| Message ID | 865b5c872814e3291fe7afabcc110f53b3457b56.1634190022.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Fix LKDTM for PPC64/IA64/PARISC | expand |
Excerpts from Christophe Leroy's message of October 14, 2021 3:49 pm: > dereference_function_descriptor() and > dereference_kernel_function_descriptor() are identical on the > three architectures implementing them. > > Make them common and put them out-of-line in kernel/extable.c > which is one of the users and has similar type of functions. We should be moving more stuff out of extable.c (including all the kernel address tests). lib/kimage.c or kelf.c or something. It could be after your series though. > > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > --- > arch/ia64/include/asm/sections.h | 19 ------------------- > arch/parisc/include/asm/sections.h | 9 --------- > arch/parisc/kernel/process.c | 21 --------------------- > arch/powerpc/include/asm/sections.h | 23 ----------------------- > include/asm-generic/sections.h | 2 ++ > kernel/extable.c | 23 ++++++++++++++++++++++- > 6 files changed, 24 insertions(+), 73 deletions(-) > > diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h > index 1aaed8882294..96c9bb500c34 100644 > --- a/arch/ia64/include/asm/sections.h > +++ b/arch/ia64/include/asm/sections.h > @@ -31,23 +31,4 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b > extern char __start_unwind[], __end_unwind[]; > extern char __start_ivt_text[], __end_ivt_text[]; > > -#undef dereference_function_descriptor > -static inline void *dereference_function_descriptor(void *ptr) > -{ > - struct fdesc *desc = ptr; > - void *p; > - > - if (!get_kernel_nofault(p, (void *)&desc->addr)) > - ptr = p; > - return ptr; > -} > - > -#undef dereference_kernel_function_descriptor > -static inline void *dereference_kernel_function_descriptor(void *ptr) > -{ > - if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd) > - return ptr; > - return dereference_function_descriptor(ptr); > -} > - > #endif /* _ASM_IA64_SECTIONS_H */ > diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h > index 37b34b357cb5..6b1fe22baaf5 100644 > --- a/arch/parisc/include/asm/sections.h > +++ b/arch/parisc/include/asm/sections.h > @@ -13,13 +13,4 @@ typedef Elf64_Fdesc func_desc_t; > > extern char __alt_instructions[], __alt_instructions_end[]; > > -#ifdef CONFIG_64BIT > - > -#undef dereference_function_descriptor > -void *dereference_function_descriptor(void *); > - > -#undef dereference_kernel_function_descriptor > -void *dereference_kernel_function_descriptor(void *); > -#endif > - > #endif > diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c > index 38ec4ae81239..7382576b52a8 100644 > --- a/arch/parisc/kernel/process.c > +++ b/arch/parisc/kernel/process.c > @@ -266,27 +266,6 @@ get_wchan(struct task_struct *p) > return 0; > } > > -#ifdef CONFIG_64BIT > -void *dereference_function_descriptor(void *ptr) > -{ > - Elf64_Fdesc *desc = ptr; > - void *p; > - > - if (!get_kernel_nofault(p, (void *)&desc->addr)) > - ptr = p; > - return ptr; > -} > - > -void *dereference_kernel_function_descriptor(void *ptr) > -{ > - if (ptr < (void *)__start_opd || > - ptr >= (void *)__end_opd) > - return ptr; > - > - return dereference_function_descriptor(ptr); > -} > -#endif > - > static inline unsigned long brk_rnd(void) > { > return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; > diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h > index 1322d7b2f1a3..fbfe1957edbe 100644 > --- a/arch/powerpc/include/asm/sections.h > +++ b/arch/powerpc/include/asm/sections.h > @@ -72,29 +72,6 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end) > (unsigned long)_stext < end; > } > > -#ifdef PPC64_ELF_ABI_v1 > - > -#undef dereference_function_descriptor > -static inline void *dereference_function_descriptor(void *ptr) > -{ > - struct ppc64_opd_entry *desc = ptr; > - void *p; > - > - if (!get_kernel_nofault(p, (void *)&desc->addr)) > - ptr = p; > - return ptr; > -} > - > -#undef dereference_kernel_function_descriptor > -static inline void *dereference_kernel_function_descriptor(void *ptr) > -{ > - if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd) > - return ptr; > - > - return dereference_function_descriptor(ptr); > -} > -#endif /* PPC64_ELF_ABI_v1 */ > - > #endif > > #endif /* __KERNEL__ */ > diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h > index cbec7d5f1678..76163883c6ff 100644 > --- a/include/asm-generic/sections.h > +++ b/include/asm-generic/sections.h > @@ -60,6 +60,8 @@ extern __visible const void __nosave_begin, __nosave_end; > > /* Function descriptor handling (if any). Override in asm/sections.h */ > #ifdef HAVE_FUNCTION_DESCRIPTORS > +void *dereference_function_descriptor(void *ptr); > +void *dereference_kernel_function_descriptor(void *ptr); > #else > #define dereference_function_descriptor(p) ((void *)(p)) > #define dereference_kernel_function_descriptor(p) ((void *)(p)) > diff --git a/kernel/extable.c b/kernel/extable.c > index b0ea5eb0c3b4..013ccffade11 100644 > --- a/kernel/extable.c > +++ b/kernel/extable.c > @@ -3,6 +3,7 @@ > Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM. > > */ > +#include <linux/elf.h> > #include <linux/ftrace.h> > #include <linux/memory.h> > #include <linux/extable.h> > @@ -159,12 +160,32 @@ int kernel_text_address(unsigned long addr) > } > > /* > - * On some architectures (PPC64, IA64) function pointers > + * On some architectures (PPC64, IA64, PARISC) function