[Bug libc/1970] getgrnam_r() and groups with more than 1024 bytes

["burnus at gmx dot de" <sourceware-bugzilla at sourceware dot org>]

------- Additional Comments From burnus at gmx dot de  2005-12-09 12:27 -------
Created an attachment (id=789)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=789&action=view)
Test program, compile with g++ (uses "new")

I thought I attached the program here, but seemingly I didn't -- doing so now.

> > I get the crash only with compat, with file I also get ERANGE.
> So why did you wrote something complete different in the initial comment?
> "(independent of group:files vs. group:compat)".

Well, both is true:

Using	 getgrnam_r(name = "test", grp, buffer, bufsize=1024,result)
it only crashes with "group: compat". (Otherwise I get a ERANGE)

But using a buffer > 1024 it crashes with both group:compat and group:files
(stopping the nscd makes sense, otherwise the results can come from the cache,
I believe)

(gdb) run test
Starting program: /tmp/getent_test2 test
_SC_GETGR_R_SIZE_MAX = 1024

Call getgrnam_r(name = "test", grp, buffer, bufsize=2048,result)

Program received signal SIGSEGV, Segmentation fault.
0x4000b46a in fixup () from /lib/ld-linux.so.2
(gdb) bt
#0  0x4000b46a in fixup () from /lib/ld-linux.so.2
#1  0x4000b2c0 in _dl_runtime_resolve () from /lib/ld-linux.so.2
#2  0x4001cd54 in internal_endent () from /lib/libnss_files.so.2
#3  0x4001d0a2 in _nss_files_getgrnam_r () from /lib/libnss_files.so.2
#4  0x401c7354 in getgrnam_r@@GLIBC_2.1.2 () from /lib/tls/libc.so.6
#5  0x080485b4 in mygetgrnam_r (name=0xbfa390a9 "test", bufsize=2048) at
getent_test2.cpp:15
#6  0x08048628 in main (argc=2, argv=0xbfa376e4) at getent_test2.cpp:23


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http://sourceware.org/bugzilla/show_bug.cgi?id=1970

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