fix issues with shell detection on attach

[lxc.git] / debian / patches / pve / 0010-PVE-Config-attach-always-use-getent.patch

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] 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 | 29 ++---------------------------
 1 file changed, 2 insertions(+), 27 deletions(-)

diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index 117e3778f..8b34a412e 100644
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -1548,11 +1548,7 @@ int lxc_attach_run_command(void *payload)
 int lxc_attach_run_shell(void* payload)
 {
 	uid_t uid;
-	struct passwd pwent;
-	struct passwd *pwentp = NULL;
 	char *user_shell;
-	char *buf;
-	size_t bufsize;
 	int ret;
 
 	/* Ignore payload parameter. */
@@ -1560,32 +1556,13 @@ int lxc_attach_run_shell(void* payload)
 
 	uid = getuid();
 
-	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
 	 * 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);
 
@@ -1595,9 +1572,7 @@ 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);
 
-	free(buf);
 	return -1;
 }
-- 
2.20.1