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yaml
---
r: 204808
b: refs/heads/master
c: 3264d3f
h: refs/heads/master
v: v3
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Linus Torvalds authored and Rusty Russell committed Aug 5, 2010
1 parent a80384a commit 797a06d
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Showing 2 changed files with 126 additions and 104 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 44032e631691adf1f406843d5e54deb795973ff7
refs/heads/master: 3264d3f9dd532ed9c3eb9491619e3f485b72747f
228 changes: 125 additions & 103 deletions trunk/kernel/module.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2148,8 +2148,17 @@ static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
}
#endif

static int copy_and_check(Elf_Ehdr **hdrp,
const void __user *umod, unsigned long len)
struct load_info {
Elf_Ehdr *hdr;
unsigned long len;
Elf_Shdr *sechdrs;
char *secstrings, *args, *strtab;
struct {
unsigned int sym, str, mod, vers, info, pcpu;
} index;
};

static int copy_and_check(struct load_info *info, const void __user *umod, unsigned long len)
{
int err;
Elf_Ehdr *hdr;
Expand All @@ -2159,7 +2168,7 @@ static int copy_and_check(Elf_Ehdr **hdrp,

/* Suck in entire file: we'll want most of it. */
/* vmalloc barfs on "unusual" numbers. Check here */
if (len > 64 * 1024 * 1024 || (hdr = *hdrp = vmalloc(len)) == NULL)
if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
return -ENOMEM;

if (copy_from_user(hdr, umod, len) != 0) {
Expand All @@ -2181,13 +2190,89 @@ static int copy_and_check(Elf_Ehdr **hdrp,
err = -ENOEXEC;
goto free_hdr;
}
info->hdr = hdr;
info->len = len;
return 0;

free_hdr:
vfree(hdr);
return err;
}

/*
* Set up our basic convenience variables (pointers to section headers,
* search for module section index etc), and do some basic section
* verification.
*
* Return the temporary module pointer (we'll replace it with the final
* one when we move the module sections around).
*/
static struct module *setup_load_info(struct load_info *info)
{
unsigned int i;
struct module *mod;

/* Set up the convenience variables */
info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
info->secstrings = (void *)info->hdr + info->sechdrs[info->hdr->e_shstrndx].sh_offset;
info->sechdrs[0].sh_addr = 0;

for (i = 1; i < info->hdr->e_shnum; i++) {
if (info->sechdrs[i].sh_type != SHT_NOBITS
&& info->len < info->sechdrs[i].sh_offset + info->sechdrs[i].sh_size)
goto truncated;

/* Mark all sections sh_addr with their address in the
temporary image. */
info->sechdrs[i].sh_addr = (size_t)info->hdr + info->sechdrs[i].sh_offset;

/* Internal symbols and strings. */
if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
info->index.sym = i;
info->index.str = info->sechdrs[i].sh_link;
info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
}
#ifndef CONFIG_MODULE_UNLOAD
/* Don't load .exit sections */
if (strstarts(info->secstrings+info->sechdrs[i].sh_name, ".exit"))
info->sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
#endif
}

info->index.mod = find_sec(info->hdr, info->sechdrs, info->secstrings,
".gnu.linkonce.this_module");
if (!info->index.mod) {
printk(KERN_WARNING "No module found in object\n");
return ERR_PTR(-ENOEXEC);
}
/* This is temporary: point mod into copy of data. */
mod = (void *)info->sechdrs[info->index.mod].sh_addr;

if (info->index.sym == 0) {
printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
mod->name);
return ERR_PTR(-ENOEXEC);
}

info->index.vers = find_sec(info->hdr, info->sechdrs, info->secstrings, "__versions");
info->index.info = find_sec(info->hdr, info->sechdrs, info->secstrings, ".modinfo");
info->index.pcpu = find_pcpusec(info->hdr, info->sechdrs, info->secstrings);

/* Don't keep modinfo and version sections. */
info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;

