Blame SOURCES/0063-login-mount-fix-__SC_GETPW_R_SIZE_MAX-usage.patch

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From 3d1333293ef48117060cd4e285e9c49a6d061e83 Mon Sep 17 00:00:00 2001
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From: Karel Zak <kzak@redhat.com>
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Date: Tue, 15 Dec 2015 12:25:56 +0100
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Subject: [PATCH 63/84] login, mount: fix __SC_GETPW_R_SIZE_MAX usage
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sysconf(_SC_GETPW_R_SIZE_MAX) returns initial suggested size for pwd
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buffer (see getpwnam_r man page or POSIX). This is not large enough in
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some cases.
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Yes, this sysconf option is misnamed (should be _SC_GETPW_R_SIZE_MIN).
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Upstream: http://github.com/karelzak/util-linux/commit/f7ac9e71b18fa7314151f2ab65ee0bdd2ea89c07
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Addresses: http://bugzilla.redhat.com/show_bug.cgi?id=1290689
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Signed-off-by: Karel Zak <kzak@redhat.com>
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---
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 include/c.h          |  7 +++++++
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 libmount/src/utils.c | 25 ++++++-------------------
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 login-utils/login.c  | 12 ++----------
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 3 files changed, 15 insertions(+), 29 deletions(-)
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diff --git a/include/c.h b/include/c.h
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index a50e8a5..7b59ce8 100644
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--- a/include/c.h
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+++ b/include/c.h
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@@ -300,4 +300,11 @@ static inline int usleep(useconds_t usec)
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 # define SEEK_HOLE	4
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 #endif
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+/*
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+ * Note that sysconf(_SC_GETPW_R_SIZE_MAX) returns *initial* suggested size for
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+ * pwd buffer and in some cases it is not large enough. See POSIX and
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+ * getpwnam_r man page for more details.
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+ */
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+#define UL_GETPW_BUFSIZ	(16 * 1024)
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+
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 #endif /* UTIL_LINUX_C_H */
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diff --git a/libmount/src/utils.c b/libmount/src/utils.c
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index 9305bb8..7c6f5b1 100644
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--- a/libmount/src/utils.c
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+++ b/libmount/src/utils.c
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@@ -538,16 +538,6 @@ int mnt_get_filesystems(char ***filesystems, const char *pattern)
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 	return rc;
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 }
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-static size_t get_pw_record_size(void)
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-{
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-#ifdef _SC_GETPW_R_SIZE_MAX
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-	long sz = sysconf(_SC_GETPW_R_SIZE_MAX);
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-	if (sz > 0)
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-		return sz;
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-#endif
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-	return 16384;
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-}
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-
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 /*
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  * Returns allocated string with username or NULL.
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  */
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@@ -555,14 +545,13 @@ char *mnt_get_username(const uid_t uid)
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 {
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         struct passwd pwd;
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 	struct passwd *res;
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-	size_t sz = get_pw_record_size();
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 	char *buf, *username = NULL;
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-	buf = malloc(sz);
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+	buf = malloc(UL_GETPW_BUFSIZ);
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 	if (!buf)
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 		return NULL;
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-	if (!getpwuid_r(uid, &pwd, buf, sz, &res) && res)
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+	if (!getpwuid_r(uid, &pwd, buf, UL_GETPW_BUFSIZ, &res) && res)
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 		username = strdup(pwd.pw_name);
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 	free(buf);
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@@ -574,17 +563,16 @@ int mnt_get_uid(const char *username, uid_t *uid)
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 	int rc = -1;
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         struct passwd pwd;
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 	struct passwd *pw;
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-	size_t sz = get_pw_record_size();
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 	char *buf;
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 	if (!username || !uid)
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 		return -EINVAL;
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-	buf = malloc(sz);
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+	buf = malloc(UL_GETPW_BUFSIZ);
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 	if (!buf)
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 		return -ENOMEM;
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-	if (!getpwnam_r(username, &pwd, buf, sz, &pw) && pw) {
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+	if (!getpwnam_r(username, &pwd, buf, UL_GETPW_BUFSIZ, &pw) && pw) {
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 		*uid= pw->pw_uid;
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 		rc = 0;
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 	} else {
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@@ -602,17 +590,16 @@ int mnt_get_gid(const char *groupname, gid_t *gid)
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 	int rc = -1;
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         struct group grp;
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 	struct group *gr;
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-	size_t sz = get_pw_record_size();
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 	char *buf;
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 	if (!groupname || !gid)
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 		return -EINVAL;
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-	buf = malloc(sz);
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+	buf = malloc(UL_GETPW_BUFSIZ);
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 	if (!buf)
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 		return -ENOMEM;
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-	if (!getgrnam_r(groupname, &grp, buf, sz, &gr) && gr) {
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+	if (!getgrnam_r(groupname, &grp, buf, UL_GETPW_BUFSIZ, &gr) && gr) {
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 		*gid= gr->gr_gid;
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 		rc = 0;
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 	} else {
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diff --git a/login-utils/login.c b/login-utils/login.c
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index a59dd3a..e0e960f 100644
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--- a/login-utils/login.c
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+++ b/login-utils/login.c
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@@ -671,22 +671,14 @@ static struct passwd *get_passwd_entry(const char *username,
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 					 struct passwd *pwd)
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 {
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 	struct passwd *res = NULL;
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-	size_t sz = 16384;
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 	int x;
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 	if (!pwdbuf || !username)
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 		return NULL;
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-#ifdef _SC_GETPW_R_SIZE_MAX
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-	{
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-		long xsz = sysconf(_SC_GETPW_R_SIZE_MAX);
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-		if (xsz > 0)
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-			sz = (size_t) xsz;
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-	}
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-#endif
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-	*pwdbuf = xrealloc(*pwdbuf, sz);
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+	*pwdbuf = xrealloc(*pwdbuf, UL_GETPW_BUFSIZ);
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-	x = getpwnam_r(username, pwd, *pwdbuf, sz, &res;;
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+	x = getpwnam_r(username, pwd, *pwdbuf, UL_GETPW_BUFSIZ, &res;;
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 	if (!res) {
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 		errno = x;
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 		return NULL;
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-- 
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2.7.4
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