Re: bugreport - SEGFAULT on 'git show-branch --current --reflog=3'

[Gregory David <gregory.david@p1sec.com>]

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Thanks a lot Aevar!

Don't you mean this:

diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index 330b0553b9..2a5c31729d 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -881,7 +881,7 @@ int cmd_show_branch(int ac, const char **av, const
char *prefix)
                                       get_color_reset_code(), ref_name[i]);
                        }

-                       if (!reflog) {
+                       if (!reflog || !rev[i]) {
                                /* header lines never need name */
                                show_one_commit(rev[i], 1);
                        }

Best regards.

On 13/04/2022 13:57, Ævar Arnfjörð Bjarmason wrote:
> 
> On Wed, Apr 13 2022, Gregory David wrote:
> 
>> [[PGP Signed Part:Undecided]]
>> Hi, this bugreport is about a SEGFAULT on git binary when running in
>> this repository (for example, as it also segfault on other private
>> repositories): https://framagit.org/groolot-association/osc_looper.git
>>
>>
>> What did you do before the bug happened? (Steps to reproduce your
>> issue) I just wanted to list branches, and so playing with 'git
>> show-branch --current --reflog=3' in the repository
>> https://framagit.org/groolot-association/osc_looper.git
>>
>> What did you expect to happen? (Expected behavior)
>> Not to segfault
>>
>> What happened instead? (Actual behavior)
>> This command fails with a SEGFAULT on version 2.35.1, 2.20.1 and 2.17.1
>> It also SEGFAULT on branch 'next' of github git repository.
>>
>> What's different between what you expected and what actually happened?
>> Segfault
>>
>> Anything else you want to add:
>> Segfaut happened when '--current' AND '--reflog=3' are provided together
>>
>> Please review the rest of the bug report below.
>> You can delete any lines you don't wish to share.
>>
>>
>> [System Info]
>> git version:
>> git version 2.35.1
>> cpu: x86_64
>> no commit associated with this build
>> sizeof-long: 8
>> sizeof-size_t: 8
>> shell-path: /bin/sh
>> uname: Linux 5.16.0-4-amd64 #1 SMP PREEMPT Debian 5.16.12-1 (2022-03-08)
>> x86_64
>> compiler info: gnuc: 11.2
>> libc info: glibc: 2.33
>> $SHELL (typically, interactive shell): /usr/bin/zsh
> 
> This appears to fix it, but I didn't have time to further validate it,
> come up with a test etc:
> 
> diff --git a/builtin/show-branch.c b/builtin/show-branch.c
> index 330b0553b9d..be3890b2dd6 100644
> --- a/builtin/show-branch.c
> +++ b/builtin/show-branch.c
> @@ -881,10 +881,9 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
>  				       get_color_reset_code(), ref_name[i]);
>  			}
>  
> -			if (!reflog) {
> +			if (!reflog || !reflog_msg[i])
>  				/* header lines never need name */
>  				show_one_commit(rev[i], 1);
> -			}
>  			else
>  				puts(reflog_msg[i]);
>  
> 

-- 
Gregory David
Security Engineer
https://www.p1sec.com

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