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[PATCH] fix Module taint flags listing in Oops/panic
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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: Florin Malita <fmalita@gmail.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Florin Malita authored and Linus Torvalds committed Oct 11, 2006
1 parent 3719bc5 commit fa3ba2e
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Showing 2 changed files with 49 additions and 48 deletions.
3 changes: 0 additions & 3 deletions include/linux/module.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
94 changes: 49 additions & 45 deletions kernel/module.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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) ||
Expand Down Expand Up @@ -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);
}
}

Expand Down Expand Up @@ -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)) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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

Expand Down Expand Up @@ -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);
Expand All @@ -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;
}
Expand Down Expand Up @@ -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)
{
Expand Down

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