Bug 741 – SIGSEGV on sudo cp pam_unix.so /usr/lib/security/

Bug 741 - SIGSEGV on sudo cp pam_unix.so /usr/lib/security/


Summary:	SIGSEGV on sudo cp pam_unix.so /usr/lib/security/

Status:	RESOLVED INVALID

Product:	Sudo
Classification:	Unclassified
Component:	Sudo
Version:	1.8.15
Hardware:	PC Linux

Importance:	normal normal
Assigned To:	Todd C. Miller

URL:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2016-03-26 08:00 MDT by kitteboss
Modified:	2016-03-26 08:16 MDT (History)
CC List:	1 user (show)

See Also:

Attachments
Output of valgrind and ltrace (37.79 KB, application/octet-stream) 2016-03-26 08:00 MDT, kitteboss	Details
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Description kitteboss 2016-03-26 08:00:28 MDT

Created attachment 473 [details]
Output of valgrind and ltrace

copying pam_unix.so to /usr/lib/security (Arch Linux) to overwrite the existing one will cause a segmentation fault

valgrind and ltrace are attached

Comment 1 Todd C. Miller 2016-03-26 08:16:45 MDT

This is not a bug in sudo.  If you overwrite a shared object that is in use by a program you almost guarantee that the program will crash.

You almost never want to install a shared object with cp since it will overwrite the existing file/inode which may be mapped by running processes.  It's better to use the install program which unlinks the destination first and thus doesn't suffer from this problem.

E.g.

$ sudo install pam_unix.so /usr/lib/security/