From 34f5a39899f3f3e815da64f48ddb72942d86c366 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 10 Feb 2007 01:45:24 -0800 Subject: [PATCH] [PATCH] Add TAINT_USER and ability to set taint flags from userspace Allow taint flags to be set from userspace by writing to /proc/sys/kernel/tainted, and add a new taint flag, TAINT_USER, to be used when userspace has potentially done something dangerous that might compromise the kernel. This will allow support personnel to ask further questions about what may have caused the user taint flag to have been set. For example, they might examine the logs of the realtime JVM to see if the Java program has used the really silly, stupid, dangerous, and completely-non-portable direct access to physical memory feature which MUST be implemented according to the Real-Time Specification for Java (RTSJ). Sigh. What were those silly people at Sun thinking? [akpm@osdl.org: build fix] [bunk@stusta.de: cleanup] Signed-off-by: "Theodore Ts'o" Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 1 + kernel/panic.c | 6 ++++-- kernel/sysctl.c | 27 +++++++++++++++++++++++++-- 3 files changed, 30 insertions(+), 4 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 63fb18dcac..e1a429ada9 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -200,6 +200,7 @@ extern enum system_states { #define TAINT_FORCED_RMMOD (1<<3) #define TAINT_MACHINE_CHECK (1<<4) #define TAINT_BAD_PAGE (1<<5) +#define TAINT_USER (1<<6) extern void dump_stack(void); diff --git a/kernel/panic.c b/kernel/panic.c index 525e365f72..623d182825 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -150,6 +150,7 @@ EXPORT_SYMBOL(panic); * 'R' - User forced a module unload. * 'M' - Machine had a machine check experience. * 'B' - System has hit bad_page. + * 'U' - Userspace-defined naughtiness. * * The string is overwritten by the next call to print_taint(). */ @@ -158,13 +159,14 @@ const char *print_tainted(void) { static char buf[20]; if (tainted) { - snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c", + snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c", tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G', tainted & TAINT_FORCED_MODULE ? 'F' : ' ', tainted & TAINT_UNSAFE_SMP ? 'S' : ' ', tainted & TAINT_FORCED_RMMOD ? 'R' : ' ', tainted & TAINT_MACHINE_CHECK ? 'M' : ' ', - tainted & TAINT_BAD_PAGE ? 'B' : ' '); + tainted & TAINT_BAD_PAGE ? 'B' : ' ', + tainted & TAINT_USER ? 'U' : ' '); } else snprintf(buf, sizeof(buf), "Not tainted"); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 16ef870fa7..7733ef58aa 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -151,6 +151,8 @@ static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen, #ifdef CONFIG_PROC_SYSCTL static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos); +static int proc_dointvec_taint(ctl_table *table, int write, struct file *filp, + void __user *buffer, size_t *lenp, loff_t *ppos); #endif static ctl_table root_table[]; @@ -174,6 +176,7 @@ extern ctl_table inotify_table[]; int sysctl_legacy_va_layout; #endif + static void *get_uts(ctl_table *table, int write) { char *which = table->data; @@ -344,14 +347,16 @@ static ctl_table kern_table[] = { .proc_handler = &proc_dostring, .strategy = &sysctl_string, }, +#ifdef CONFIG_PROC_SYSCTL { .ctl_name = KERN_TAINTED, .procname = "tainted", .data = &tainted, .maxlen = sizeof(int), - .mode = 0444, - .proc_handler = &proc_dointvec, + .mode = 0644, + .proc_handler = &proc_dointvec_taint, }, +#endif { .ctl_name = KERN_CAP_BSET, .procname = "cap-bound", @@ -1927,6 +1932,7 @@ int proc_dointvec(ctl_table *table, int write, struct file *filp, #define OP_SET 0 #define OP_AND 1 +#define OP_OR 2 static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp, int *valp, @@ -1938,6 +1944,7 @@ static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp, switch(op) { case OP_SET: *valp = val; break; case OP_AND: *valp &= val; break; + case OP_OR: *valp |= val; break; } } else { int val = *valp; @@ -1970,6 +1977,22 @@ int proc_dointvec_bset(ctl_table *table, int write, struct file *filp, do_proc_dointvec_bset_conv,&op); } +/* + * Taint values can only be increased + */ +static int proc_dointvec_taint(ctl_table *table, int write, struct file *filp, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int op; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + op = OP_OR; + return do_proc_dointvec(table,write,filp,buffer,lenp,ppos, + do_proc_dointvec_bset_conv,&op); +} + struct do_proc_dointvec_minmax_conv_param { int *min; int *max; -- 2.39.5