From 05c19c4369b40357c726a224fe51a3f5ff21f9bd Mon Sep 17 00:00:00 2001 From: Kirill Korotaev Date: Sat, 11 Nov 2006 01:08:49 +0100 Subject: ia64/sparc: fix local DoS with corrupted ELFs (CVE-2006-4538) This patch prevents cross-region mappings on IA64 and SPARC which could lead to system crash. Adrian Bunk: Adapted to 2.6.16. Signed-Off-By: Kirill Korotaev Signed-off-by: Adrian Bunk --- arch/ia64/kernel/sys_ia64.c | 28 ++++++++++++++++------------ arch/sparc/kernel/sys_sparc.c | 27 +++++++++++++++------------ arch/sparc64/kernel/sys_sparc.c | 30 +++++++++++++++++------------- include/asm-ia64/mman.h | 8 ++++++++ include/asm-sparc/mman.h | 8 ++++++++ include/asm-sparc64/mman.h | 8 ++++++++ mm/mmap.c | 17 +++++++++++++++-- 7 files changed, 87 insertions(+), 39 deletions(-) diff --git a/arch/ia64/kernel/sys_ia64.c b/arch/ia64/kernel/sys_ia64.c index c7b943f10199..302e5b9bc9ae 100644 --- a/arch/ia64/kernel/sys_ia64.c +++ b/arch/ia64/kernel/sys_ia64.c @@ -164,10 +164,25 @@ sys_pipe (void) return retval; } +int ia64_mmap_check(unsigned long addr, unsigned long len, + unsigned long flags) +{ + unsigned long roff; + + /* + * Don't permit mappings into unmapped space, the virtual page table + * of a region, or across a region boundary. Note: RGN_MAP_LIMIT is + * equal to 2^n-PAGE_SIZE (for some integer n <= 61) and len > 0. + */ + roff = REGION_OFFSET(addr); + if ((len > RGN_MAP_LIMIT) || (roff > (RGN_MAP_LIMIT - len))) + return -EINVAL; + return 0; +} + static inline unsigned long do_mmap2 (unsigned long addr, unsigned long len, int prot, int flags, int fd, unsigned long pgoff) { - unsigned long roff; struct file *file = NULL; flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); @@ -189,17 +204,6 @@ do_mmap2 (unsigned long addr, unsigned long len, int prot, int flags, int fd, un goto out; } - /* - * Don't permit mappings into unmapped space, the virtual page table of a region, - * or across a region boundary. Note: RGN_MAP_LIMIT is equal to 2^n-PAGE_SIZE - * (for some integer n <= 61) and len > 0. - */ - roff = REGION_OFFSET(addr); - if ((len > RGN_MAP_LIMIT) || (roff > (RGN_MAP_LIMIT - len))) { - addr = -EINVAL; - goto out; - } - down_write(¤t->mm->mmap_sem); addr = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); up_write(¤t->mm->mmap_sem); diff --git a/arch/sparc/kernel/sys_sparc.c b/arch/sparc/kernel/sys_sparc.c index 0cdfc9d294b4..fc8cdcc206b8 100644 --- a/arch/sparc/kernel/sys_sparc.c +++ b/arch/sparc/kernel/sys_sparc.c @@ -219,6 +219,21 @@ out: return err; } +int sparc_mmap_check(unsigned long addr, unsigned long len, unsigned long flags) +{ + if (ARCH_SUN4C_SUN4 && + (len > 0x20000000 || + ((flags & MAP_FIXED) && + addr < 0xe0000000 && addr + len > 0x20000000))) + return -EINVAL; + + /* See asm-sparc/uaccess.h */ + if (len > TASK_SIZE - PAGE_SIZE || addr + len > TASK_SIZE - PAGE_SIZE) + return -EINVAL; + + return 0; +} + /* Linux version of mmap */ static unsigned long do_mmap2(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long fd, @@ -233,25 +248,13 @@ static unsigned long do_mmap2(unsigned long addr, unsigned long len, goto out; } - retval = -EINVAL; len = PAGE_ALIGN(len); - if (ARCH_SUN4C_SUN4 && - (len > 0x20000000 || - ((flags & MAP_FIXED) && - addr < 0xe0000000 && addr + len > 0x20000000))) - goto out_putf; - - /* See asm-sparc/uaccess.h */ - if (len > TASK_SIZE - PAGE_SIZE || addr + len > TASK_SIZE - PAGE_SIZE) - goto out_putf; - flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); down_write(¤t->mm->mmap_sem); retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); up_write(¤t->mm->mmap_sem); -out_putf: if (file) fput(file); out: diff --git a/arch/sparc64/kernel/sys_sparc.c b/arch/sparc64/kernel/sys_sparc.c index 5f8c822a2b4a..b7ebd48da112 100644 --- a/arch/sparc64/kernel/sys_sparc.c +++ b/arch/sparc64/kernel/sys_sparc.c @@ -322,6 +322,23 @@ asmlinkage long sparc64_personality(unsigned long personality) return ret; } +int sparc64_mmap_check(unsigned