[BUG][SIGSEGV] Segmentation fault when user doesn't exist

[nil0x42]

Issue:

____    __    ____ .______          ___       __  .___________. __    __                                                                                                     
\   \  /  \  /   / |   _  \        /   \     |  | |           ||  |  |  |                                                                                                    
 \   \/    \/   /  |  |_)  |      /  ^  \    |  | `---|  |----`|  |__|  |                                                                                                    
  \            /   |      /      /  /_\  \   |  |     |  |     |   __   |                                                                                                    
   \    /\    /    |  |\  \----./  _____  \  |  |     |  |     |  |  |  |                                                                                                    
    \__/  \__/     | _| `._____/__/     \__\ |__|     |__|     |__|  |__|                                                                                                    
                                                                                                                                                                             
                                                                                                                                                                             
                                                                                                                                                                             
wraith v0.0.6 started at 2021-03-08T16:01:08Z                                                                                                                                
Loaded 0 signatures.                                                                                                                                                         
Web interface available at http://127.0.0.1:9393                                                                                                                             Gathering users...
Unable to collect user <nil>: GET https://api.github.com/users/USER1234567777: 404 Not Found []
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xcf3ac3]

goroutine 1 [running]:
wraith/core.(*Session).addUser(0xc00017c580, 0x0)
        /root/tools/git/wraith/core/github.go:66 +0xe3
wraith/core.GatherUsers(0xc00017c580)
        /root/tools/git/wraith/core/github.go:100 +0x1d9
wraith/cmd.glob..func1(0x1654840, 0xc000128480, 0x0, 0x8)
        /root/tools/git/wraith/cmd/scanGithub.go:52 +0x8e6
github.com/spf13/cobra.(*Command).execute(0x1654840, 0xc000128400, 0x8, 0x8, 0x1654840, 0xc000128400)
        /root/tools/go/pkg/mod/github.com/spf13/[email protected]/command.go:854 +0x2c2
github.com/spf13/cobra.(*Command).ExecuteC(0x16545a0, 0x44736a, 0x15b16c0, 0xc000000180)
        /root/tools/go/pkg/mod/github.com/spf13/[email protected]/command.go:958 +0x375
github.com/spf13/cobra.(*Command).Execute(...)
        /root/tools/go/pkg/mod/github.com/spf13/[email protected]/command.go:895
wraith/cmd.Execute()
        /root/tools/git/wraith/cmd/root.go:22 +0x31
main.main()
        /root/tools/git/wraith/main.go:29 +0x25

Steps to reproduce:

I go this problem by running this command:

wraith scanGithub --num-threads 4 --github-api-token $GITHUB_ACCESS_TOKEN --github-users user1,user2,user3,...

Note: the list of users was large (~100), and the bug was due to the fact that one of the users in the list did not exist anymore.

[mattyjones]

I will look into this, looking at the above is, it looks like the user was not found, not an issue with wraith. I can look to add some defensive coding around this. There is already a branch looking at adding significant defensive code for exceptions and missing configs. Always happy to take pull requests off the develop branch.

@nil0x42

[shreyas-sriram]

The execution needs to continue onto next iteration if user is not found. Otherwise, execution goes to sess.addUser(u) where the segmentation fault is thrown.

wraith/core/github.go

Lines 95 to 102 in 5efcf84

	if err != nil {
	sess.Out.Error("Unable to collect user %s: %s\n", u, err)
	}
	// Add the user to the session and increment the user count
	sess.addUser(u)
	sess.Stats.IncrementUsers()
	sess.Out.Debug("Added user %s\n", *u.Login)