Modules updates for v5.8
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
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084623e468
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@ -1946,7 +1946,6 @@ static void mod_sysfs_teardown(struct module *mod)
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mod_sysfs_fini(mod);
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mod_sysfs_fini(mod);
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}
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}
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#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
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/*
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/*
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* LKM RO/NX protection: protect module's text/ro-data
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* LKM RO/NX protection: protect module's text/ro-data
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* from modification and any data from execution.
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* from modification and any data from execution.
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@ -1960,6 +1959,14 @@ static void mod_sysfs_teardown(struct module *mod)
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*
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*
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* These values are always page-aligned (as is base)
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* These values are always page-aligned (as is base)
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*/
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*/
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/*
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* Since some arches are moving towards PAGE_KERNEL module allocations instead
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* of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the
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* CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of
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* whether we are strict.
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*/
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#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
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static void frob_text(const struct module_layout *layout,
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static void frob_text(const struct module_layout *layout,
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int (*set_memory)(unsigned long start, int num_pages))
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int (*set_memory)(unsigned long start, int num_pages))
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{
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{
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@ -1969,6 +1976,15 @@ static void frob_text(const struct module_layout *layout,
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layout->text_size >> PAGE_SHIFT);
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layout->text_size >> PAGE_SHIFT);
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}
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}
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static void module_enable_x(const struct module *mod)
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{
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frob_text(&mod->core_layout, set_memory_x);
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frob_text(&mod->init_layout, set_memory_x);
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}
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#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
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static void module_enable_x(const struct module *mod) { }
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#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
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#ifdef CONFIG_STRICT_MODULE_RWX
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#ifdef CONFIG_STRICT_MODULE_RWX
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static void frob_rodata(const struct module_layout *layout,
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static void frob_rodata(const struct module_layout *layout,
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int (*set_memory)(unsigned long start, int num_pages))
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int (*set_memory)(unsigned long start, int num_pages))
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@ -2026,20 +2042,29 @@ static void module_enable_nx(const struct module *mod)
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frob_writable_data(&mod->init_layout, set_memory_nx);
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frob_writable_data(&mod->init_layout, set_memory_nx);
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}
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}
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static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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char *secstrings, struct module *mod)
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{
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const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
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int i;
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for (i = 0; i < hdr->e_shnum; i++) {
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if ((sechdrs[i].sh_flags & shf_wx) == shf_wx)
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return -ENOEXEC;
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}
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return 0;
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}
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#else /* !CONFIG_STRICT_MODULE_RWX */
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#else /* !CONFIG_STRICT_MODULE_RWX */
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static void module_enable_nx(const struct module *mod) { }
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static void module_enable_nx(const struct module *mod) { }
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static void module_enable_ro(const struct module *mod, bool after_init) {}
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static void module_enable_ro(const struct module *mod, bool after_init) {}
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#endif /* CONFIG_STRICT_MODULE_RWX */
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static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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static void module_enable_x(const struct module *mod)
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char *secstrings, struct module *mod)
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{
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{
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frob_text(&mod->core_layout, set_memory_x);
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return 0;
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frob_text(&mod->init_layout, set_memory_x);
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}
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}
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#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
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#endif /* CONFIG_STRICT_MODULE_RWX */
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static void module_enable_nx(const struct module *mod) { }
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static void module_enable_x(const struct module *mod) { }
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#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
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#ifdef CONFIG_LIVEPATCH
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#ifdef CONFIG_LIVEPATCH
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/*
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/*
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@ -3385,6 +3410,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
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if (err < 0)
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if (err < 0)
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return ERR_PTR(err);
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return ERR_PTR(err);
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err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
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info->secstrings, info->mod);
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if (err < 0)
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return ERR_PTR(err);
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/* We will do a special allocation for per-cpu sections later. */
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/* We will do a special allocation for per-cpu sections later. */
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info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
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info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
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