From: Kirill Korotaev Date: Thu, 7 Sep 2006 10:17:04 +0000 (+0400) Subject: [PATCH] IA64,sparc: local DoS with corrupted ELFs X-Git-Tag: v2.6.18-rc7~25 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3a459756810912d2c2bf188cef566af255936b4d;p=linux-2.6 [PATCH] IA64,sparc: local DoS with corrupted ELFs This prevents cross-region mappings on IA64 and SPARC which could lead to system crash. They were correctly trapped for normal mmap() calls, but not for the kernel internal calls generated by executable loading. This code just moves the architecture-specific cross-region checks into an arch-specific "arch_mmap_check()" macro, and defines that for the architectures that needed it (ia64, sparc and sparc64). Architectures that don't have any special requirements can just ignore the new cross-region check, since the mmap() code will just notice on its own when the macro isn't defined. Signed-off-by: Pavel Emelianov Signed-off-by: Kirill Korotaev Acked-by: David Miller Signed-off-by: Greg Kroah-Hartman [ Cleaned up to not affect architectures that don't need it ] Signed-off-by: Linus Torvalds --- diff --git a/arch/ia64/kernel/sys_ia64.c b/arch/ia64/kernel/sys_ia64.c index 40722d8860..9ef62a3fbf 100644 --- a/arch/ia64/kernel/sys_ia64.c +++ b/arch/ia64/kernel/sys_ia64.c @@ -163,10 +163,25 @@ 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); @@ -188,17 +203,6 @@ 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 a41c8a5c20..94ff58c9d4 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 054d0abdb7..bf5f14ee73 100644 --- a/arch/sparc64/kernel/sys_sparc.c +++ b/arch/sparc64/kernel/sys_sparc.c @@ -548,6 +548,26 @@ 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 >= STACK_TOP32) + return -EINVAL; + + if ((flags & MAP_FIXED) && addr > STACK_TOP32 - len) + return -EINVAL; + } else { + if (len >= VA_EXCLUDE_START) + return -EINVAL; + + if ((flags & MAP_FIXED) && invalid_64bit_range(addr, len)) + 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, @@ -563,27 +583,11 @@ 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 >= STACK_TOP32) - goto out_putf; - - if ((flags & MAP_FIXED) && addr > STACK_TOP32 - len) - goto out_putf; - } else { - if (len >= VA_EXCLUDE_START) - goto out_putf; - - if ((flags & MAP_FIXED) && invalid_64bit_range(addr, len)) - 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 6ba179f127..c73b87832a 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 88d1886abf..b7dc40bc68 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 6fd878e614..8cc1860be6 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 c1868ecdbc..e66a0b524a 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); @@ -913,6 +917,10 @@ 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) @@ -1859,6 +1867,7 @@ 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) @@ -1867,6 +1876,12 @@ 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? */ @@ -1907,8 +1922,6 @@ 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))