POSIX allows sysconf(_SC_GETPW_R_SIZE_MAX) to return -1 if there is no fixed limit, and requires ERANGE errors to track real size. http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwuid_r.html Also, on error for get*_r functions, errno is undefined, and the real error was the return value. * src/util/util.c (virGetUserEnt, virGetUserID, virGetGroupID) (virSetUIDGID): Cope with sysconf failure or too small buffer. Reported by Matthias Bolte. --- This pretty much copies the example implementation straight from POSIX for getting a hint for initial size, then iterating until ERANGE no longer occurs. src/util/util.c | 74 +++++++++++++++++++++++++++++++++++++----------------- 1 files changed, 51 insertions(+), 23 deletions(-) diff --git a/src/util/util.c b/src/util/util.c index f169e54..240f776 100644 --- a/src/util/util.c +++ b/src/util/util.c @@ -603,7 +603,7 @@ virExecWithHook(const char *const*argv, goto fork_error; } - openmax = sysconf (_SC_OPEN_MAX); + openmax = sysconf(_SC_OPEN_MAX); for (i = 3; i < openmax; i++) if (i != infd && i != null && @@ -2743,11 +2743,11 @@ static char *virGetUserEnt(uid_t uid, struct passwd *pw = NULL; long val = sysconf(_SC_GETPW_R_SIZE_MAX); size_t strbuflen = val; + int rc; - if (val < 0) { - virReportSystemError(errno, "%s", _("sysconf failed")); - return NULL; - } + /* sysconf is a hint; if it fails, fall back to a reasonable size */ + if (val < 0) + strbuflen = 1024; if (VIR_ALLOC_N(strbuf, strbuflen) < 0) { virReportOOMError(); @@ -2761,8 +2761,15 @@ static char *virGetUserEnt(uid_t uid, * 0 or ENOENT or ESRCH or EBADF or EPERM or ... * The given name or uid was not found. */ - if (getpwuid_r(uid, &pwbuf, strbuf, strbuflen, &pw) != 0 || pw == NULL) { - virReportSystemError(errno, + while ((rc = getpwuid_r(uid, &pwbuf, strbuf, strbuflen, &pw)) == ERANGE) { + if (VIR_RESIZE_N(strbuf, strbuflen, strbuflen, strbuflen) < 0) { + virReportOOMError(); + VIR_FREE(strbuf); + return NULL; + } + } + if (rc != 0 || pw == NULL) { + virReportSystemError(rc, _("Failed to find user record for uid '%u'"), (unsigned int) uid); VIR_FREE(strbuf); @@ -2800,11 +2807,11 @@ int virGetUserID(const char *name, struct passwd *pw = NULL; long val = sysconf(_SC_GETPW_R_SIZE_MAX); size_t strbuflen = val; + int rc; - if (val < 0) { - virReportSystemError(errno, "%s", _("sysconf failed")); - return -1; - } + /* sysconf is a hint; if it fails, fall back to a reasonable size */ + if (val < 0) + strbuflen = 1024; if (VIR_ALLOC_N(strbuf, strbuflen) < 0) { virReportOOMError(); @@ -2818,8 +2825,15 @@ int virGetUserID(const char *name, * 0 or ENOENT or ESRCH or EBADF or EPERM or ... * The given name or uid was not found. */ - if (getpwnam_r(name, &pwbuf, strbuf, strbuflen, &pw) != 0 || pw == NULL) { - virReportSystemError(errno, + while ((rc = getpwnam_r(name, &pwbuf, strbuf, strbuflen, &pw)) == ERANGE) { + if (VIR_RESIZE_N(strbuf, strbuflen, strbuflen, strbuflen) < 0) { + virReportOOMError(); + VIR_FREE(strbuf); + return -1; + } + } + if (rc != 0 || pw == NULL) { + virReportSystemError(rc, _("Failed to find user record for name '%s'"), name); VIR_FREE(strbuf); @@ -2842,11 +2856,11 @@ int virGetGroupID(const char *name, struct group *gr = NULL; long val = sysconf(_SC_GETGR_R_SIZE_MAX); size_t strbuflen = val; + int rc; - if (val < 0) { - virReportSystemError(errno, "%s", _("sysconf failed")); - return -1; - } + /* sysconf is a hint; if it fails, fall back to a reasonable size */ + if (val < 0) + strbuflen = 1024; if (VIR_ALLOC_N(strbuf, strbuflen) < 0) { virReportOOMError(); @@ -2860,8 +2874,15 @@ int virGetGroupID(const char *name, * 0 or ENOENT or ESRCH or EBADF or EPERM or ... * The given name or uid was not found. */ - if (getgrnam_r(name, &grbuf, strbuf, strbuflen, &gr) != 0 || gr == NULL) { - virReportSystemError(errno, + while ((rc = getgrnam_r(name, &grbuf, strbuf, strbuflen, &gr)) == ERANGE) { + if (VIR_RESIZE_N(strbuf, strbuflen, strbuflen, strbuflen) < 0) { + virReportOOMError(); + VIR_FREE(strbuf); + return -1; + } + } + if (rc != 0 || gr == NULL) { + virReportSystemError(rc, _("Failed to find group record for name '%s'"), name); VIR_FREE(strbuf); @@ -2897,6 +2918,7 @@ virSetUIDGID(uid_t uid, gid_t gid) struct passwd pwd, *pwd_result; char *buf = NULL; size_t bufsize; + int rc; bufsize = sysconf(_SC_GETPW_R_SIZE_MAX); if (bufsize == -1) @@ -2906,10 +2928,16 @@ virSetUIDGID(uid_t uid, gid_t gid) virReportOOMError(); return -1; } - getpwuid_r(uid, &pwd, buf, bufsize, &pwd_result); - if (!pwd_result) { - virReportSystemError(errno, - _("cannot getpwuid_r(%d)"), + while ((rc = getpwuid_r(uid, &pwd, buf, bufsize, + &pwd_result)) == ERANGE) { + if (VIR_RESIZE_N(buf, bufsize, bufsize, bufsize) < 0) { + virReportOOMError(); + VIR_FREE(buf); + return -1; + } + } + if (rc || !pwd_result) { + virReportSystemError(rc, _("cannot getpwuid_r(%d)"), (unsigned int) uid); VIR_FREE(buf); return -1; -- 1.7.4.4 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list