path: root/security
diff options
authorEric Paris <eparis@redhat.com>2007-11-26 18:47:46 -0500
committerJames Morris <jmorris@namei.org>2007-12-06 00:24:30 +1100
commitab5a91a8364c3d6fc617abc47cc81d162c01d90a (patch)
tree0b7f4ef877f56be57f75b8b455b9f694f19da633 /security
parentd313f948309ab22797316e789a7ff8fa358176b6 (diff)
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')
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;

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