Re: [PATCH v3] powerpc/64s/pgtable: fix an undefined behaviour
On Thu, 5 Mar 2020 23:48:52 -0500, Qian Cai wrote: > Booting a power9 server with hash MMU could trigger an undefined > behaviour because pud_offset(p4d, 0) will do, > > 0 >> (PAGE_SHIFT:16 + PTE_INDEX_SIZE:8 + H_PMD_INDEX_SIZE:10) > > Fix it by converting pud_index() and friends to static inline > functions. > > [...] Applied to powerpc/next. [1/1] powerpc/64s/pgtable: fix an undefined behaviour https://git.kernel.org/powerpc/c/c2e929b18cea6cbf71364f22d742d9aad7f4677a cheers
Re: [PATCH v3] powerpc/64s/pgtable: fix an undefined behaviour
> On Mar 6, 2020, at 1:56 AM, Christophe Leroy wrote: > > > > Le 06/03/2020 à 05:48, Qian Cai a écrit : >> Booting a power9 server with hash MMU could trigger an undefined >> behaviour because pud_offset(p4d, 0) will do, >> 0 >> (PAGE_SHIFT:16 + PTE_INDEX_SIZE:8 + H_PMD_INDEX_SIZE:10) >> Fix it by converting pud_index() and friends to static inline >> functions. >> UBSAN: shift-out-of-bounds in arch/powerpc/mm/ptdump/ptdump.c:282:15 >> shift exponent 34 is too large for 32-bit type 'int' >> CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4-next-20200303+ #13 >> Call Trace: >> dump_stack+0xf4/0x164 (unreliable) >> ubsan_epilogue+0x18/0x78 >> __ubsan_handle_shift_out_of_bounds+0x160/0x21c >> walk_pagetables+0x2cc/0x700 >> walk_pud at arch/powerpc/mm/ptdump/ptdump.c:282 >> (inlined by) walk_pagetables at arch/powerpc/mm/ptdump/ptdump.c:311 >> ptdump_check_wx+0x8c/0xf0 >> mark_rodata_ro+0x48/0x80 >> kernel_init+0x74/0x194 >> ret_from_kernel_thread+0x5c/0x74 >> Suggested-by: Christophe Leroy >> Signed-off-by: Qian Cai > > Reviewed-by: Christophe Leroy Michael, can you take a look at this patch when you have a chance? It looks falling through the cracks. > >> --- >> v3: convert pud_index() etc to static inline functions. >> v2: convert pud_offset() etc to static inline functions. >> arch/powerpc/include/asm/book3s/64/pgtable.h | 23 >> 1 file changed, 19 insertions(+), 4 deletions(-) >> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h >> b/arch/powerpc/include/asm/book3s/64/pgtable.h >> index 201a69e6a355..bd432c6706b9 100644 >> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h >> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h >> @@ -998,10 +998,25 @@ extern struct page *pgd_page(pgd_t pgd); >> #define pud_page_vaddr(pud) __va(pud_val(pud) & ~PUD_MASKED_BITS) >> #define pgd_page_vaddr(pgd) __va(pgd_val(pgd) & ~PGD_MASKED_BITS) >> -#define pgd_index(address) (((address) >> (PGDIR_SHIFT)) & (PTRS_PER_PGD - >> 1)) >> -#define pud_index(address) (((address) >> (PUD_SHIFT)) & (PTRS_PER_PUD - 1)) >> -#define pmd_index(address) (((address) >> (PMD_SHIFT)) & (PTRS_PER_PMD - 1)) >> -#define pte_index(address) (((address) >> (PAGE_SHIFT)) & (PTRS_PER_PTE - >> 1)) >> +static inline unsigned long pgd_index(unsigned long address) >> +{ >> +return (address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1); >> +} >> + >> +static inline unsigned long pud_index(unsigned long address) >> +{ >> +return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1); >> +} >> + >> +static inline unsigned long pmd_index(unsigned long address) >> +{ >> +return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); >> +} >> + >> +static inline unsigned long pte_index(unsigned long address) >> +{ >> +return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); >> +} >>/* >> * Find an entry in a page-table-directory. We combine the address region
Re: [PATCH v3] powerpc/64s/pgtable: fix an undefined behaviour
Le 06/03/2020 à 05:48, Qian Cai a écrit : Booting a power9 server with hash MMU could trigger an undefined behaviour because pud_offset(p4d, 0) will do, 0 >> (PAGE_SHIFT:16 + PTE_INDEX_SIZE:8 + H_PMD_INDEX_SIZE:10) Fix it by converting pud_index() and friends to static inline functions. UBSAN: shift-out-of-bounds in arch/powerpc/mm/ptdump/ptdump.c:282:15 shift exponent 34 is too large for 32-bit type 'int' CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4-next-20200303+ #13 Call Trace: dump_stack+0xf4/0x164 (unreliable) ubsan_epilogue+0x18/0x78 __ubsan_handle_shift_out_of_bounds+0x160/0x21c walk_pagetables+0x2cc/0x700 walk_pud at arch/powerpc/mm/ptdump/ptdump.c:282 (inlined by) walk_pagetables at arch/powerpc/mm/ptdump/ptdump.c:311 ptdump_check_wx+0x8c/0xf0 mark_rodata_ro+0x48/0x80 kernel_init+0x74/0x194 ret_from_kernel_thread+0x5c/0x74 Suggested-by: Christophe Leroy Signed-off-by: Qian Cai Reviewed-by: Christophe Leroy --- v3: convert pud_index() etc to static inline functions. v2: convert pud_offset() etc to static inline functions. arch/powerpc/include/asm/book3s/64/pgtable.h | 23 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 201a69e6a355..bd432c6706b9 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -998,10 +998,25 @@ extern struct page *pgd_page(pgd_t pgd); #define pud_page_vaddr(pud) __va(pud_val(pud) & ~PUD_MASKED_BITS) #define pgd_page_vaddr(pgd) __va(pgd_val(pgd) & ~PGD_MASKED_BITS) -#define pgd_index(address) (((address) >> (PGDIR_SHIFT)) & (PTRS_PER_PGD - 1)) -#define pud_index(address) (((address) >> (PUD_SHIFT)) & (PTRS_PER_PUD - 1)) -#define pmd_index(address) (((address) >> (PMD_SHIFT)) & (PTRS_PER_PMD - 1)) -#define pte_index(address) (((address) >> (PAGE_SHIFT)) & (PTRS_PER_PTE - 1)) +static inline unsigned long pgd_index(unsigned long address) +{ + return (address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1); +} + +static inline unsigned long pud_index(unsigned long address) +{ + return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1); +} + +static inline unsigned long pmd_index(unsigned long address) +{ + return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); +} + +static inline unsigned long pte_index(unsigned long address) +{ + return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); +} /* * Find an entry in a page-table-directory. We combine the address region