/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
return ERR_PTR(-ENOEXEC);

return mod;

truncated:
printk(KERN_ERR "Module len %lu truncated\n", info->len);
return ERR_PTR(-ENOEXEC);
}

static int check_modinfo(struct module *mod,
const Elf_Shdr *sechdrs,
unsigned int infoindex, unsigned int versindex)
Expand Down Expand Up @@ -2412,13 +2497,7 @@ static noinline struct module *load_module(void __user *umod,
unsigned long len,
const char __user *uargs)
{
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
char *secstrings, *args, *strtab = NULL;
unsigned int i;
unsigned int symindex = 0;
unsigned int strindex = 0;
unsigned int modindex, versindex, infoindex, pcpuindex;
struct load_info info = { NULL, };
struct module *mod;
long err;
unsigned long symoffs, stroffs, *strmap;
Expand All @@ -2429,80 +2508,28 @@ static noinline struct module *load_module(void __user *umod,
DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
umod, len, uargs);

err = copy_and_check(&hdr, umod, len);
err = copy_and_check(&info, umod, len);
if (err)
return ERR_PTR(err);

/* Convenience variables */
sechdrs = (void *)hdr + hdr->e_shoff;
secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
sechdrs[0].sh_addr = 0;

for (i = 1; i < hdr->e_shnum; i++) {
if (sechdrs[i].sh_type != SHT_NOBITS
&& len < sechdrs[i].sh_offset + sechdrs[i].sh_size)
goto truncated;

/* Mark all sections sh_addr with their address in the
temporary image. */
sechdrs[i].sh_addr = (size_t)hdr + sechdrs[i].sh_offset;

/* Internal symbols and strings. */
if (sechdrs[i].sh_type == SHT_SYMTAB) {
symindex = i;
strindex = sechdrs[i].sh_link;
strtab = (char *)hdr + sechdrs[strindex].sh_offset;
}
#ifndef CONFIG_MODULE_UNLOAD
/* Don't load .exit sections */
if (strstarts(secstrings+sechdrs[i].sh_name, ".exit"))
sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
#endif
}

modindex = find_sec(hdr, sechdrs, secstrings,
".gnu.linkonce.this_module");
if (!modindex) {
printk(KERN_WARNING "No module found in object\n");
err = -ENOEXEC;
goto free_hdr;
}
/* This is temporary: point mod into copy of data. */
mod = (void *)sechdrs[modindex].sh_addr;

if (symindex == 0) {
printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
mod->name);
err = -ENOEXEC;
goto free_hdr;
}

versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);

/* Don't keep modinfo and version sections. */
sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC;

/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(sechdrs, versindex, mod)) {
err = -ENOEXEC;
mod = setup_load_info(&info);
if (IS_ERR(mod)) {
err = PTR_ERR(mod);
goto free_hdr;
}

err = check_modinfo(mod, sechdrs, infoindex, versindex);
err = check_modinfo(mod, info.sechdrs, info.index.info, info.index.vers);
if (err)
goto free_hdr;

/* Now copy in args */
args = strndup_user(uargs, ~0UL >> 1);
if (IS_ERR(args)) {
err = PTR_ERR(args);
info.args = strndup_user(uargs, ~0UL >> 1);
if (IS_ERR(info.args)) {
err = PTR_ERR(info.args);
goto free_hdr;
}

strmap = kzalloc(BITS_TO_LONGS(sechdrs[strindex].sh_size)
strmap = kzalloc(BITS_TO_LONGS(info.sechdrs[info.index.str].sh_size)
* sizeof(long), GFP_KERNEL);
if (!strmap) {
err = -ENOMEM;
Expand All @@ -2512,30 +2539,30 @@ static noinline struct module *load_module(void __user *umod,
mod->state = MODULE_STATE_COMING;

/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(hdr, sechdrs, secstrings, mod);
err = module_frob_arch_sections(info.hdr, info.sechdrs, info.secstrings, mod);
if (err < 0)
goto free_mod;

if (pcpuindex) {
if (info.index.pcpu) {
/* We have a special allocation for this section. */
err = percpu_modalloc(mod, sechdrs[pcpuindex].sh_size,
sechdrs[pcpuindex].sh_addralign);
err = percpu_modalloc(mod, info.sechdrs[info.index.pcpu].sh_size,
info.sechdrs[info.index.pcpu].sh_addralign);
if (err)
goto free_mod;
sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
info.sechdrs[info.index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
}
/* Keep this around for failure path. */
percpu = mod_percpu(mod);

