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It can be accessed and reviewed at: https://github.com/lxc/lxc/pull/2396
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=== Description (from pull-request) ===
Signed-off-by: Donghwa Jeong <dh48.je...@samsung.com>
From 2dce415b621e4c7cc78f679f8ec54a5b401c785b Mon Sep 17 00:00:00 2001
From: Donghwa Jeong <dh48.je...@samsung.com>
Date: Tue, 12 Jun 2018 17:09:13 +0900
Subject: [PATCH] fix getpwnam() thread safe issue
Signed-off-by: Donghwa Jeong <dh48.je...@samsung.com>
---
src/lxc/pam/pam_cgfs.c | 28 +++++++++++++++++++++++-----
src/lxc/tools/lxc_unshare.c | 34 ++++++++++++++++++++++++++++------
2 files changed, 51 insertions(+), 11 deletions(-)
diff --git a/src/lxc/pam/pam_cgfs.c b/src/lxc/pam/pam_cgfs.c
index d5196f8a0..81ce912e8 100644
--- a/src/lxc/pam/pam_cgfs.c
+++ b/src/lxc/pam/pam_cgfs.c
@@ -1520,14 +1520,32 @@ static void cg_escape(void)
/* Get uid and gid for @user. */
static bool get_uid_gid(const char *user, uid_t *uid, gid_t *gid)
{
- struct passwd *pwent;
+ strcut passwd pwent;
+ struct passwd *pwentp = NULL;
+ char *buf;
+ size_t bufsize;
+ int ret;
+
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1)
+ bufsize = 1024;
+
+ buf = malloc(bufsize);
+ if (!buf)
+ return false;
+
+ ret = getpwnam_r(user, &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ mysyslog(LOG_ERR, "Could not find matched password
record.\n", NULL);
- pwent = getpwnam(user);
- if (!pwent)
+ free(buf);
return false;
+ }
- *uid = pwent->pw_uid;
- *gid = pwent->pw_gid;
+ *uid = pwent.pw_uid;
+ *gid = pwent.pw_gid;
+ free(buf);
return true;
}
diff --git a/src/lxc/tools/lxc_unshare.c b/src/lxc/tools/lxc_unshare.c
index 54f0fd545..eb69068af 100644
--- a/src/lxc/tools/lxc_unshare.c
+++ b/src/lxc/tools/lxc_unshare.c
@@ -82,29 +82,51 @@ static void usage(char *cmd)
static bool lookup_user(const char *optarg, uid_t *uid)
{
char name[TOOL_MAXPATHLEN];
- struct passwd *pwent = NULL;
+ struct passwd pwent;
+ struct passwd *pwentp = NULL;
+ char *buf;
+ size_t bufsize;
+ int ret;
if (!optarg || (optarg[0] == '\0'))
return false;
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1)
+ bufsize = 1024;
+
+ buf = malloc(bufsize);
+ if (!buf)
+ return false;
+
if (sscanf(optarg, "%u", uid) < 1) {
/* not a uid -- perhaps a username */
if (sscanf(optarg, "%s", name) < 1)
return false;
- pwent = getpwnam(name);
- if (!pwent) {
+ ret = getpwnam_r(name, &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ fprintf(stderr, "could not find matched
password record\n");
+
fprintf(stderr, "invalid username %s\n", name);
+ free(buf);
return false;
}
- *uid = pwent->pw_uid;
+ *uid = pwent.pw_uid;
} else {
- pwent = getpwuid(*uid);
- if (!pwent) {
+ ret = getpwuid_r(*uid, &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ fprintf(stderr, "could not find matched
password record\n");
+
fprintf(stderr, "invalid uid %u\n", *uid);
+ free(buf);
return false;
}
}
+
+ free(buf);
return true;
}
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