acl_from_text leaking memory
Jim Wilcoxson
prirun at gmail.com
Sun Nov 15 17:20:27 UTC 2009
I've been working on a new backup program, HashBackup, and believe I
have found a memory leak with ACLs in PCBSD/FreeBSD 7.1 and OSX
(Leopard).
acl_from_text is a function that takes a text string as input, and
returns a pointer to a malloc'd acl. This acl is then freed with
acl_free. I noticed that acl_from_text appears to leak memory. This
is not used during the backup of a filesystem, but is needed to do a
restore.
After looking at the acl_from_text source in /usr/src/lib/libc/posix1e
(from PCBSD7.1), I believe the problem is that the duplicate text
string, mybuf_p, is not freed on normal return of this function. Here
is the end of this function:
}
#if 0
/* XXX Should we only return ACLs valid according to acl_valid? */
/* Verify validity of the ACL we read in. */
if (acl_valid(acl) == -1) {
errno = EINVAL;
goto error_label;
}
#endif
return(acl);
error_label:
acl_free(acl);
free(mybuf_p);
return(NULL);
}
I think there should be a free(mybuf_p) before return(acl).
Here is a PCBSD/FreeBSD test program that causes the memory leak:
#include <stdio.h>
#include <sys/types.h>
#include <sys/acl.h>
main() {
acl_t acl;
char* acltext;
acltext = "user::rw-\n group::r--\n mask::r--\n other::r--\n";
while (1) {
acl = acl_from_text(acltext);
if (acl == NULL)
printf("acl_from_text failed\n");
if (acl_free(acl) != 0)
printf("acl_free failed\n");
}
}
I've subscribed to the lists for a few days in case there are
questions or I can help test something.
Thanks,
Jim
--
HashBackup beta: http://sites.google.com/site/hashbackup
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