[systemd-commits] src/libsystemd

[David Herrmann]

 src/libsystemd/sd-bus/bus-message.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

New commits:
commit 1ac36c67dd4d3fb5b73939293673fcd6debae699
Author: David Herrmann <dh.herrmann at gmail.com>
Date:   Mon Aug 18 23:54:10 2014 +0200

    bus: map sealed memfds as MAP_PRIVATE
    
    Mapping files as MAP_SHARED is handled by the kernel as 'writable'
    mapping. Always! Even with PROT_READ. Reason for that is,
    mprotect(PROT_WRITE) could change the mapping underneath and currently
    there is no kernel infrastructure to add protection there. This might
    change in the future, but until then, map sealed files as MAP_PRIVATE so
    we don't get EPERM.

diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 3e60842..c058b06 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -2840,7 +2840,7 @@ int bus_body_part_map(struct bus_body_part *part) {
         psz = PAGE_ALIGN(part->size);
 
         if (part->memfd >= 0)
-                p = mmap(NULL, psz, PROT_READ, MAP_SHARED, part->memfd, 0);
+                p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE, part->memfd, 0);
         else if (part->is_zero)
                 p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
         else