1 mod.ko | tail -n6 00004d80: b9 d5 04 00 00 02 00 00 ........ <<<<<< 00004d88: 00 00 00 00 00 02 d3 7e .......~ 00004d90: 4d 6f 64 75 6c 65 20 73 Module s 00004d98: 69 67 6e 61 74 75 72 65 ignature 00004da0: 20 61 70 70 65 6e 64 65 appende 00004da8: 64 7e 0a d~. See line marked above. It should match a struct module_signature. So: id_type =3D=3D 0x2 // PKCS7 hash =3D=3D 0 // md4 algo =3D=3D 0 // dsa Looking at scripts/sign-file.c, indeed id_type is the only field that is filled out. CC'ing David Howells as well. Any input here? Lucas De Marchi > > > Thanks in advance and kind regards, > > > Ferry van Steen > Linux Developer > Ferry.van.Steen@Citrus.nl > > Citrus Software > =E2=97=8F Almystraat 10A > =E2=97=8F 5061 PA Oisterwijk > =E2=97=8F +31 (0)13 - 529 91 55 > =E2=97=8F www.citrus.nl > ______________________________________________________ > > This message may contain confidential or privileged information. If you a= re > not the addressee, please notify the sender and delete it from your files= . > Please consider the environmental impact before printing this e-mail. > --=20 Lucas De Marchi