Le 17/05/2021 à 05:28, Jordan Niethe a écrit :
Make module_alloc() use PAGE_KERNEL protections instead of
PAGE_KERNEL_EXEX if Strict Module RWX is enabled.
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
---
v14: - Split out from powerpc: Set ARCH_HAS_STRICT_MODULE_RWX
- Add and use strict_module_rwx_enabled() helper
---
arch/powerpc/include/asm/mmu.h | 5 +++++
arch/powerpc/kernel/module.c | 4 +++-
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 607168b1aef4..7710bf0cbf8a 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -357,6 +357,11 @@ static inline bool strict_kernel_rwx_enabled(void)
return false;
}
#endif
+
+static inline bool strict_module_rwx_enabled(void)
+{
+ return IS_ENABLED(CONFIG_STRICT_MODULE_RWX) &&
strict_kernel_rwx_enabled();
+}
Looking at arch/Kconfig, I have the feeling that it is possible to select CONFIG_STRICT_MODULE_RWX
without selecting CONFIG_STRICT_KERNEL_RWX.
In that case, strict_kernel_rwx_enabled() will return false.
#endif /* !__ASSEMBLY__ */
/* The kernel use the constants below to index in the page sizes array.
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index 3f35c8d20be7..ed04a3ba66fe 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -92,12 +92,14 @@ int module_finalize(const Elf_Ehdr *hdr,
static __always_inline void *
__module_alloc(unsigned long size, unsigned long start, unsigned long end)
{
+ pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL :
PAGE_KERNEL_EXEC;
+
/*
* Don't do huge page allocations for modules yet until more testing
* is done. STRICT_MODULE_RWX may require extra work to support this
* too.
*/
- return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL,
PAGE_KERNEL_EXEC,
+ return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL, prot,
VM_FLUSH_RESET_PERMS | VM_NO_HUGE_VMAP,
NUMA_NO_NODE, __builtin_return_address(0));
}
