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* Update copyright dates with scripts/update-copyrights.Joseph Myers2016-01-041-1/+1
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* CVE-2014-8121: Do not close NSS files database during iteration [BZ #18007]Florian Weimer2015-04-291-0/+118
Robin Hack discovered Samba would enter an infinite loop processing certain quota-related requests. We eventually tracked this down to a glibc issue. Running a (simplified) test case under strace shows that /etc/passwd is continuously opened and closed: … open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3 lseek(3, 0, SEEK_CUR) = 0 read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 2717 lseek(3, 2717, SEEK_SET) = 2717 close(3) = 0 open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3 lseek(3, 0, SEEK_CUR) = 0 lseek(3, 0, SEEK_SET) = 0 read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 2717 lseek(3, 2717, SEEK_SET) = 2717 close(3) = 0 open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3 lseek(3, 0, SEEK_CUR) = 0 … The lookup function implementation in nss/nss_files/files-XXX.c:DB_LOOKUP has code to prevent that. It is supposed skip closing the input file if it was already open. /* Reset file pointer to beginning or open file. */ \ status = internal_setent (keep_stream); \ \ if (status == NSS_STATUS_SUCCESS) \ { \ /* Tell getent function that we have repositioned the file pointer. */ \ last_use = getby; \ \ while ((status = internal_getent (result, buffer, buflen, errnop \ H_ERRNO_ARG EXTRA_ARGS_VALUE)) \ == NSS_STATUS_SUCCESS) \ { break_if_match } \ \ if (! keep_stream) \ internal_endent (); \ } \ keep_stream is initialized from the stayopen flag in internal_setent. internal_setent is called from the set*ent implementation as: status = internal_setent (stayopen); However, for non-host database, this flag is always 0, per the STAYOPEN magic in nss/getXXent_r.c. Thus, the fix is this: - status = internal_setent (stayopen); + status = internal_setent (1); This is not a behavioral change even for the hosts database (where the application can specify the stayopen flag) because with a call to sethostent(0), the file handle is still not closed in the implementation of gethostent.