From 3a459756810912d2c2bf188cef566af255936b4d Mon Sep 17 00:00:00 2001 From: Kirill Korotaev Date: Thu, 7 Sep 2006 14:17:04 +0400 Subject: [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 --- arch/sparc/kernel/sys_sparc.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) (limited to 'arch/sparc') diff --git a/arch/sparc/kernel/sys_sparc.c b/arch/sparc/kernel/sys_sparc.c index a41c8a5c200..94ff58c9d4a 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: -- cgit v1.2.3-70-g09d2