pointers > * are actually only tokens to some data that then holds the > * real function address. As a result, to find if a function > * pointer is part of the kernel text, we need to do some > * special dereferencing first. > */ > +#ifdef HAVE_FUNCTION_DESCRIPTORS > +void *dereference_function_descriptor(void *ptr) > +{ > + func_desc_t *desc = ptr; > + void *p; > + > + if (!get_kernel_nofault(p, (void *)&desc->addr)) > + ptr = p; I know you're just copying existing code. This seems a bit risky though. I don't think anything good could come of just treating the descriptor address like a function entry address if we failed to load from it for whatever reason. Existing callers might be benign but the API is not good. It should give a nice fail return or BUG. If we change that then we should also change the name and pass the correct type to it too. Thanks, Nick
diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h index 1aaed8882294..96c9bb500c34 100644 --- a/arch/ia64/include/asm/sections.h +++ b/arch/ia64/include/asm/sections.h @@ -31,23 +31,4 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b extern char __start_unwind[], __end_unwind[]; extern char __start_ivt_text[], __end_ivt_text[]; -#undef dereference_function_descriptor -static inline void *dereference_function_descriptor(void *ptr) -{ - struct fdesc *desc = ptr; - void *p; - - if (!get_kernel_nofault(p, (void *)&desc->addr)) - ptr = p; - return ptr; -} - -#undef dereference_kernel_function_descriptor -static inline void *dereference_kernel_function_descriptor(void *ptr) -{ - if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd) - return ptr; - return dereference_function_descriptor(ptr); -} - #endif /* _ASM_IA64_SECTIONS_H */ diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h index 37b34b357cb5..6b1fe22baaf5 100644 --- a/arch/parisc/include/asm/sections.h +++ b/arch/parisc/include/asm/sections.h @@ -13,13 +13,4 @@ typedef Elf64_Fdesc func_desc_t; extern char __alt_instructions[], __alt_instructions_end[]; -#ifdef CONFIG_64BIT - -#undef dereference_function_descriptor -void *dereference_function_descriptor(void *); - -#undef dereference_kernel_function_descriptor -void *dereference_kernel_function_descriptor(void *); -#endif - #endif diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index 38ec4ae81239..7382576b52a8 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -266,27 +266,6 @@ get_wchan(struct task_struct *p) return 0; } -#ifdef CONFIG_64BIT -void *dereference_function_descriptor(void *ptr) -{ - Elf64_Fdesc *desc = ptr; - void *p; - - if (!get_kernel_nofault(p, (void *)&desc->addr)) - ptr = p; - return ptr; -} - -void *dereference_kernel_function_descriptor(void *ptr) -{ - if (ptr < (void *)__start_opd || - ptr >= (void *)__end_opd) - return ptr; - - return dereference_function_descriptor(ptr); -} -#endif - static inline unsigned long brk_rnd(void) { return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index 1322d7b2f1a3..fbfe1957edbe 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -72,29 +72,6 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end) (unsigned long)_stext < end; } -#ifdef PPC64_ELF_ABI_v1 - -#undef dereference_function_descriptor -static inline void *dereference_function_descriptor(void *ptr) -{ - struct ppc64_opd_entry *desc = ptr; - void *p; - - if (!get_kernel_nofault(p, (void *)&desc->addr)) - ptr = p; - return ptr; -} - -#undef dereference_kernel_function_descriptor -static inline void *dereference_kernel_function_descriptor(void *ptr) -{ - if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd) - return ptr; - - return dereference_function_descriptor(ptr); -} -#endif /* PPC64_ELF_ABI_v1 */ - #endif #endif /* __KERNEL__ */ diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index cbec7d5f1678..76163883c6ff 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -60,6 +60,8 @@ extern __visible const void __nosave_begin, __nosave_end; /* Function descriptor handling (if any). Override in asm/sections.h */ #ifdef HAVE_FUNCTION_DESCRIPTORS +void *dereference_function_descriptor(void *ptr); +void *dereference_kernel_function_descriptor(void *ptr); #else #define dereference_function_descriptor(p) ((void *)(p)) #define dereference_kernel_function_descriptor(p) ((void *)(p)) diff --git a/kernel/extable.c b/kernel/extable.c index b0ea5eb0c3b4..013ccffade11 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -3,6 +3,7 @@ Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM. */ +#include <linux/elf.h> #include <linux/ftrace.h> #include <linux/memory.h> #include <linux/extable.h> @@ -159,12 +160,32 @@ int kernel_text_address(unsigned long addr) } /* - * On some architectures (PPC64, IA64) function pointers + * On some architectures (PPC64, IA64, PARISC) function pointers * are actually only tokens to some data that then holds the * real function address. As a result, to find if a function * pointer is part of the kernel text, we need to do some * special dereferencing first. */ +#ifdef HAVE_FUNCTION_DESCRIPTORS +void *dereference_function_descriptor(void *ptr) +{ + func_desc_t *desc = ptr; + void *p; + + if (!get_kernel_nofault(p, (void *)&desc->addr)) + ptr = p; + return ptr; +} + +void *dereference_kernel_function_descriptor(void *ptr) +{ + if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd) + return ptr; + + return dereference_function_descriptor(ptr); +} +#endif + int func_ptr_is_kernel_text(void *ptr) { unsigned long addr;