aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorCedric Le Goater <clg@fr.ibm.com>2006-10-02 05:19:00 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-02 10:57:25 -0400
commit9ec52099e4b8678a60e9f93e41ad87885d64f3e6 (patch)
treea68fe051b39f8f8e8be469cbd3c2f653b9b71a9d /kernel
parent1a657f78dcc8ea7c53eaa1f2a45ea2315738c15f (diff)
[PATCH] replace cad_pid by a struct pid
There are a few places in the kernel where the init task is signaled. The ctrl+alt+del sequence is one them. It kills a task, usually init, using a cached pid (cad_pid). This patch replaces the pid_t by a struct pid to avoid pid wrap around problem. The struct pid is initialized at boot time in init() and can be modified through systctl with /proc/sys/kernel/cad_pid [ I haven't found any distro using it ? ] It also introduces a small helper routine kill_cad_pid() which is used where it seemed ok to use cad_pid instead of pid 1. [akpm@osdl.org: cleanups, build fix] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sys.c6
-rw-r--r--kernel/sysctl.c30
2 files changed, 30 insertions, 6 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 3a4776e8f16e..2314867ae34f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -92,7 +92,8 @@ EXPORT_SYMBOL(fs_overflowgid);
92 */ 92 */
93 93
94int C_A_D = 1; 94int C_A_D = 1;
95int cad_pid = 1; 95struct pid *cad_pid;
96EXPORT_SYMBOL(cad_pid);
96 97
97/* 98/*
98 * Notifier list for kernel code which wants to be called 99 * Notifier list for kernel code which wants to be called
@@ -773,10 +774,9 @@ void ctrl_alt_del(void)
773 if (C_A_D) 774 if (C_A_D)
774 schedule_work(&cad_work); 775 schedule_work(&cad_work);
775 else 776 else
776 kill_proc(cad_pid, SIGINT, 1); 777 kill_cad_pid(SIGINT, 1);
777} 778}
778 779
779
780/* 780/*
781 * Unprivileged users may change the real gid to the effective gid 781 * Unprivileged users may change the real gid to the effective gid
782 * or vice versa. (BSD-style) 782 * or vice versa. (BSD-style)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index a79ccf9d113b..8020fb273c4f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -68,7 +68,6 @@ extern int sysrq_enabled;
68extern int core_uses_pid; 68extern int core_uses_pid;
69extern int suid_dumpable; 69extern int suid_dumpable;
70extern char core_pattern[]; 70extern char core_pattern[];
71extern int cad_pid;
72extern int pid_max; 71extern int pid_max;
73extern int min_free_kbytes; 72extern int min_free_kbytes;
74extern int printk_ratelimit_jiffies; 73extern int printk_ratelimit_jiffies;
@@ -137,6 +136,9 @@ static int parse_table(int __user *, int, void __user *, size_t __user *,
137static int proc_do_uts_string(ctl_table *table, int write, struct file *filp, 136static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
138 void __user *buffer, size_t *lenp, loff_t *ppos); 137 void __user *buffer, size_t *lenp, loff_t *ppos);
139 138
139static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
140 void __user *buffer, size_t *lenp, loff_t *ppos);
141
140static ctl_table root_table[]; 142static ctl_table root_table[];
141static struct ctl_table_header root_table_header = 143static struct ctl_table_header root_table_header =
142 { root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) }; 144 { root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };
@@ -543,10 +545,10 @@ static ctl_table kern_table[] = {
543 { 545 {
544 .ctl_name = KERN_CADPID, 546 .ctl_name = KERN_CADPID,
545 .procname = "cad_pid", 547 .procname = "cad_pid",
546 .data = &cad_pid, 548 .data = NULL,
547 .maxlen = sizeof (int), 549 .maxlen = sizeof (int),
548 .mode = 0600, 550 .mode = 0600,
549 .proc_handler = &proc_dointvec, 551 .proc_handler = &proc_do_cad_pid,
550 }, 552 },
551 { 553 {
552 .ctl_name = KERN_MAX_THREADS, 554 .ctl_name = KERN_MAX_THREADS,
@@ -2427,6 +2429,28 @@ proc_minmax:
2427} 2429}
2428#endif 2430#endif
2429 2431
2432static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
2433 void __user *buffer, size_t *lenp, loff_t *ppos)
2434{
2435 struct pid *new_pid;
2436 pid_t tmp;
2437 int r;
2438
2439 tmp = pid_nr(cad_pid);
2440
2441 r = __do_proc_dointvec(&tmp, table, write, filp, buffer,
2442 lenp, ppos, NULL, NULL);
2443 if (r || !write)
2444 return r;
2445
2446 new_pid = find_get_pid(tmp);
2447 if (!new_pid)
2448 return -ESRCH;
2449
2450 put_pid(xchg(&cad_pid, new_pid));
2451 return 0;
2452}
2453
2430#else /* CONFIG_PROC_FS */ 2454#else /* CONFIG_PROC_FS */
2431 2455
2432int proc_dostring(ctl_table *table, int write, struct file *filp, 2456int proc_dostring(ctl_table *table, int write, struct file *filp,