Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-24 05:02:12 +00:00
Code Issues Packages Projects Releases Wiki Activity

Modules updates for v5.8

Browse Source 
Summary of modules changes for the 5.8 merge window:
 
 - Harden CONFIG_STRICT_MODULE_RWX by rejecting any module that has
   SHF_WRITE|SHF_EXECINSTR sections
 - Remove and clean up nested #ifdefs, as it makes code hard to read
 
 Signed-off-by: Jessica Yu <jeyu@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJEBAABCAAuFiEEVrp26glSWYuDNrCUwEV+OM47wXIFAl7Z+qkQHGpleXVAa2Vy
 bmVsLm9yZwAKCRDARX44zjvBcm+vEACo/JelhaEDjjLzVuTBN4FQfXgBRbh6CGeF
 br7J1VtI9B0Coun0wfrDewwDieB2uHXQqivdC+KzNGXrBVhvFNLWuTTFcG7yce0K
 KZlbVREpiTRlenEa6A5EdIdvH0Ttg/+PFfkvOvvQOrbx5woZKptG49VdII9mhPuE
 LKnZk1xrK6jQLbOCPtUjyfB+eLqi0swhwstcfdIPUXsi2HtuLKmu7JPRpbW3Yz1v
 0Y9xix7ByTSg+wsphiKgvDnoJ9TYC3bFlAwpw+A+tsOKE0pmyetWKvkJ/hH42W9D
 7w6odSlG85d4ZExO2K8fHHsKmW2HgWx0cgLFf91sXCALqRYNjwTRkXH2OBXggLsz
 n3k8PmTRkDwS1oElrNG9E4LjKhjFbZZpP4kz+VlVe7YAsnlYpOBOcroTuaiuSV/A
 xmAP6mHgVAeUugwF5vHAPV4mwGJBLUVcvHENzge4jnyl/rSHsWE7hhwLnik9qkua
 cWINAVhBJpQvk3nrDr0dmUAXRJ7CXXtyPBbNh8ivvA4XeDNBLcYr8mcHPLpAoN4C
 xVcTRBxDXTRkw246zlQRcTySVpovtSv2C+IiaaHxA3j7lo4C1xhj6ihUIKz3Z1/A
 70zvBxmg3zpMwZWiRGeasAIu69a0qvBh0AOfVTbHBrIp5RokibtdoyuOu7ZGOU9B
 Un1WJNrSYQ==
 =OlVv
 -----END PGP SIGNATURE-----

Merge tag 'modules-for-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull module updates from Jessica Yu:

 - Harden CONFIG_STRICT_MODULE_RWX by rejecting any module that has
   SHF_WRITE|SHF_EXECINSTR sections

 - Remove and clean up nested #ifdefs, as it makes code hard to read

* tag 'modules-for-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: Harden STRICT_MODULE_RWX
  module: break nested ARCH_HAS_STRICT_MODULE_RWX and STRICT_MODULE_RWX #ifdefs
This commit is contained in:
Linus Torvalds 2020-06-05 12:31:16 -07:00
commit 084623e468
1 changed files with 40 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
kernel/module.c
View File

@ -1946,7 +1946,6 @@ static void mod_sysfs_teardown(struct module *mod)
mod_sysfs_fini(mod);
}
#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
/*
* LKM RO/NX protection: protect module's text/ro-data
* from modification and any data from execution.
@ -1960,6 +1959,14 @@ static void mod_sysfs_teardown(struct module *mod)
*
* These values are always page-aligned (as is base)
*/
/*
* Since some arches are moving towards PAGE_KERNEL module allocations instead
* of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the
* CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of
* whether we are strict.
*/
#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
static void frob_text(const struct module_layout *layout,
int (*set_memory)(unsigned long start, int num_pages))
{
@ -1969,6 +1976,15 @@ static void frob_text(const struct module_layout *layout,
layout->text_size >> PAGE_SHIFT);
}
static void module_enable_x(const struct module *mod)
{
frob_text(&mod->core_layout, set_memory_x);
frob_text(&mod->init_layout, set_memory_x);
}
#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
static void module_enable_x(const struct module *mod) { }
#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
#ifdef CONFIG_STRICT_MODULE_RWX
static void frob_rodata(const struct module_layout *layout,
int (*set_memory)(unsigned long start, int num_pages))
@ -2026,20 +2042,29 @@ static void module_enable_nx(const struct module *mod)
frob_writable_data(&mod->init_layout, set_memory_nx);
}
static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod)
{
const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
int i;
for (i = 0; i < hdr->e_shnum; i++) {
if ((sechdrs[i].sh_flags & shf_wx) == shf_wx)
return -ENOEXEC;
}
return 0;
}
#else /* !CONFIG_STRICT_MODULE_RWX */
static void module_enable_nx(const struct module *mod) { }
static void module_enable_ro(const struct module *mod, bool after_init) {}
#endif /* CONFIG_STRICT_MODULE_RWX */
static void module_enable_x(const struct module *mod)
static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod)
{
frob_text(&mod->core_layout, set_memory_x);
frob_text(&mod->init_layout, set_memory_x);
return 0;
}
#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
static void module_enable_nx(const struct module *mod) { }
static void module_enable_x(const struct module *mod) { }
#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
#endif /* CONFIG_STRICT_MODULE_RWX */
#ifdef CONFIG_LIVEPATCH
/*
@ -3385,6 +3410,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
if (err < 0)
return ERR_PTR(err);
err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
info->secstrings, info->mod);
if (err < 0)
return ERR_PTR(err);
/* We will do a special allocation for per-cpu sections later. */
info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;