From 3c0e680cc2e3df6503f96eeea347eaa957386224 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Fri, 10 Apr 2009 11:02:24 +0200 Subject: [PATCH] login: use open(2) rather then access(2) for $HOME/.hushlogin As an NFS client with home directories on mounted NFS share - If the NFS server exports the share with default root squashed, login cannot access the filesystem to check for the existence of .hushlogin file. It seems better to use open(2) rather than access(2). Signed-off-by: Karel Zak --- login-utils/login.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/login-utils/login.c b/login-utils/login.c index c924a1f5..f3154259 100644 --- a/login-utils/login.c +++ b/login-utils/login.c @@ -352,6 +352,21 @@ get_pam_username(pam_handle_t *pamh, char **name) } #endif +/* + * We need to check effective UID/GID. For example $HOME could be on root + * squashed NFS or on NFS with UID mapping and access(2) uses real UID/GID. + * The open(2) seems as the surest solution. + * -- kzak@redhat.com (10-Apr-2009) + */ +int +effective_access(const char *path, int mode) +{ + int fd = open(path, mode); + if (fd != -1) + close(fd); + return fd == -1 ? -1 : 0; +} + int main(int argc, char **argv) { @@ -885,7 +900,7 @@ main(int argc, char **argv) sprintf(tmpstr, "%s/%s", pwd->pw_dir, _PATH_HUSHLOGIN); setregid(-1, pwd->pw_gid); setreuid(0, pwd->pw_uid); - quietlog = (access(tmpstr, R_OK) == 0); + quietlog = (effective_access(tmpstr, O_RDONLY) == 0); setuid(0); /* setreuid doesn't do it alone! */ setreuid(ruid, 0); setregid(-1, egid); -- 2.39.5