long addr, unsigned long len, + unsigned long flags) +{ + if (test_thread_flag(TIF_32BIT)) { + if (len > 0xf0000000UL || + ((flags & MAP_FIXED) && addr > 0xf0000000UL - len)) + return -EINVAL; + } else { + if (len > -PAGE_OFFSET || + ((flags & MAP_FIXED) && + addr < PAGE_OFFSET && addr + len > -PAGE_OFFSET)) + return -EINVAL; + } + + return 0; +} + /* Linux version of mmap */ asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long fd, @@ -337,24 +354,11 @@ asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len, } flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); len = PAGE_ALIGN(len); - retval = -EINVAL; - - if (test_thread_flag(TIF_32BIT)) { - if (len > 0xf0000000UL || - ((flags & MAP_FIXED) && addr > 0xf0000000UL - len)) - goto out_putf; - } else { - if (len > -PAGE_OFFSET || - ((flags & MAP_FIXED) && - addr < PAGE_OFFSET && addr + len > -PAGE_OFFSET)) - goto out_putf; - } down_write(¤t->mm->mmap_sem); retval = do_mmap(file, addr, len, prot, flags, off); up_write(¤t->mm->mmap_sem); -out_putf: if (file) fput(file); out: diff --git a/include/asm-ia64/mman.h b/include/asm-ia64/mman.h index 6ba179f12718..c73b87832a1e 100644 --- a/include/asm-ia64/mman.h +++ b/include/asm-ia64/mman.h @@ -22,4 +22,12 @@ #define MCL_CURRENT 1 /* lock all current mappings */ #define MCL_FUTURE 2 /* lock all future mappings */ +#ifdef __KERNEL__ +#ifndef __ASSEMBLY__ +#define arch_mmap_check ia64_mmap_check +int ia64_mmap_check(unsigned long addr, unsigned long len, + unsigned long flags); +#endif +#endif + #endif /* _ASM_IA64_MMAN_H */ diff --git a/include/asm-sparc/mman.h b/include/asm-sparc/mman.h index 88d1886abf3b..b7dc40bc68f4 100644 --- a/include/asm-sparc/mman.h +++ b/include/asm-sparc/mman.h @@ -35,4 +35,12 @@ #define MADV_FREE 0x5 /* (Solaris) contents can be freed */ +#ifdef __KERNEL__ +#ifndef __ASSEMBLY__ +#define arch_mmap_check sparc_mmap_check +int sparc_mmap_check(unsigned long addr, unsigned long len, + unsigned long flags); +#endif +#endif + #endif /* __SPARC_MMAN_H__ */ diff --git a/include/asm-sparc64/mman.h b/include/asm-sparc64/mman.h index 6fd878e61435..8cc1860be630 100644 --- a/include/asm-sparc64/mman.h +++ b/include/asm-sparc64/mman.h @@ -35,4 +35,12 @@ #define MADV_FREE 0x5 /* (Solaris) contents can be freed */ +#ifdef __KERNEL__ +#ifndef __ASSEMBLY__ +#define arch_mmap_check sparc64_mmap_check +int sparc64_mmap_check(unsigned long addr, unsigned long len, + unsigned long flags); +#endif +#endif + #endif /* __SPARC64_MMAN_H__ */ diff --git a/mm/mmap.c b/mm/mmap.c index 47556d2b3e90..fba355c06528 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -30,6 +30,10 @@ #include #include +#ifndef arch_mmap_check +#define arch_mmap_check(addr, len, flags) (0) +#endif + static void unmap_region(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end); @@ -906,6 +910,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, if (!len) return -EINVAL; + error = arch_mmap_check(addr, len, flags); + if (error) + return error; + /* Careful about overflows.. */ len = PAGE_ALIGN(len); if (!len || len > TASK_SIZE) @@ -1846,6 +1854,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len) unsigned long flags; struct rb_node ** rb_link, * rb_parent; pgoff_t pgoff = addr >> PAGE_SHIFT; + int error; len = PAGE_ALIGN(len); if (!len) @@ -1854,6 +1863,12 @@ unsigned long do_brk(unsigned long addr, unsigned long len) if ((addr + len) > TASK_SIZE || (addr + len) < addr) return -EINVAL; + flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; + + error = arch_mmap_check(addr, len, flags); + if (error) + return error; + /* * mlock MCL_FUTURE? */ @@ -1894,8 +1909,6 @@ unsigned long do_brk(unsigned long addr, unsigned long len) if (security_vm_enough_memory(len >> PAGE_SHIFT)) return -ENOMEM; - flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; - /* Can we just expand an old private anonymous mapping? */ if (vma_merge(mm, prev, addr, addr + len, flags, NULL, NULL, pgoff, NULL)) -- cgit v1.2.3