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| author |  Joey Hess <joeyh@joeyh.name> | 2017-08-17 22:11:31 -0400 |
|---|---|---|
| committer | Joey Hess <joeyh@joeyh.name> | 2017-08-17 22:11:31 -0400 |
| commit | c1aec2ae837c24b602c7a0ca3fc7b0fcad565758 (patch) | |
| tree | 6ce58560d65d4a3a6529569cfdde4c80b6b5e5bf /Remote/Helper | |
| parent | d998fce1481a4bc7779e21cb2ff6a0fa42d72c7a (diff) | |
avoid the dashed ssh hostname class of security holes
Security fix: Disallow hostname starting with a dash, which would get
passed to ssh and be treated an option. This could be used by an attacker
who provides a crafted ssh url (for eg a git remote) to execute arbitrary
code via ssh -oProxyCommand.
No CVE has yet been assigned for this hole.
The same class of security hole recently affected git itself,
CVE-2017-1000117.
Method: Identified all places where ssh is run, by git grep '"ssh"'
Converted them all to use a SshHost, if they did not already, for
specifying the hostname.
SshHost was made a data type with a smart constructor, which rejects
hostnames starting with '-'.
Note that git-annex already contains extensive use of Utility.SafeCommand,
which fixes a similar class of problem where a filename starting with a
dash gets passed to a program which treats it as an option.
This commit was sponsored by Jochen Bartl on Patreon.
Diffstat (limited to 'Remote/Helper')
| -rw-r--r-- | Remote/Helper/Ssh.hs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/Remote/Helper/Ssh.hs b/Remote/Helper/Ssh.hs index 6dfadd117..a4d91ab92 100644 --- a/Remote/Helper/Ssh.hs +++ b/Remote/Helper/Ssh.hs @@ -19,13 +19,17 @@ import Remote.Helper.Messages import Messages.Progress import Utility.Metered import Utility.Rsync +import Utility.SshHost import Types.Remote import Types.Transfer import Config toRepo :: ConsumeStdin -> Git.Repo -> RemoteGitConfig -> SshCommand -> Annex (FilePath, [CommandParam]) toRepo cs r gc remotecmd = do - let host = fromMaybe (giveup "bad ssh url") $ Git.Url.hostuser r + let host = maybe + (giveup "bad ssh url") + (either error id . mkSshHost) + (Git.Url.hostuser r) sshCommand cs (host, Git.Url.port r) gc remotecmd {- Generates parameters to run a git-annex-shell command on a remote |