Re: clearenv(3): implies that it's a security tool
From: Stéphane Aulery <hidden>
Date: 2016-02-19 16:43:57
Possibly related (same subject, not in this thread)
- 2016-02-19 · Re: clearenv(3): implies that it's a security tool · Matt Zimmerman <hidden>
- 2016-02-19 · Re: clearenv(3): implies that it's a security tool · Stéphane Aulery <hidden>
- 2016-02-19 · Re: clearenv(3): implies that it's a security tool · Michael Kerrisk (man-pages) <hidden>
- 2016-02-18 · Re: clearenv(3): implies that it's a security tool · Matt Zimmerman <hidden>
- 2016-02-18 · clearenv(3): implies that it's a security tool · Stéphane Aulery <hidden>
tags 679323 + fixed-upstream stop ----- Will be fixed in man-pages-4.04. See commit c66649c83598652222ff2a464e5b82284e6b1acf by Michael Kerrisk [off-list ref], 2016-02-19 12:04:51 (GMT) https://git.kernel.org/cgit/docs/man-pages/man-pages.git/commit/man3/clearenv.3?id=c66649c83598652222ff2a464e5b82284e6b1acf ----- Matt Zimmerman [off-list ref] a écrit :
On Fri, Feb 19, 2016 at 12:59:05PM +0100, Michael Kerrisk (man-pages) wrote:quoted
On 18 February 2016 at 21:34, Matt Zimmerman [off-list ref] wrote:quoted
Thanks for following up. My recommendation is to say something like: This function DOES NOT securely erase the contents of the environment. Security-conscious applications which need to do this should use .... instead.So, I think this report is a little confused, but mainly because of the poor description in the man page. The security-conscious applications in this context are those that want to precisely control the environment passed to an exec()ed program. clearenv() cannot, indeed must not, try to erase the buffers containing the environment definitions. (See putenv(3) to understand why.) I've adjusted the man page in away that I hope explains things better: The clearenv() function may be useful in security-conscious applications that want to precisely control the environment that is passed to programs executed using exec(3). The application would do this by first clearing the environment and then adding select environment variables. Note that the main effect of clearenv() is to adjust the value of the pointer environ(7); this function does not erase the contents of the buffers containing the environment definitions.Yes, that's much clearer, thank you!
Case classified, thank you for your help Matt and Michael! Regards, -- Stéphane Aulery -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html