Bug 59978
| Summary: | dynamic linker ld.so searches current working directory (cwd) for libraries when : is last item in LD_LIBRARY_PATH | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Joel Griffiths <joelgriffiths> |
| Component: | glibc | Assignee: | Jakub Jelinek <jakub> |
| Status: | CLOSED NOTABUG | QA Contact: | Brian Brock <bbrock> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 7.2 | CC: | fweimer |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2002-02-17 14:33:34 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
This is a bug in Sun script, not anything else. ELF Generic ABI mandates this behaviour. The script should do something like: test -n "$LD_LIBRARY_PATH" && LD_LIBRARY_PATH=":$LD_LIBRARY_PATH" LD_LIBRARY_PATH="$DBROOT/lib:$LD_LIBRARY_PATH" |
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010913 Description of problem: When doing an ls on an NFS mounted directory (with wildcards - I'm lazy), I noticed attempted mounts to i686, libc.so.6, libtermcap.so.2, and mmx in the current working directory. I search ld.so.conf and found nothing unusual. Next, I examined the LD_LIBRARY_PATH variable and found only the adabas link added, when I installed StarOffice, to my ~/.bashrc: LD_LIBRARY_PATH="/home/joelg/adabas/lib:" Here lies the problem.... The : at the end was added by the following .bashrc commands: # by Sun Microsystems setup DBROOT=/home/joelg/adabas DBWORK=/home/joelg/adabas/sql DBCONFIG=/home/joelg/adabas/sql PATH=$DBROOT/bin:$DBROOT/pgm:$PATH LD_LIBRARY_PATH=$DBROOT/lib:$LD_LIBRARY_PATH export DBROOT DBWORK DBCONFIG PATH LD_LIBRARY_PATH I had nothing in my LD_LIBRARY_PATH, so a :[null]" was added to the end of my LD_LIBRARY_PATH. I didn't think that the dynamic linker should interpret the empty field as ${CWD}, but it does. This seems like a nice way for a hacker with a shell account to break other user's access (including root if StarOffice was installed or LD_LIBRARY_PATH was set without checking it first). Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1.Install StarOffice or export LD_LIBRARY_PATH=/nada: 2.cd /tmp 3.strace ls Actual Results: The following dynamic libraries were loaded (or attempted to be loaded) from the current working directory: i686 libc.so.6 libtermcap.so.2 mmx. Expected Results: Libraries loaded from place other than the CWD. Additional info: Here is an example of the affected portion of a strace: # strace ls execve("/bin/ls", ["ls"], [/* 31 vars */]) = 0 uname({sys="Linux", node="taz.aver-computer.com", ...}) = 0 brk(0) = 0x80541a4 open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory) open("/home/joelg/adabas/lib/i686/mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/home/joelg/adabas/lib/i686/mmx", 0xbfffebbc) = -1 ENOENT (No such file or directory) open("/home/joelg/adabas/lib/i686/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/home/joelg/adabas/lib/i686", 0xbfffebbc) = -1 ENOENT (No such file or directory) open("/home/joelg/adabas/lib/mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/home/joelg/adabas/lib/mmx", 0xbfffebbc) = -1 ENOENT (No such file or directory) open("/home/joelg/adabas/lib/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/home/joelg/adabas/lib", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0 open("i686/mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("i686/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 I search ld.so.conf and found nothing unusual. Next, I examined the LD_LIBRARY_PATH variable and found only the adabas link added, when I installed StarOffice, to my ~/.bashrc: LD_LIBRARY_PATH="/home/joelg/adabas/lib:" Here lies the problem.... The : at the end was added by the following .bashrc commands: # by Sun Microsystems setup DBROOT=/home/joelg/adabas DBWORK=/home/joelg/adabas/sql DBCONFIG=/home/joelg/adabas/sql PATH=$DBROOT/bin:$DBROOT/pgm:$PATH LD_LIBRARY_PATH=$DBROOT/lib:$LD_LIBRARY_PATH export DBROOT DBWORK DBCONFIG PATH LD_LIBRARY_PATH I had nothing in my LD_LIBRARY_PATH, so a :[null]" was added to the end of my LD_LIBRARY_PATH. I didn't think that the dynamic linker should interpret the empty field as ${CWD}, but it does. I verified this in the following way: [joelg@taz home]$ export LD_LIBRARY_PATH=/nada: [joelg@taz home]$ env | grep LD_L LD_LIBRARY_PATH=/nada: [joelg@taz home]$ strace ls execve("/bin/ls", ["ls"], [/* 31 vars */]) = 0 uname({sys="Linux", node="taz.aver-computer.com", ...}) = 0 brk(0) = 0x80541a4 open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory) open("/nada/i686/mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/nada/i686/mmx", 0xbfffebcc) = -1 ENOENT (No such file or directory) open("/nada/i686/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/nada/i686", 0xbfffebcc) = -1 ENOENT (No such file or directory) open("/nada/mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/nada/mmx", 0xbfffebcc) = -1 ENOENT (No such file or directory) open("/nada/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/nada", 0xbfffebcc) = -1 ENOENT (No such file or directory) open("i686/mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("i686/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("mmx/libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("libtermcap.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3