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=== Description (from pull-request) ===
Hello,
fix getpwuid() thread safe issue.
Thanks.
Signed-off-by: Donghwa Jeong <dh48.je...@samsung.com>
From cb7aa5e8cae121f2d63db60d9e3687a8ac554800 Mon Sep 17 00:00:00 2001
From: Donghwa Jeong <dh48.je...@samsung.com>
Date: Thu, 14 Jun 2018 15:32:03 +0900
Subject: [PATCH] fix getpwuid() thread safe issue
Signed-off-by: Donghwa Jeong <dh48.je...@samsung.com>
---
src/lxc/attach.c | 29 ++++++++++++++++++++++++-----
src/lxc/cmd/lxc_user_nic.c | 31 ++++++++++++++++++++++++++-----
src/lxc/cmd/lxc_usernsexec.c | 38 +++++++++++++++++++++++++++++++++-----
src/lxc/conf.c | 30 ++++++++++++++++++++++++++----
4 files changed, 109 insertions(+), 19 deletions(-)
diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index 9bbdd0e6a..dd98a6d33 100644
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -1501,14 +1501,32 @@ int lxc_attach_run_command(void* payload)
int lxc_attach_run_shell(void* payload)
{
uid_t uid;
- struct passwd *passwd;
+ struct passwd pwent;
+ struct passwd *pwentp = NULL;
char *user_shell;
+ char *buf;
+ size_t bufsize;
+ int ret;
/* Ignore payload parameter. */
(void)payload;
uid = getuid();
- passwd = getpwuid(uid);
+
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1)
+ bufsize = 1024;
+
+ buf = malloc(bufsize);
+ if (buf) {
+ ret = getpwuid_r(uid, &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ WARN("Could not find matched password record.");
+
+ WARN("Failed to get password record - %u", uid);
+ }
+ }
/* This probably happens because of incompatible nss implementations in
* host and container (remember, this code is still using the host's
@@ -1516,10 +1534,10 @@ int lxc_attach_run_shell(void* payload)
* the information by spawning a [getent passwd uid] process and parsing
* the result.
*/
- if (!passwd)
+ if (!pwentp)
user_shell = lxc_attach_getpwshell(uid);
else
- user_shell = passwd->pw_shell;
+ user_shell = pwent.pw_shell;
if (user_shell)
execlp(user_shell, user_shell, (char *)NULL);
@@ -1528,7 +1546,8 @@ int lxc_attach_run_shell(void* payload)
*/
execlp("/bin/sh", "/bin/sh", (char *)NULL);
SYSERROR("Failed to execute shell");
- if (!passwd)
+ if (!pwentp)
free(user_shell);
+ free(buf);
return -1;
}
diff --git a/src/lxc/cmd/lxc_user_nic.c b/src/lxc/cmd/lxc_user_nic.c
index d071ce0b5..2b0ee6059 100644
--- a/src/lxc/cmd/lxc_user_nic.c
+++ b/src/lxc/cmd/lxc_user_nic.c
@@ -103,15 +103,35 @@ static int open_and_lock(char *path)
static char *get_username(void)
{
- struct passwd *pwd;
+ struct passwd pwent;
+ struct passwd *pwentp = NULL;
+ char *buf;
+ char *username;
+ size_t bufsize;
+ int ret;
+
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1)
+ bufsize = 1024;
+
+ buf = malloc(bufsize);
+ if (!buf)
+ return NULL;
+
+ ret = getpwuid_r(getuid(), &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ usernic_error("%s", "Could not find matched password
record\n");
- pwd = getpwuid(getuid());
- if (!pwd) {
- usernic_error("Failed to get username: %s\n", strerror(errno));
+ usernic_error("Failed to get username: %s(%u)\n",
strerror(errno), getuid());
+ free(buf);
return NULL;
}
- return pwd->pw_name;
+ username = strdup(pwent.pw_name);
+ free(buf);
+
+ return username;
}
static void free_groupnames(char **groupnames)
@@ -1170,6 +1190,7 @@ int main(int argc, char *argv[])
}
n = get_alloted(me, args.type, args.link, &alloted);
+ free(me);
if (request == LXC_USERNIC_DELETE) {
int ret;
diff --git a/src/lxc/cmd/lxc_usernsexec.c b/src/lxc/cmd/lxc_usernsexec.c
index 725796270..56e1bdbcb 100644
--- a/src/lxc/cmd/lxc_usernsexec.c
+++ b/src/lxc/cmd/lxc_usernsexec.c
@@ -253,14 +253,42 @@ static int read_default_map(char *fnam, int which, char
*username)
static int find_default_map(void)
{
- struct passwd *p = getpwuid(getuid());
- if (!p)
+ struct 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 -1;
- if (read_default_map(subuidfile, ID_TYPE_UID, p->pw_name) < 0)
+
+ ret = getpwuid_r(getuid(), &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ printf("WARN: could not find matched password
record\n");
+
+ printf("Failed to get password record - %u\n", getuid());
+ free(buf);
return -1;
- if (read_default_map(subgidfile, ID_TYPE_GID, p->pw_name) < 0)
+ }
+
+ if (read_default_map(subuidfile, ID_TYPE_UID, pwent.pw_name) < 0) {
+ free(buf);
return -1;
- return 0;
+ }
+
+ if (read_default_map(subgidfile, ID_TYPE_GID, pwent.pw_name) < 0) {
+ free(buf);
+ return -1;
+ }
+
+ free(buf);
+ return 0;
}
int main(int argc, char *argv[])
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index c5586b33c..66f5c915b 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -4508,13 +4508,35 @@ int userns_exec_full(struct lxc_conf *conf, int
(*fn)(void *), void *data,
/* not thread-safe, do not use from api without first forking */
static char *getuname(void)
{
- struct passwd *result;
+ struct passwd pwent;
+ struct passwd *pwentp = NULL;
+ char *buf;
+ char *username;
+ size_t bufsize;
+ int ret;
- result = getpwuid(geteuid());
- if (!result)
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1)
+ bufsize = 1024;
+
+ buf = malloc(bufsize);
+ if (!buf)
return NULL;
- return strdup(result->pw_name);
+ ret = getpwuid_r(geteuid(), &pwent, buf, bufsize, &pwentp);
+ if (!pwentp) {
+ if (ret == 0)
+ WARN("Could not find matched password record.");
+
+ ERROR("Failed to get password record - %u", geteuid());
+ free(buf);
+ return NULL;
+ }
+
+ username = strdup(pwent.pw_name);
+ free(buf);
+
+ return username;
}
/* not thread-safe, do not use from api without first forking */
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