* Re: [PATCH] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-04 18:04 ` [PATCH] system.3: Document bug and workaround when the command name starts with a hypen Alejandro Colomar
@ 2021-01-04 18:32 ` Alejandro Colomar (man-pages)
2021-01-04 20:02 ` Alejandro Colomar (man-pages)
2021-01-08 14:20 ` [PATCH v3] " Alejandro Colomar
2021-01-08 14:22 ` [PATCH v4] " Alejandro Colomar
2 siblings, 1 reply; 10+ messages in thread
From: Alejandro Colomar (man-pages) @ 2021-01-04 18:32 UTC (permalink / raw)
To: mtk.manpages; +Cc: libc-alpha, linux-man, Ciprian Dorin Craciun, Florian Weimer
Hi Michael,
See a few corrections below.
Cheers,
Alex
On 1/4/21 7:04 PM, Alejandro Colomar wrote:
> man-pages bug: 211029
> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>
> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
> Cc: Florian Weimer <fweimer@redhat.com>
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
> ---
> man3/system.3 | 34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/man3/system.3 b/man3/system.3
> index aef40417a..0310d9a04 100644
> --- a/man3/system.3
> +++ b/man3/system.3
> @@ -250,6 +250,40 @@ are not executed.
> Such risks are especially grave when using
> .BR system ()
> from a privileged program.
> +.SH BUGS
> +./" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
> +./" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
> +./" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
> +If the command name starts with a hyphen,
> +.BR sh (1)
> +interprets the command name as an option,
> +and the behavior is undefined
> +(See the
> +.B \-c
> +option in
option to
> +.BR sh (1).).
> +To work around this problem,
> +prepend the command with a space as below:
> +.PP
> +.RS 4
> +.EX
> +/* system_hyphen.c */
> +
> +#include <stdlib.h>
> +
> +int
> +main(void)
> +{
> + system(" -echo Hello world!");
\-echo
> + exit(EXIT_SUCCESS);
> +}
> +.PP
> +.RB "$" " sudo ln \-s \-T /usr/bin/echo /usr/bin/\-echo;"
> +.RB "$" " cc \-o system_hyphen system_hyphen.c;"
> +.RB "$" " ./system_hyphen;"
> +Hello world!
> +.EE
> +.RE
> .SH SEE ALSO
> .BR sh (1),
> .BR execve (2),
>
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-04 18:32 ` Alejandro Colomar (man-pages)
@ 2021-01-04 20:02 ` Alejandro Colomar (man-pages)
0 siblings, 0 replies; 10+ messages in thread
From: Alejandro Colomar (man-pages) @ 2021-01-04 20:02 UTC (permalink / raw)
To: mtk.manpages; +Cc: libc-alpha, linux-man, Ciprian Dorin Craciun, Florian Weimer
D'oh
On 1/4/21 7:32 PM, Alejandro Colomar (man-pages) wrote:
> Hi Michael,
>
> See a few corrections below.
>
> Cheers,
>
> Alex
>
> On 1/4/21 7:04 PM, Alejandro Colomar wrote:
>> man-pages bug: 211029
>> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>>
>> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
>> Cc: Florian Weimer <fweimer@redhat.com>
>> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
>> ---
>> man3/system.3 | 34 ++++++++++++++++++++++++++++++++++
>> 1 file changed, 34 insertions(+)
>>
>> diff --git a/man3/system.3 b/man3/system.3
>> index aef40417a..0310d9a04 100644
>> --- a/man3/system.3
>> +++ b/man3/system.3
>> @@ -250,6 +250,40 @@ are not executed.
>> Such risks are especially grave when using
>> .BR system ()
>> from a privileged program.
>> +.SH BUGS
>> +./" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
>> +./" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
>> +./" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
s%/%\\%
>> +If the command name starts with a hyphen,
>> +.BR sh (1)
>> +interprets the command name as an option,
>> +and the behavior is undefined
>> +(See the
>> +.B \-c
>> +option in
>
> option to
>
>> +.BR sh (1).).
