diff options
| author | Eric Paris <eparis@redhat.com> | 2007-11-26 18:47:46 -0500 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2007-12-06 00:24:30 +1100 |
| commit | ab5a91a8364c3d6fc617abc47cc81d162c01d90a (patch) | |
| tree | 0b7f4ef877f56be57f75b8b455b9f694f19da633 /security/dummy.c | |
| parent | d313f948309ab22797316e789a7ff8fa358176b6 (diff) | |
| download | lwn-ab5a91a8364c3d6fc617abc47cc81d162c01d90a.tar.gz lwn-ab5a91a8364c3d6fc617abc47cc81d162c01d90a.zip | |
Security: allow capable check to permit mmap or low vm space
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>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/dummy.c')
| -rw-r--r-- | security/dummy.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/security/dummy.c b/security/dummy.c index 6d895ade73de..3ccfbbe973b6 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; } |