From d477da6618660c38dcae3635feb97ee2dd2f6502 Mon Sep 17 00:00:00 2001 From: Chen Qi Date: Tue, 21 Apr 2015 17:30:46 +0800 Subject: shadow: fix `su' behaviour 0001-su.c-fix-to-exec-command-correctly.patch is removed. Below is the reason. This patch is introduced to solve the 'su: applet not found' problem when executing `su -l xxx -c env'. The patch references codes of previous release of shadow. However, this patch introduces bug#5359. So it's not correct. Let's first look at the root cause of 'su: applet not found' problem. This problem appears when /bin/sh is provided by busybox. When executing `su -l xxx -c env' command, the following function is invoked. execve("/bin/sh", ["-su", "-c", "env"], [/* 6 vars */]) Note that the argv[0] provided to new executable file (/bin/sh) is "-su". As /bin/sh is a symlink to /bin/busybox. It's /bin/busybox that is executed. In busybox's appletlib.c, it would examine argv[0], try to find an applet that has the same name, and then try to execute the main function of the applet. This logic results in `su' applet from busybox to be executed. However, we default to set 'BUSYBOX_SPLIT_SUID' to "1", so 'su' is not found. Further more, even if we set 'BUSYBOX_SPLIT_SUID' to "0", so that 'su' applet is found. The whole behaviour is still not correct. Because 'su' from shadow takes higher priority than that from busybox, so 'su' from busybox should never be executed on such system unless it's specified clearly by the end user. The logic of busybox's appletlib.c is totally correct from the point of busybox itself. It's an integration problem. To solve the above problem, this patch comment out SU_NAME in /etc/login.defs so that the final function executed in shadow's su is as below. execve("/bin/sh", ["-sh", "-c", "env"], [/* 6 vars */]) [YOCTO #5359] [YOCTO #7137] (From OE-Core rev: 6820f05dad0b4f9b9bbcf7c2a0af8c34f66199ae) Signed-off-by: Chen Qi Signed-off-by: Richard Purdie --- meta/recipes-extended/shadow/shadow.inc | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'meta/recipes-extended/shadow/shadow.inc') diff --git a/meta/recipes-extended/shadow/shadow.inc b/meta/recipes-extended/shadow/shadow.inc index 7c63d88c70..5451718cce 100644 --- a/meta/recipes-extended/shadow/shadow.inc +++ b/meta/recipes-extended/shadow/shadow.inc @@ -14,7 +14,6 @@ SRC_URI = "http://pkg-shadow.alioth.debian.org/releases/${BPN}-${PV}.tar.xz \ file://shadow-4.1.3-dots-in-usernames.patch \ file://usermod-fix-compilation-failure-with-subids-disabled.patch \ file://fix-installation-failure-with-subids-disabled.patch \ - file://0001-su.c-fix-to-exec-command-correctly.patch \ file://0001-Do-not-read-login.defs-before-doing-chroot.patch \ file://check_size_of_uid_t_and_gid_t_using_AC_CHECK_SIZEOF.patch \ ${@bb.utils.contains('PACKAGECONFIG', 'pam', '${PAM_SRC_URI}', '', d)} \ @@ -108,6 +107,10 @@ do_install() { # Disable checking emails. sed -i 's/MAIL_CHECK_ENAB/#MAIL_CHECK_ENAB/g' ${D}${sysconfdir}/login.defs + # Comment out SU_NAME to work correctly with busybox + # See Bug#5359 and Bug#7173 + sed -i 's:^SU_NAME:#SU_NAME:g' ${D}${sysconfdir}/login.defs + # Use proper encryption for passwords sed -i 's/^#ENCRYPT_METHOD.*$/ENCRYPT_METHOD SHA512/' ${D}${sysconfdir}/login.defs -- cgit v1.2.3-54-g00ecf