>> +To work around this problem,
>> +prepend the command with a space as below:
>> +.PP
>> +.RS 4
>> +.EX
>> +/* system_hyphen.c */
>> +
>> +#include <stdlib.h>
>> +
>> +int
>> +main(void)
>> +{
>> + system(" -echo Hello world!");
>
> \-echo
>
>> + exit(EXIT_SUCCESS);
>> +}
>> +.PP
>> +.RB "$" " sudo ln \-s \-T /usr/bin/echo /usr/bin/\-echo;"
>> +.RB "$" " cc \-o system_hyphen system_hyphen.c;"
>> +.RB "$" " ./system_hyphen;"
>> +Hello world!
>> +.EE
>> +.RE
>> .SH SEE ALSO
>> .BR sh (1),
>> .BR execve (2),
>>
>
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-04 18:04 ` [PATCH] system.3: Document bug and workaround when the command name starts with a hypen Alejandro Colomar
2021-01-04 18:32 ` Alejandro Colomar (man-pages)
@ 2021-01-08 14:20 ` Alejandro Colomar
2021-01-08 14:22 ` [PATCH v4] " Alejandro Colomar
2 siblings, 0 replies; 10+ messages in thread
From: Alejandro Colomar @ 2021-01-08 14:20 UTC (permalink / raw)
To: mtk.manpages
Cc: libc-alpha, Alejandro Colomar, linux-man, Ciprian Dorin Craciun,
Florian Weimer
man-pages bug: 211029
https://bugzilla.kernel.org/show_bug.cgi?id=211029
Complete workaround
(it was too long for the page, but it may be useful here):
......
$ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
$ cc -o system_hyphen -x c - ;
int
main(void)
{
system(" -echo Hello world!");
exit(EXIT_SUCCESS);
}
$ ./system_hyphen;
Hello world!
Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
Hi Michael,
I forgot to remove some escapings in the commit message in v2.
I hope it arrives in time :)
Cheers,
Alex
man3/system.3 | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/man3/system.3 b/man3/system.3
index 753d46f7d..ead35ab30 100644
--- a/man3/system.3
+++ b/man3/system.3
@@ -255,6 +255,26 @@ are not executed.
Such risks are especially grave when using
.BR system ()
from a privileged program.
+.SH BUGS
+.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
+.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
+.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
+If the command name starts with a hyphen,
+.BR sh (1)
+interprets the command name as an option,
+and the behavior is undefined.
+(See the
+.B \-c
+option to
+.BR sh (1).)
+To work around this problem,
+prepend the command with a space as in the following call:
+.PP
+.RS 4
+.EX
+ system(" \-unfortunate\-command\-name");
+.EE
+.RE
.SH SEE ALSO
.BR sh (1),
.BR execve (2),
--
2.29.2
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-04 18:04 ` [PATCH] system.3: Document bug and workaround when the command name starts with a hypen Alejandro Colomar
2021-01-04 18:32 ` Alejandro Colomar (man-pages)
2021-01-08 14:20 ` [PATCH v3] " Alejandro Colomar
@ 2021-01-08 14:22 ` Alejandro Colomar
2021-01-08 14:28 ` Alejandro Colomar (man-pages)
2021-01-18 15:35 ` Michael Kerrisk (man-pages)
2 siblings, 2 replies; 10+ messages in thread
From: Alejandro Colomar @ 2021-01-08 14:22 UTC (permalink / raw)
To: mtk.manpages
Cc: libc-alpha, Alejandro Colomar, linux-man, Ciprian Dorin Craciun,
Florian Weimer
man-pages bug: 211029
https://bugzilla.kernel.org/show_bug.cgi?id=211029
Complete workaround
(it was too long for the page, but it may be useful here):
......
$ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
$ cc -o system_hyphen -x c - ;
#include <stdlib.h>
int
main(void)
{
system(" -echo Hello world!");
exit(EXIT_SUCCESS);
}
$ ./system_hyphen;
Hello world!
Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
D'oh!
man3/system.3 | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/man3/system.3 b/man3/system.3
index 753d46f7d..ead35ab30 100644
--- a/man3/system.3
+++ b/man3/system.3
@@ -255,6 +255,26 @@ are not executed.
Such risks are especially grave when using
.BR system ()
from a privileged program.
+.SH BUGS
+.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
+.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
+.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
+If the command name starts with a hyphen,
+.BR sh (1)
+interprets the command name as an option,
+and the behavior is undefined.
