Messages in this thread Patch in this message | | | Subject | [PATCH 3/3] security: allow capable check to permit mmap or low vm space | From | Eric Paris <> | Date | Fri, 16 Nov 2007 15:55:45 -0500 |
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On a kernel with CONFIG_SECURITY but without an LSM which implements security_file_mmap it is impossible for an application to mmap addresses lower than mmap_min_addr. Based on a suggestion from a developer in the openwall community this patch adds a check for CAP_SYS_RAWIO. It is assumed that any process with this capability can harm the system a lot more easily than writing some stuff on the zero page and then trying to get the kernel to trip over itself. It also means that programs like X on i686 which use vm86 emulation can work even with mmap_min_addr set.
Signed-off-by: Eric Paris <eparis@redhat.com>
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security/dummy.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/security/dummy.c b/security/dummy.c index 6d895ad..3ccfbbe 100644 --- a/security/dummy.c +++ b/security/dummy.c @@ -426,7 +426,7 @@ static int dummy_file_mmap (struct file *file, unsigned long reqprot, unsigned long addr, unsigned long addr_only) { - if (addr < mmap_min_addr) + if ((addr < mmap_min_addr) && !capable(CAP_SYS_RAWIO)) return -EACCES; return 0; }
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