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util-linux
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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 <kzak@redhat.com>
This commit is contained in:
Karel Zak 2009-04-10 11:02:24 +02:00
parent 402e795813
commit 3c0e680cc2
1 changed files with 16 additions and 1 deletions
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17
login-utils/login.c
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@ -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);