+(See the
+.B \-c
+option to
+.BR sh (1).)
+To work around this problem,
+prepend the command with a space as in the following call:
+.PP
+.RS 4
+.EX
+ system(" \-unfortunate\-command\-name");
+.EE
+.RE
.SH SEE ALSO
.BR sh (1),
.BR execve (2),
--
2.29.2
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-08 14:22 ` [PATCH v4] " Alejandro Colomar
@ 2021-01-08 14:28 ` Alejandro Colomar (man-pages)
2021-01-18 15:28 ` Ping: " Alejandro Colomar (man-pages)
2021-01-18 15:36 ` Michael Kerrisk (man-pages)
2021-01-18 15:35 ` Michael Kerrisk (man-pages)
1 sibling, 2 replies; 10+ messages in thread
From: Alejandro Colomar (man-pages) @ 2021-01-08 14:28 UTC (permalink / raw)
To: mtk.manpages; +Cc: libc-alpha, linux-man, Ciprian Dorin Craciun, Florian Weimer
On 1/8/21 3:22 PM, Alejandro Colomar wrote:
> man-pages bug: 211029
> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>
> Complete workaround
Maybe a bit more readable:
Complete workaround example
> (it was too long for the page, but it may be useful here):
>
> ......
>
> $ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
> $ cc -o system_hyphen -x c - ;
> #include <stdlib.h>
>
> int
> main(void)
> {
> system(" -echo Hello world!");
> exit(EXIT_SUCCESS);
> }
>
> $ ./system_hyphen;
> Hello world!
>
> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
> Cc: Florian Weimer <fweimer@redhat.com>
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
> ---
>
> D'oh!
>
> man3/system.3 | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/man3/system.3 b/man3/system.3
> index 753d46f7d..ead35ab30 100644
> --- a/man3/system.3
> +++ b/man3/system.3
> @@ -255,6 +255,26 @@ are not executed.
> Such risks are especially grave when using
> .BR system ()
> from a privileged program.
> +.SH BUGS
> +.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
> +.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
> +.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
> +If the command name starts with a hyphen,
> +.BR sh (1)
> +interprets the command name as an option,
> +and the behavior is undefined.
> +(See the
> +.B \-c
> +option to
> +.BR sh (1).)
> +To work around this problem,
> +prepend the command with a space as in the following call:
> +.PP
> +.RS 4
> +.EX
> + system(" \-unfortunate\-command\-name");
> +.EE
> +.RE
> .SH SEE ALSO
> .BR sh (1),
> .BR execve (2),
>
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
^ permalink raw reply [flat|nested] 10+ messages in thread* Ping: [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-08 14:28 ` Alejandro Colomar (man-pages)
@ 2021-01-18 15:28 ` Alejandro Colomar (man-pages)
2021-01-18 15:37 ` Michael Kerrisk (man-pages)
2021-01-18 15:36 ` Michael Kerrisk (man-pages)
1 sibling, 1 reply; 10+ messages in thread
From: Alejandro Colomar (man-pages) @ 2021-01-18 15:28 UTC (permalink / raw)
To: mtk.manpages; +Cc: libc-alpha, linux-man, Ciprian Dorin Craciun, Florian Weimer
Hi Michael,
Ping!
And now I noticed a typo in the subject:
s/hypen/hyphen/
Thanks,
Alex
On 1/8/21 3:28 PM, Alejandro Colomar (man-pages) wrote:
>
>
> On 1/8/21 3:22 PM, Alejandro Colomar wrote:
>> man-pages bug: 211029
>> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>>
>> Complete workaround
>
> Maybe a bit more readable:
> Complete workaround example
>
>
>> (it was too long for the page, but it may be useful here):
>>
>> ......
>>
>> $ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
>> $ cc -o system_hyphen -x c - ;
>> #include <stdlib.h>
>>
>> int
>> main(void)
>> {
>> system(" -echo Hello world!");
>> exit(EXIT_SUCCESS);
>> }
>>
>> $ ./system_hyphen;
>> Hello world!
>>
>> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
>> Cc: Florian Weimer <fweimer@redhat.com>
>> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
>> ---
>>
>> D'oh!
