Bug 3497

Summary:

setresuid/setresgid configure check may need _GNU_SOURCE

Product:

Portable OpenSSH

Reporter:

Sam James <sam>

Component:

Build system

Assignee:

Assigned to nobody <unassigned-bugs>

Status:

CLOSED FIXED

Severity:

enhancement

CC:

dtucker

Priority:

Version:

9.1p1

Hardware:

amd64

OS:

Linux

Bug Depends on:

Bug Blocks:

3480

Attachments:

Description	Flags
config.log.xz	none
Add -D_GNU_SOURCE	none
config.log.xz	none
config.log.xz	none
Fix setres*id tests to work with clang-16	none

Description Sam James 2022-11-06 15:39:39 AEDT

OpenSSH's configure check for setresuid omits _GNU_SOURCE which, on Linux systems with glibc+gcc at least, is needed to expose setresuid.

```
error: call to undeclared function 'setresuid'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
```

Reproduced on master of openssh-portable at 6b17e128879ec6cc32ca2c28b5d894b4aa72e32d but originally hit with 9.1_p1.

It's technically harmless, I think, as OpenSSH provides its own implementation if the system's copy is nonexistent or unsuitable, but it's at least noise when trying to find broader Clang 16 issues (see https://lwn.net/Articles/913505/ etc).

Comment 1 Sam James 2022-11-06 15:44:00 AEDT

Created attachment 3620 [details]
config.log.xz

Comment 2 Sam James 2022-11-06 15:49:23 AEDT

Note my config.log has an issue with openpty too but I've filed https://github.com/openssh/openssh-portable/pull/355 for that as it's a simple case.

Comment 3 Sam James 2022-11-06 15:49:57 AEDT

The original bug remains for setresuid and setresgid.

Comment 4 Darren Tucker 2022-11-06 18:51:11 AEDT

Created attachment 3621 [details]
Add -D_GNU_SOURCE

The way we deal with this on other platforms (eg HPUX) is to add the requisite flag to CPPFLAGS in configure like so.  Does this resolve your issue (after running "autoreconf" to regenerate configure)?

Comment 5 Sam James 2022-11-06 19:06:30 AEDT

Created attachment 3622 [details]
config.log.xz

Comment 6 Sam James 2022-11-06 19:07:18 AEDT

Created attachment 3623 [details]
config.log.xz

It doesn't seem to make any difference (I guess because I don't have audit installed and I've not passed any arg for it).

(I've confirmed -D_GNU_SOURCE appears in the generated configure, it's just that the path isn't taken.)

Comment 7 Darren Tucker 2022-11-07 10:30:12 AEDT

Created attachment 3624 [details]
Fix setres*id tests to work with clang-16

There were two problems: I put _GNU_SOURCE in the wrong place, and the tests themselves did not include unistd.h for the prototypes.  This seems to fix both when compiling with a self-built clang/llvm from git.

Comment 8 Darren Tucker 2022-11-07 10:44:05 AEDT

Patch applied and will be in 9.2p1.  Thanks for the report.

Comment 9 Sam James 2022-11-07 15:39:28 AEDT

Confirmed that works great, thank you!

Comment 10 Damien Miller 2023-03-17 13:42:28 AEDT

OpenSSH 9.3 has been released. Close resolved bugs