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Groups > linux.kernel > #1648617
| From | Ken Goldman <kgold@linux.vnet.ibm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() |
| Date | 2017-05-23 22:50 +0200 |
| Message-ID | <tKoUG-8uq-37@gated-at.bofh.it> (permalink) |
| References | <tHKf0-5Iw-7@gated-at.bofh.it> <tHQ14-157-19@gated-at.bofh.it> <tI1zb-8vR-7@gated-at.bofh.it> <tI9ZL-5oT-11@gated-at.bofh.it> <tIq4x-8sq-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 5/18/2017 5:38 AM, Roberto Sassu wrote: > On 5/17/2017 6:28 PM, Ken Goldman wrote: >> On 5/17/2017 3:25 AM, Roberto Sassu wrote: >>> >>> The format of digestN is: <algo name>:\0<digest value>, the same used >>> for the file digest. >> >> Since the format is changing from the SHA-1 log format anyway ... >> >> How do people feel about the colon and null terminated string format for >> algorithm identifiers? >> >> The TCG standard enumerations are uint16_t, and there is a registry of >> hash algorithms. >> >> As a consuming parser, it feels nice to know it's always 2 bytes and not >> have to worry about a missing colon or a missing nul terminator risking >> a buffer overflow. > > There cannot be buffer overflow, because the length of each digest > field is known. > > Roberto > I was not referring to the digest, but the digest algorithm. I wanted opinions on the colon and null terminated string format for algorithm identifiers. The TCG standard log uses the TCG standard enumerations. They're always exactly 2 bytes. Parsing is trivial. If IMA uses strings, the attacker can send, e.g., sha1: and not null terminate it. A careful parser can go a byte at a time until it reaches a maximum length - if you specify a maximum length. But it is an attack surface. Is there a corresponding advantage?
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[PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-16 15:00 +0200
[PATCH 4/7] ima: declare get_binary_runtime_size() as non-static Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-16 15:00 +0200
[PATCH 1/7] ima: introduce ima_parse_buf() Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-16 15:00 +0200
[PATCH 7/7] ima: fix get_binary_runtime_size() Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-16 15:00 +0200
[PATCH 6/7] ima: add securityfs interface to restore a measurements list Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-16 15:00 +0200
[PATCH 5/7] ima: add securityfs interface to save a measurements list with kexec header Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-16 15:00 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Ken Goldman <kgold@linux.vnet.ibm.com> - 2017-05-16 21:10 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-17 09:30 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Ken Goldman <kgold@linux.vnet.ibm.com> - 2017-05-17 18:30 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-18 11:40 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Ken Goldman <kgold@linux.vnet.ibm.com> - 2017-05-23 22:50 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Roberto Sassu <roberto.sassu@huawei.com> - 2017-05-24 10:30 +0200
Re: [Linux-ima-devel] [PATCH 0/7] IMA: new parser for ima_restore_measurement_list() Ken Goldman <kgold@linux.vnet.ibm.com> - 2017-05-23 23:20 +0200
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