>>
>> man3/system.3 | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/man3/system.3 b/man3/system.3
>> index 753d46f7d..ead35ab30 100644
>> --- a/man3/system.3
>> +++ b/man3/system.3
>> @@ -255,6 +255,26 @@ are not executed.
>> Such risks are especially grave when using
>> .BR system ()
>> from a privileged program.
>> +.SH BUGS
>> +.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
>> +.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
>> +.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
>> +If the command name starts with a hyphen,
>> +.BR sh (1)
>> +interprets the command name as an option,
>> +and the behavior is undefined.
>> +(See the
>> +.B \-c
>> +option to
>> +.BR sh (1).)
>> +To work around this problem,
>> +prepend the command with a space as in the following call:
>> +.PP
>> +.RS 4
>> +.EX
>> + system(" \-unfortunate\-command\-name");
>> +.EE
>> +.RE
>> .SH SEE ALSO
>> .BR sh (1),
>> .BR execve (2),
>>
>
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: Ping: [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-18 15:28 ` Ping: " Alejandro Colomar (man-pages)
@ 2021-01-18 15:37 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 10+ messages in thread
From: Michael Kerrisk (man-pages) @ 2021-01-18 15:37 UTC (permalink / raw)
To: Alejandro Colomar (man-pages)
Cc: mtk.manpages, libc-alpha, linux-man, Ciprian Dorin Craciun,
Florian Weimer
On 1/18/21 4:28 PM, Alejandro Colomar (man-pages) wrote:
> Hi Michael,
>
> Ping!
>
> And now I noticed a typo in the subject:
> s/hypen/hyphen/
D'oh! I missed that.
In cases like these, where there's already two amendments to the patch,
perhaps better is a new complete patch, rather than a ping :-).
Thanks,
Michael
> On 1/8/21 3:28 PM, Alejandro Colomar (man-pages) wrote:
>>
>>
>> On 1/8/21 3:22 PM, Alejandro Colomar wrote:
>>> man-pages bug: 211029
>>> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>>>
>>> Complete workaround
>>
>> Maybe a bit more readable:
>> Complete workaround example
>>
>>
>>> (it was too long for the page, but it may be useful here):
>>>
>>> ......
>>>
>>> $ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
>>> $ cc -o system_hyphen -x c - ;
>>> #include <stdlib.h>
>>>
>>> int
>>> main(void)
>>> {
>>> system(" -echo Hello world!");
>>> exit(EXIT_SUCCESS);
>>> }
>>>
>>> $ ./system_hyphen;
>>> Hello world!
>>>
>>> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
>>> Cc: Florian Weimer <fweimer@redhat.com>
>>> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
>>> ---
>>>
>>> D'oh!
>>>
>>> man3/system.3 | 20 ++++++++++++++++++++
>>> 1 file changed, 20 insertions(+)
>>>
>>> diff --git a/man3/system.3 b/man3/system.3
>>> index 753d46f7d..ead35ab30 100644
>>> --- a/man3/system.3
>>> +++ b/man3/system.3
>>> @@ -255,6 +255,26 @@ are not executed.
>>> Such risks are especially grave when using
>>> .BR system ()
>>> from a privileged program.
>>> +.SH BUGS
>>> +.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
>>> +.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
>>> +.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
>>> +If the command name starts with a hyphen,
>>> +.BR sh (1)
>>> +interprets the command name as an option,
>>> +and the behavior is undefined.
>>> +(See the
>>> +.B \-c
>>> +option to
>>> +.BR sh (1).)
>>> +To work around this problem,
>>> +prepend the command with a space as in the following call:
>>> +.PP
>>> +.RS 4
>>> +.EX
>>> + system(" \-unfortunate\-command\-name");
>>> +.EE
>>> +.RE
>>> .SH SEE ALSO
>>> .BR sh (1),
>>> .BR execve (2),
>>>
>>
>
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-08 14:28 ` Alejandro Colomar (man-pages)
2021-01-18 15:28 ` Ping: " Alejandro Colomar (man-pages)
@ 2021-01-18 15:36 ` Michael Kerrisk (man-pages)
1 sibling, 0 replies; 10+ messages in thread
From: Michael Kerrisk (man-pages) @ 2021-01-18 15:36 UTC (permalink / raw)
To: Alejandro Colomar (man-pages)
Cc: mtk.manpages, libc-alpha, linux-man, Ciprian Dorin Craciun,
Florian Weimer
On 1/8/21 3:28 PM, Alejandro Colomar (man-pages) wrote:
>
>
> On 1/8/21 3:22 PM, Alejandro Colomar wrote:
>> man-pages bug: 211029
>> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>>
>> Complete workaround
>
> Maybe a bit more readable:
> Complete workaround example
Changed.
