From d2d56c5f51028cb9f3d800882eb6f4cbd3f9099f Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Fri, 17 Aug 2007 21:47:58 +0200 Subject: [PATCH] Reset current->pdeath_signal on SUID binary execution This fixes a vulnerability in the "parent process death signal" implementation discoverd by Wojciech Purczynski of COSEINC PTE Ltd. and iSEC Security Research. http://marc.info/?l=bugtraq&m=118711306802632&w=2 Signed-off-by: Marcel Holtmann Signed-off-by: Linus Torvalds --- fs/exec.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 7bdea7937ee8..ce62f7b65f17 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1084,9 +1084,12 @@ int flush_old_exec(struct linux_binprm * bprm) */ current->mm->task_size = TASK_SIZE; - if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || - file_permission(bprm->file, MAY_READ) || - (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { + if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { + suid_keys(current); + set_dumpable(current->mm, suid_dumpable); + current->pdeath_signal = 0; + } else if (file_permission(bprm->file, MAY_READ) || + (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { suid_keys(current); set_dumpable(current->mm, suid_dumpable); } @@ -1177,8 +1180,10 @@ void compute_creds(struct linux_binprm *bprm) { int unsafe; - if (bprm->e_uid != current->uid) + if (bprm->e_uid != current->uid) { suid_keys(current); + current->pdeath_signal = 0; + } exec_keys(current); task_lock(current);