ce15d645be
CVE-2010-4346: install_special_mapping skips security_file_mmap check CVE-2010-4649: IB/uverbs: Handle large number of entries in poll CQ CVE-2011-0006: ima: fix add LSM rule bug CVE-2010-4648: orinoco: fix TKIP countermeasure behaviour CVE-2010-4650: fuse: verify ioctl retries
108 lines
3.3 KiB
Diff
108 lines
3.3 KiB
Diff
From: Tavis Ormandy <taviso@cmpxchg8b.com>
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Date: Thu, 9 Dec 2010 14:29:42 +0000 (+0100)
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Subject: install_special_mapping skips security_file_mmap check.
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X-Git-Tag: v2.6.37-rc6~5
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X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=462e635e5b73ba9a4c03913b77138cd57ce4b050
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install_special_mapping skips security_file_mmap check.
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[ Trivial backport to 2.6.34 ]
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The install_special_mapping routine (used, for example, to setup the
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vdso) skips the security check before insert_vm_struct, allowing a local
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attacker to bypass the mmap_min_addr security restriction by limiting
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the available pages for special mappings.
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bprm_mm_init() also skips the check, and although I don't think this can
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be used to bypass any restrictions, I don't see any reason not to have
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the security check.
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$ uname -m
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x86_64
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$ cat /proc/sys/vm/mmap_min_addr
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65536
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$ cat install_special_mapping.s
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section .bss
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resb BSS_SIZE
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section .text
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global _start
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_start:
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mov eax, __NR_pause
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int 0x80
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$ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s
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$ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o
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$ ./install_special_mapping &
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[1] 14303
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$ cat /proc/14303/maps
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0000f000-00010000 r-xp 00000000 00:00 0 [vdso]
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00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping
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00011000-ffffe000 rwxp 00000000 00:00 0 [stack]
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It's worth noting that Red Hat are shipping with mmap_min_addr set to
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4096.
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Signed-off-by: Tavis Ormandy <taviso@google.com>
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Acked-by: Kees Cook <kees@ubuntu.com>
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Acked-by: Robert Swiecki <swiecki@google.com>
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[ Changed to not drop the error code - akpm ]
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Reviewed-by: James Morris <jmorris@namei.org>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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diff --git a/fs/exec.c b/fs/exec.c
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index d68c378..c62efcb 100644
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--- a/fs/exec.c
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+++ b/fs/exec.c
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@@ -275,6 +275,11 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
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vma->vm_flags = VM_STACK_FLAGS;
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vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
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INIT_LIST_HEAD(&vma->anon_vma_chain);
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+
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+ err = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
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+ if (err)
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+ goto err;
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+
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err = insert_vm_struct(mm, vma);
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if (err)
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goto err;
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diff --git a/mm/mmap.c b/mm/mmap.c
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index b179abb..50a4aa0 100644
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--- a/mm/mmap.c
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+++ b/mm/mmap.c
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@@ -2462,6 +2462,7 @@ int install_special_mapping(struct mm_struct *mm,
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unsigned long addr, unsigned long len,
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unsigned long vm_flags, struct page **pages)
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{
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+ int ret;
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struct vm_area_struct *vma;
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vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
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@@ -2479,16 +2480,23 @@ int install_special_mapping(struct mm_struct *mm,
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vma->vm_ops = &special_mapping_vmops;
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vma->vm_private_data = pages;
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- if (unlikely(insert_vm_struct(mm, vma))) {
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- kmem_cache_free(vm_area_cachep, vma);
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- return -ENOMEM;
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- }
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+ ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
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+ if (ret)
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+ goto out;
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+
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+ ret = insert_vm_struct(mm, vma);
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+ if (ret)
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+ goto out;
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mm->total_vm += len >> PAGE_SHIFT;
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perf_event_mmap(vma);
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return 0;
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+
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+out:
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+ kmem_cache_free(vm_area_cachep, vma);
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+ return ret;
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}
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static DEFINE_MUTEX(mm_all_locks_mutex);
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