Thanks,
Michael
>
>
>> (it was too long for the page, but it may be useful here):
>>
>> ......
>>
>> $ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
>> $ cc -o system_hyphen -x c - ;
>> #include <stdlib.h>
>>
>> int
>> main(void)
>> {
>> system(" -echo Hello world!");
>> exit(EXIT_SUCCESS);
>> }
>>
>> $ ./system_hyphen;
>> Hello world!
>>
>> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
>> Cc: Florian Weimer <fweimer@redhat.com>
>> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
>> ---
>>
>> D'oh!
>>
>> man3/system.3 | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/man3/system.3 b/man3/system.3
>> index 753d46f7d..ead35ab30 100644
>> --- a/man3/system.3
>> +++ b/man3/system.3
>> @@ -255,6 +255,26 @@ are not executed.
>> Such risks are especially grave when using
>> .BR system ()
>> from a privileged program.
>> +.SH BUGS
>> +.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
>> +.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
>> +.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
>> +If the command name starts with a hyphen,
>> +.BR sh (1)
>> +interprets the command name as an option,
>> +and the behavior is undefined.
>> +(See the
>> +.B \-c
>> +option to
>> +.BR sh (1).)
>> +To work around this problem,
>> +prepend the command with a space as in the following call:
>> +.PP
>> +.RS 4
>> +.EX
>> + system(" \-unfortunate\-command\-name");
>> +.EE
>> +.RE
>> .SH SEE ALSO
>> .BR sh (1),
>> .BR execve (2),
>>
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen
2021-01-08 14:22 ` [PATCH v4] " Alejandro Colomar
2021-01-08 14:28 ` Alejandro Colomar (man-pages)
@ 2021-01-18 15:35 ` Michael Kerrisk (man-pages)
1 sibling, 0 replies; 10+ messages in thread
From: Michael Kerrisk (man-pages) @ 2021-01-18 15:35 UTC (permalink / raw)
To: Alejandro Colomar
Cc: mtk.manpages, libc-alpha, linux-man, Ciprian Dorin Craciun,
Florian Weimer
Hi Alex,
On 1/8/21 3:22 PM, Alejandro Colomar wrote:
> man-pages bug: 211029
> https://bugzilla.kernel.org/show_bug.cgi?id=211029
>
> Complete workaround
> (it was too long for the page, but it may be useful here):
>
> ......
>
> $ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
> $ cc -o system_hyphen -x c - ;
> #include <stdlib.h>
>
> int
> main(void)
> {
> system(" -echo Hello world!");
> exit(EXIT_SUCCESS);
> }
>
> $ ./system_hyphen;
> Hello world!
>
> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
> Cc: Florian Weimer <fweimer@redhat.com>
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Thanks for the ping. Patch applied, but see man-pages(7)
and my small fix-up in the next commit.
Cheers,
Michael
> ---
>
> D'oh!
>
> man3/system.3 | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/man3/system.3 b/man3/system.3
> index 753d46f7d..ead35ab30 100644
> --- a/man3/system.3
> +++ b/man3/system.3
> @@ -255,6 +255,26 @@ are not executed.
> Such risks are especially grave when using
> .BR system ()
> from a privileged program.
> +.SH BUGS
> +.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
> +.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
> +.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
> +If the command name starts with a hyphen,
> +.BR sh (1)
> +interprets the command name as an option,
> +and the behavior is undefined.
> +(See the
> +.B \-c
> +option to
> +.BR sh (1).)
> +To work around this problem,
> +prepend the command with a space as in the following call:
> +.PP
> +.RS 4
> +.EX
> + system(" \-unfortunate\-command\-name");
> +.EE
> +.RE
> .SH SEE ALSO
> .BR sh (1),
> .BR execve (2),
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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