/* Determine total sizes, and put offsets in sh_entsize. For now
this is done generically; there doesn't appear to be any
special cases for the architectures. */
layout_sections(mod, hdr, sechdrs, secstrings);
symoffs = layout_symtab(mod, sechdrs, symindex, strindex, hdr,
secstrings, &stroffs, strmap);
layout_sections(mod, info.hdr, info.sechdrs, info.secstrings);
symoffs = layout_symtab(mod, info.sechdrs, info.index.sym, info.index.str, info.hdr,
info.secstrings, &stroffs, strmap);

/* Allocate and move to the final place */
mod = move_module(mod, hdr, sechdrs, secstrings, modindex);
mod = move_module(mod, info.hdr, info.sechdrs, info.secstrings, info.index.mod);
if (IS_ERR(mod)) {
err = PTR_ERR(mod);
goto free_percpu;
Expand All @@ -2548,50 +2575,50 @@ static noinline struct module *load_module(void __user *umod,

/* Now we've got everything in the final locations, we can
* find optional sections. */
find_module_sections(mod, hdr, sechdrs, secstrings);
find_module_sections(mod, info.hdr, info.sechdrs, info.secstrings);

err = check_module_license_and_versions(mod, sechdrs);
err = check_module_license_and_versions(mod, info.sechdrs);
if (err)
goto free_unload;

/* Set up MODINFO_ATTR fields */
setup_modinfo(mod, sechdrs, infoindex);
setup_modinfo(mod, info.sechdrs, info.index.info);

/* Fix up syms, so that st_value is a pointer to location. */
err = simplify_symbols(sechdrs, symindex, strtab, versindex, pcpuindex,
err = simplify_symbols(info.sechdrs, info.index.sym, info.strtab, info.index.vers, info.index.pcpu,
mod);
if (err < 0)
goto cleanup;

err = apply_relocations(mod, hdr, sechdrs, symindex, strindex);
err = apply_relocations(mod, info.hdr, info.sechdrs, info.index.sym, info.index.str);
if (err < 0)
goto cleanup;

/* Set up and sort exception table */
mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
mod->extable = section_objs(info.hdr, info.sechdrs, info.secstrings, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
sort_extable(mod->extable, mod->extable + mod->num_exentries);

/* Finally, copy percpu area over. */
percpu_modcopy(mod, (void *)sechdrs[pcpuindex].sh_addr,
sechdrs[pcpuindex].sh_size);
percpu_modcopy(mod, (void *)info.sechdrs[info.index.pcpu].sh_addr,
info.sechdrs[info.index.pcpu].sh_size);

add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex,
symoffs, stroffs, secstrings, strmap);
add_kallsyms(mod, info.sechdrs, info.hdr->e_shnum, info.index.sym, info.index.str,
symoffs, stroffs, info.secstrings, strmap);
kfree(strmap);
strmap = NULL;

if (!mod->taints)
debug = section_objs(hdr, sechdrs, secstrings, "__verbose",
debug = section_objs(info.hdr, info.sechdrs, info.secstrings, "__verbose",
sizeof(*debug), &num_debug);

err = module_finalize(hdr, sechdrs, mod);
err = module_finalize(info.hdr, info.sechdrs, mod);
if (err < 0)
goto cleanup;

flush_module_icache(mod);

mod->args = args;
mod->args = info.args;

/* Now sew it into the lists so we can get lockdep and oops
* info during argument parsing. Noone should access us, since
Expand Down Expand Up @@ -2625,11 +2652,11 @@ static noinline struct module *load_module(void __user *umod,
if (err < 0)
goto unlink;

add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
add_sect_attrs(mod, info.hdr->e_shnum, info.secstrings, info.sechdrs);
add_notes_attrs(mod, info.hdr->e_shnum, info.secstrings, info.sechdrs);

/* Get rid of temporary copy */
vfree(hdr);
vfree(info.hdr);

trace_module_load(mod);

Expand Down Expand Up @@ -2657,16 +2684,11 @@ static noinline struct module *load_module(void __user *umod,
free_percpu:
free_percpu(percpu);
free_mod:
kfree(args);
kfree(info.args);
kfree(strmap);
free_hdr:
vfree(hdr);
vfree(info.hdr);
return ERR_PTR(err);

truncated:
printk(KERN_ERR "Module len %lu truncated\n", len);
err = -ENOEXEC;
goto free_hdr;
}

/* Call module constructors. */
Expand Down

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