From 790b8dda4455865cb8c3a47801f4304c1a43baf6 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 19 May 2020 14:09:38 +0200 Subject: nss_compat: internal_end*ent may clobber errno, hiding ERANGE [BZ #25976] During cleanup, before returning from get*_r functions, the end*ent calls must not change errno. Otherwise, an ERANGE error from the underlying implementation can be hidden, causing unexpected lookup failures. This commit introduces an internal_end*ent_noerror function which saves and restore errno, and marks the original internal_end*ent function as warn_unused_result, so that it is used only in contexts were errors from it can be handled explicitly. Reviewed-by: DJ Delorie --- nss/nss_compat/compat-grp.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'nss/nss_compat/compat-grp.c') diff --git a/nss/nss_compat/compat-grp.c b/nss/nss_compat/compat-grp.c index 14aadc6f01..d4f750b95c 100644 --- a/nss/nss_compat/compat-grp.c +++ b/nss/nss_compat/compat-grp.c @@ -144,7 +144,7 @@ _nss_compat_setgrent (int stayopen) } -static enum nss_status +static enum nss_status __attribute_warn_unused_result__ internal_endgrent (ent_t *ent) { if (ent->stream != NULL) @@ -165,6 +165,15 @@ internal_endgrent (ent_t *ent) return NSS_STATUS_SUCCESS; } +/* Like internal_endgrent, but preserve errno in all cases. */ +static void +internal_endgrent_noerror (ent_t *ent) +{ + int saved_errno = errno; + enum nss_status unused __attribute__ ((unused)) = internal_endgrent (ent); + __set_errno (saved_errno); +} + enum nss_status _nss_compat_endgrent (void) { @@ -485,7 +494,7 @@ _nss_compat_getgrnam_r (const char *name, struct group *grp, if (result == NSS_STATUS_SUCCESS) result = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop); - internal_endgrent (&ent); + internal_endgrent_noerror (&ent); return result; } @@ -614,7 +623,7 @@ _nss_compat_getgrgid_r (gid_t gid, struct group *grp, if (result == NSS_STATUS_SUCCESS) result = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop); - internal_endgrent (&ent); + internal_endgrent_noerror (&ent); return result; } -- cgit 1.4.1