From 8cf948e744e0218af604c32edecde10006dc8e9e Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Fri, 31 Jul 2009 12:54:05 -0400 Subject: SELinux: call cap_file_mmap in selinux_file_mmap Currently SELinux does not check CAP_SYS_RAWIO in the file_mmap hook. This means there is no DAC check on the ability to mmap low addresses in the memory space. This function adds the DAC check for CAP_SYS_RAWIO while maintaining the selinux check on mmap_zero. This means that processes which need to mmap low memory will need CAP_SYS_RAWIO and mmap_zero but will NOT need the SELinux sys_rawio capability. Signed-off-by: Eric Paris Signed-off-by: James Morris --- security/selinux/hooks.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 1e8cfc4c2ed6..e6d1432b0800 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3030,9 +3030,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot, int rc = 0; u32 sid = current_sid(); - if (addr < mmap_min_addr) + /* + * notice that we are intentionally putting the SELinux check before + * the secondary cap_file_mmap check. This is such a likely attempt + * at bad behaviour/exploit that we always want to get the AVC, even + * if DAC would have also denied the operation. + */ + if (addr < mmap_min_addr) { rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT, MEMPROTECT__MMAP_ZERO, NULL); + if (rc) + return rc; + } + + /* do DAC check on address space usage */ + rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only); if (rc || addr_only) return rc; -- cgit v1.2.2 From 788084aba2ab7348257597496befcbccabdc98a3 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Fri, 31 Jul 2009 12:54:11 -0400 Subject: Security/SELinux: seperate lsm specific mmap_min_addr Currently SELinux enforcement of controls on the ability to map low memory is determined by the mmap_min_addr tunable. This patch causes SELinux to ignore the tunable and instead use a seperate Kconfig option specific to how much space the LSM should protect. The tunable will now only control the need for CAP_SYS_RAWIO and SELinux permissions will always protect the amount of low memory designated by CONFIG_LSM_MMAP_MIN_ADDR. This allows users who need to disable the mmap_min_addr controls (usual reason being they run WINE as a non-root user) to do so and still have SELinux controls preventing confined domains (like a web server) from being able to map some area of low memory. Signed-off-by: Eric Paris Signed-off-by: James Morris --- security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index e6d1432b0800..8d8b69c5664e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3036,7 +3036,7 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot, * at bad behaviour/exploit that we always want to get the AVC, even * if DAC would have also denied the operation. */ - if (addr < mmap_min_addr) { + if (addr < CONFIG_LSM_MMAP_MIN_ADDR) { rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT, MEMPROTECT__MMAP_ZERO, NULL); if (rc) -- cgit v1.2.2