From: Hugh Dickins Date: Sat, 28 Mar 2009 23:20:19 +0000 (+0000) Subject: fix setuid sometimes doesn't X-Git-Tag: v2.6.30-rc1~633 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e426b64c412aaa3e9eb3e4b261dc5be0d5a83e78;p=pandora-kernel.git fix setuid sometimes doesn't Joe Malicki reports that setuid sometimes doesn't: very rarely, a setuid root program does not get root euid; and, by the way, they have a health check running lsof every few minutes. Right, check_unsafe_exec() notes whether the files_struct is being shared by more threads than will get killed by the exec, and if so sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid. But /proc//fd and /proc//fdinfo lookups make transient use of get_files_struct(), which also raises that sharing count. There's a rather simple fix for this: exec's check on files->count has been redundant ever since 2.6.1 made it unshare_files() (except while compat_do_execve() omitted to do so) - just remove that check. [Note to -stable: this patch will not apply before 2.6.29: earlier releases should just remove the files->count line from unsafe_exec().] Reported-by: Joe Malicki Narrowed-down-by: Michael Itz Tested-by: Joe Malicki Signed-off-by: Hugh Dickins Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed