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Commit fa3ba2e8 authored by Florin Malita's avatar Florin Malita Committed by Linus Torvalds
Browse files

[PATCH] fix Module taint flags listing in Oops/panic 



Module taint flags listing in Oops/panic has a couple of issues:

* taint_flags() doesn't null-terminate the buffer after printing the flags

* per-module taints are only set if the kernel is not already tainted
  (with that particular flag) => only the first offending module gets its
  taint info correctly updated

Some additional changes:

* 'license_gplok' is no longer needed - equivalent to !(taints &
  TAINT_PROPRIETARY_MODULE) - so we can drop it from struct module *
  exporting module taint info via /proc/module:

pwc 88576 0 - Live 0xf8c32000
evilmod 6784 1 pwc, Live 0xf8bbf000 (PF)

Signed-off-by: default avatarFlorin Malita <fmalita@gmail.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3719bc5c

include/linux/module.h

+0 −3
Original line number Diff line number Diff line
@@ -317,9 +317,6 @@ struct module 
	/* Am I unsafe to unload? */

	int unsafe;



	/* Am I GPL-compatible */

	int license_gplok;



	unsigned int taints;	/* same bits as kernel:tainted */



#ifdef CONFIG_MODULE_UNLOAD

kernel/module.c

+49 −45
Original line number Diff line number Diff line
@@ -87,6 +87,12 @@ static inline int strong_try_module_get(struct module *mod) 
	return try_module_get(mod);

}



static inline void add_taint_module(struct module *mod, unsigned flag)

{

	add_taint(flag);

	mod->taints |= flag;

}



/* A thread that wants to hold a reference to a module only while it

 * is running can call ths to safely exit.

 * nfsd and lockd use this.
@@ -847,12 +853,10 @@ static int check_version(Elf_Shdr *sechdrs, 
		return 0;

	}

	/* Not in module's version table.  OK, but that taints the kernel. */

	if (!(tainted & TAINT_FORCED_MODULE)) {

	if (!(tainted & TAINT_FORCED_MODULE))

		printk("%s: no version for \"%s\" found: kernel tainted.\n",

		       mod->name, symname);

		add_taint(TAINT_FORCED_MODULE);

		mod->taints |= TAINT_FORCED_MODULE;

	}

	add_taint_module(mod, TAINT_FORCED_MODULE);

	return 1;

}
@@ -910,7 +914,8 @@ static unsigned long resolve_symbol(Elf_Shdr *sechdrs, 
	unsigned long ret;

	const unsigned long *crc;



	ret = __find_symbol(name, &owner, &crc, mod->license_gplok);

	ret = __find_symbol(name, &owner, &crc,

			!(mod->taints & TAINT_PROPRIETARY_MODULE));

	if (ret) {

		/* use_module can fail due to OOM, or module unloading */

		if (!check_version(sechdrs, versindex, name, mod, crc) ||
@@ -1335,12 +1340,11 @@ static void set_license(struct module *mod, const char *license) 
	if (!license)

		license = "unspecified";



	mod->license_gplok = license_is_gpl_compatible(license);

	if (!mod->license_gplok && !(tainted & TAINT_PROPRIETARY_MODULE)) {

		printk(KERN_WARNING "%s: module license '%s' taints kernel.\n",

		       mod->name, license);

		add_taint(TAINT_PROPRIETARY_MODULE);

		mod->taints |= TAINT_PROPRIETARY_MODULE;

	if (!license_is_gpl_compatible(license)) {

		if (!(tainted & TAINT_PROPRIETARY_MODULE))

			printk(KERN_WARNING "%s: module license '%s' taints"

				"kernel.\n", mod->name, license);

		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);

	}

}
@@ -1619,8 +1623,7 @@ static struct module *load_module(void __user *umod, 
	modmagic = get_modinfo(sechdrs, infoindex, "vermagic");

	/* This is allowed: modprobe --force will invalidate it. */

	if (!modmagic) {

		add_taint(TAINT_FORCED_MODULE);

		mod->taints |= TAINT_FORCED_MODULE;

		add_taint_module(mod, TAINT_FORCED_MODULE);

		printk(KERN_WARNING "%s: no version magic, tainting kernel.\n",

		       mod->name);

	} else if (!same_magic(modmagic, vermagic)) {
@@ -1714,14 +1717,10 @@ static struct module *load_module(void __user *umod, 
	/* Set up license info based on the info section */

	set_license(mod, get_modinfo(sechdrs, infoindex, "license"));



	if (strcmp(mod->name, "ndiswrapper") == 0) {

		add_taint(TAINT_PROPRIETARY_MODULE);

		mod->taints |= TAINT_PROPRIETARY_MODULE;

	}

	if (strcmp(mod->name, "driverloader") == 0) {

		add_taint(TAINT_PROPRIETARY_MODULE);

		mod->taints |= TAINT_PROPRIETARY_MODULE;

	}

	if (strcmp(mod->name, "ndiswrapper") == 0)

		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);

	if (strcmp(mod->name, "driverloader") == 0)

		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);



	/* Set up MODINFO_ATTR fields */

	setup_modinfo(mod, sechdrs, infoindex);
@@ -1766,8 +1765,7 @@ static struct module *load_module(void __user *umod, 
	    (mod->num_unused_gpl_syms && !unusedgplcrcindex)) {

		printk(KERN_WARNING "%s: No versions for exported symbols."

		       " Tainting kernel.\n", mod->name);

		add_taint(TAINT_FORCED_MODULE);

		mod->taints |= TAINT_FORCED_MODULE;

		add_taint_module(mod, TAINT_FORCED_MODULE);

	}

#endif
@@ -2132,9 +2130,33 @@ static void m_stop(struct seq_file *m, void *p) 
	mutex_unlock(&module_mutex);

}



static char *taint_flags(unsigned int taints, char *buf)

{

	int bx = 0;



	if (taints) {

		buf[bx++] = '(';

		if (taints & TAINT_PROPRIETARY_MODULE)

			buf[bx++] = 'P';

		if (taints & TAINT_FORCED_MODULE)

			buf[bx++] = 'F';

		/*

		 * TAINT_FORCED_RMMOD: could be added.

		 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't

		 * apply to modules.

		 */

		buf[bx++] = ')';

	}

	buf[bx] = '\0';



	return buf;

}



static int m_show(struct seq_file *m, void *p)

{

	struct module *mod = list_entry(p, struct module, list);

	char buf[8];



	seq_printf(m, "%s %lu",

		   mod->name, mod->init_size + mod->core_size);

	print_unload_info(m, mod);
@@ -2147,6 +2169,10 @@ static int m_show(struct seq_file *m, void *p) 
	/* Used by oprofile and other similar tools. */

	seq_printf(m, " 0x%p", mod->module_core);



	/* Taints info */

	if (mod->taints)

		seq_printf(m, " %s", taint_flags(mod->taints, buf));



	seq_printf(m, "\n");

	return 0;

}
@@ -2235,28 +2261,6 @@ struct module *module_text_address(unsigned long addr) 
	return mod;

}



static char *taint_flags(unsigned int taints, char *buf)

{

	*buf = '\0';

	if (taints) {

		int bx;



		buf[0] = '(';

		bx = 1;

		if (taints & TAINT_PROPRIETARY_MODULE)

			buf[bx++] = 'P';

		if (taints & TAINT_FORCED_MODULE)

			buf[bx++] = 'F';

		/*

		 * TAINT_FORCED_RMMOD: could be added.

		 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't

		 * apply to modules.

		 */

		buf[bx] = ')';

	}

	return buf;

}



/* Don't grab lock, we're oopsing. */

void print_modules(void)

{