From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Wolfgang Bumiller <w.bumiller@proxmox.com>

Date: Tue, 13 Aug 2019 13:57:22 +0200

Subject: [PATCH lxc] PVE: [Config] attach: always use getent

In debian buster, some libnss plugins (if installed) can

cause getpwent to segfault instead of erroring out cleanly.

To avoid this, stick to always using getent.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

---

 src/lxc/attach.c | 28 ++--------------------------

 1 file changed, 2 insertions(+), 26 deletions(-)

diff --git a/src/lxc/attach.c b/src/lxc/attach.c

index cd526ab6b..845270ee5 100644

--- a/src/lxc/attach.c

+++ b/src/lxc/attach.c

@@ -1841,12 +1841,8 @@ int lxc_attach_run_command(void *payload)

 int lxc_attach_run_shell(void* payload)

 {

-	__do_free char *buf = NULL;

 	uid_t uid;

-	struct passwd pwent;

-	struct passwd *pwentp = NULL;

 	char *user_shell;

-	ssize_t bufsize;

 	int ret;

 	/* Ignore payload parameter. */

@@ -1854,32 +1850,13 @@ int lxc_attach_run_shell(void* payload)

 	uid = getuid();

-	bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);

-	if (bufsize < 0)

-		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

 	 * glibc but our mount namespace is in the container) we may try to get

 	 * the information by spawning a [getent passwd uid] process and parsing

 	 * the result.

 	 */

-	if (!pwentp)

-		user_shell = lxc_attach_getpwshell(uid);

-	else

-		user_shell = pwent.pw_shell;

-

+	user_shell = lxc_attach_getpwshell(uid);

 	if (user_shell)

 		execlp(user_shell, user_shell, (char *)NULL);

@@ -1889,8 +1866,7 @@ int lxc_attach_run_shell(void* payload)

 	execlp("/bin/sh", "/bin/sh", (char *)NULL);

 	SYSERROR("Failed to execute shell");

-	if (!pwentp)

-		free(user_shell);

+	free(user_shell);

 	return -1;

 }