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authorKees Cook <kees.cook@canonical.com>2009-11-08 09:37:00 -0800
committerJames Morris <jmorris@namei.org>2009-11-09 08:34:22 +1100
commit0e1a6ef2dea88101b056b6d9984f3325c5efced3 (patch)
treebef312c242dd472ca00f0dc8bcebee4f094a85e3 /security
parent31bde71c202722a76686c3cf69a254c8a912275a (diff)
downloadlinux-0e1a6ef2dea88101b056b6d9984f3325c5efced3.tar.gz
sysctl: require CAP_SYS_RAWIO to set mmap_min_addr
Currently the mmap_min_addr value can only be bypassed during mmap when
the task has CAP_SYS_RAWIO.  However, the mmap_min_addr sysctl value itself
can be adjusted to 0 if euid == 0, allowing a bypass without CAP_SYS_RAWIO.
This patch adds a check for the capability before allowing mmap_min_addr to
be changed.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/min_addr.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/security/min_addr.c b/security/min_addr.c
index c844eed7915d..fc43c9d37084 100644
--- a/security/min_addr.c
+++ b/security/min_addr.c
@@ -33,6 +33,9 @@ int mmap_min_addr_handler(struct ctl_table *table, int write,
 {
 	int ret;
 
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
 	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 
 	update_mmap_min_addr();