From: Marcel Holtmann <marcel@holtmann.org>
Date: Sat, 6 Oct 2007 22:03:26 +0000 (+0200)
Subject: Reset current->pdeath_signal on SUID binary execution (CVE-2007-3848)
X-Git-Tag: v2.6.16.55-rc1~7
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9236d592ceee5d4033cd90d2f7d02440aea9b778;p=karo-tx-linux.git

Reset current->pdeath_signal on SUID binary execution (CVE-2007-3848)

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 <marcel@holtmann.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
---

diff --git a/fs/exec.c b/fs/exec.c
index 0b515ac53134..91a36b27ec91 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -891,9 +891,12 @@ 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);
+		current->mm->dumpable = suid_dumpable;
+		current->pdeath_signal = 0;
+	} else if (file_permission(bprm->file, MAY_READ) ||
+			(bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
 		suid_keys(current);
 		current->mm->dumpable = suid_dumpable;
 	}
@@ -991,8 +994,10 @@ 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);